Need some help please.

The car is a 2002 zo6. Just installed the trick flow cam 228/230 .585 lift on a 112. Car also has basic mods - vararam, lt headers, no cats, ported tb. The tune is stock with exception of cooler fan temps and deleted rear o2's.

The Problem- We were taking the car to be tuned, but LTFT were maxed so they wouldn't mess with it. Both banks are the same. We looked everywhere for vacuum leaks but nothing

Things we have tried: new MAF, new o2's, new MAP, new gaskets (intake, tb, inj orings), tried new intake manifold and TB from another car, capped EVERY port on intake.

Again tune is stock, so we figures maybe it is just way off with his mods so we used HPtuners to add some fuel but still max lean. Disabled MAF - tried SD mode. Still not right.

Any other ideas? we are stumped.

Thanks
Matt

 

Fuel pressure gauge. Post reading.

 

It just needs to be tuned! All those mods make the engine "breathe" more air, and you haven't done anything to the tune to account for the increase in airflow, so the computer is doing the only thing it can: it is adding more fuel via the fuel trims. Who refused to tune it because of the LTFT's being high? I am sorry if they are a friend of yours, but that just doesn't make any sense at all to me. If you are taking your car to them to have it tuned, shouldn't they tune it?

 

Regarding fuel pressure we did check that as well and replaced fuel filter. I will recheck tomorrow and post actual #s

As for tune- I agree it absolutely needs to be tuned. He was just concerned with the fact the fuel trims were maxed and were not readily responding to changes. He was thinking things should be more in the 14-18% range not 25% and holding.

Any other ideas?

Matt

 

Well, once again, I do apologize if he is your friend, but he is doing you a mis-service. He or someone else needs to get in there and tune the engine. It is that simple. The actual tuning part may not be simple, but the simple fact is that it needs to be tuned. But if you don't want to take my word for it, that's fine. It's your car, do with it what you want. It is just that I am still confused as to why a "tuner" refused to tune an engine.

 

Fuel pressure is 58 #s in park and in gear.

Any other ideas? or should we just start chasing the tune?

Thanks
Matt

 

Your fuel pump is ruled out since you're getting 58psi at the rail.

Scan your IAC count value at operating temp idle, closed loop. Let's see if you have an air leak somewhere.