EGR/VAC Issue

[Neelskit]

I have a 1994 Astro CL EXT 4.3L TBI with 153k. After getting the van, I noticed the A/C vents would deflect back to the windshield defroster once you got up to highway speed. (65-70 MPH) After slowing back down, the vents would work fine again. Yesterday, while dropping my kids off at daycare, the SES light came on. I pulled a code 32 (EGR failure) code. My question is: do I need to replace the EGR vacuum solenoid or the valve itself? Could this EGR problem also be causing the vent problem?

Thanks in advance!

[ericn1300]

sounds more like you have a vacumm leak, probably a loose or cracked hose. check for that first.

[Blue Bowtie]

Just for grins, check the PCV valve to make sure it is the correct one for the engine. Long story short - I've been there, with the same symptoms, Code 32, Code 44, along with an uncontrollably higher idle RPM. The Fram "OEM quality" replacement PCV was NOT calibrated the same as the AC/Delco OEM part, and I chased it for days until I installed the old AC PCV valve.

[Neelskit]

Sorry haven't posted back my results: I haven't touched the van- The day I posted the problem, it quit doing it! (at least the SES light never came on again) I don't know about the vents since it's been to cold here lately to run the A/C. Anybody know what to make of this? Still driving the van as usual- no SES light in over a week.

[355smallblock]

Is It A Vortec Engine If So The Egr Valve May Intermittenly Stick Open Due To Peices Of Carbon From The Intake.solution Is To Buy A Gasket With A Screen Built In To Prevent This.the Vent Problem Is A Vaccum Leak Problem For Sure Find And Follow The Hose Until You Find The Leak

[Neelskit]

No, it has TBI injection. Also, it feels like it's missing at highway speeds. Thanks again for all your help.

[Blue Bowtie]

Originally Posted by ericn1300

... probably a loose or cracked hose...

Crack 'Hos are never a good thing to have in your van...

Even a TBI engine can have contamination of the EGR valve which prevents proper sealing. The resulting vacuum leak can cause your symptoms. It's probably a good idea to check the EGR valve pintle and valve seat, as well as the passages in the intake for carbon buildup.

If the EGR valve is sealing properly, temprarily disconnect the EGR valve vacuum hose and see if the heater control prolem still occurs. If not, the EGR may be inadvertently opening due to a sticking/internally leaking EGR solenoid valve.