PearlWhiteGT

Posting this for a friend....[/align][/align]92 Ford Mustang 5.0, ~125K on the clock, pretty stock (just full exhaust and a 50 shot).

Crusing on the freeway, heard a loud bang/pop, backfire and flames out of the exhaust and then shut down.

The car wont start. New coil, the ignition module checked out ok, timing is dead on, distributer is working, no broken plugs or wires. The plugs look to be normal, no weird material or not burned up or anything. The car cranks over and if weturn the distributer around, it barely idles very roughly - popping and backfiring, sounding pretty nasty.

Figured the timing chain skipped a tooth, threw off the timing. Tore it down, the chain is fine, what seems to be normal play, timing is DEAD ON.

SOOOO, what the hell coud it be?? Theres no loud clatter or anything when we get the car barely idleing, but we can barely get it to run if at all. No broken/damaged plugs, no water in the oil, has compression in all cylinders (dont know how much yet, but it does have what seems to be pretty strong compression in all cylinders). Any help will be appreciated.

Im thinking its something in the head/valvetrain, especially since it seems to be a timing issue and we've checked all the external stuff and the timing chain. Id like to have an idea on whats wrong before we tear into this thing.

Let me know what you guys thing, thanks.[/align]

mjr46

?????? MAN I sure hope you didn't do all that work without performing simple troubleshooting procedures like check for spark??? strength of spark?? fuel pressure check (and for crap sake don't tell me you pushed the schredor valve and fuel came out so you know fuel pressure/volume is fine[&:]) need to put a gauge on it......check your basics first before tearing motor apart.....you only tear the motor apart once you confirm or surely suspect a internal issue......For sure your timing is now off and did you remove the spout connector to set base timing first after reinstall?? you could have a ignition issue....lightly mist the wires with water and look for spark arcing check cap and rotor and mist coil if it's cracked it'll jump spark out or ground out. also try unplugging the mass air meter and try to start it...if that crapped out it'll really screw the cars load value calculations up for air fuel mixture.

PearlWhiteGT

He said that he didn't have spark until he started to rotate the distributer about 180 degrees & it started & ran but it was ruuning very rough & was popping, backfiring & just sounded very bad. I'm not sure if has checked foe fuel pressure yet but I will let him know.

mjr46

did he check to see if the roll pin was sheared on the end of the dizzy shaft gear??? if so better replace the oil pump[:@]

MEM 302 5.0L

Mine would barely idle awhile back when it was just my MAF sensor.....doubt thats the case now...haha'

could be more than one thing...

WhiteWindsor

If you havn't pulled the distributor, do that and make sure thereis no damage to the gear.

PearlWhiteGT

He said he pulled the distributer & it looked fine.

mattdel

uhh...
hmm..

well if you really have checked all that stuff, then its gotta be a valvetrain issue.