I think i know whats wrong with my car, now how can i fix it
09-30-2003, 10:43 PM
#1
I think i know whats wrong with my car, now how can i fix it refer to this post for background information
here is exactly what happens. everytime i start the car, whether the engine is hot or cold, the car stumbles and hesitates for the first 3-4 minutes. after that its fine. i can get in, start the car, and drive around dealing with the hesitation for 3-4 minutes and it goes away, or i can start the car and wait 3-4 minutes to get in and drive and it drives fine. after those couple minutes the car drives perfect, both at part throttle and wide open throttle
this makes me this there is something up with the open loop tuning of the car
i scanned it on atap
here are a couple wot throttle runs
does this look ok, i dont know much about atap
also what can i do about the 3-4 minutes on stumbling upon starting the car. can that be fixed with tuning
thanks for any input
ryan
here is exactly what happens. everytime i start the car, whether the engine is hot or cold, the car stumbles and hesitates for the first 3-4 minutes. after that its fine. i can get in, start the car, and drive around dealing with the hesitation for 3-4 minutes and it goes away, or i can start the car and wait 3-4 minutes to get in and drive and it drives fine. after those couple minutes the car drives perfect, both at part throttle and wide open throttle
this makes me this there is something up with the open loop tuning of the car
i scanned it on atap
here are a couple wot throttle runs
does this look ok, i dont know much about atap
also what can i do about the 3-4 minutes on stumbling upon starting the car. can that be fixed with tuning
thanks for any input
ryan
10-01-2003, 05:31 PM
#2
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Re: I think i know whats wrong with my car, now how can i fix it Looks like your B2 is running rich compared to B1. Thats a problem for sure. They should both be fairly close. You're sure that you have no intake leaks or exhaust leaks right? As for tuning..what have you done? When the car is stumbling, is it running really rich? Hows it smell? Whats the timing when the engine is warming up in open loop? I'm willing to bet something happened to a sensor or a harness during the head install. Also, hows the power during WOT?
10-01-2003, 06:19 PM
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Re: I think i know whats wrong with my car, now how can i fix it If it's only acting like this in open loop, you need to adjust your spark vs coolant temp table in LS1 Edit v1.3 Mine did this very same thing and if you look at that table, the PCM pulls timing (as much as 8 degrees) until the engine warms up. I zeroed out those cells, and mine starts up and idles fine now 
10-01-2003, 06:22 PM
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Re: I think i know whats wrong with my car, now how can i fix it I just read your other post, and mine wasn't stumbling like yours. It just hunted for idle on cold startup. Could be an O2 sensor problem?
10-01-2003, 07:03 PM
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Re: I think i know whats wrong with my car, now how can i fix it URPREY can you elaborate more on your cold start issues that you had. I have the new version of Edit and haven't had a chance to mess with it. But I do have the cold start problems. Once I blip the throttle when its cold it idles around 400 rpms then up to 1000rpm and back and forth until its finally warmed up. If I start it up and let it sit and idle w/o touching the pedal its fine.
Thanks
Thanks
10-01-2003, 07:26 PM
#6
Re: I think i know whats wrong with my car, now how can i fix it the car idles fine no matter when i start it
but it stumbles for the first 3-4 minutes after starting when i get on the gas (try to drive it, rev the motor, etc) whether the motor is warm or cold. exhuast smells very strong, but always since i put in my cam back in january. dont know about the timing in open loop, i can check that next time i atap it
power during wot it pretty impressive to me, car fuggen hauls
but it stumbles for the first 3-4 minutes after starting when i get on the gas (try to drive it, rev the motor, etc) whether the motor is warm or cold. exhuast smells very strong, but always since i put in my cam back in january. dont know about the timing in open loop, i can check that next time i atap it
power during wot it pretty impressive to me, car fuggen hauls
10-01-2003, 07:34 PM
#7
Re: I think i know whats wrong with my car, now how can i fix it It's a tuning problem.Post in the tuning section.
You will need to take out fuel in the crank VE table and main VE table at 1200rpm and under.Also you will need to adjust your idle timing tables.
I have a 236/230 Cam idling like a kitten now after ussing those tables.
You will need to take out fuel in the crank VE table and main VE table at 1200rpm and under.Also you will need to adjust your idle timing tables.
I have a 236/230 Cam idling like a kitten now after ussing those tables.
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10-01-2003, 08:23 PM
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Re: I think i know whats wrong with my car, now how can i fix it I'm running a 228/228 112 XER with stock tuning. Runs fine. FWIW, that VE tuning made mine worse actually, so I went back to stock. The LTFTs were high at idle after messing with that. I only adjusted it by 10% too. All I have right now is a drilled TB.