HELP!!! wont start

97 gmc z71 k 1500 4x4 5.7 4l60e-- rebuilt the tranny got it installed-- when I took out the tranny the 2 wiring harnesses that go to the neutral safety switch(nss) were glued in-- upon removal I broke the NSS -- bought a new one--- but now the 2 harnesses wont make a good connection (the harnesses barley make a connection)
Would that stop the vehicle from starting?? THe nss itself??
- now that is out of the way--
Started up the truck last night, it ran like a champ. -- But one other thing-- the exhaust on the passenger side cracked just past the manifold at the donut connection. There is an o2 sensor right past the broken area -- tried starting it but all the plugs were covered in fuel-- pulled all the plugs cleaned them up- checked for spark-- everything got spark. Thought that the o2 sensor was telling the "injectors too much air --add fuel" while engine is being cranked over -- maybe that is why the plugs fouled. Fixed that area of exhaust that was damaged but still the vehicle will crank quick as it should and seems like it wants to start but not strong enough to start. I NEED HELP HERE IAM AT A LOSS AND CONFUSED!!!!

First problem, NSS was probably not glued in but rather the heat of the tranny fused them in, dealer should have or be able to order new connectors, there is a TSB. The NSS could prevent the starter from turning. On startup the PCM should be in open loop mode(preprogrammed fuel/air ratio), not dependant on O2 sensor readings, I would fix the exhaust, it probably will affect mileage during closed loop operation and may set a lean code eventually and the excess fuel may destroy a cat converter(nevermind, see you posted that you fixed).

Do a fuel pressure test, 60-66psi with key on and engine off, the pressure should stay steady after the fuel pump quits. If the pressure drops quickly(or if you can see or smell in the throttle body)you may need a new fuel pressure regulator and/or injectors. The problem there is that it is about a 2 hour job just to remove and replace the upper intake manifold, which needs to be removed to access the injectors and pressure regulator. If you take off the upper intake manifold, the regulator is on the passenger side of the injector assembly. Look for clean areas of the intake as it should indicate fuel leaks inside the intake and if enough fuel puddled in there it could be the cause of your wet plugs

Thank you for the post-- I will try it once I can get a test guage-- Is that something you can pick up anywhere?? Also, do you test the fuel pressure at the line on the drivers side behind throttle body on the inline fuel lines-- do you hook up the tester to the connection that appears to be a tire nozzle (for lack of a better term) Thanks, Joe


First problem, NSS was probably not glued in but rather the heat of the tranny fused them in, dealer should have or be able to order new connectors, there is a TSB. The NSS could prevent the starter from turning. On startup the PCM should be in open loop mode(preprogrammed fuel/air ratio), not dependant on O2 sensor readings, I would fix the exhaust, it probably will affect mileage during closed loop operation and may set a lean code eventually and the excess fuel may destroy a cat converter(nevermind, see you posted that you fixed).

Do a fuel pressure test, 60-66psi with key on and engine off, the pressure should stay steady after the fuel pump quits. If the pressure drops quickly(or if you can see or smell in the throttle body)you may need a new fuel pressure regulator and/or injectors. The problem there is that it is about a 2 hour job just to remove and replace the upper intake manifold, which needs to be removed to access the injectors and pressure regulator. If you take off the upper intake manifold, the regulator is on the passenger side of the injector assembly. Look for clean areas of the intake as it should indicate fuel leaks inside the intake and if enough fuel puddled in there it could be the cause of your wet plugs

Should be able to get tester at any auto parts, make sure the dial is rated for at least 66 psi and it hooks up to the large tire nozzle(actually called a schrader valve) near the throttle body

I never got a tester-- friend that has one wasnt available and I wasnt about to spend 45.00 on it-- if I could borrow one-- So to continue working on vehicle I changed the fuel filter -- that wasnt it-- so then I tore apart the upper manifold to get to the fuel pressure regulator and the injectors-- cleaned all of the carbon and built up gunk out of everything I could reach including cleaning the intake where the injectors go into w/a q-tip-- put it all back together and I'll be damned she started ON THE FIRST CRANK!!!!!!!!! YEAH SATISFACTION FINNALLY!!!!!!!! Now have to test drive make sure she shifts fine!!! Thank you Jeremy for your suggestions!!!!! YOU ROCK!!!!!!!!


Should be able to get tester at any auto parts, make sure the dial is rated for at least 66 psi and it hooks up to the large tire nozzle(actually called a schrader valve) near the throttle body