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Thread: 1999 wont start

  1. #1

    Default 1999 wont start

    Hi guys. Hope you can help. I am working on a 99 7.4 suburban.swapped in an engine with 97,000 miles to replace the 220,000.Everything went well but took it to the dealer for a code and to have distributor flashed.2.5 weeks later gal calls and has an oil leak.Underside is just coated with oil. Took exhuast off from manifolds and the heat shield to inpect for leak.Ended up oil pressure sensor was cracked.Replace and delivered.Ran great.2 hours later she call stuck on side of road.She said it just died.Fried starter before I got there.Towed to my place.
    Has spark and 80 lbs at fuel filter and 56 and then holds 50 at the fuel rail.Replaced crank position sensor,cap,rotor,Oil pressure sensor,fuel punp relay and fuel pressure regulator. When I replaced fuel pressure reg I also put old injectors and fpr off old engine.It was 56 and hold 50.That makes three.Original,old,and new fpr. Replace the injector and fpr that I took off and cranked engine injectors squirted.Spark at all cylinders.
    Turn key pump primes for the 2 sec but dont hear it while cranking.No security light staying on. Flashes and goes out.Although when I hooked up the second battery in engine compartment the alarm was going off.Horn wire was cut.Info on that was that it went off and she had someone pull bat conections and cut horn wires.This was in between when i gave the rig back engine r&r and oil leak.But the rig ran great that way when i delivered after leak fix.Also alarm system is aftermarket. No key fob working.

    So cranks and sometimes kicks back. If i put starter fluid in plenum it back fires.

    Help! Thanks

  2. #2


    Were all the parts you used AC Delco or just store brand like Dorman? You would be surprised that a GM truck will not like non GM parts and stop working right. I was helping a guy yesterday with a starting issue and just replacing his aftermarket plugs with AC Delco plugs fixed it. AC Delco parts are high quality and cheap if bought from amazon.

    Also are any code popping up? Is this a Suburban 2500 and what drive 4x4 or 4x2? I will assume it is a 4L80e because that's what the 7.4 needs.

    - - - Updated - - -

    Also just one sensor not being hooked up right can cause the truck not to start. I would reinspect every connection to make sure they are all sound.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

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  3. #3


    This thing have an aftermarket security system? If so, I would bet on that causing the problem. We don't even work on vehicles with aftermarket security systems, car dealer remote kill systems or state installed breathalyzer devices specifically for this reason.
    "It went together didn't it? Well then there has to be a way to take it apart!" - Me.

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