Strange check engine light
 

1988 C1500, 350 tbi. 2 wheel drive 4 speed automatic.

Seems like when I'm at cruising speed the CEL comes on. It will stay on for quite a white, then shut off on its own. When I come to a stop the CEL goes out. I stopped at Autozone to hook up a scanner and no codes are being stored. Truck runs great otherwise. Any ideas? It's really annoying me. Egr related?

Thanks,
Kevin C

Re: Strange check engine light
 

Sounds like EGR. The scan tool at Autozone probably can't read it. Try the paper clip method by jumping pins A & B on the OBD I connector and wait for the SES light to flash codes

Re: Strange check engine light
 

i second the egr valve code. i have a 1990 and about 5 years ago i hit the highway and after about 10 minutes the light would come on. i was able to scan mine as i worked basically right off the highway. changed the egr valve and went away. only CEL ive ever had with this truck in the past 7 years

Re: Strange check engine light
 

I borrowed a hand operator vacuum pump to check it out. Sure enough, the EGR wouldn't hold any vacuum. So that's the next thing on my shopping list.

Thanks again,
Kevin C

Re: Strange check engine light
 

Make sure you get the correct EGR valve, and stay away from universal ones. You may have to order one vs going to the parts store. Pull the part number from the one you have to verify the correct part.

Re: Strange check engine light
 

I will second this. They are not exactly cheap and it is cheaper to buy a GM to start with than buy one to replace the aftermarket unit that doesn't work correctly!

Re: Strange check engine light
 

I ordered an AC Delco valve. Should be here hopefully by the weekend.

Re: Strange check engine light
 

Just wanted to say that I tripped over this topic the other day & it just so happened that I was getting engine light as well on my 95 sierra when I hit highways! pulled off EGR valve & this is what I found!

Re: Strange check engine light
 

I need to replace the one on our 95. I ordered one that I thought would be the correct part.

I ordered a Delco and got a "universal" part.

http://67-72chevytrucks.com/vboard/s...d.php?t=549711

Sent it back for credit, and since the truck is seldom driven, I never have gotten the correct part.

Think I'll go ahead and order one. Where are ya'll getting the correct EGR's (not the universal type)?

Re: Strange check engine light
 

The one I got is the link I provided in that thread. https://www.amazon.com/ACDelco-214-5...dp/B000C9GLEI/

There were a couple different EGR types, so the one above is a negative backpressure valve. You'll need to compare the part numbers to ensure you get the correct one.

Re: Strange check engine light
 

You can also try a local (not chain) auto parts store. They buy from multiple suppliers and may be able to find an OEM part.