Help identifying unknown electrical part

justacruzr2

Greasemonkey

Jun 16, 2017

186

209

43

Midlothian, Illinois

• Sep 27, 2024

• #1

On my 84 GP there is what looks like some sort of relay encased in a rubber flap that screws into the firewall at about the midpoint of the firewall and just above the top of the engine. It has a wiring harness connected to it. Sorry I don't have a picture of it at the moment (my car is at the body shop getting its paint job) but I'm hoping someone knows what I'm talking about and what this relay is called. Only some years of GP's had it. If necessary, I can get a picture of it and post it here but that won't be until I get the car back which will be next week. Thanks.

 

383_StealthRam

G-Body Guru

Supporting Member

Dec 29, 2016

547

1,076

93

• Sep 27, 2024

• #2

Definitely post a pic, I'm sure someone can identify it.

I was gonna guess it might be something related to an aftermarket alarm system, like a motion or vibration sensor. They used to like to plop them on the firewall in that area.

 

justacruzr2

Greasemonkey

Jun 16, 2017

186

209

43

Midlothian, Illinois

• Sep 30, 2024

• #3

OK. Here's the picture.

 

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ELCAM

Royal Smart Person

Jun 19, 2021

1,253

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• Sep 30, 2024

• #4

Looks like the relay that controls the idle solenoid on the carburetor controlled by the computer. To be sure might try starting the engine turn on the AC and see if the solenoid engages and increases the idle, if so turn it off disconnect the relay and see if it still works.

 

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383_StealthRam

G-Body Guru

Supporting Member

Dec 29, 2016

547

1,076

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• Sep 30, 2024

• #5

Yup, agree with ELCAM

Looks the same as the early Corvette/Camaro/Firebird fuel injection relays for MAF Power, MAF Burn Off and Fuel Pump they used to use with those same riveted extended mount brackets. They went bad a lot, (tap to unstick) and the later years changed to the oval style (14089936) until they pretty much did away with the MAF sensors, and used speed density.

Fairly easy to get if you need to replace it, since they were so widely used in the 80's on lots of GM cars.

 

justacruzr2

Greasemonkey

Jun 16, 2017

186

209

43

Midlothian, Illinois

• Oct 1, 2024

• #6

ELCAM said:

Looks like the relay that controls the idle solenoid on the carburetor controlled by the computer. To be sure might try starting the engine turn on the AC and see if the solenoid engages and increases the idle, if so turn it off disconnect the relay and see if it still works.

Click to expand...

OK. That solenoid has been working correctly. I've been having a computer problem and thought that might have something to do with it but obviously not. The check engine light is on and when I put the scanner on it there are no readouts. It says RPM 0, Dwell 0, TPS 0, Vacuum -2.9 and the prom ID keeps changing. Bad computer, bad PROM or both?

 

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ELCAM

Royal Smart Person

Jun 19, 2021

1,253

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• Oct 1, 2024

• #7

I would start with the computer wiring and connectors make sure they are all clean and making a good connection, wiring undamaged. See if it looks like water ever got in there where the computer is.

 

justacruzr2

Greasemonkey

Jun 16, 2017

186

209

43

Midlothian, Illinois

• Oct 1, 2024

• #8

ELCAM said:

I would start with the computer wiring and connectors make sure they are all clean and making a good connection, wiring undamaged. See if it looks like water ever got in there where the computer is.

Click to expand...

Water didn't get into where the computer is but last Tuesday we did get a big torrential rain right when I had to go to work. There were some pretty large puddles I had to go thru and that has been on my mind as to what got wet in the engine compartment. This problem started the very next day.

 

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ELCAM

Royal Smart Person

Jun 19, 2021

1,253

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• Oct 1, 2024

• #9

If it happened after going thru big puddles I would disconnect every connector that is part of the computer harness under the hood and either:

Blow them dry with compressed air, but make sure the air is clean and dry or you are just blowing oil and/or water in them at high pressure.

Blow them clean with a can of that computer duster stuff.

Heat them all up with a hair dryer, let them set and do it again.

 

justacruzr2

Greasemonkey

Jun 16, 2017

186

209

43

Midlothian, Illinois

• Oct 2, 2024

• #10

ELCAM said:

If it happened after going thru big puddles I would disconnect every connector that is part of the computer harness under the hood and either:

Blow them dry with compressed air, but make sure the air is clean and dry or you are just blowing oil and/or water in them at high pressure.

Blow them clean with a can of that computer duster stuff.

Heat them all up with a hair dryer, let them set and do it again.

Click to expand...

Good idea. I'm going to see what I can do this weekend. It's also possible that the 2 computers I bought off eBay were bad to begin with. One worked for 2 days though.