jska

Update #2 -- Problem SOLVED! Check bottom post.

My trusty 94' PU (5speed, 115k) left me stranded on the side of the road for the first time yesterday (on my way to my first day at a new job to boot!)

Coming off an exit ramp my RPMs became erratic, jumping from 2k, down to 0, back to 2k, til the truck finally lost all power.

It turns over fine, but doesn't start. Here's a video I took of it in the driveway after it got towed home:

http://www.youtube.com/watch?v=QpLIhe1vYEM

There's an exhaust leak, by the way. Got the new muffler sitting in the garage.



Fuel starvation? UPDATE: Probably air starvation, see last post.


Before I took this video, I got it to start up for 2-3 seconds, then it died. I tried to do the fuel pump jumper trick with the paperclip at the diagnostics box on the passengers side engine bay, but my diagnostic box is all crudded up, and I couldn't get the paper clip all the way in the terminals to make contact.

Also checked the 15a + 7.5a EFI fuses, both look fine.

By chance, I have a new fuel filter on the way for regular maintenance. I hope it's just that all clogged up, don't wanna drop the tank to fiddle with the fuel pump.

Any/all help or advice appreciated.

WagonDude

That's what it sounds like to me. If the fuel filter doesn't fix it, then check the fuel lines. The fuel pump is another thing to test, but that would be the last thing I'd check. Muffler shouldn't have any effect on starting, unless it's really plugged up.

drmix

Whens the last time you replaced the fuel filter?

Have you tried checking for codes?

Could your timing belt have jumped a tooth?

jska

Fuel filter is the same one that has been in the truck since the day I bought it at 98k -- so it has a minimum of 17k on it.

Codes -- it's not throwing a check engine light? Perhaps there are other codes I should be looking for?

Can't comment on whether the timing belt jumped or not -- haven't heard of such a thing so I wouldn't know how to diagnose it.

Thanks for your tips.

combatcarl

22re, so chain, no timing belt. Still slightly possible it jumped timing, but it sounds like a fueling issue. Did you pull dist cap and see if the rotor is pointing to the right spot with number 1 at TDC?

jska

I knew it was a timing chain, too.

Haven't pulled the dist cap, but I have a new one + rotor + plugs + wires that I was planning to do anyways, so after I change the fuel filter -- if that doesn't work -- I'll check the cap and report back.

Forgive my lack of knowledge here -- but how do I make sure the engine is at TDC?

Mandy Tuning

rpms bouncing from 2k to 0 have nothing to do with fuel. did you have a constant spark out of the coil? if you spray starting fluid or carb cleaner to the intake engine runs?

jska

RPM's bouncing from 2k to 0 happened real quick, over the course of 2-3 seconds -- it was as if the engine was dying then coming back on, then dying again, real quick. That could be fuel starvation, right? Gummed up fuel filter on its last legs letting out just a small amount of fuel.

Heading out to the truck now and replacing my fuel filter, cap, rotor, plugs and wires.

Will report back.

OverTheEdge

Yep, sounds like a fuel issue to me as well. However, I have had more than, who knows how many, cranks but wont start vehicals come in on a hook that sound similar. Most turn out to be a fuel delivery problem but many lead to ECM, coil, etc. Even had more than one over the years that the customer believed they were rolling with a 1/4 tank when infact they were on E. (I/P cluster/sending unit, etc). Keep it simple and start with the basics. Good luck!

jska

Figured I'd update again before I go further. Just went out to the truck and tried cranking it since it's been sitting for a few days. The truck tried to start, and then I was greeted by a loud POOF and a bunch of white smoke from under the hood.

Popped the hood and the smoke was coming from the air filter, took the filter off and there was a pool of smoke below the filter.

This could be unrelated -- but any ideas?

combatcarl

Dunno about the poof and smoke...that's um..different? But for TDC, rotate engine by hand, (socket on crank pulley nut) until timing mark is on 0. Verify its actually at top by using dowel to touch top of piston, then remove disty cap and make sure rotor points at about 10 o'clock-ish. If ya have FSM links or chilton's type book, it'll have the steps there, too.

Mandy Tuning

again, your puff was a backfire, some kind ignition problems.a fuel starvation will not bounce your rpms so fast in so little time,fuel starv will bog your engine.just throw some fuel on the intake and see if it runs for a few seconds or your backfire is bigger LOL. put a timing light and see where your timing is when cranking,i wish your where near of me i like to troubleshoot.

jska

Thanks for the TDC info. This all involves pulling the valve cover, right? I'm starting to doubt that this is a timing issue though.

I'm now thinking that it's air starved, and not fuel starved.

Took the air filter out and tried briefly starting the truck. Started up and idled this time, but bogged and died when I gave it gas. Got another poof of smoke from the air box.

After that poof of smoke, I started disassembling the airbox/intake to take a peak inside, and pulled the tubes off from the intake manifold. Full of white smoke.

I'm thinking this is the problem. I disconnected the coolant overflow to try to disassemble the lower airbox to check for clogs, and the head of the bolt torqued right off.

Anyways -- where should I check for clogs? They would have to be before the air filter. Any idea what is causing the white smoke?

Thanks a million.

jska

See my other posts -- After I took off the air filter, it idled for about three seconds, but it bogged and died when I gave it gas.

Had a bigger puff of smoke that time, too.

Wish you were closer too! I'm in MA, by the way.

andrewflores17

same thing happend to me after i got it home couldnt figure it unscrewed the gas cap and it was like it never happend been two months since that happend to me

TNRabbit

Have you checked for engine codes. That's always the first thing you should do.

Did you done anything under the hood in the past few days before this happened?

A backfire is normally caused by valve timing or ignition timing.

jska

Haven't checked for engine codes -- no check engine light though?

I'll look up a procedure for doing so.

Nothing done under the hood recently. Did a little mudding a week ago, but ran fine in between then and now.

WagonDude

Back fire can also be caused by sticky valves. Some Seafoam should take care of that, if you can keep it running long enough for it to get from the gas tank to the engine. 5-10 minuets should be long enough for that.

jska

Problem solved!

I was waiting on my fuel filter to come in, and to borrow a breaker bar to get my wheels off so I decided to do the long overdue tuneup that I had the parts for:

Replaced the air filter, plugs, wires, cap and rotor. Plugs 2, 3, and 4 came out easy, but plug #1 required WAY TOO MUCH force. By the time I got it out, with the help of PB Blaster and a 1/2" wrench, I figured I'd have to retap the spark plug hole. Anyways -- here's what my plugs looked like:



Plug #1 is on the right. Bought this truck 15k ago, should have tuned it up right away. The rotor was pretty bad, too.

Anyways -- truck started right up after all the new parts went in! Even though the spark plugs were awful, and all had different gaps, the truck still ran decent before. Not sure why it just randomly died one day after running at least 15,000 miles like this. Lesson learned either way.

Thanks for everyones suggestions and help!

andrewflores17

isnt it amazing how its always the simple little things that can cause the bigest poblem