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90 Chevy Silverado Code 42


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Jhenriksen
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Dec 26, 2011, 1:11 PM

Post #1 of 14 (20827 views)
90 Chevy Silverado Code 42 Sign In

I have a 90 Chevy Silverado, 5.7 Truck 110000 miles, running sluggish, has a code 42. With vehicle running I unplugged the EST wire and it almost died so i would say its getting a good connection between the distributor and the ECM. I replaced the module in the distributor, still runs the same. Not sure where to go from here.


Hammer Time
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Dec 26, 2011, 1:14 PM

Post #2 of 14 (20814 views)
Re: 90 Chevy Silverado Code 42 Sign In

If it has a knock sensor, try unplugging that.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Jhenriksen
User

Dec 26, 2011, 3:57 PM

Post #3 of 14 (20792 views)
Re: 90 Chevy Silverado Code 42 Sign In

Yes it has one. What should happen when I unplug it.


Hammer Time
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Dec 26, 2011, 4:02 PM

Post #4 of 14 (20789 views)
Re: 90 Chevy Silverado Code 42 Sign In

See if it runs any better.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Jhenriksen
User

Dec 31, 2011, 11:46 AM

Post #5 of 14 (20761 views)
Re: 90 Chevy Silverado Code 42 Sign In

Runs the same with it unplugged.


Discretesignals
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Dec 31, 2011, 11:51 AM

Post #6 of 14 (20755 views)
Re: 90 Chevy Silverado Code 42 Sign In

Clear that code by disconnecting the battery for 10 secs. See if the code comes back. If it comes back let us know. That code can set if you open the bypass circuit to set your ignition timing.







Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 31, 2011, 11:56 AM)


Hammer Time
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Dec 31, 2011, 11:52 AM

Post #7 of 14 (20751 views)
Re: 90 Chevy Silverado Code 42 Sign In

OK, it's not the sensor causing the problem. It's going to take some in depth testing to check all the wiring and ECM.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Jhenriksen
User

Dec 31, 2011, 11:57 AM

Post #8 of 14 (20745 views)
Re: 90 Chevy Silverado Code 42 Sign In

Thanks, I have some one sending me a wire diagram and a trouble tree. I guess I know what I'm doing today. I'll let ya know what I find. Thanks Again.


Discretesignals
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Dec 31, 2011, 12:01 PM

Post #9 of 14 (20744 views)
Re: 90 Chevy Silverado Code 42 Sign In

HT, I think that your getting 43 and 42 switched. 42 has to do with the ESC bypass circuit being open or shorted.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


Discretesignals
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Dec 31, 2011, 12:04 PM

Post #10 of 14 (20741 views)
Re: 90 Chevy Silverado Code 42 Sign In

You might wanna make sure that you didn't set that code by playing with you ignition timing from disconnecting the bypass connector (tan/blk wire). If that code set because you disconnected the bypass at one time, your just going to take yourself on a wild goose chase.

If you clear the code and the bypass connector is plugged in and the code comes back, that's when you need to trouble shoot using your chart.


In fact, I am looking at the chart right now and clearing the code and seeing if it comes back is the first step.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 31, 2011, 12:09 PM)


Hammer Time
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Dec 31, 2011, 12:22 PM

Post #11 of 14 (20730 views)
Re: 90 Chevy Silverado Code 42 Sign In


Quote
HT, I think that your getting 43 and 42 switched. 42 has to do with the ESC bypass circuit being open or shorted.


Yep, I was chasing EST.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Jhenriksen
User

Dec 31, 2011, 4:47 PM

Post #12 of 14 (20717 views)
Re: 90 Chevy Silverado Code 42 Sign In

Well, I think I got it, I started looking at the wires and all the connections, and noticed that the EST wire had a flat spot in it from being pinch under the black cover that covers all those electrical goodies on the firewall. so I replaced that section of wire, cleared the code, drove it around for a bit, seems to be fine now. I even checked the timing again just to make sure. And yes I cleared the code again after I check the timing. Thanks guys for your help.


Discretesignals
Ultimate Carjunky / Moderator
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Dec 31, 2011, 5:03 PM

Post #13 of 14 (20715 views)
Re: 90 Chevy Silverado Code 42 Sign In

Good eye Smile Happy New Year!





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


Jhenriksen
User

Dec 31, 2011, 5:08 PM

Post #14 of 14 (20710 views)
Re: 90 Chevy Silverado Code 42 Sign In

I call it better to be lucky than good...Thanks again






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