97 jimmy 4x4 edi ignition 176000 miles . car has driven fine for over a month. had the vehicle out around 35 mph just dies. so i tow it home.

when its cranking itl just stop. with the hood up i can hear it backfireing which explains that.

no codes. my scanner sees rpms when it cranks, i have spark, and ignition control module tests out with a test light.

cap and rotor are 2 months old and show no signs of advanced wear. plugs look good and are 5000 miles old same with wires. rotor turns when cranked.

adding any type of fuel or starting fluid just gives a bigger back fire.

im thinking my timing chain jumped but im open to some alternate ideas.



ive heard no mechanical noises(valves hitting) and have had no warning signs.was getting great gas milage also.

anything else i should look for or do to prove or disprove?

just to be clear, it makes no attempt to turn over. just cranks and stops cranking do to a backfire.

 

Maybe your ignition timing. If you got time you can always check to see if it jumped a link

 

i did a quick check but im not going with the results yet. im not sure if i was on the compression stroke of number 1. il have help on sunday to verify that. but rotor was pointing at six with the damper marks in place.

what electrical can get that out of whack that woulndnt through a code?

 

when my fuel pump was bad/weak it did this.

 

it would crank and backfire? any time ive had a bad fuel pump i can usally get it to try to start with starter fluid. now i just get a bigger back fire?

 

mine wasnt dead,it was just super weak. i would feather the throttle and it would backfire. Now im thinking about it,i do remember the timing was a little off. Maybe that was the main issue.

 

ya, i get no sign of life. after i can verify timing chain is still good im just going to pay the 80.00 bucks for a dealer diagnoses. dont just want to through money at every sensor

 

got it. after verifing everything. my 5000 mile old cap was shot. replaced cap and up and running.