Well it has bit me so now time to chase it all down. Not looking forward to this project but it could be worse. 1987 stock, any quick tips I should know. Thanks in advance.

 

Do you get an SES light while cruising down the road?

There are two ways to get an error code 32. When the ignition is turned on the ECM checks the EGR temperature switch to see if it's grounded (it should not be). If it sees a ground it sets error code 32.

The second way to get an error code 32 is when the ECM commands EGR and the EGR temperature switch does not send a ground to the ECM. The sequence goes like this: the ECM commands EGR by turning on the EGR solenoid. The EGR solenoid applies vacuum to the EGR valve. The EGR valve opens and hot exhaust gases flow through the EGR valve and into the intake manifold. The EGR temperature switch senses the hot exhaust gases flowing through the EGR pipe and closes, applying a ground to a pin in the ECM connector. If the ECM does not see that ground it sets error code 32. There is some time delay built in to all this and the ECM waits several minutes to see if the EGR temperature switch ground is there. That's why the SES light just seems to come on for no reason while you're driving down the road.

You can check for which error code you're seeing by clearing the error codes and then turning on the ignition. If you get an error code 32 right away, then it's caused by the first type of problem. Clear the error codes by disconnecting this connector for a second or so:

 

Yeah mine is number two checked it out yesterday to be sure which one. Takes about 6 or 7 miles before it pops the ses light. I had read your post when I did a search here good info. Still reading to determine how to check everything out before I just start changing parts.

 

My '88 had the same symptoms of turning on the light after some miles on the highway. I checked everything else, but mine turned out to be the EGR valve.

If yours turns out to be the EGR valve, take a look at the replacement before you do all the installation work. I got a replacement from Advance Auto and it was bad. When I applied vacuum, it would not work the diaphragm to open it. I took it back and got another one. It was bad too (plus it was the wrong one in the right box). I finally got an AC Delco one from an online source and it worked fine before and after I installed it.

Good luck.

 

There IS a REAL problem with this.......

that's because there are LOTS of EGR valve "types" that all look the same and have almost identical parts numbers and applications.
The problem is that the C4 requires a negative back pressure valve, while other GM 350 engines use a positive or standard valve. The Correct EGR valve will have a "N" stamped on the bonnet somewhere.

Negative back pressure is just vacuum. This allows the valve operation to still take place during sudden changes in the intake vacuum during WOT to fully closed throttle operation. Because someone at GM assumed that the C4 throttle might see some WOT on occasion, they decided to use this "type" of EGR valve so it did not linger open and rob power when the ECM saw a need to open the EGR for a second.

Most, if not all of the aftermarket valves do not distinguish between the neg and pos EGR valve. If you want to be certain, you will have to buy a Delco. The pos style EGR does work on SOME engines, likely because that particular engine is not requiring much use of the EGR, so the difference is never noticed.

So, just because the new EGR will not hold vacuum, does NOT mean its bad. It just means that its probably a positive pressure return valve.

That's what I was told......

 

I started getting an error code 32 and the problem turned out to be the plastic vacuum line between the EGR solenoid and the EGR valve. It had touched something hot that melted a hole in it. I think it was the small tube in the runners on the passenger side. Exhaust gases from the EGR valve go through that tube when EGR is turned on, so it gets pretty hot.

The moral of this story: Check all your vacuum connections.

 

Absolutely !


...check hoses and fittings. AND, do vac test on the EGR itself, while its installed to see if there is a sticking or leaking problem. Hard to do when the hose is buried and hidden under the plenum and the solenoid is hidden on a bolt under the TB on the T-stat housing. Another good idea from a rookie GM engineer.

and we all know from experience how difficult this can be !
This is why I relocated my solenoid to the back of the alt bracket so I could get to the vac hose that leads to the EGR valve...without having to pull the plenum or do a bunch of other BS just to find that 1 hose...
Now I have a clean and accessible set-up. The solenoid is right there, the hose to the ported vac source (underside of TB) and the hose to the EGR itself. One of several sensor/servo relocations I've done to make my life easier when it comes time to do maintenance or diagnostics....

 

Interesting solution.....should check this solenoid, make sure it is in good working condition. Mine was ok, but i decided to replace it while i had all of the top TPI off the car, just so it would be new and look good. turned out i got the code 32 with the new sol! CC gave me credit to take it back. But what i did with the the T-stat housing bolt, was just put in a long stud, and use a 3/8" flange nut to hold it down. Then put the EGR sol on the stud, with another flange nut, and didnt tighten that down too much. Now i can access it without taking off anything else! there was just enough room so all the lines and connections cleared everything good.

 

I had same issue it was a vacuum line! here is the picture of where mine broke. I had code 32 for a long time, I discovered this break by accident when removing the TB!


http://s599.photobucket.com/user/gun...ml?sort=2&o=26