1997 Oldsmobile Bravada 4.3L Vortec engine

[screwhead]

My 1997 Oldsmobile Bravada 4.3L Vortec engine turns over but doesn't start...Fuel pressure reading 61psi when cranking, new battery, new battery screws, new distributor cap, rotor, ignition coil, plugs...intake manifold gasket, fuel pump and pressure regulator changed around 5 years ago...I am trying to get vehicle ready to sell but no luck...I had this problem a couple of weeks ago, got it running somehow, then let someone borrow the truck and it died and now its back in my driveway...hooked ground by from battery to ground wires by jumper cables to ensure proper grounding and no luck...i'm frustrated and angry...all i can think of is crank or cam sensor, ECM, or ignition module and of course a short in wiring somewhere...Please help!

[Chris Stewart]

Take the air cleaner duct off the throttle body, pour 2 tablespoons of gasoline into the throttle, reinstall the air cleaner duct then try to start the engine.
Post the results, I'll be here a while.

[screwhead]

I was hoping you would respond Chris...saw that you answered most other postings and had great results...battery is dead now so may take couple of minutes to repost

[screwhead]

still doesn't want to start Chris...battery seems to be sufficent to turn over motor...

[Chris Stewart]

Pull one sparkplug wire and put a known good sparkplug in it...lawnmower, whatever is easily available. Be sure it's grounded good the try to start and see if it sparks.

Is the Check Engine light on?

[screwhead]

I just installed Bosch Platinum Plus plugs earlier today to help fix it...I gapped to .060 and still nothing-haven't had it running in a while so i dont know if engine light was on...only light is on is the red battery light when ignition is on and when cranking...just hooked up spark tester and its showing spark...a small flash ever 2 seconds or so

[Chris Stewart]

Let the battery charge up a little while, pull a spark plug wire and put an old plug in it, make sure it's grounded then observe the spark while cranking the engine over.

[screwhead]

Ok...I was jumping it with my car throughout all the tests because battery is dead...gonna try and get a battery charger maybe tomorrow...Well, hopefully tomorrow will be better...Thanks for the help...May not post tomorrow because going out of town, but definitely monday...

[Chris Stewart]

That'll be fine. A poor battery kinds messes up things. The ignition system requires at least 7.5 VDC while everything else is on.

[screwhead]

Sorry...got back later than expected...Just got back with new battery starter and charger...Too late to test tonight...Tomorrow after work, I'll put it on the charger and begin troubleshooting....

[screwhead]

Got it charging now...Tried a known working plug...same results...looks a little faint to me, but there's spark...I used the charger in ENGINE START mode to test which delivers 275 amps...Gonna check again when battery is fully charged...about and hour more, but I think i'm gonna have the same results...any thing else i should try???

[Chris Stewart]

A weak spark points to a bad ignition coil and bad wires.
Since it's getting dark, have someone try to start the engine while you observe the coil and distributor cap wires....look for spark.

[screwhead]

Tried a used ignition coil...no luck...watched for spark around wires, cap, and coil...no luck...

[CutlassOlds88]

i had a very similar situation on my 98 Bravada. after i replaced the engine in it, it wouldn't start. plugs, wires, distributor, cam sensor, crank sensor, coil, ignition module, they were all new or taken from my old engine that spun a bearing but always started up. i tried every test in the service manual. for days i tested wires and replaced parts. i got it to start once, but the next day it wouldn't fire again. finally, i get sick of it and had the dealership tow it to their workshop. they worked on it for a couple of days and finally got it running good. it turned out that the electrical harness that goes to the ignition module was worn out. either a wire was broken in the connector or the wire was not making contact with the terminal on the ignition module. i would have never guessed that in a million years. make sure you check your electrical connections and make sure they are good.

[screwhead]

Thank you for the feedback Cutlassolds88...I disconnected all the connectors and reconnected them before but i really didn't inspect them. Now i will go back and inspect them. This truck is driving me crazy...