I get a "CHECK ENGINE" light intermittently. The code is always "32", and it only comes on when I've been on the freeway for a while, never during city driving. I've took it to a good shop when I last got code "32"; turned out to be only a disconnected vacuum line to the solenoid (or valve? the one closest to the firewall). Everything else checked out. My test equipment inventory is one (1) volt/ohm meter, and a basic set of tools. Any advice on what I can check? Should I return to the shop?
'85, 60K, L98, 4+3, excellent condition and bone stock
Thanks, Josh

 

I had the same problem. Code 32 is EGR valve. Check the vacuum hoses
around the EGR valve(by the water neck). I had to replace the valve and
the problem went away. :D

 

First check the EGR valve. Apply about 15" of vacuum and you should see it move. To check vacuum supply to the valve, purchase or borrow a vacuum gauge and tee it in to the vacuum line going to the valve. Observe the gauge while driving. Vacuum should decrease while driving, increase while stopped. (engine needs to be warmed up). This will verify that the solenoid is sending vacuum to the valve and that the valve is opening and closing correctly. Assuming the solenoid (which controls EGR vacuum) and the ECM are working properly, it's probably a sluggish or intermittent EGR switch. The ECM sets a Code 32 when it doesn't see a decrease in voltage on the signal it's sending to the switch. This mounts in a tube which runs from the right header to the manifold. A properly functioning EGR valve will cause exhaust (heat) to flow across the switch which causes the electrical signal from the ECM to drop. This let's the ECM know that EGR took place. Make sure the wiring to the switch is in good shape including the plastic connector to the wiring harness. Verify the continuity of the wire from the connector to the ECM. The switch or wire could be opening intermittently causing the ECM to lose the signal. Testing it can be a bit dicey without a scan tool. You need to connect a DVM to terminal C15 of the ECM and monitor it while driving. You should see 12 volts upon starting out and then the voltage should drop when EGR is commanded and the switch heats up. If it is the switch, be careful when taking it out of the tube as they can snap off at the base and drilling them out and chasing the threads is a real chore.

 

CODE 32: means that the EGR diagnostic switch was closed during start-up or that the switch was not detected closed under the following conditions:

coolant temp greater than 80 C or 176 F
EGR duty cycle commanded by the ECM is greater than 48%
TPS less than WOT, but not at idle.
codes 21,22,33, 34 not present

If the switch is detected closed during start-up, or if the switch is detected open when the above conditions are met, the "service engine soon" light will remain "on" unless the switch changes state.

Description of circuit: The EGR valve vacuum is controlled by an ECM controlled solenoid. THe ECM will turn the EGR "on" and "off" (duty cycle) by grounding the CKT 435 (grey wire at the solenoid). The duty cycle is is calulated by the ECM based on information from the coolent and MAF sensor and engine RPMs. There should be no EGR when in park or neutral when TPS input is below a specified value or when TPS is indicating WOT.

With the ign "on", eng stopped, the EGR solenoid is de-energized and by grounding the diagnostic terminal, (switch on EGR tube), the solenoid is energized. Diagnostic switch will close when the EGR valve opens and exhaust gas is present at the switch.

The above information was taken from "Chevy TPI Fuel Injection Swapper's Guide" by John Baechtel.

 

Had the same problem on my '85. Replaced the egr valve and temp switch (figured might as well do it all while the plenum is off), haven't had a problem with it since. It's not a bad do it yourselfer (this coming from someone w/ NO mechanical background).
Good luck
Joe

 

I would start with replacing the EGR temp switch. It is the sensor that screws into the metal tube that goes from the exhaust manifold to the intake manifold. The switch costs about $10. The wire is conected behind the distributor. You may need to pull the dist cap off to get to it. I believe the part number is AC delco 212-336. It is hard to find in the parts book because the Corvette is the only car that uses this switch.

Also check the connection to the EGR switch (it is mounted on one of the thermostat cover bolts. Make sure all the vacuum hoses are attached.

 

Read a tech article some time back and it said that when the code strikes after highway driving it's most often the sensor.

I believe the 85 has the same setup as the 86 which has a single wire sensor on the manifold, passenger side rear which has the pipe leading to #8 exhaust.

That's the sensor the article was referring to.

BTW, I eliminated my entire EGR system and had the EGR turned off in the PROM. I got tired of fooling with that heat pipe everytime I wanted to pull that valve cover.

Jake