:::RHMT::: Real Home Made Turbo
General Category => Engine Management => Topic started by: TTC on September 26, 2010, 12:23:50 PM
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A buddies car is acting really fucked and we can't figure out why. Hes in a different province so i'm not there with a multimeter checking it out. Here is the issue: the logs are showing that he gets a violent stutter, at idle and during regular driving. The car goes super lean then stutters like crazy, afrs in the 18s and higher ect as it stumbles. Things ive told him,
If ign was cutting it would probably go rich since it wasnt burning fuel. He has checked the following for me:
85 corolla, Megasquirt vs 1 with ms EDIS
Fuel pressure, it has it, hes tried 2 ,guages all show that he has constant FP not causing it to lean out.
replaced edis unit
replaced vr sensor
rewired harness 2x
tried 3 different MS ecus
checked grounds
Hes put a scope on int, and from what I recall the ecu is getting proper ign pw's with no noise or anything erratic.
Nothing has changed this issue yet, hes currently going to a external dsm ignitor while using the VR as a hall sensor or something.
Only thing I'm thinking of is that the ign drivers are over heating or something and cutting fuel
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if ign is cutting it will read lean because oxygen sensors read just that OXYGEN if your not burning up oxygen in a combustion it just blows through the motor and the o2 sensor picks it up. Same way high overlap cams are hard to tune on big turbo setups because you basically blow air through the motor without burning it giving you what appears to be lean but infact is oxygen and lots of unburnt fuel.
from what you have said could it be a miss from running very very rich? has he been adding fuel to get rid of this "lean" condition?
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Hrm, never thought of it that way. Ill mentiopn it to him and see what he thinks. We haven't added fuel because we know its not a tuning issue its a hardware issue. It ran fine for a few days before it started doing this shit.
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if he has a noid light try hooking up to the injectors my thought is its actually holding them open and flooding the engine.
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MAPdot or TPSdot acceleration enrichment?
90-91 turbo Miata I tuned with MS1. Early Miatas have on/off style TPS, so it was never wired in and I tuned for MAPdot enrich - fast enough change in MAP pressure brings in X amount of enrichment. Everything is great, then time goes by and the car has stutter problems, especially under acceleration.
Datalogs show that the TPSdot enrich is turning on due to noise on the TPS input, grounding the TPS pin solved the problem.
Get your friend to post some logs online, or we'll drive to Canadaland and take turns kicking you in your French ballsack.
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MAPdot or TPSdot acceleration enrichment?
90-91 turbo Miata I tuned with MS1. Early Miatas have on/off style TPS, so it was never wired in and I tuned for MAPdot enrich - fast enough change in MAP pressure brings in X amount of enrichment. Everything is great, then time goes by and the car has stutter problems, especially under acceleration.
Datalogs show that the TPSdot enrich is turning on due to noise on the TPS input, grounding the TPS pin solved the problem.
Get your friend to post some logs online, or we'll drive to Canadaland and take turns kicking you in your French ballsack.
I'll do it for you and save you the trip.
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Oh. So this is someone Tom would try to help, that should really be neaten with crowbars?
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Hes in the midst of nigger rigging th stock fuel system using garbage cans and shit. Idles fine, but its hard to tell till its at wot
I checked his AE enrichment JD and nothing wonky going on it turns on only when hit hits the pedal and its only for a a ms or so. Nothing irratic or noisy.
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pull the cover off the box and touch the transistors, are they getting hot? hell is the case getting warm at all?
do you have the dwell setting correct for the edis, some guys have it set wrong but it works for a while then stops working.
i know the dwell is set by the edis mod but the trigger signal still has to be the correct one its looking for.
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Oh. So this is someone Tom would try to help, that should really be neaten with crowbars?
Likely, yes. I was more looking for an excuse to kick Tom in the balls.
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Racewars? Probably never you big pussy
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i had some shit fucked up with the launch control/overrun/flatshift settings were conflicting and i would have the pw drop to zero for a sec then be back to normal.
get the msq up here, at the same time post it up at msextra.com, those guys know what they are looking for. especially that jmscortina dude