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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: sawblade6 on March 22, 2015, 10:40:06 pm

Title: ALDL 5 Pin wont show code, just growls
Post by: sawblade6 on March 22, 2015, 10:40:06 pm

I have an 84 C10 with the quadjet on a 350. My check engine light comes on after the truck is warm.

I jumped the ALDL "A and B" on the far right side and all it did was make a growl fizz noise and the light went out. I immediately turned the key off. Everything I read was very clear about the difference between the 12 and 5 pin. For the heck of it I tried to jump the other side too and it wouldnt show me the code either. Im lost as what to do minus drive it to a shop to have them empty my wallet.

What could be the issue?

Title: Re: ALDL 5 Pin wont show code, just growls
Post by: Irish_Alley on March 23, 2015, 09:56:42 am

does the cel come back on for a couple seconds when you turn the key on


http://forum.73-87chevytrucks.com/smforum/index.php?topic=29949.0

Title: Re: ALDL 5 Pin wont show code, just growls
Post by: sawblade6 on March 23, 2015, 07:59:27 pm

the CEL comes on and stays on when i turn the key. It goes off once the truck is fired up, but returns to the on position once the truck is warm.

I have gone over all the ALDL sites you can mention, I think there is a bigger issue. When i jumped it at the AB it just makes the same noise  (a growl, fizz, like opening a soda bottle) and the light goes off. This is all happening when the engine is off and the key is in the On position.

Why wont it let me read the codes and what is the fizz?

thanks for the link!

Title: Re: ALDL 5 Pin wont show code, just growls
Post by: Irish_Alley on March 24, 2015, 02:37:18 pm

the only thing i can think of is the pin was upside down or something and you jumped the wrong ports. if it only comes on when it warms up i would think egr or o2 sensor but those are guesses

Title: Re: ALDL 5 Pin wont show code, just growls
Post by: VileZambonie on March 24, 2015, 06:24:35 pm

Is this an original setup? Post a pic of what you are jumping out that is fizzing. Also, stop jumping this for now.

Title: Re: ALDL 5 Pin wont show code, just growls
Post by: VileZambonie on March 24, 2015, 06:41:00 pm

Check terminal B (second to the right on the top) and see if someone tapped into that wire for an accessory ie cig lighter, radio, aftermarket gauges etc The sizzling you are hearing sounds like electrical arcing as if you are running a direct short to ground. Terminal A is ground for the instrument panel harness.

Title: Re: ALDL 5 Pin wont show code, just growls
Post by: sawblade6 on March 26, 2015, 07:20:58 pm

The O2 is new and so is the EGR.

I had to take it in to get tuned and smog`d, so my mech is looking into it. I was hoping to have it resolved prior but its in good hands.

I will post results or developments so everyone knows.