camz28arro

iTrader: (12)

Well after installing the heads, 36lb injectors and getting a tune I had both PO171 and PO174 turn on 4-5 times over maybe 220 miles. Usually comes on after I restart the car, didn't go over 3k rpm today and after startup the light went on. Under WOT the car also seems slower than right after the install, thinking the computer is dumping fuel to try to fix the problem. The car seems to run fine besides this issue.

Also my car used to go up to the correct 1200rpm on initial startup, then it was 1600rpm, now sometimes it can go as high as 2000rpm and it is very annoying at night and in the morning with my loudmouth exhaust, could this be contributed to a lean A/F.

I already checked for exhaust leaks and got new gaskets for the AIR tubes, I replaced the dryrotted 2" PCV tube with 3/8 fuel hose that runs from the PCV valve to the throttle body but tested the little tube section and it wasn't leaking. I cleaned the MAF with MAF cleaner, checked the fuel pressure with the engine off at 58psi, plugs look the correct color also. Any insight to this problem and the high rpm startup with be very helpful. THanks.

camz28arro

iTrader: (12)

Anybody, I hope nothing happens because I need it to go back and forth to college.

Darkman

iTrader: (2)

Attached. You may have a bad injector.

camz28arro

iTrader: (12)

Thanks for the documents, I don't think it is a bad injector though because both banks are lean and the brand new injectors were flowmatched from FIC.

Darkman

iTrader: (2)

Agree, it would take at least one bad injector on each bank, which is not likely, and you would also be getting a P0300.

camz28arro

iTrader: (12)

Could my dyno tune at any chance be the culprit. When I had the dyno tune done my heads may have been slightly leaking from the cometic gaskets, into the coolant but I have replaced them with GM gaskets. Would that cause him to tune the A/F ratios wrong?

camz28arro

iTrader: (12)

Well checked fuel pressure today by turning the ignition, not engine, on. It went up to 58-59psi while the fuel pump was spinning, then went down to 50psi real fast when it stopped and stayed there.

Also got to clean the MAF, still waiting on the AIR emissions gaskets.

flintwrench69

iTrader: (11)

Its most likely a vacuum leak, its idling high cuz youre pullin unmetered air in from somewhere. When I first bought my car I had the same codes, I found a rotted vacuum line going to the TB.

coD

I would just add that yes, those leaks around the EGR, AIR, PCV tubing/tubes/gaskets do affect things significantly.

In order to get both 171-driver's side, and 174-passenger side, the computer is adding +25% fuel to both sides. Setting aside a tuning issue, sounds like you have a leak(s).

camz28arro

iTrader: (12)

Well I was spraying the tb and egr valve plus some other places with starter fluid and the idle didn't change. I did mess with the IAC valve and cleaned it also. I cleaned the MAF too.

I guess it has to be a leak at the rear of the intake manifold so I will have to pull that off to be sure because I can't drive my car running 25% too rich although I hear no wistles of air getting into the intake.

My car has been for the past half year, running like it doesn't want to idle down. I need to come to a full stop for it to go from 1000rpm to the set idle of 800rpm and at most speeds it seems to slow down extremely slow when I just lift off the gas also making the brakes feel weaker. Such as 55 down to 50mph might take 10-15 seconds. Wouldn't this be symptoms of running lean and not 25% too rich?

Also when they do the dyno tune, don't they go off the wideband in the tail pipe for the A/F ratio and not the PCM?

RedRocketZ28

iTrader: (19)

My car has been doing the exact same thing. My car was running perfect after my last tune then all of the sudden it started acting weird. On a warm start the car would idle at 500 rpm for a few secs and then slowly climb up to 900 rpm. I messed with the set screw on the TB to give it more air on startup for the time being and now it rockets to 2000 rpm on a warm start and sometimes it wont even come back down. Just hangs there.

Coming to a stop mine does the same thing as yours as well. Wont idle down until I come to a full stop, and like mentioned above somtimes it wont come down. I have messed with everything I can think of and checked for leaks around the intake. Not sure what is going on but it is pretty annoying.

camz28arro

iTrader: (12)

Yep, this problem is really pissing me off too. Are you getting any engine codes with your issues?

camz28arro

iTrader: (12)

Could this be the dyno tune, maybe the part throttle calibrations of the bigger fuel injectors was not set correctly or something? This is really getting to me now.

I'm pretty much narrowed down to a leak at the rear of the manifold which I'll check tomorrow, bad O2's, or the tune is off. I don't see two 02's going bad at the same time though.

I swapped the loose fitting MSD wires back to the stockers to see if that would make a difference.

RedRocketZ28

iTrader: (19)

I am getting no engine codes at all. I think mine is a tune issue. My TPS sensor is also not showing right either which I know can cause some problems too.

camz28arro

iTrader: (12)

Well was spraying starter fluld at the back of the manifold, the rear EGR valvecover connections and no change. This has to be a problem with the dyno tune.....

Anybody else figuring that is the problem, IDK why there aren't that much replies?

camz28arro

iTrader: (12)

Just thought I would update: Got the fuel trims set and now car is running fine, so it was running lean making it feel there was a cruise control stuck on.