How to determine if igniter or coilpack is bad?
02-26-2012, 08:04 PM
#1
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How to determine if igniter or coilpack is bad?
Hi All,
I purchased a 1992 Miata last month which had issues starting and have been working on it on/off. It has about 212K thus lots of miles. I've been using the following start up guide:
http://forum.miata.net/vb/showthread.php?t=279746
I determined I was not getting any spark by having my girlfriend crank the car while I observed for spark at the sparkplugs. To my dismay, no spark was observed at any of the wires.
This leads me to believe the coilpack is either bad but could it also be the ignitor chip? I'm leaning towards the coilpack but wanted to make sure it was the right part before I changed it.
Any help would be greatly appreciated it.
Some other side notes/symptoms:
-Replaced all sparkplugs and sparkplug wires with NGK's, replaced fuel filter. Fuel pump tested and works.
-I unplugged the connector to the coil pack assembly (3 wires: red, white, black). Approx. 12 volt from the red to white and red to black wires (when car is on run).
The car no longer starts up at all (cranks but doesn't fire). Prior to that, if the car sat for a while, the car started up and ran idle for about 1-2 minutes and would then die and not start up anymore. RPMS would not go up if i opened the throttle.
I purchased a 1992 Miata last month which had issues starting and have been working on it on/off. It has about 212K thus lots of miles. I've been using the following start up guide:
http://forum.miata.net/vb/showthread.php?t=279746
I determined I was not getting any spark by having my girlfriend crank the car while I observed for spark at the sparkplugs. To my dismay, no spark was observed at any of the wires.
This leads me to believe the coilpack is either bad but could it also be the ignitor chip? I'm leaning towards the coilpack but wanted to make sure it was the right part before I changed it.
Any help would be greatly appreciated it.
Some other side notes/symptoms:
-Replaced all sparkplugs and sparkplug wires with NGK's, replaced fuel filter. Fuel pump tested and works.
-I unplugged the connector to the coil pack assembly (3 wires: red, white, black). Approx. 12 volt from the red to white and red to black wires (when car is on run).
The car no longer starts up at all (cranks but doesn't fire). Prior to that, if the car sat for a while, the car started up and ran idle for about 1-2 minutes and would then die and not start up anymore. RPMS would not go up if i opened the throttle.
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02-26-2012, 08:16 PM
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I smell fuel on the sparkplug after I try cranking it (i took the plug out). Unfortunately I didn't see a wet tip so perhaps the injectors aren't spraying or spraying very weakly.
I do have a stock motor sitting around with a CAS on it..I'll try changing it first since it would be free.
Thanks for the tip.
I do have a stock motor sitting around with a CAS on it..I'll try changing it first since it would be free.
Thanks for the tip.
Last edited by Solomon; 02-27-2012 at 02:27 AM.
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02-27-2012, 12:14 AM
#5
How are you checking for spark at the plugs?
Have you verified that the "wiring" of the plug wires from the coil packs to the plugs is correct?
Have you checked for stored fault codes in the ECU (procedure is detailed on Miata.net)?
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
Have you done a continuity test on both coil packs?
Have you looked at the valve train thru the oil filler hole to make sure the cams are turning (and the timig belt isn't broken) while the engine is cranking?
Have you pulled the plugs and done a static compression test on all 4 cylinders?
Have you checked fuel pressure at the injector rail and verified it doesn't leak down after a few minutes?
Have you verified that the "wiring" of the plug wires from the coil packs to the plugs is correct?
Have you checked for stored fault codes in the ECU (procedure is detailed on Miata.net)?
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
Have you done a continuity test on both coil packs?
Have you looked at the valve train thru the oil filler hole to make sure the cams are turning (and the timig belt isn't broken) while the engine is cranking?
Have you pulled the plugs and done a static compression test on all 4 cylinders?
Have you checked fuel pressure at the injector rail and verified it doesn't leak down after a few minutes?
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02-27-2012, 02:19 AM
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Thanks for your questions/suggestions!
How are you checking for spark at the plugs?
i have all the wires connected to the coil back (new NGK wires) and have sparkplugs on all ends of the plugs. I had my gf crank the car while visually observed (seeing if there is spark). No spark observed.
Have you verified that the "wiring" of the plug wires from the coil packs to the plugs is correct?
Yes, I took a picture before I changed the wires to have them in the same place as well as double check with the wiring online. Even if they were incorrectly connected, I should have still saw spark at the sparkplugs
Have you checked for stored fault codes in the ECU (procedure is detailed on Miata.net)?
I tried the technique (connecting pin in the diagnostics port on driver side..forgot which ones) and turning the key on to count the number of blinks shown...none observed. Will try again tomorrow.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
Have you done a continuity test on both coil packs?
Don't know how to do a continuity test (will look that up later). Please explain how I can do that =)
Have you looked at the valve train thru the oil filler hole to make sure the cams are turning (and the timig belt isn't broken) while the engine is cranking?
The timing belt isn't broken. I also replaced the valve cover gasket and spark plug well gaskets since when I got the car, the sparkplugs were swimming in oil thus I saw the timing belt which seemed to be in good condition
Have you pulled the plugs and done a static compression test on all 4 cylinders?
I have yet to do that. However since it was able to run a few times (for only a minute at a time) I assume compression is good enough? I did not observe any oil or "milky" coolant thus headgasket seems to be okay. Don't know about the rings though.
Have you checked fuel pressure at the injector rail and verified it doesn't leak down after a few minutes? Nope. I suppose I do have dirty injectors. As previously mentioned, I smell fuel on the spark plug tips after I crank the car thus would mean fuel is getting into the cylinders. Will check this out as well.
As mentioned in my post, no spark observed which I think is my root cause. Thank you for your questions and/or suggestions. Keep em coming!
How are you checking for spark at the plugs?
i have all the wires connected to the coil back (new NGK wires) and have sparkplugs on all ends of the plugs. I had my gf crank the car while visually observed (seeing if there is spark). No spark observed.
Have you verified that the "wiring" of the plug wires from the coil packs to the plugs is correct?
Yes, I took a picture before I changed the wires to have them in the same place as well as double check with the wiring online. Even if they were incorrectly connected, I should have still saw spark at the sparkplugs
Have you checked for stored fault codes in the ECU (procedure is detailed on Miata.net)?
I tried the technique (connecting pin in the diagnostics port on driver side..forgot which ones) and turning the key on to count the number of blinks shown...none observed. Will try again tomorrow.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
Have you done a continuity test on both coil packs?
Don't know how to do a continuity test (will look that up later). Please explain how I can do that =)
Have you looked at the valve train thru the oil filler hole to make sure the cams are turning (and the timig belt isn't broken) while the engine is cranking?
The timing belt isn't broken. I also replaced the valve cover gasket and spark plug well gaskets since when I got the car, the sparkplugs were swimming in oil thus I saw the timing belt which seemed to be in good condition
Have you pulled the plugs and done a static compression test on all 4 cylinders?
I have yet to do that. However since it was able to run a few times (for only a minute at a time) I assume compression is good enough? I did not observe any oil or "milky" coolant thus headgasket seems to be okay. Don't know about the rings though.
Have you checked fuel pressure at the injector rail and verified it doesn't leak down after a few minutes? Nope. I suppose I do have dirty injectors. As previously mentioned, I smell fuel on the spark plug tips after I crank the car thus would mean fuel is getting into the cylinders. Will check this out as well.
As mentioned in my post, no spark observed which I think is my root cause. Thank you for your questions and/or suggestions. Keep em coming!
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02-27-2012, 09:48 PM
#7
Thanks for your questions/suggestions!
Have you verified that the "wiring" of the plug wires from the coil packs to the plugs is correct?
Yes, I took a picture before I changed the wires to have them in the same place as well as double check with the wiring online. Even if they were incorrectly connected, I should have still saw spark at the sparkplugs
You are assuming the prior owner (PO) had the plug wirirg correct; not always a good assumption. Cylinder 1 is @ front of engine, then 2, 3 in order going back with 4 closest to firewall. Looking at the coilpacks from the front of engine bay, 4,1,2,3 from left to right on my '90 1.6.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
I've never tested this while cranking but this 3v drop seems a bit much. Have you checked/cleaned all your grounds in the engine compartment? Location @ rear of head on passenger side with multiple black wires secured by one bolt, ground strap on DS rear of head (look below dipstick) that goes to firewall, funky little plastic junction box below the clutch master cylinder (search Mnet for pics of all of these and for location of ECU ground too).
Have you done a continuity test on both coil packs?
Don't know how to do a continuity test (will look that up later). Please explain how I can do that =)
Primary resistance: .78-94ohm
DVOM leads in two outer coilpack connector terminals (connector flat side down) &
DVOM leads in middle and left coilpack connector terminals (connector flat side down)
Secondary resistance: 11.2-15.2 Kohm
DVOM Black in Leftmost plug terminal, DVOM Red in second to left (1st coilpack)
DVOM Red in righmost plug terminal, DVOM Black in adjacent plug terminal (2nd coilpack)
As mentioned in my post, no spark observed which I think is my root cause. Thank you for your questions and/or suggestions. Keep em coming!
Have you verified that the "wiring" of the plug wires from the coil packs to the plugs is correct?
Yes, I took a picture before I changed the wires to have them in the same place as well as double check with the wiring online. Even if they were incorrectly connected, I should have still saw spark at the sparkplugs
You are assuming the prior owner (PO) had the plug wirirg correct; not always a good assumption. Cylinder 1 is @ front of engine, then 2, 3 in order going back with 4 closest to firewall. Looking at the coilpacks from the front of engine bay, 4,1,2,3 from left to right on my '90 1.6.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
I've never tested this while cranking but this 3v drop seems a bit much. Have you checked/cleaned all your grounds in the engine compartment? Location @ rear of head on passenger side with multiple black wires secured by one bolt, ground strap on DS rear of head (look below dipstick) that goes to firewall, funky little plastic junction box below the clutch master cylinder (search Mnet for pics of all of these and for location of ECU ground too).
Have you done a continuity test on both coil packs?
Don't know how to do a continuity test (will look that up later). Please explain how I can do that =)
Primary resistance: .78-94ohm
DVOM leads in two outer coilpack connector terminals (connector flat side down) &
DVOM leads in middle and left coilpack connector terminals (connector flat side down)
Secondary resistance: 11.2-15.2 Kohm
DVOM Black in Leftmost plug terminal, DVOM Red in second to left (1st coilpack)
DVOM Red in righmost plug terminal, DVOM Black in adjacent plug terminal (2nd coilpack)
As mentioned in my post, no spark observed which I think is my root cause. Thank you for your questions and/or suggestions. Keep em coming!
See if you can beg, borrow a steal a factory service manual for your car; they have complete wiring diagrams that will enable you to slowly (and somewhat painfully) follow the electrical trail from the ignition switch to ECU, CAS, Ignitor and coil.
Last edited by sn95; 02-27-2012 at 10:57 PM. Reason: chaned ohms to kohms
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02-27-2012, 10:45 PM
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The ignition coil pack is measured in a couple of steps.
First, use an ohmmeter to test the resistance between the sparkplug terminals on the 1/3 coil and then on the 2/4 coil. Pull of the plug wires and stick the probes down into the coil. You should read somewhere between 10-15 kiloohms (appx) on each one.
Now, disconnect the 3 pin connector on the low-voltage side, and check for continuity from blue to white and from blue to red. Expect less than one ohm here- the factory manual calls for 0.78 to 0.94 ohms, which is very difficult to read accurately with an average meter.
I don't think it's the ignition coils, though. For both to fail at the same time is improbable, and the engine would start and run (quite poorly) on only one.
Testing the igniter is somewhat more involved, and requires an oscilloscope if you really want to do it right. If you have access to a good analog voltmeter, you can unplug the igniter and then check, at the lowest range, for voltage between the brown wire and the black wire, and between the brown/yellow wire and the black wire, while cranking. The ECU will be putting out brief (6ms) pulses of +5v, which should cause the meter to twitch a bit. Some meters will show nothing, so this isn't a perfectly reliable test.
Does the Check Engine light in the dash come on when you turn the key to Run without starting it?
First, use an ohmmeter to test the resistance between the sparkplug terminals on the 1/3 coil and then on the 2/4 coil. Pull of the plug wires and stick the probes down into the coil. You should read somewhere between 10-15 kiloohms (appx) on each one.
Now, disconnect the 3 pin connector on the low-voltage side, and check for continuity from blue to white and from blue to red. Expect less than one ohm here- the factory manual calls for 0.78 to 0.94 ohms, which is very difficult to read accurately with an average meter.
I don't think it's the ignition coils, though. For both to fail at the same time is improbable, and the engine would start and run (quite poorly) on only one.
Testing the igniter is somewhat more involved, and requires an oscilloscope if you really want to do it right. If you have access to a good analog voltmeter, you can unplug the igniter and then check, at the lowest range, for voltage between the brown wire and the black wire, and between the brown/yellow wire and the black wire, while cranking. The ECU will be putting out brief (6ms) pulses of +5v, which should cause the meter to twitch a bit. Some meters will show nothing, so this isn't a perfectly reliable test.
Does the Check Engine light in the dash come on when you turn the key to Run without starting it?
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02-28-2012, 12:40 AM
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The only test the factory service manual shows for the ignitor requires a Mazda special service tool, so I can't help you there. FWIW, the Mazda enthusiast manual suggests connecting a jumper wire between the F/P and GND terminals in the diagnostic connector and seeing if the car will start (this supposedly identifies a faulty circuit opening relay). I'm not sure I'd want to try this before reviewing a wiring diagram though.
See if you can beg, borrow a steal a factory service manual for your car; they have complete wiring diagrams that will enable you to slowly (and somewhat painfully) follow the electrical trail from the ignition switch to ECU, CAS, Ignitor and coil.
See if you can beg, borrow a steal a factory service manual for your car; they have complete wiring diagrams that will enable you to slowly (and somewhat painfully) follow the electrical trail from the ignition switch to ECU, CAS, Ignitor and coil.
Yea..don't have FSM but guess if all else fails will have to go that route. I still need to check some other things as well.
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02-28-2012, 12:45 AM
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The ignition coil pack is measured in a couple of steps.
First, use an ohmmeter to test the resistance between the sparkplug terminals on the 1/3 coil and then on the 2/4 coil. Pull of the plug wires and stick the probes down into the coil. You should read somewhere between 10-15 kiloohms (appx) on each one.
Now, disconnect the 3 pin connector on the low-voltage side, and check for continuity from blue to white and from blue to red. Expect less than one ohm here- the factory manual calls for 0.78 to 0.94 ohms, which is very difficult to read accurately with an average meter.
I don't think it's the ignition coils, though. For both to fail at the same time is improbable, and the engine would start and run (quite poorly) on only one.
Testing the igniter is somewhat more involved, and requires an oscilloscope if you really want to do it right. If you have access to a good analog voltmeter, you can unplug the igniter and then check, at the lowest range, for voltage between the brown wire and the black wire, and between the brown/yellow wire and the black wire, while cranking. The ECU will be putting out brief (6ms) pulses of +5v, which should cause the meter to twitch a bit. Some meters will show nothing, so this isn't a perfectly reliable test.
Does the Check Engine light in the dash come on when you turn the key to Run without starting it?
First, use an ohmmeter to test the resistance between the sparkplug terminals on the 1/3 coil and then on the 2/4 coil. Pull of the plug wires and stick the probes down into the coil. You should read somewhere between 10-15 kiloohms (appx) on each one.
Now, disconnect the 3 pin connector on the low-voltage side, and check for continuity from blue to white and from blue to red. Expect less than one ohm here- the factory manual calls for 0.78 to 0.94 ohms, which is very difficult to read accurately with an average meter.
I don't think it's the ignition coils, though. For both to fail at the same time is improbable, and the engine would start and run (quite poorly) on only one.
Testing the igniter is somewhat more involved, and requires an oscilloscope if you really want to do it right. If you have access to a good analog voltmeter, you can unplug the igniter and then check, at the lowest range, for voltage between the brown wire and the black wire, and between the brown/yellow wire and the black wire, while cranking. The ECU will be putting out brief (6ms) pulses of +5v, which should cause the meter to twitch a bit. Some meters will show nothing, so this isn't a perfectly reliable test.
Does the Check Engine light in the dash come on when you turn the key to Run without starting it?
so I doubt it will read as accurately as you describe..but it's worth a shot.
Regarding the Check Engine Light, it does not show up anymore (when I got the car initially and it did start up I did remember seeing it). Now the car doesn't crank over =(
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02-28-2012, 01:33 AM
#11
Not sure if you saw my comments that were embedded above:
You are assuming the prior owner (PO) had the plug wirirg correct; not always a good assumption. Cylinder 1 is @ front of engine, then 2, 3 in order going back with 4 closest to firewall. Looking at the coilpacks from the front of engine bay, 4,1,2,3 from left to right on my '90 1.6.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
I've never tested this while cranking but this 3v drop seems a bit much. Have you checked/cleaned all your grounds in the engine compartment? Location @ rear of head on passenger side with multiple black wires secured by one bolt, ground strap on DS rear of head (look below dipstick) that goes to firewall, funky little plastic junction box below the clutch master cylinder (search Mnet for pics of all of these and for location of ECU ground too).
NAs do have some ground problems, I'd suggest making sure all your grounds are secure and clean. Also carefully check the wiring harness around the ignitor, coil and CAS and make sure it isn't frayed, stretched, broken, damaged or "hacked".
I tend to agree with Joe on the coils probably not being the problem too; I replaced mine last summer trying to run down an intermittent electrical gremlin that would cause my car to lose "spark"..turned out the real problem was in a piggyback harness for a knock sensor that the PO had "hacked" into the ignitor harness.
You are assuming the prior owner (PO) had the plug wirirg correct; not always a good assumption. Cylinder 1 is @ front of engine, then 2, 3 in order going back with 4 closest to firewall. Looking at the coilpacks from the front of engine bay, 4,1,2,3 from left to right on my '90 1.6.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
I've never tested this while cranking but this 3v drop seems a bit much. Have you checked/cleaned all your grounds in the engine compartment? Location @ rear of head on passenger side with multiple black wires secured by one bolt, ground strap on DS rear of head (look below dipstick) that goes to firewall, funky little plastic junction box below the clutch master cylinder (search Mnet for pics of all of these and for location of ECU ground too).
NAs do have some ground problems, I'd suggest making sure all your grounds are secure and clean. Also carefully check the wiring harness around the ignitor, coil and CAS and make sure it isn't frayed, stretched, broken, damaged or "hacked".
I tend to agree with Joe on the coils probably not being the problem too; I replaced mine last summer trying to run down an intermittent electrical gremlin that would cause my car to lose "spark"..turned out the real problem was in a piggyback harness for a knock sensor that the PO had "hacked" into the ignitor harness.
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02-28-2012, 01:47 AM
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Not sure if you saw my comments that were embedded above:
You are assuming the prior owner (PO) had the plug wirirg correct; not always a good assumption. Cylinder 1 is @ front of engine, then 2, 3 in order going back with 4 closest to firewall. Looking at the coilpacks from the front of engine bay, 4,1,2,3 from left to right on my '90 1.6.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
I've never tested this while cranking but this 3v drop seems a bit much. Have you checked/cleaned all your grounds in the engine compartment? Location @ rear of head on passenger side with multiple black wires secured by one bolt, ground strap on DS rear of head (look below dipstick) that goes to firewall, funky little plastic junction box below the clutch master cylinder (search Mnet for pics of all of these and for location of ECU ground too).
NAs do have some ground problems, I'd suggest making sure all your grounds are secure and clean. Also carefully check the wiring harness around the ignitor, coil and CAS and make sure it isn't frayed, stretched, broken, damaged or "hacked".
I tend to agree with Joe on the coils probably not being the problem too; I replaced mine last summer trying to run down an intermittent electrical gremlin that would cause my car to lose "spark"..turned out the real problem was in a piggyback harness for a knock sensor that the PO had "hacked" into the ignitor harness.
You are assuming the prior owner (PO) had the plug wirirg correct; not always a good assumption. Cylinder 1 is @ front of engine, then 2, 3 in order going back with 4 closest to firewall. Looking at the coilpacks from the front of engine bay, 4,1,2,3 from left to right on my '90 1.6.
Have you verified that you have 12V at the coil pack when cranking (you've already verified 12V with the ignition on)?
With ignition on, 12v is present. When cranking, 12v drops down to about 9v
I've never tested this while cranking but this 3v drop seems a bit much. Have you checked/cleaned all your grounds in the engine compartment? Location @ rear of head on passenger side with multiple black wires secured by one bolt, ground strap on DS rear of head (look below dipstick) that goes to firewall, funky little plastic junction box below the clutch master cylinder (search Mnet for pics of all of these and for location of ECU ground too).
NAs do have some ground problems, I'd suggest making sure all your grounds are secure and clean. Also carefully check the wiring harness around the ignitor, coil and CAS and make sure it isn't frayed, stretched, broken, damaged or "hacked".
I tend to agree with Joe on the coils probably not being the problem too; I replaced mine last summer trying to run down an intermittent electrical gremlin that would cause my car to lose "spark"..turned out the real problem was in a piggyback harness for a knock sensor that the PO had "hacked" into the ignitor harness.
Perhaps I've tried starting the car too many times that the battery is very weak which is why the severe drop of 3v (just a thought)...I will try to swap out the battery with the one on my car.
I will try regrounding it and possibly making some additional grounds (just to be on the safe side).
I think I noticed some "hacked" wires to the CAS but didn't see any exposed wires..but I'll take a look again and tape it up to make sure no 2 wires are touching.
Thanks again for the input. I appreciate everyone's responses as this will help me tackle the problem. Hopefully when I'll have some time this weekend to work on this.
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02-28-2012, 04:19 PM
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Well, that right there tells you that the ECU isn't working. (assuming the bulb isn't blown.)
I'd be looking in the vicinity of:
The white/red wire coming out of the Main Relay (this carries switched +12 to darn near everything ECU-related),
The blue wire coming from the ignition switch, which is supplied by the 80A "Main" fuse (this also carries +12 to the ignition coils, and I think you may have already eliminated this as a suspect, but check it again),
The blk/white wire carrying power from the 15A "Engine" fuse to the coil of the Main Relay, and
The white/grn wire coming from the 30A "INJ" fuse which supplies power to the contacts of the Main Relay.
Test #1 is to see if you have +12 on the white/red wire when the key is on. You can test this at the ECU connector, relative to ground. (It can also be accessed at the diagnostic box under the hood, as "B+", however I'd prefer to see a measurement right at the ECU itself.
Until you know that the ECU is getting power, and you see the Check Engine light come on when you turn the key to "Run" without starting the engine, all other considerations are secondary.
I'd be looking in the vicinity of:
The white/red wire coming out of the Main Relay (this carries switched +12 to darn near everything ECU-related),
The blue wire coming from the ignition switch, which is supplied by the 80A "Main" fuse (this also carries +12 to the ignition coils, and I think you may have already eliminated this as a suspect, but check it again),
The blk/white wire carrying power from the 15A "Engine" fuse to the coil of the Main Relay, and
The white/grn wire coming from the 30A "INJ" fuse which supplies power to the contacts of the Main Relay.
Test #1 is to see if you have +12 on the white/red wire when the key is on. You can test this at the ECU connector, relative to ground. (It can also be accessed at the diagnostic box under the hood, as "B+", however I'd prefer to see a measurement right at the ECU itself.
Until you know that the ECU is getting power, and you see the Check Engine light come on when you turn the key to "Run" without starting the engine, all other considerations are secondary.
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03-02-2012, 03:03 AM
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I found the problem (at least i hope is the only problem)...the ECU as you had described. I took the ecu out and it looked alright..however, there was lots of moisture in the vicinity (also explains why it has an old damp smell).
Took the cover off the ECU to discover a lot of corrosion on some parts of the ECU. I've taken some pictures to share but this can explain why the check engine light wasn't even showing on the car.
Now I need to find a stock ECU OR maybe invest in a MS since my plans are to turbo this car eventually.
Thanks for everyone's input. Hope after I change this out the car will run...
As you can see massive corrosion...2 of the pins are totally gone.
Took the cover off the ECU to discover a lot of corrosion on some parts of the ECU. I've taken some pictures to share but this can explain why the check engine light wasn't even showing on the car.
Now I need to find a stock ECU OR maybe invest in a MS since my plans are to turbo this car eventually.
Thanks for everyone's input. Hope after I change this out the car will run...
As you can see massive corrosion...2 of the pins are totally gone.
Well, that right there tells you that the ECU isn't working. (assuming the bulb isn't blown.)
I'd be looking in the vicinity of:
The white/red wire coming out of the Main Relay (this carries switched +12 to darn near everything ECU-related),
The blue wire coming from the ignition switch, which is supplied by the 80A "Main" fuse (this also carries +12 to the ignition coils, and I think you may have already eliminated this as a suspect, but check it again),
The blk/white wire carrying power from the 15A "Engine" fuse to the coil of the Main Relay, and
The white/grn wire coming from the 30A "INJ" fuse which supplies power to the contacts of the Main Relay.
Test #1 is to see if you have +12 on the white/red wire when the key is on. You can test this at the ECU connector, relative to ground. (It can also be accessed at the diagnostic box under the hood, as "B+", however I'd prefer to see a measurement right at the ECU itself.
Until you know that the ECU is getting power, and you see the Check Engine light come on when you turn the key to "Run" without starting the engine, all other considerations are secondary.
I'd be looking in the vicinity of:
The white/red wire coming out of the Main Relay (this carries switched +12 to darn near everything ECU-related),
The blue wire coming from the ignition switch, which is supplied by the 80A "Main" fuse (this also carries +12 to the ignition coils, and I think you may have already eliminated this as a suspect, but check it again),
The blk/white wire carrying power from the 15A "Engine" fuse to the coil of the Main Relay, and
The white/grn wire coming from the 30A "INJ" fuse which supplies power to the contacts of the Main Relay.
Test #1 is to see if you have +12 on the white/red wire when the key is on. You can test this at the ECU connector, relative to ground. (It can also be accessed at the diagnostic box under the hood, as "B+", however I'd prefer to see a measurement right at the ECU itself.
Until you know that the ECU is getting power, and you see the Check Engine light come on when you turn the key to "Run" without starting the engine, all other considerations are secondary.
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03-04-2012, 01:34 AM
#15
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Car runs now!!! (although a bit rough considering it has about 216K). I replaced ECU and it started right up. Thanks everyone for their input and help. I believe the previous owner never cleared the drains in the rocker panels thus water backed up and got the ECU wet which explains the corrosion/moisture.
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03-04-2012, 02:19 AM
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I know you got it running and the coils weren't the issue but I figure I'd throw this out there for anyone that ever wants or needs to test their coils out..from All data
SECONDARY COIL WINDING
Remove high-tension leads.
Measure secondary winding resistance of each coil. It should be 8.7 - 12.9K ohms @ 68°F (20°C).
If not within specification, replace coil.
CASE INSULATION RESISTANCE
Remove high-tension leads and unplug connectors.
Use a 500V megger tester to measure insulation resistance between primary terminal and coil case. It should be above 10M ohms.
If not within specification, replace coil.
SECONDARY COIL WINDING
Remove high-tension leads.
Measure secondary winding resistance of each coil. It should be 8.7 - 12.9K ohms @ 68°F (20°C).
If not within specification, replace coil.
CASE INSULATION RESISTANCE
Remove high-tension leads and unplug connectors.
Use a 500V megger tester to measure insulation resistance between primary terminal and coil case. It should be above 10M ohms.
If not within specification, replace coil.
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03-14-2012, 01:25 PM
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Grease-monkey slang for a mega-ohmmeter.
The way an ohm-meter works is that it applies a very small DC voltage across the circuit in question, and measures the current flow through (or voltage drop across) the device.
A "megger" differs from a traditional ohmmeter in that it uses a much higher voltage, typically in the hundreds or even thousands of volts, and is generally user-selectable. This allows you to measure insulation breakdown resistance, which is something not possible to do with very low voltages.
The test procedure above instructs the user to set the instrument to the 500 volt position in order to measure the resistance between the coil primary and the case. A normal ohmmeter would show this as an open circuit- you need the extra voltage to force a bit of current leakage across the insulation and get an accurate measurement.
The way an ohm-meter works is that it applies a very small DC voltage across the circuit in question, and measures the current flow through (or voltage drop across) the device.
A "megger" differs from a traditional ohmmeter in that it uses a much higher voltage, typically in the hundreds or even thousands of volts, and is generally user-selectable. This allows you to measure insulation breakdown resistance, which is something not possible to do with very low voltages.
The test procedure above instructs the user to set the instrument to the 500 volt position in order to measure the resistance between the coil primary and the case. A normal ohmmeter would show this as an open circuit- you need the extra voltage to force a bit of current leakage across the insulation and get an accurate measurement.
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