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Thread: 89 chevy pickup with 5.3

  1. #21
    Tuner in Training
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    Jan 2019
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    Ocala FL
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    OK I think that I have the issue fix with O2's. I was watching a you tube video on how to test your O2 and the guy said that if you have .5 volts on you post O2's they are reading correctly. WOW that what I am reading on my PRE O2 sensor, make sense now. I am using a ACDELCO afs98 and for my ECM that is a post O2. I have order some AFS123 which for my ECM is a PRE O2 sensor. I hope this blind hog has found a nut. Thanks guy Norm

  2. #22
    Tuner in Training
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    Jan 2019
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    OK, I finely got the new O2's and 28LBS injector in. I am installing them and new plugs tomorrow and will update everyone when I finish. Thanks Norm

  3. #23
    Norm,
    How is everything working so far?

  4. #24
    Tuner in Training
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    Jan 2019
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    Ocala FL
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    eugine test tune.hptI put in the new 28lbs injectors, new plugs, new o2 sensors, and still no o2 and the thing ran worst than before. I downloaded a stock tune and will go from there. I have just finish with the tune and now I am going over it to make sure I have not left anything out or wrong. I will keep this updated as I find thing out. One of issues was have the editor in basic not advance so now I can see a lot more area I need to look at. I am just making sure of what I have change. Thanks Norm

  5. #25
    The no O2 thing is a bummer and obviously needs resolved. Are you sure on the harness part number from PSI?
    Did you input the injector data into the tune file correctly? Where did you get the injectors and what is the part number?
    Which ECM are you using?

    Basic versus advanced view is a big deal, lots more to see.

  6. #26
    Senior Tuner
    Join Date
    Mar 2011
    Location
    Ripley, MS
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    1,865
    Hope you can determine the issue with the O2 sensors soon.
    In the meantime, this tune will be something for you to try.
    I bumped the idle speed and the min airflow tables for the bigger cam. Increased the timing at idle just a bit as well.
    The big change was to remove fuel from the VE table at idle. I removed approx. 20% fuel at an idle. It's hard to say if that's enough or not, but you'll know soon enough.


    eugine test tunemod1.hpt

  7. #27
    Tuner in Training
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    Jan 2019
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    OK, I finely done what I should have done a week ago and pull the harness out. Keep in mine that was a new harness when this project started and not much to my surprise here is what I found. All the injectors connector have been change and 5 of the 8 just had tape over the spice with both wires touching. The other two had heat shrink that I could move just by pulling lightly on them. The Crank sensor wires had been very hot at some point and although I was getting a reading on the three wires it was not correct. The chasses ground was not in a great place on a medal support in the dash. There is a lot of plastic in those 89 Chevy trucks. I order a new harness and hope this fixes this truck. Thanks for all your inputs and I will keep you updated on this project Norm. DHC, thanks for the input, I am sure of the part number, on the injector data I copy and pasted the info from another truck pcm that is running 28LBS injectors with no problems. Part number 25317628. Kevin87turbot, thanks for the input and again I will keep you guys updated on the project, I hate it when you don't know what the end result are never posted.

  8. #28
    Norm,
    I hope this plan resolves the problems, sounds like it should.
    Let us know when you are ready to button this headache up.

  9. #29
    Tuner in Training
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    Jan 2019
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    OK first of all thanks to all of your for you help. I finely finish hooking all the sensor up on the truck and fired it up. It idle and ran great in fact the best it has every ran. Took it for a long drive and it ran and drove great, well except for the transmission not shifting correctly and that is mechanical and need to be overhaul. when we got back I unhooked the battery and reinstalled the harness fuse box and dress up the wiring under the dash. We fire the truck up and it was like the devil had gotten into it and it fat rich. I hooked the scanner to it and the A/F was at 7.5 and then I ran the truck at 2K RPM for a few minutes and it cleaned up the A/F to 14.4 and ran great again. I just don't know if some of the setting reset them self or what. The only thing what was not working correctly was the bank one O2 sensor and it just stay at .5 volts, but the bank 2 sensor started working correctly. I just need to go back and look at the scan data and see if I can find something. I do know that all the sensor data on the scanner was great and nothing of them was not working correctly. The story continues thank Norm