Idle problem after warm restart

[mweber]

I am having a problem with the idle after restart when the car is warm. Once the O2 lights off again and it goes to closed loop, it is OK but it barely says running when its warm and in open loop. I have tried changing the warm park position but it really hasn't made any effect. It seems to be too rich but it is hard to tell (need to get a wideband O2).

Specs
84T converted to 87 ECM with MAT and Electric fan
Stock 87 turbo
LT1 3" MAF with Translator
Ford Green Top Injectors (42lb)
the rest is stock 84

All other conditions seem OK except for the warm start after being off for 5 to 10 minutes.

If someone could point me in the right direction I would appreciate it.

Thanks,

Mike

 

[BJM]

I have had similar issues. Check your O/L fueling. The factory chip is really lean at those temperatures, even leaner than stoich for some reason. The timeout fuel and the timeout delay is probably okay to get you through the start and initial idleing.

On my car I wound up moving the C/L threshold up to 140 degrees. My O/L enrichment at that temp is just a little rich, 10% or even 5% so it helps for when the car has cooled off for about an hour.

For shorter cool down where the coolant is still quite warm I changed the C/L timer to 20-30 seconds rather than the stock value of 5 seconds. That helps a lot too, once you have richened the O/L fuel. You will also want to alter the threshold temperature for warm versus cold start so that the cold timer of 140-180 sec is only below 140 deg or so.

On my car it has helped a lot. The Extender for instance will delay the idle cell only from going C/L for 300 seconds regardless of temperature for the same reason. It will be C/L in just a few seconds if moving but idle will be O/L for the 5 minutes.

 

[mweber]

Thanks for info. I will give it a try. It is a little too cold today to be messing around with the car but I have to get through emission before the end of next month.

Thanks,

Mike