I have a 1989 corvette and I am planning on a trip in the next few months. It is gonna be about 800 miles of nonstop driving other than the random breaks.

I am wondering what needs to be done to make sure it will be safe and run properly. I would really hat to break down in the middle of nowhere because of something stupid.

I am planning on doing the normal maintenance such as replacing all fluids and checking the lights. I have new Nitto tires that are about 2 months old. I plan on checking my vacuum hoses for leaks or cracks.

This car is a daily driver with about 90% of it being in-town driving and has had no major issues recently. I'd say around 200-300 miles a week.

The only problem I currently have is every now and then I get a code 32 or the EGR system. It only happens while driving on the highway after about 10 minutes or more. I can turn the car off and then back on and the code is gone and does not come back until I drive on the highway again. I have also noticed that since this started happening my gas mileage has gone down. Instead of getting about 350 miles to a tank before I fill up, I am now only getting about 250 before I HAVE to fill up. Is this just a coincidence or is it possible the EGR is causing this problem due it it possibly being stuck open or closed?

I plan on figuring out the problem soon for the EGR.

If there is anything else I may have missed, then please let me know, because again I don't feel like breaking down in the middle of nowhere.

Any and all help is appreciated.

Thanks, Stephen

 

If you got the 32 just after startup it would signal the EGR was stuck open.
After steady state driving with coolant temp >175deg F the ECM will call for EGR, which is where you are getting the code, so either:
-the EGR valve is not opening
-or the EGR Temp sensor is not detecting exhaust gas flow
When the ECM sets the code it is likely the cause of your poor mileage.

One way around the EGR issue is to install a 160deg T-stat. Around town coolant temps will run as usual but on a trip temp will not likely rise above 170deg F at highway speeds.

BTW, I've run a 160deg T-stat year around in my '88 Vettes for >14yrs with the only effect being a slight power increase.

If you want to trouble shoot the EGR issue, ask and I'll list a simple procedure.
BTW, do you have the FSM for your '89?

 

I would definitely like the simple procedure so that I can fix the problem and put it in the past where I do not have to worry about it anymore.

And yes, I do have the FSM for the car. I have not looked into it yet in the FSM only due to lacking of time recently. I also wanted to hear if anyone had some simple tips or suggestions on testing it.

 

Just got back from a 1K+ trip. I always carry small tool kit with a few hose clamps and zip ties, plug in air pump, tire plug kit, extra belt, spare hose kit. most everything fits under the glove boxes. Never needed anything but carry it just in case.

Just do a good pre-trip check and don't forget to check the spare.

Have fun, by the way I got 27mpg.

 

I would begin with a visual inspection:
-the electrical connector on the EGR Sol
-the vac line between the EGR Sol & EGR Valve connected and in tact
-the Grn wire connected to the EGR Temp sensor

If all looks ok, start the engine and ground the Gry wire going to the EGR Sol, while monitoring the voltage on the Grn wire from the EGR Temp sensor.
If the EGR Valve closes the engine may idle a little roughly (increase idle speed if needed). If so the EGR Sol & the EGR valve are ok.
The voltage on the Grn wire at the EGR Temp sensor should soon drop to 0 Vdc as the exhaust gas through the EGR pipe heats the sensor and closes the internal switch. If it does not, replace the sw.

I suspect that somewhere during one of the above tests you will find the problem area be it EGR Sol, EGR Valve or EGR Temp sw or an electrical or vac connection. Good luck.

The wire colors mentioned are found on pp 20-0 of my '88 FSM.

 

The EGR valve vacuum line looks a little bit rough so i might have to replace it anyway which will be a pain. It might just be something wrapped around it but could not tell in such a tight space. Other than that all other lines looks great. The EGR valve also operates freely if you press the underside of it, it makes the idle rough and car want to stall though, not sure if that is normal or not.

The temp switch wires looks good and I also unplugged it and then turned on the car and it set off the code 32, I dont know if doing this matters or not.

The Grn wire also looks intact.

I will check everything a step further later on so that I can make sure it is all good.

Thanks for all the information.

 

Sounds like all is ok save possibly for the EGR Temp sw or the Grn wire to the ECM.
At this point I would connect a DMM to the end of the EGR Temp sw, activate the EGR Valve and watch for the voltage to drop to zero. If after a few minutes of fast idle with a warm engine the voltage does not drop, I would replace the sw. Then do a highway steady speed test drive to verify the fix.

If the voltage does drop to zero then you have missed the problem. I would go back to that difficult to access EGR Sol. Trace the Pnk/Blk and the Gry wires from the Sol, pierce the insulation of the Gry wire with engine warm and running to verify that the EGR Valve is activated.

Good luck; I think you are close to the resolution of the issue.

 

I have just now started the daignoses even further.

I have ruled out the EGR valve itself and any vacuum line issues. I even stuck a fancy camera into the port on the intake to look for carbon buildup and saw none present. Now to move onto the solenoid and the temp switch.

I should hopefully have it figured out by tonight and if not tomorrow night for sure.

 

Ok, so the EGR valve itself is intermittently sticking opened or close depending on how it feels I guess.

So, I am gonna replace it.

Anyone have any tips on replacing it and how exactly I should go about it.

Also how do I figure out if the new one is working or not since it seems like a part that is commonly bad out of the box.

Thanks, Stephen