Code 43

Tiny
STEVE W.
  • MECHANIC
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That will make it much harder to keep the performance parts you currently have as most performance cams are not emissions friendly to begin with. It is also likely to be the reason it does not run correctly. The factory ECM is designed to match the camshaft and engine as it was in stock form. Change the cam and now the ECM fuel tables are all wrong. That is why most folks strip the computers out or buy a custom aftermarket unit that can be tuned to match the new parts. Those are not real options in a state that does tailpipe testing like AZ does as removing the factory ECM falls under the tampering section of the inspection and is an automatic fail.

However, you might want to check the routing of the wiring harness the knock sensor wire is in. If it gets routed near the plug wires (or the wires are just laying all over and not in a plug wire loom) you can get a code 43 due to ignition voltage inducing a voltage in the knock sensor wiring.

Even eliminating the code will probably not let it pass testing because they do actual tailpipe testing. Does the truck have all of the OEM pieces on it like the converter, air pump and the rest? If any of the factory smog gear is gone, that is also a fail.
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Tuesday, March 27th, 2018 AT 7:11 AM
Tiny
LAYLO.C10
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Everything is still there as far as emissions go we left it there so they won't make it a big deal. The spark wires are currently not in a loom and the knock sensor runs up the original harness bolted to the back of the head. The ECM has been changed but does not allow me to run a JET chip. I have a question about the chip? Do I need the light blue chip as well as the piggy back they sell? I believe the blue chip is called a memcal or something like that. Truck does not accept the JET piggy back chip I bought. Thanks for your help guys!
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Tuesday, March 27th, 2018 AT 7:21 AM
Tiny
STEVE W.
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Just having it does not help if it does not work. The sniffer they use measures the exhaust gases, if they are not low enough it fails. You need to get it running clean without any chip because those chips for that vintage generally make the system run in open loop to turn off emissions equipment and just allow enough control so the engine runs. That will make it fail instantly when they run it and it shows open loop.
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Tuesday, March 27th, 2018 AT 11:48 AM
Tiny
LAYLO.C10
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So how do I go about this? I am about ready to part ways with it since I have put money into a engine that is not going to work.
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Tuesday, March 27th, 2018 AT 11:51 AM
Tiny
STEVE W.
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You need to decide what you want to do. To get it running correctly you need to determine what the issues are that are causing the problems you are having. You need to know what the cam is that is in it and if it has hydraulic or solid lifters. If you are hearing lifter clatter and it has hydraulic lifters you have either an oil pressure or adjustment issue. If it has solid lifters you will probably never get it to work with a factory computer system that uses a knock sensor if the sensor is causing the problem. What do you have for test equipment?
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Tuesday, March 27th, 2018 AT 12:21 PM
Tiny
LAYLO.C10
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I just want to get what I already have here running good. With minimal spending if possible. I already spent a lot on it since I bought the truck.
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Tuesday, March 27th, 2018 AT 12:53 PM
Tiny
LAYLO.C10
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  • 17 POSTS
It has an RV cam and hydro lifters. 1.5 arms performance intake. Bigger spring in fuel regulator. Stock heads stock bottom. ECM is all stock just added MSD cap rotor wires. Shorty headers.
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Tuesday, March 27th, 2018 AT 12:55 PM
Tiny
LAYLO.C10
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I am using a mt2500 Snap on scanner.
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Tuesday, March 27th, 2018 AT 12:55 PM
Tiny
STEVE W.
  • MECHANIC
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If it has hydraulic lifters and you still here lifter clatter something is not right. Those should be quiet and they will not trigger the knock sensor if they are adjusted correctly. The different cam and rockers will probably work but you might want to pop them off and install stock ratio, then get it running and go from there. Basically try to lower the "new" parts down until you get it running, then try adding the other parts back. The stronger spring in the regulator will alter the fuel flow as well. Again I would go back to stock and at least get it to run and inspected. Then add one item and dial that in, then the next.

Most of those parts should work but you will need to either test them as you go. I built a lot of engines over the years, only a handful used a computer. The rest were old school, and test as you build was a pretty good idea.
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Tuesday, March 27th, 2018 AT 4:38 PM
Tiny
TOLBERT54
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  • 1994 CHEVROLET TRUCK
  • V8
  • 2WD
  • AUTOMATIC
  • 218,000 MILES
I have engine codes 43 66 67 81 82 looked every where for a book to tell what these are but only shows 43 which is esc but 66 67 81 82 are no where to be found also lost 1st and 4th in trans all the sudden other than that it runs good I think the other codes are trans codes
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Tuesday, November 26th, 2019 AT 7:47 PM (Merged)
Tiny
BLUELIGHTNIN6
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Code 43 = knock sensor with spark control module

code 66 = open or shorted ABS pump motor relay

code 67 = open motor circuit or shorted BPMV output

code 81 = brake switch circuit shorted or open

code 82 = solenoid "A" stuck off ( 1st & 4th gear only)
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+3
Tuesday, November 26th, 2019 AT 7:47 PM (Merged)
Tiny
TOLBERT54
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Thanks, I will do some checking for the obvious. Bad wires/fuses
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Tuesday, November 26th, 2019 AT 7:47 PM (Merged)

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