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  1. #11

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    Is there a way to zero out the timing without useing a programer? If I can time it manually I know how to do that I'm not any good with computers and stuff.

  2. #12
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    Yes you can, if you can find the pcm wire to disconnect it. The last guy I tried to help do this, never could find it, so your sucess depends on finding it & disconnecting it before you set the initial timing. On my '88 it is a small 16ga. brown wire with a black tracer. It is located behind the black plastic cover on the firewall near the distributor. This is the wire that the computer controlls the ignition timing with. On your year it might be a different color so you will need to get a wiring diagram for YOUR YEAR VEHICLE.. Disconnect it & you can set your initial crankshaft timing. You can experiment here for better starting, running, mpg etc. Mine ran best between 8 & 12 degrees advanced. The ecm will reset it, but like I said before the ecu can only adjust it so far because it has parameters that it works within. If you get it too far advanced, for the octane fuel you're running it will ping, so be prepared to set it back a little. The ecm will retard it if the knock sensor feels it pinging but here again the ecm has limits so it can only retard it so much. If your engine struggles to crank over when starting, then it is too far advanced, & you will have to retard it a bit. If your engine is gutless, or has a bad hesitation upon acceleration, then it is too far retarded & needs more advance.
    1988 Chevy C-3500 2wd (no pic)
    350 c.i. 5.7 L Stock Block, 4 Bolt Mains
    L-31 Vortec Heads, Edelbrock Cam & Intake,
    Holley 650, Flowtech Headers, Magnaflow exh.
    Jet Trans 700R4, B&M Ratchet, 4:10 gears,
    3" susp. lift kit "shadetree"
    No rev limiter, No speed limiter lol


  3. #13

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    Ok thanks I'll give it a try and let you guys know.

    Phillip

  4. #14

    Default

    I tried to find the wire and failed. I did some reserch and it turns out on this model there is no wire you can disconnect it is all done by computer I will try to find someone with a programmer but thanks for all the help.

    Phillip

  5. #15
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    stephan's Avatar
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    Far West, Oregon USA,
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    Phillip, they are all controlled by the computer, that is why you have to disconnect the wire before setting the timing.
    1988 Chevy C-3500 2wd (no pic)
    350 c.i. 5.7 L Stock Block, 4 Bolt Mains
    L-31 Vortec Heads, Edelbrock Cam & Intake,
    Holley 650, Flowtech Headers, Magnaflow exh.
    Jet Trans 700R4, B&M Ratchet, 4:10 gears,
    3" susp. lift kit "shadetree"
    No rev limiter, No speed limiter lol


  6. #16

    Default

    Hi guys haven't been on in a while dicided to start messen with the truck again. I have replaced the roter cap, ditributor cap, wires plugs, crank position sensor and a coil. It has spark and fuel it tries to start after you let off the key. Could it be a ignition switch? Is there a way to check it?

    Phillip

  7. #17

    Default

    That is a good point but it will not start off starting fluid ethier. I will try and get a fuel pressure gauge and check my fuel pressure.

    Thank you
    Phillip
    Last edited by durr711; 01-05-2011 at 06:30 PM.

  8. #18

    Default suburban

    hello are you still having problems with your suburban or did u solve it ? Because mine wont start either . I have tried everything fuel pump too , pressure gauge

  9. #19

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    Durr you said you changed plugs, double check your wires and make sure your firing order is correct. I think the vortec's use the same firing order as the old chevys, but don't quote me on that. old is 1-8-4-3-6-5-7-2
    1986 Chevy G20 Tow Rig - 5.7 TBI conversion
    1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior.

  10. #20

    Default

    no i have not changed the plugs since last year. it started this morning and ran fine. But when you shut it off it wont start back up until about 45 min later and you have to pump it alot. Did you ever find out what the problem was ? Its seem like there are many that are having the same problem. Very frustrating, Thanks for all your input.

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