HELP Dead Ex...

[pope_face]

Alright, I never thought I'd have to make one of these threads, but here I am...

My truck has been running a little rough the past couple weeks. It wasn't getting all the power it used to, but it was only a subtle difference. Two weekends ago, I was driving up a slight incline when I noticed that it started losing a lot of power... I would press on the accelerator (I was at a stop light) and the engine would continue to idle for a second before revving up. I drove about two blocks and noticed that my idle had come down to only about 500 RPM. I tried revving the car a couple times, and each time it would bog and almost sputter. I could also smell a bit of exhaust inside the cabin, and it smelt like I was burning something, potentially oil. I checked the engine and everything seemed fairly normal... oil level was fine, all the other fluids seemed good. I restarted the car, revved a couple times, and noticed that there was black smoke coming out the exhaust under hard acceleration. I did it a couple more times, and eventually the smoke cleared and the idle returned.

Now, this happened on and off for the past couple weeks... black smoke under heavy acceleration, bogging, rough idle (As if it was missing a cylinder)... Normally I've got a bit of vibration in the transfer case shifter, but a couple times the engine was running so roughly the 4by shifter was shaking side to side about a good half inch in each direction, if not more... more than enough to be noticable.

Now, last night I went to see a movie... After the movie, I went down to the underground parking lot to leave. I got in the car, started cranking the engine, and it didn't catch. I continued to try a few times, and eventually I could smell unburnt gas in the cabin. It did catch a couple times, but proceeded to run extremely hard, with a very low idle, and die within a few seconds. A couple times during cranking the engine completely stopped, no sound coming from the engine, as if it just couldn't turn over, but a second later it would start turning over again. I figured I'd flooded the engine compartment, so I looked under the hood. On one of the vacuum hookups (I think) on the driver's side at the very back of the intake there appeared to be a steady drip of gas... it was coming out fairly quickly. I took off the intake tubing connecting to the TB to try to give it some air directly to lean out the mixture, and I could get it to start and catch long enough to go to the front and open the butterfly valve, at which point the engine caught, ran strongly, and then died as soon as I let off the valve. I took the little rubber nub off the vacuum plug and noticed it was cracked in half... I tried taping it shut just so I could get home, but as I was putting it back on it slipped and fell into the depths of the engine. So, I took a piece of tape and just temporarily taped over the vacuum plug. I started the engine, and it ran, albeit rough. I pulled the butterfly valve, it revved, and then next thing I know I heard a "pop", the engine died, and smoke started coming out through the intake tubing where it connects to the TB... I think it was coming from the crankcase breather hose that connects to the intake tubing.

Now, I've switched to full synthetic back in about Feb. The truck has about 150,000 km (93,000 miles?) on it, and I have what appears to be a bit of a valve tick. I also have some oil on the outside of the engine block, so it appears to be leaking, although I can only tell when I'm underneath the truck, so I'm not sure where it could be coming from.

Now, does ANYONE know what the problem could be? I don't know when the fuel filter or the spark plugs and wires have last been changed, and so I've intended on doing that for a while... hopefully if it's that it hasn't ####ed anything else up. Other than that... I don't know what to tell you. If anyone has any idea what it possibly could be, I'll check it out... I just need the truck for work as soon as possible, otherwise it's time to buy another truck (which is a last resort).

Thanks...

 

[budwich]

The "pop" that you heard might have been a backfire. Pull your plugs and see if they are all the "same" in appearance.... might give you a clue as to a misfire and dead cylinder. Do a compression test on all cylinders. Check your fuel pressure (with a gauge).

 

[410Fortune]

sounds like you have a few things to check

first fix your vacuum line problems
next check the fuel pressure regulator vacuum line for gas.
If there is gas you need a new pressure regulator
After that I would check the fuel rail pressure

Sounds like your FPR is on its way out, also sounds like a possible weak fuel pump.
I would suspect they both may need to be replaced.

Fuel pressure test is what I recommend

 

[pope_face]

Alright, I pulled all the plugs to check them... they were all black. A couple were in slightly better shape, but they were definately dead. I replaced them with new ones, and I've checked to see if they're all getting spark... as far as I can tell, they are. I've also replaced the cap on the vacuum line, so those two issues should be good.

Now, I don't think it's a weak fuel pump as I'm getting gas... in fact, I think the engine is drowning. When I remove the cap from the vacuum line (not sure which one it is) gas starts coming out... I've got the intake piping off the TB, and I've got a little pool of gas sitting just in front of the butterfly valve, which is completely closed with the car off and foot off the gas. When I try cranking the engine, it'll crank, then sort of "thud" to a halt, as if there's too much pressure in the cylinders, and then slowly start turning over again. Also, after I try cranking it a couple times, if I open the butterfly valve in the TB I get a little stream of gas coming out. I tried cranking the engine with the number six spark plug removed (to check for spark on it), and gas sprayed out from the spark plug hole and partially cleared the driver's side fender.

So, from what I can tell, the electrical is alright, but it might be the FPR... I assume it redirects excess gas back to the tank, correct? I had to tow the truck last night, so it's sitting in my backyard, and I can't exactly afford to tow it to a shop and pay them to fix it unless I have to, so a compression test and fuel pressure test is pretty much out of the question for now...

Thanks again...

 

[pope_face]

Six spark plugs: $16.
Vacuum hose cap: $4.
Fuel Pressure Regulator: $116.

Having a running truck: Priceless


Thanks for the help with the FPR... I never would have figured it out myself... however, it's still running a little rough. The idle seems a bit low (about 6/700 RPM) and there is a lot of vibration. I think it's not firing on all cylinders, although the spark plugs appear to be getting power, so I'm not quite sure what it is. After replacing the FPR the car started fine, and it spewed a bit of white smoke for a while, but that cleared up. I ended up pulling the vacuum cap off that I'd replaced, and the idle jumped to about 1500 RPM, but it ran a lot smoother... almost no vibration, and no smoke. If I replaced the cap, it would die, but when I started it up again the idle was low again, and there was a little bit of smoke. At the moment, I've got a little hole cut in the vacuum cap to allow a little more air through, so it's idling a lot smoother and at about 900 RPM, with no smoke. Anyone have any ideas what could be causing it to (potentially) not fire on all cylinders and have a low idle?

 

[budwich]

change your oil.... flooding may have caused it to lose viscosity. also sounds like your idle control valve (or equivalent) might need cleaning.

 

[pope_face]

Alright I checked the Idle Air Control (IAC) valve, and I'm getting about 10 ohms resistance across the terminal, like the Hayne's suggests, but only about 2 volts across the wires with the ignition on, engine off... Hayne's says 10.5 to 12.5 volts... I suppose that means that the IAC is good, but it's suggesting the PCM is bad...

But, maybe I'll just remove and clean the IAC and see if that helps...