Red12secZ28

iTrader: (2)

I just recently put headers and trues on my camaro. Then put the stock maf back on. Ever since then i can't tune the idle for sh@#. I tried everthing. Ses light popped on code po507 high idle. could it be my iac is bad. The symptoms are that it surges from 400rpm up to 1200 them starts to cruise on higher without any throttle.
THen dips down to 400 and surges again. When driving around I get the cruising effect. The engine keeps pulling me and reving high. I tried lowering base timing and raf setting. Car is running pig rich. Can anyone help.

Camaroholic

iTrader: (1)

Is your throttle body ported?

Almost sounds like a vacuum leak of some sort. Intake manifold sealed down tight? EGR tube broken?

-Andrew

Red12secZ28

iTrader: (2)

My throttle body is ported. Plus I just recently put a freeze plug in the opening of the egr port on the intake manifold. How do I check for intake gasket sealing and overall intake manifold vaccum?

Slowhawk

iTrader: (12)

I would check the freeze plug area first.Spray WD-40 in the area and see if idle changes.

Red12secZ28

iTrader: (2)

Tried the wd-40 trick. Nothing happened. sprayed around the tb, egr(freeze plug),pcv hose,around the map sensor, sprayed between the gaps in the intake manifold neck the cylinder in 4 places and didn't do anything. Map sensor reads around 14.9-16.5 on autotap. Could it be that I drilled the tb hole to big and that my ported tb and the iac can't support idle? Will I have to open up the opening to the iac valve?

Cal

iTrader: (1)

No it's not your TB hole. You said the problem started when you installed some parts. At what point did you install the cam? That's what I think started these problems you're having. Once you get it tuned right for the cam, things will be much better.

jeromio

I have a similar problem. Mine idles fine in open loop, when it switches to closed at 180* it turns into a piece of ****. Idle is crap, low RPM cruising is possible, but it misses, etc. Tries to die at stoplights and I have to struggle with the throttle to keep it alive (which makes cars next to me think I'm being a punk). It's way rich and will puff black smoke and generally run like ***.

HOWEVER! If I drive for more than an hour on the highway, all the problems go away! It will idle just fine. Turn it off and if it sits for 20-30minutes, all problems return. Which to me means that if it stays hot, up there past 180* after this magical post-hour-long-drive fix occurs, then I'm golden. As soon as it has to dip back down into open loop, it starts from scratch. Freakin wierd.

I only have basic ATAP, so I can't get IAC readings. The O2s seem to work fine, although B2 is a bit higher - 900-950 as opposed to 850-900 for B1. I've got new plugs (Bosch Platinum).

Motor is stock LS1/T56 except for 4" air intake (with a 90* elbow betw. MAF & TB - someone said that matters?), !EGR, !S2O2s and a slightly bigger exhaust with no cats (2.5 Y-> 3).