No fuel/No spark... ideas?
10-10-2013, 10:18 AM
#1
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No fuel/No spark... ideas?
I am having a no fuel, no spark issue.
I have a 1992 1.6L turbo miata running on a Link ECU. It has been running without issues for over a year. While coming back from a trip, the car suddenly started running rough, the tach was jumping all over the place. I pulled over and it would start, run rough, then turn off. I had it towed home. The next day it started and ran with no issues for a 10 mile drive. I made a stop on the way home and it happened again - I would start it up, it would run rough and turn off while the tach would jump erratically. The next morning, I brought help to diagnose the problem - but it ran fine and I drove it home.
Now it cranks and doesn't start. I have no fuel, no spark. It turns over, I can see the cams turning (my valve cover is cut to allow access the cams) but the tach does not move.
There is no CEL and there are no codes when I jumper the diagnostic box
The fuel pump sounds like it is turning on. No fuel on the plugs when checking for spark.
I have replaced the CAS sensor with a used one with no change.
I have tried replacing the igniter with no change.
I have tried plugging in a stock ECU with no change. ECU is getting power.
I have tried replacing the main relay with no change.
I have cleaned the ignition.
I have tested the coilpacks and they seem to check out based on the values listed on miata.net
what else effects both fuel and spark? Anything else I should try/check out before diving into the harness?
I have a 1992 1.6L turbo miata running on a Link ECU. It has been running without issues for over a year. While coming back from a trip, the car suddenly started running rough, the tach was jumping all over the place. I pulled over and it would start, run rough, then turn off. I had it towed home. The next day it started and ran with no issues for a 10 mile drive. I made a stop on the way home and it happened again - I would start it up, it would run rough and turn off while the tach would jump erratically. The next morning, I brought help to diagnose the problem - but it ran fine and I drove it home.
Now it cranks and doesn't start. I have no fuel, no spark. It turns over, I can see the cams turning (my valve cover is cut to allow access the cams) but the tach does not move.
There is no CEL and there are no codes when I jumper the diagnostic box
The fuel pump sounds like it is turning on. No fuel on the plugs when checking for spark.
I have replaced the CAS sensor with a used one with no change.
I have tried replacing the igniter with no change.
I have tried plugging in a stock ECU with no change. ECU is getting power.
I have tried replacing the main relay with no change.
I have cleaned the ignition.
I have tested the coilpacks and they seem to check out based on the values listed on miata.net
what else effects both fuel and spark? Anything else I should try/check out before diving into the harness?
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10-10-2013, 12:17 PM
#3
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took a plug out, grounded to chassis, cranked.
how would a fuel filter cause no spark?
the first time it died was driving for 2 hours, stopping for gas, and trying to start it again.
how would a fuel filter cause no spark?
the first time it died was driving for 2 hours, stopping for gas, and trying to start it again.
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10-12-2013, 01:00 AM
#5
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I had this happen to me once on my 92. If anything that works with 5v gets grounded where its not supposed to, the ECU pretty much says "nope", even if its getting power.
My AFM was shorted internally, and replacing it fixed everything.
Does your check engine light turn on at all? If the light won't turn on KOEO, something is forcing the ECU to turn off.
EDIT: Just in case your CEL isn't turning on, turn the ignition on and start unplugging things under the hood. When it turns on, you found your problem. That's how I fixed my car anyway.
My AFM was shorted internally, and replacing it fixed everything.
Does your check engine light turn on at all? If the light won't turn on KOEO, something is forcing the ECU to turn off.
EDIT: Just in case your CEL isn't turning on, turn the ignition on and start unplugging things under the hood. When it turns on, you found your problem. That's how I fixed my car anyway.
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10-18-2013, 08:40 AM
#7
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I had this happen to me once on my 92. If anything that works with 5v gets grounded where its not supposed to, the ECU pretty much says "nope", even if its getting power.
My AFM was shorted internally, and replacing it fixed everything.
Does your check engine light turn on at all? If the light won't turn on KOEO, something is forcing the ECU to turn off.
EDIT: Just in case your CEL isn't turning on, turn the ignition on and start unplugging things under the hood. When it turns on, you found your problem. That's how I fixed my car anyway.
My AFM was shorted internally, and replacing it fixed everything.
Does your check engine light turn on at all? If the light won't turn on KOEO, something is forcing the ECU to turn off.
EDIT: Just in case your CEL isn't turning on, turn the ignition on and start unplugging things under the hood. When it turns on, you found your problem. That's how I fixed my car anyway.
Does temperature point to anything? Temperature doesn't matter at the moment since it's not sparking/getting fuel to the cylinders at all (confirmed fuel pump is working).
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