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Discussion Starter · #1 ·
Ok, so I have a slight backfire (very slight, only noticeable by engine bogging for a split second) and I'm trying to get it sorted out. So I figure adjust my idle, check timing, and tps etc etc. Lo and behold as soon as I start the car with the ten pin grounded, it runs like a dream. The exhaust no longer smells like it's burning rich, the idle is smooth, throttle is responsive as it should be, and no issues at all.

So I go about setting the idle to ~700 rpm, get it stabilized, everything should be good right? No....

When I remove the jumper and start her up, she starts no problems, but the idle sits at ~1300 rpm and won't come down, still having minor backfire too. I plug in the jumper pin again, and all is well as I set it.

Could this be an ecm problem? It's almost like it won't go into closed loop... I would drive it with the ten pin shorted, but the fans turning on with throttle would be annoying as hell, and it can't be good to drive all the time like that.

Please anyone with suggestions? I'm stumped on this one...
 

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sounds like a ground problem or something. TPS has a grounding wire that goes into it. i think ur problem is ur TPS. either bad or going bad or set wrong
 

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I actually this problem right now. The only times I've noticed a difference is when I would swap TPS/VAF and ECU. When I used Lambera's ECU and a known good kl01 vaf and a known working TPS, it was perfect. It would idle correctly when stopped at a light everytime. No small little backfires or bogs.

Right now, I have my modded aspec ecu with a kl31 chip, je50 vaf, and the good TPS. I'm still getting the old bad idle and small little backfires and I'm thinking it's either my je50 vaf (which could be out of spec) or my ecu. I'm trying to find another JE50 to test out
 

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Discussion Starter · #4 ·
Tried something today, and I'm really starting to lean towards the ecm being pooched...

I put in the 93 ecm (for sheetz and giggles) to see if it would make a difference. Aside from the cooling fans being on all the time (extra coolant sensor that's not there on a 94), the car ran like a dream! Perfect idle, no backfire, clean smelling exhaust. So, can someone with better knowledge of these 6 ecm's reinforce my suspicions, or shoot them down?

Hopefully if I need another ecm, I can get to the yard and pull one soon!
 
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