Engine running rich at ideal only with no ECU correction.

bataradena · Post by **bataradena** » Mon Dec 03, 2007 9:03 am

I just completed any engine swap (89 K1500) to a TBI-7.4L from a TBI-5.7L. I also swapped in the 747-ECU and the TBI from the 7.4L engine. I did leave off the smog pump. My question is the engine seems to be running OK but at ideal the A/F mixer gauge show the engine is always rich with little or no ECU adjustments being made to correct for this imbalance in fuel air mixture. Am I missing something? I need your help!
Thanks
Byron T.

HarpSeal1 · Post by **HarpSeal1** » Fri Dec 21, 2007 4:50 pm

You have 80#/hr injections with that big block throttle body.

You have the big block chip on the computer correct? I wouldnt run that motor with the chip for the big block since thats a good part of your problem. If i were you id put your stock 350 computer back on and tone down the fuel pessure a few PSI or until it didnt run so rich.

fastblue231 · Post by **fastblue231** » Mon Jul 14, 2008 10:33 pm

When you say it is running rich do you mean rich like you can smell it or rich like it lopes. If it dose it only when it is hot it is just the computer trying to keep the motor cool. Also, malfunctions in the EGR, EES, O2 sensor and vaccum leaks can cause one to run rich.