Idle stumbles when coming to a stop, then recovers
#22
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Re: Idle stumbles when coming to a stop, then recovers
Don't want to sound stupid, but I have the same problem and it's not due to a cam change.
I found that K&N filter oil was accumulating in my TB port and causing that effect. Now I clean it more periodicaly and no more problem. Also I started to soak up the excess oil with absorbant paper towel after re-oiling.
I found that K&N filter oil was accumulating in my TB port and causing that effect. Now I clean it more periodicaly and no more problem. Also I started to soak up the excess oil with absorbant paper towel after re-oiling.
#24
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Re: Idle stumbles when coming to a stop, then recovers
Yep, that is caused by over oiling your K&N air filter. It gets on your MAF thermistors (the three little gizmos attached to your MAF wires) and causes the MAF to improperly report airflow.
You need to get some sort of spray electriclean and clean off your thermistors.
You need to get some sort of spray electriclean and clean off your thermistors.
#25
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Re: Idle stumbles when coming to a stop, then recovers
I vote for drilling a smaller second hole. We used to do that all the time in Carb throttle plates. If you go back to stock, you can fill the smaller hole with Steel Putty, JB weld, etc.
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Re: Idle stumbles when coming to a stop, then recovers
What you guys need to do is increase the values in the Airflow Decay table. I recomend changing all the table values from 0 to 14 mph to 31. This problem is caused by the PCM over compensating; for those that understand control systems, it means the gain is too high causing overshoot. It's like someone learning to drive that moves the steering wheel too much and weaves all over the road.
Here's my next question for you. What can I do to get the car to start and stay running without me holding the gas pedal in a bit and helping it start idling?
Thanks,
Jordan
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Re: Idle stumbles when coming to a stop, then recovers
Multiply the main ve values for your idle range by 90%, and this seems to do the trick for the idle start up problem. You can try decreasing more if 10% doesn't cut it.
#28
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Re: Idle stumbles when coming to a stop, then recovers
What you guys need to do is increase the values in the Airflow Decay table. I recomend changing all the table values from 0 to 14 mph to 31. This problem is caused by the PCM over compensating; for those that understand control systems, it means the gain is too high causing overshoot. It's like someone learning to drive that moves the steering wheel too much and weaves all over the road.
Here's my next question for you. What can I do to get the car to start and stay running without me holding the gas pedal in a bit and helping it start idling?
Thanks,
Jordan
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Re: Idle stumbles when coming to a stop, then recovers
I have my main VE tables multiplied by .85 for low engine speed. should I try going up to .90 instead? The startup thing seems to always happen, even if the car is warmed up, would adjusting that new ls1 edit thing help still?
Jordan
Jordan
#30
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Re: Idle stumbles when coming to a stop, then recovers
OK, so I have the newest LS1 Edit version (1.3). I'm looking at the Spark vs Coolant Temp table. Which cells need adjustment and how much?
#31
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Re: Idle stumbles when coming to a stop, then recovers
Sorry man, you're in uncharted waters now! I don't have 1.3 yet so I haven't messed with that yet. But you should be able to do it from trial and error with the help of EFIlive. Log some startups and idling and watch what the timing vs. ECT does between startup and when the idle finally goes smooth, and try to tune out the slow idle out by giving it more timing below 100 deg ECT. I'm thinking the timing jump at 100*F was about 5 degrees.
#32
Okay guys, I'm digging up this old thread. I just installed headers on my car and got new plugs. Runs really smooth and I'm really happy with it. The only thing is, the car seems to stumble when I'm pulling in to parking spaces and just generally really low speeds. Is it possible I messed up my front O2s? The front passenger has thrown a slow response code before, and I have a light that's intermittent. I have yet to get it checked.