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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Skunksmash on March 10, 2011, 10:17:52 am

Title: Service engine light only comes on when I accelerate?
Post by: Skunksmash on March 10, 2011, 10:17:52 am

87 TBI 5.7L. I was at the jack in the box drive through last night, and all the sudden the check engine light came on. Then four seconds later the truck died. Luckily it restarted, after cranking on it for a second. But all the way home, any time I needed to mash the accelerator, the light came on again. Then as soon as I let off the gas, the light went off. Weird. Anyone know what this could be?

Title: Re: Service engine light only comes on when I accelerate?
Post by: topp on March 10, 2011, 10:35:35 am

Pull the code with a paper clip....
That'll tell us what the problem is.

Title: Re: Service engine light only comes on when I accelerate?
Post by: Irish_Alley on March 11, 2011, 02:07:08 pm

I would lean to oxygen sensor. Maybe bad or picking up to lean or to rich. if you can get a code

Title: Re: Service engine light only comes on when I accelerate?
Post by: Skunksmash on March 12, 2011, 09:59:28 am

I got a code reader, I'll read the codes when the truck gets back from the AC shop. AC quit and it was still under warranty cause I had the whole system replaced last year. So when that is done, I'll let yall know what the codes say. One code that I know it stores in the memory, is the MAP sensor. But I have replaced that sensor before, and nothing changes. Its like its not the sensor itself. Need to just slap a motor out of an '09 in there but that has to wait until I'm done with school.

Title: Re: Service engine light only comes on when I accelerate?
Post by: VileZambonie on March 12, 2011, 04:00:25 pm

So you get a code for a map sensor and that means replace the map sensor but if that doesn't work put in a new motor?  ???

It is very easy to check the map signal circuit.

Title: Re: Service engine light only comes on when I accelerate?
Post by: Skunksmash on March 13, 2011, 08:12:51 am

Heh, naw that is just something I've been wanting to do anyway.

Title: Re: Service engine light only comes on when I accelerate?
Post by: topp on March 13, 2011, 08:34:28 am

Newer motors have more complex electronics....
If you can't get this one figured out, you'll have more issues with a newer motor...

Just my $0.02..

Title: Re: Service engine light only comes on when I accelerate?
Post by: Skunksmash on March 16, 2011, 11:19:04 am

Oh I wasn't going to do it myself