Vortec Engine Experts

Discussion in 'Engine Topic' started by DCR 1979 Z28, Feb 3, 2016.

  1. DCR 1979 Z28

    DCR 1979 Z28 Veteran Member

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    Yeah I replaced that right after I bought it. I had to replace the Y tubes and valve for the rear heat, and I just replaced it with a standard hose and hose barb.
     
  2. SupplySgt

    SupplySgt Veteran Member Lifetime Gold Member

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    Don't forget to check the throttle position sensor. I have an L31 Vortec in my 78 Camaro, and I had a hesitation issue. Replaced plugs, wires, etc, still had it. Kept looking things up and read that the TPS is tough to diagnose because it rarely actually throws a code. Just another thing to keep in mind.

    I had a 93 Burb for years. The TBI 350 was a gutless turd in a 5500+ lb SUV, but it got me from point A to point B. Finally got to the point where the only thing I was not leaking was transmission fluid and rear gear oil. Even then, I still would have kept driving it if I had been able to get the heat working again.
     
  3. DCR 1979 Z28

    DCR 1979 Z28 Veteran Member

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    Thanks for all of the replys and suggestions, so I thought I would post an update. As stated above I found a multi-port injector at O'reilly's. I put it in yesterday, and while I do believe it is better I still have a problem. What should I look at next tps, fuel pump, what about EGR? I have downloaded shop manuals for other vehicles is there one available for a suburban some where?
     
  4. DCR 1979 Z28

    DCR 1979 Z28 Veteran Member

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    Well tonight I checked for vacuum leaks by spraying brake clean around everything in and around the intake with no luck. I also checked the map sensor thoroughly and it seems to be fine.
     
  5. krabben1

    krabben1 Veteran Member Lifetime Gold Member

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    Have you checked over at fullsizechevy.com?
    That site is all those vehicles.
     
  6. MyBoTy

    MyBoTy Veteran Member

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    It sounds like it's acting like the older TBI engines did when the coolant temp sensor for the computer acted up - it "thought" it was cold so ran rich to try to warm up. I've not heard of a Vortec acting like that.

    Test for the TBI was to simply unplug the sensor and lay a new one on top of the intake and plug it in without threading it in. If the problem was cured, the sensor was replaced with the new one. If not, you could get your $ back for the new sensor.
     
  7. DCR 1979 Z28

    DCR 1979 Z28 Veteran Member

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    Well I finally figured it out after a little research, and the answer is TIMING. When I pulled the distributor I marked it and dropped back in same place by just a quick visual line up. I thought with this being computer controlled it only had to be close and the computer would take over. Boy was I wrong after a little research I found out these engines are unbelievably finicky. It has to be manually position within 2 degrees than fine tuned with a real time scanner with a process that I think is going to take 3 people. Dang I miss a good ole HEI.

    Two other things that compound getting to the right solution. First none the information on the web or youtube is right. I finally found the right procedure from a Indmar Marine manual I downloaded for this engine. Second even after I got the distributor positioned and disconnected the battery it didn't drive any differently at first. Finally after many minutes of driving it was ok.

    Thanks guys for all of your post maybe this will be helpful to somebody else.
     
  8. SupplySgt

    SupplySgt Veteran Member Lifetime Gold Member

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    I didn't think about that myself. Should have, since I went through the same thing in my Camaro. Only difference is I was able to get it within the 2 degrees without the scanner. I'm not sure if you looked on some of the GM truck forums but IIRC that's where I found the info needed, included a backdoor trick or two to get close enough. I'll probably fine tune it a little more when I have access to a scanner but I won't even mess with it till I have the transmission in it.
     
  9. Damon

    Damon Veteran Member

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    DCR- Good update. Any reason why it's so finnicky about timing? I've pulled the distributor out and dropped them back in before without these kinds of problems. Like you, marked it and dropped it back in close as I could but certainly not "perfect" for first refire. Or maybe I just got lucky.

    If I recall correctly, the ECM also uses the distributor as a sort of poor man's cam position sensor on Vortec motors, but still... 2*?? Wow.
     
  10. DCR 1979 Z28

    DCR 1979 Z28 Veteran Member

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    Well I claimed victory a bit prematurely. After I got the distributor positioned correctly it seemed to drive fine, but my daughter who is the daily driver said it wasn't much better, so I drove it this weekend, and she's right. I am sure that the distributor is not A tooth off, although I have not done the final timing with scan tool.

    I took it to O'rielly's today to check the timing with scan tool turns out their tool won't read it, but I did find that it had the following error codes P0132, P0134, P0141, P0151, P0154, P0300, P1345.

    Ant thoughts?
     

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