ECM stutters dead at wide open
10-06-2018, 11:28 PM
#1
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Car: 80 Camaro Z28
Engine: ~400hp Vortec 355ci
Transmission: T56 6-speed
Axle/Gears: 4.10 Moser 8.5" 10-bolt
ECM stutters dead at wide open
Last July I had one of my five runs at the track with a weird anomaly where the ECM (7730) went dead for a sample and then came right back to life. It caused a big misfire (felt like hitting a rev limiter) and then right back. But it only happened once and I almost forgot about it.
Today I went to another track and two of my five runs had the same issue. It's been in 2 different gears and 3 different RPM, but always at WOT. I've attached some screen shots showing the monitors and the data itself right before, during and after the error.
Any idea what it might be? I've been emulating from my laptop via Autoprom since this spring. Should I burn a chip and see if that changes it? I'm hoping to get back to the track in a week or two before they close.
Today I went to another track and two of my five runs had the same issue. It's been in 2 different gears and 3 different RPM, but always at WOT. I've attached some screen shots showing the monitors and the data itself right before, during and after the error.
Any idea what it might be? I've been emulating from my laptop via Autoprom since this spring. Should I burn a chip and see if that changes it? I'm hoping to get back to the track in a week or two before they close.
10-07-2018, 05:11 PM
#3
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Car: check
Engine: check
Transmission: check
Re: ECM stutters dead at wide open
According to the data log it is reporting 404, "ECM not found."
OK, joking aside, If you have another ECM try it. Also check the ignition feed and battery feed to the ECM. Lose either for an instant and that is what the ECM will do.
RBob.
OK, joking aside, If you have another ECM try it. Also check the ignition feed and battery feed to the ECM. Lose either for an instant and that is what the ECM will do.
RBob.
10-07-2018, 08:25 PM
#4
Re: ECM stutters dead at wide open
It's EMI/RFI interference on the ribbon cable from the ECM to the Autoprom. Wrap the entire ribbon cable in several layers of tin foil or burn a chip. That will stop it. I ran into the same problem - took quite a while and a lot of emails to Moates to figure it out.
GD
GD
10-07-2018, 10:06 PM
#5
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Car: 80 Camaro Z28
Engine: ~400hp Vortec 355ci
Transmission: T56 6-speed
Axle/Gears: 4.10 Moser 8.5" 10-bolt
Re: ECM stutters dead at wide open
I was hoping someone had run into this before. I wondered if it was emulation-related, because I just started that this year and I've been burning chips since 09. Thanks, I will do that!
10-08-2018, 10:52 AM
#6
Re: ECM stutters dead at wide open
It's EMI/RFI interference on the ribbon cable from the ECM to the Autoprom. Wrap the entire ribbon cable in several layers of tin foil or burn a chip. That will stop it. I ran into the same problem - took quite a while and a lot of emails to Moates to figure it out.
GD
GD
10-08-2018, 11:35 AM
#7
Re: ECM stutters dead at wide open
Ferrite beads are only useful for high frequency interference. So it depends on what the frequency of the interference is..... which I have no idea. I just shielded the whole wire and I no longer had stalling issues.
GD
GD
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10-08-2018, 12:05 PM
#8
Re: ECM stutters dead at wide open
did you ground the shield to chassis ground somehow?
10-08-2018, 12:15 PM
#9
Re: ECM stutters dead at wide open
No - just wrapped it in tin foil based on some suggestions from other posts and talking to Moates, etc. Looks like I'm trying to stop the alien transmissions..... but it works. Never stalled on me since I did that. Makes sense because I only had problems emulating - when I would burn a chip it worked fine on the same file. And there appeared to be no problems with the AutoProm. I even bought a second one and it still did the same thing.
That long ribbon cable has to carry really low voltage intended for chip communication across a short circuit board path. It really wasn't designed to pull data from an EPROM at the end of a radio antenna (ribbon cable).
GD
That long ribbon cable has to carry really low voltage intended for chip communication across a short circuit board path. It really wasn't designed to pull data from an EPROM at the end of a radio antenna (ribbon cable).
GD
10-08-2018, 08:45 PM
#10
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Car: 80 Camaro Z28
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Transmission: T56 6-speed
Axle/Gears: 4.10 Moser 8.5" 10-bolt
Re: ECM stutters dead at wide open
Think the adhesive-back aluminum tape for ducting would work? That's about the best thing I can think that would actually stay put. I have my Autoprom in the glove box and the cable moves as the glove box is opened and closed. Emulating is still ideal compared to burning new chips every change.
10-08-2018, 08:51 PM
#11
Re: ECM stutters dead at wide open
Might work. A shorter cable, tin foil, and mounting the AP under the dash with some zip ties might be better. I mean if you are emulating all the time with the ECM in the stock location you may as well just have the USB cable dangling on its own.
10-09-2018, 12:03 PM
#12
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Car: 80 Camaro Z28
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Transmission: T56 6-speed
Axle/Gears: 4.10 Moser 8.5" 10-bolt
Re: ECM stutters dead at wide open
I need the AP for logging my truck though, too. Best bet I guess for the short term is to burn chips at the track. Doesn't take that long.
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