subman

A month or two ago, just cruisin, the SES light come in my 91 (L98, auto). With the help of some of the folks here, I narrowed it down to the EGR valve or the EGR solenoid. I ended up taking the car to J & D Corvette (awesome shop) and had them put the scan tool on it. I needed to replace the EGR valve. No problem. Changing it took a few hours (had to clean and polish stuff while I was in there).
Last week, again just cruisin about 70, the SES light came on again!
Pulled a code 32. So I went back through everything again. The valve works perfectly. When I checked the solenoid (grey wire to ground) at idle, nothing happened. Took revs to about 2000, still nothing. Checked the vacuum from the TB connection and no vacuum at idle and very little at 2000 RPM. The engine was not up to full running temp. All of the vacuum lines are good. On the 91, the is no EGR temp sensor, so that part is not in the equation.
The question is: is a bad solenoid now? a blocked vacuum port in the TB?
I don't mind spending $ to keep it running right, but I hate throwing money at it on a blind guess.
TIA
Subman

rick lambert

Does a 91 have the same EGR switch that an 87 has-located close to the distributor on the passenger side? if it does, you might replace it-cured my code 32.

65Z01

If you have no vacuum through the EGR sol. when you activate it I would suspect the sol. but you say there is no vacuum to the EGR sol. either.

So it sounds like an issue with that vacuum port.

Remove the EGR sol. vacuum line from the port and test the port for vacuum at idle. IF none, service the TB.

If vacuum, connect the EGR sol. vacuum line to the vacuum port and chck for vacuum at the other end of the line. If none service the line.

If vacuum, replace the EGR sol.

383LPE

I get that also sometimes on my 91 during high speed runs. I wonder if there is just not enough vacuum at high speed.

subman

Thanks for the replys!
Rick - no EGR switch that I am aware of.
65Z01 - There is no vacuum at the port that I can feel ( I have not tested with the gauge) either at idle. If there is any at RPM, it very slight. I'll double check with the gauge tonite.
I read that on some of the L98's there is a need for some back pressure to make the EGR work properly. I will try to plug 1 side of each of the Flowmasters and check to see if they are still working properly.
383 LPE - If I am running back and forth to work (on gas/off gas) or running AX (WOT or on the brakes), there doesn't seem to be any issue.
It only throws the SES when cruising at/about 60-70 mph.

dburgjohn

My LT1 is doing the same thing. Code 32 when crusing at 70 for a while. Does not do it around town. This bug must jump years.

myblue91

subman-I have the same problem with my 91.took it to the dealer because of code 32. They changed the egr and solenoid. Within 2 days I'm getting the same code 32.Take it back and everything checks out ok,but the tech finds my P/N switch out of adjustment,adjusts that,and again within 2 days the code 32. So I've about given up!!! Car runs just fine even when the SES comes on. Like yours,I get an SES only after on the freeway over 60 mph.Can drive around town all day and never get the "light". I wondering if it is just low vac at higher speeds...good luck,like you,I'm not into just replacing parts without a cure

eschoendorff

I got the same problem. No drivablilty issues, though. I just have been ignoring the code. I wish someone knew how to make this problem go away.

Tool

Good grief! I love this forum....

Our 92 just started throwing Code 32 this weekend. AFTER it went thru this finnicky start/won't start thing - if it's cold, it starts fine. if it's hot, fine. If it cools off at all, NG.

New EGR arriving tomorrow, and I think I'll test the relay and look HARD at the vacuum lines. If the haunting continues, I'll check back in. Wish me luck!

subman

Okay, I checked the vacuum at the TB at idle. 0 inches. However, just touching the throttle runs the vacuum up to 40-45 inches. Rechecked the grey to ground at operating temps and still got no reaction from the EGR diaphram. It appears from what was tested before and tonite that the solenoid just don't work. Checked with the local autoparts guy and for $18.00 (but it has to ordered), it seems to be an inexpensive test.

jzvette

I have the same problem, driving back from Carlisle this past summer and I trip a code 32 while flying (75mph) on the hiway for about 2 hours. I've been just around town and short hiway trips(45 min) and no code 32. I will be replacing EGR switch, it's the known cure. We'll see. jzvette

onedef92

Check your fuel filler cap, too, guys. If it's not sealing properly from a worn seal, it can cause this problem, too.

nitrous1

Does your car have aftermarket exhaust? Code 32 seems to be real sensitive to the reduced back-pressure from free-flowing exhaust systems. If all else fails, you could have a custom chip burned to eliminate Code 32.

Good luck

nitrous1

Tool

Good point. I usually hear a hiss when I unlock the locking gascap... seems to me I didn't hear that last few times I filled up! Going to be checking that puppy 1st, but probably do the new EGR anyway; call it PM.

dburgjohn

I have both a aftermarket locking gas cap and muffler elems, maybe this is my code 32 source. You would think with all the other electronic stuff on a Corvette, the General would have put something more usefull than a single SES light. If a display just said 'EGR Valve' I would keep driving, but when you don't know what it is, you tend to think the worse.

subman

I had to gas the car tonite and there was plenty of pressure behind the gas cap. I replaced the main cat a little over a year ago and at time I gutted the precats. The Flowmasters have been on the car for about 4 years. I am ordering the EGR solenoid tomorrow. We'll see what happens after it's in.

jzvette

I'm also ordering the switch to see what happens.

96zride

I have a 91 changed the switch and the egr, it kept coming on. When I did the intake manifold gasket I found a small crack in th plastic line that runs from the switch to the EGR valve fixed it, haven't seen it since.