Ok so I have a 90 da with a 0bd1 turbo gsr. The car is tuned on ectune. Runs great and other then idle has perfect afr. The problem is at idle it goes 100% rich or lean no matter what we do with the tune. I. have precision 1000cc with a resistor box and a walbro 255 . The fuel pressure at idle is fine. All injectors fire what could it be?

 

I have tried another jumper harness and we even made a new basemap but nothing

 

what does your wideband say? precision 1000s are difficult to idle properly.

 

What does 100% rich-lean mean. What a/f ratio are you targeting at idle and what is it changing to?

 

Slowly drops down to 10 then fluctuates to ---. Or slowly works its way to 17 and ---

 

Id like 13.5-14.5

 

is this happening in open or closed loop?

 

Is the difference on a hot and cold motor or is this on hot motor only? p&H I hectors that large without a proper controller are difficult to idle well. That being said precisions seem to like to stay around 13.0-13.5 at idle and won't have that bubbling popping sound. If leaner they fluctuate a lot and bubble pop from exhaust.

Sounds to me like your fuel corrections for idle are out of wack though. Usually when it goes that rich and slowly works its way up the coolant and air temp corrections for idle are not adjusted properly. As those temps rise it's leaning the engine out because the fuel percentage in those fields are to low and now adding enough compensation fuel to the base fuel that's on the maps

Do not change the fuel on the maps, it's all in the fuel compensation tables that needs work

 

Its not within the tune. He came to me to have his demon/rtp installed. I simply unplugged his ecu and installed the demon. Copied the tune from his chip and transferred it over to the demon. Installed the ecu back in the car and now the car runs rich constantly. Not just at idle. I runs so rich that the aem wideband stays pegged on 10. Thinking something went corrupt I started from scratch and made another calibration/basemap. This didn't fix the issue. So I took the demon out and installed the chip that I originally took out of the ecu. The issue was still present. So then I replaced his ecu all together and the issue still remained. Since all I touched was the ecu and the ecu jumper harness I thought maybe something went bad with the harness in between unplugging the ecu and plugging it back in. Instead of going through the wiring on the ecu jumper I just replaced it with another one. This didn't get rid of the issue.

I havent had the time to fix this car as of yet. I have to move other cars out of here that came in prior to this one. Bryan its not that I can't figure it out. To be honest all I have done is try another ecu jumper as of now since you were down here the other day. Patience my friend

 

Bad resistor box? Injectors getting stuck open or something causing them to dump fuel and not spray ?

 

i can verify this 100%. ive been using precisions for a few years now and idle quality falls apart real quick once you get them over 13.7-14.0 afr. on a warm motor i currently idle at 13.2-13.5 at 1000 rpm with my iacv duty cycle increased to 10%

 

It was ignition control module