Strange O2 problem

[pmcgrath]

I just got through breaking my cam in after installing GN1s, ATR 314 cam & MSD 50s. Anyway, the breakin itself went fairly well but the car was idling very rough once I brought the rpms down to idle. The following day I hooked up the otc 4000 and noticed that my O2 cross counts were all zeros and my O2 readings were .02, .03, .02 ... all in this range. I then got a code 44. So I went out and bought another O2 sensor(delco afs-74) and when I started it up tonight the cross counts started off good for about 30 seconds and then went back to zeros with the same strange values for my O2 readings. Needless to say when it went into closed loop, it idled very rough. Any thoughts on what may be causing this?

Thanks,
Paul
pmcgrath@warp.nfld.net

 

[Russ Merritt]

Massive vaccum leak! I hope you didn't need to machine the intake manifold for the new heads! Trouble code chart says could be water in the exhaust also. Get some wd40 and start trying to find the leak, could be an injector seal too. good luck!

 

[pmcgrath]

Thanks for the tip Russ. I guess the fun starts now. Hopefully, I won't have to dismantle too much to fix this.

Paul.

 

[Russ Merritt]

I hope not man, I hope it's just something stupid, make sure the MAF tube isn't leaking anywhere after the MAF,(turbo's not sucking air without the MAF reading it)

 

[pmcgrath]

I found the leak. It is the intake manifold on the passenger side where it mates to the head. The driver's side is fine but when I sprayed WD-40 on the passenger side, the idle quality improved drastically and the O2 readings looked normal again. I tried retorquing the bolts to no avail. Are there any solutions to this problem that I'm gonna like? I'm using the stock GM intake gasket right now.

Thanks again,
Paul.

 

[Russ Merritt]

Looks like intake gasket time. I have great luck with the felpro intake gasket. I don't like the plain stamped steel gasket, although they do work. The felpro is just a safer bet. Take your time, it's a piece of cake! (This will give you a chance to paint the intake, remember quality)