'96 Tahoe- No start, only backfires

[kevin2294]

Parked in on Friday, Monday it wouldn't start. Sometimes it backfires. If i use starting fluid it backfires big time!, smells like theirs fuel, and i pulled a plug, getting spark.

I already replaced the cam position sensor, that was a waste of $25.

Any idea's? there's no codes in the computer.

[j cAT]

Originally Posted by kevin2294

Parked in on Friday, Monday it wouldn't start. Sometimes it backfires. If i use starting fluid it backfires big time!, smells like theirs fuel, and i pulled a plug, getting spark.

I already replaced the cam position sensor, that was a waste of $25.

Any idea's? there's no codes in the computer.

when using starter fluid only spray 2 seconds if too much you can blow up your engine. first is the fuel pump running have someone turn key to ignition not start listen next to fuel tank for a whining sound if no sound for two seconds recycle ignition on again and hit the forward 1/3 of tank with a moderate slap if it starts then you know pump is going hopefully you won't need tow to repair shop. if it still don't run check fuses esp f/p fuse and if you want to guess but new f/p relay. fuel filter could be problem but to suddenly die is not the norm....happy hunting

[kevin2294]

Yeah the fuel pumps runs, i'm getting fuel, If it were only a fuel delivery problem i can make the truck run on starting fluid or propane.

I don't think that's it, it's not sparking all the time and when it does it's at the wrong time.

I going to try the crank position sensor next @ $75

[kevin2294]

OK i bought the crank position sensor and put that in, not change.

I also got a fuel injection presure gauge. hooked that up, get 65 PSI for 3 secs. then when the pump shuts off it drops to 55 psi, it does drop after that but very slowly.

sounds like it's backfireing,

Can anyone help?

[kevin2294]

Now I installed the ignition (spark) control module. Same problem.

Does anybody have experience with the ECC (engine control computer)?

[777stickman]

My experience with back firing has been either/or both ignition timing and valve timing. From your post to have this happen over a weekend of sitting, I would maybe look for a cracked dist cap or bad rotor. Other things could be a loose dist hold down clamp that allowed the dist to turn out of time or a timing chain that has slipped a gear or two. Another thing to check is freeplay in the rotor. You should not be able to move the rotor in either direction by hand (do not try to force it).

By the way, please tell us what motor.