MEGAsquirt A place to collectively sort out this megasquirt gizmo

tried to install megasquirt, now won't run on stock ecu

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Old 07-05-2008, 12:55 PM
  #21  
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fuel pump relay? I just have the purple fuel pump line from the MS wired up to it's proper spot on the stock harness. I haven't modified the fuel pump in any other way, besides splicing the wires and lengthening them so I could relocate my harness and put the ecu on the transmission tunnel.

So if my AIT is being weird, what components of the megasquirt should I check? Btw, on the car when i boot the megasquirt the AIT gauge starts at somewhere around 170 and then falls to an accurate reading. I feel like because it IS accurate and that temp value probably wouldn't change that quickly, it probably wouldn't make a difference, but of course I want things to run as well as possible.
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Old 07-05-2008, 02:43 PM
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is there a different way to wire the fuel pump when you're running standalone? should I splice my megasquirt's purple wire directly into the fuel pump's purple wire? That seems like the only thing I haven't tried at this point. I checked my connections and everything else looks good. my purple FP wire from my megasquirt is currently connected to a brown wire in the stock harness next to the thick blue injector wire, per braineack's instructions. (again, car is a 97)
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Old 07-06-2008, 12:14 AM
  #23  
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ok sorry about the triple post, but I have an update. I got the fuel pump to work by wiring it into a totally different wire than braineack's post. I looked for the only light green wire on my harness and plugged it in, and it worked. It wasn't even on the same plug as what braineack's diagram showed. I think my wiring is messed up to some degree. I know I didn't like, wire braineack's diagram backwards or something, but a lot of stuff doesn't work.

Important things that don't work
CLT gauge
not sure if 02 sensor is correct since i can't start the car, but when car is off it reads totally whack
2+3 sparks (running coil over packs), cranked it and i'm getting no spark on 2+3. Pretty sure my wiring isn't bad, but when I turn the key to the ready position they do the little test spark primer thing. So, when I crank, I've pulled out the plugs to see the spark, and 1 and 4 spark, 2 and 3 don't. But on ready position, all plugs do the little tiny spark

Important things that do work:
It seems like I'm getting spark and fuel at least in cylinders 1 and 4. I can crank my car and I guess my timing is also off so it backfires out of 1 and 4 of my intake runners. Because I can get ignition in cylinders 1 and 4, i feel like all my injectors are probably firing, since I believe they're on 1+3 and 2+4 right?

but yeah, fuel pump works, and I got the TPS and AIT to work as well.

please help! After I get all that **** working, then I have to work on my timing!
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Old 07-06-2008, 02:22 AM
  #24  
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I got the fuel pump to work by wiring it into a totally different wire than braineack's post. I looked for the only light green wire on my harness and plugged it in, and it worked.
Yes, Light Green at position 1U is the fuel pump relay (-) side. Not sure what you mean earlier with this "brown wire next to blue wire" thing.
Important things that don't work
CLT gauge
Hmmm. If you built your MS as per Brain's parallel specs initially but then decided to go standalone, you'll be missing two pullup resistors inside the MS: R4 and R7. You check these?
not sure if 02 sensor is correct since i can't start the car, but when car is off it reads totally whack
Define "whack." In other words, is there a flaming disembodied skull where the O2 gauge ought to be, chanting arcane hymns and urging you to desecrate the grave of John Lennon? Does it cause to to hallucinate that you are standing on a pyramid, wearing sun-god robes, with a thousand naked women screaming and throwing little pickles at you? Does it keep telling you that you must leave within two days, while insisting that it was David Bowman?

2+3 sparks (running coil over packs), cranked it and i'm getting no spark on 2+3.
Could be software, could be hardware. With the MS on but not running, measure the voltage on the two spark output pins. They should be zero. When cranking, you should measure some voltage on them.

The quick spark at turn-on is actually the result of a design defect in the way the output circuits are built. They normally are pulled high, and the CPU must actively pull them low. So at turn-on, they float high momentarily before the CPU boots up and pulls them down, causing a spark.
It seems like I'm getting spark and fuel at least in cylinders 1 and 4. I can crank my car and I guess my timing is also off so it backfires out of 1 and 4 of my intake runners.
Safe method to verify initial timing: Lock it in software to 10°. Disconnect the injectors electrical connections. Have a friend crank the engine while you observe the pulley with a timing gun.

It's actually quite easy to get it firing 180° out of sequence, which might produce the backfiring effect you note.
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Old 07-06-2008, 03:28 AM
  #25  
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well i talked to someone about my issues who has tuned megasquirts before and he said that it's normal for only one pair of coils to be firing on cranking; he said it only takes one spark to get the engine going etc etc.

So anyway, I checked my wiring, and I actually had the triggers wired wrong (brown/yellow stripe and brown mixed up.) Now the brown wire with a yellow stripe is going to 1/4. Either way, now it just backfires from 2/3 instead of 1/4. That makes me feel alright though since it lets me know that I'm getting spark and fuel in every cylinder though. I feel like every COP is wired correctly to a trigger and it's responding correctly because of that momentary spark in the beginning when i turn the key to 'ready'.

regarding my CLT gauge, yes I do have R4 and R7 installed and it works on the stim.

my 02 sensor is reading 23:1 or so right now for AFR

Gahhh I'm so close to getting this car running that it hurts. I feel like the sole culprit is the timing. How can I diagnose this and change it if it is infact 180 degrees off? I don't own a timing light/gun or anything. Do I need to get one to do this right? I feel like I shouldn't have to do any physical adjustments; it should be on the ecu, right?

Edit: btw, I'm running MS1/extra rev 029y4 as far as software goes.
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Old 07-06-2008, 03:27 PM
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Originally Posted by Joe Perez

[/INDENT]Define "whack." In other words, is there a flaming disembodied skull where the O2 gauge ought to be, chanting arcane hymns and urging you to desecrate the grave of John Lennon? Does it cause to to hallucinate that you are standing on a pyramid, wearing sun-god robes, with a thousand naked women screaming and throwing little pickles at you? Does it keep telling you that you must leave within two days, while insisting that it was David Bowman?
Can I get some of that whack you're smokin' Joe? Sounds pretty good!
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Old 07-06-2008, 07:46 PM
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Originally Posted by N3v
well i talked to someone about my issues who has tuned megasquirts before and he said that it's normal for only one pair of coils to be firing on cranking;
Whoever told you this is either an idiot or trying to sabotage you. Both ignition channels should fire during cranking.

So anyway, I checked my wiring, and I actually had the triggers wired wrong (brown/yellow stripe and brown mixed up.) Now the brown wire with a yellow stripe is going to 1/4. Either way, now it just backfires from 2/3 instead of 1/4.
The sequencing of the ignition, whether SparkA corresponds to 1/4 or 2/3, depends on how the wheel decoder is set up. The best thing to do is crank the engine with the injectors disconnected and observe the 1/4 channel with a timing gun to make sure it sparks when the mark on the crank is at (or near) TDC.

regarding my CLT gauge, yes I do have R4 and R7 installed and it works on the stim.
Well, it's hard to say what's up, then. When you twist the pots on the stim, the temp gauges in MT should respond immediately. Something ain't right if they're slow to respond.

my 02 sensor is reading 23:1 or so right now for AFR
Which may or may not be correct, depending on what signal you're feeding it and whether you have the O2 sensor correctly configured.
I don't own a timing light/gun or anything. Do I need to get one to do this right? I feel like I shouldn't have to do any physical adjustments; it should be on the ecu, right?
Yes, the adjustment is in software, but of course you need a timing gun to see what you're adjusting. Specifically, you're adjusting the Trigger Angle under Spark Settings. Do so with the Fixed Angle set to 10, which locks the timing at 10° BTDC.

Edit: btw, I'm running MS1/extra rev 029y4 as far as software goes.
That'll do for starters. You'll want to upgrade to HR10g before you start tuning, but it can wait until after you're got the engine running.

BTW- have you used EasyTherm to calibrate your CLT sensor?
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Old 07-07-2008, 12:34 AM
  #28  
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thanks joe, I really appreciate your help on this. You have been detremental to getting my car running. I got it running now. It runs every time, but it won't idle. I'm assuming my IAC just has issues and I need to address that next, but the important thing is that it will run consistantly as long as i give it a little throttle.

You want to know the solution? I had the timing right all along, or at least good enough to run. When you crank ITBs for the first time though, I had to crank it a bunch of times and there was a lot of fuel in there so it was backfiring like crazy, which is really scary looking. The fire was coming out in huge swift fireballs. I was under the impression also that fire coming out of my intake runners was crazy bad for my engine. I talked to a guy that knew about my IRTB system and he said that he had the same problem when he installed them. I just cranked it and let it crank about 20 cranks though, just letting it backfire and holding the throttle a little open. Finally it stopped backfiring and actually started after about 20-30 seconds of cranking. after that, I turned it off and tried again, it cranked after about 5 cranks. woohoo!
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Old 07-07-2008, 12:49 AM
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Originally Posted by N3v
thanks joe, I really appreciate your help on this. You have been detremental to getting my car running. I got it running now.
The word you are looking for is Instrumental.


It sounds like you have WAY too much cranking fuel, and your after start enrichments are off. I HIGHLY doubt that your IATs are causing your car not to idle at this point.
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Old 07-07-2008, 01:15 AM
  #30  
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yeah you're right, thank you. I'm not gonna edit it and fix it though; I had a couple of drinks to celebrate getting it running. But yes joe, you helped a lot, not hindered.

The idle air control though, that little gizmo I yanked off my stock throttle body, that works mechanically right? like, when the TB is 100% closed does it let some air in so the engine can idle mechanically? I know it has two wires that go into it, but aren't those just to change it from normal idle to fast idle when the coolant is cold?
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Old 07-07-2008, 01:18 AM
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Thats what you meant? ohhhhhh. Ya, you pretty much need that to idle properly :P I recommend reattaching it post haste.
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