Hi;
This one has an IAC error (code 35) and it says it's lean I think (code
44). I don't think the mixture is that far from stoich, as it passes HC and CO. Problem is it fails NOx. EGR ports are good. It also does not purge the EEC, there is a whoosh when you open the gas cap.The canister purge, EGR solenoid and TCC run off the same line, which is up, has 12 V. The main problem has something to do with EGR so we went there first. The convertor locks up we believe, but the system never goes into closed loop operation. After a several mile drive the light still flashes fast in run test so I'm not so sure about the TCC. I haven't personally driven it.
Afterward, we grounded the gray wire to the EGR and it did not actuate, later we found that it is fed with ported vacuum, and there was on vacuum at idle. So we left the gray wire shorted to ground and revved it, sure enough it actuated and the engine stumbled.
We moved on to the IAC, removed and inspected it. It seemed to be at or near maximum extention. Retracted the plunger and reinstalled leaving the electrical connector unplugged. Of course the engine ran at a high idle, and slowed down when the IAC was plugged back in, so we know it goes one way.
It is surprising to me that ported vacuum is fed to the EEC, not manifold vacuum, I thought it purged right at startup. Either I'm mistaken or they changed it.
There are four vacuum hoses at the throttle body The placement seems logical, The other two do have direct manifold vacuum.
Is this correct or is there a clog ? The vacuum I can feel is indeed ported vacuum, not simply there when the RPMs are up, so I don't think it's a clog.
The EGR has an air bleed, when it is not actuated the ported vacuum is there. This may be normal because there is an air filter. Is this normal ? A leak in that spot could concievably be taking the IAC out of range, throwing the code 35. Or is the IAC the more likely culprit ?
With a code 44 though, I guess the possibility exists that it needs an O2 sensor. Should I go there ? There should be no reason an IAC or EGR malfunction should throw a code 44, or is there ? Also an O2 error should not cause it to throw a code 35, or should it ?
Usually I can handle these things, but this one is a bit wierd. It might not be unique so therefore I post. I see where maybe it could be one simple thing with this combination of symptoms, or of course it could also be the ECM.
Any ideas ?
Thanks in advance.
JURB