lilwhitesub

First off, I hope everyone is having a great weekend.


Now for the meat;


97 Suburban 4x4, 5.7 Vortec; 250k miles. Owned for over 10 years and have put in less then $1500 in repairs, 2 fuel pumps, water pump, alt, 2 sets of brakes, 2 sets of plugs, cap/wires ect... May have spent 100k on fuel, but that's all part of the fun


But my bragging rights have came to a screeching halt, as I have a feeling this repair may humble me a bit.


And so it began;
I work in the powersport field and for the past 6 years have been dumping gas from watercraft, sleds, 4-wheelers and old motorcycles into my Sub. Never really had any troubles, maybe a day or two of some pinging but always cleared up. About a month ago I put about 5 gal of some suspect fuel in, a few days later I ran into some mornings with rough idle. One morning a no start, gave her a spray of starting fluid and she came to life and was good for another week. Then the rough morning idles came back, every 3 days to every other till it was every day, then constantly rough, it never cleaned up. During this time I have filled the tank, about 40 gallons added at 10 gal a week.


Finally no matter what I did the truck would not run good, it ran starving for fuel, idled good but when gave throttle it would stumble. It drove but was not happy. Last Saturday I limped it to a friends shop, I couldn't make it home, 15 MPH top speed.


Fuel pressure tested 60 psi key on, 54 psi running, key off would hold pressure for an hour or so later would be at 30 psi. Anyways, thought maybe it was fuel related, drop the tank, clear the fuel and while I was in there I replaced the fuel pump/sock/filter. Fired it up, same thing, wont run worth a damn.


Looked over a few things, changed the plugs just because I'd never pull a plug without having a new one to put in. Everything was checking out, no leaks, nothing visual. Unplugged the MAF and the truck got worse.


Then I was thinking, "I'll just put more gas in it, maybe there is still something bad in there". Filled another 10 gal, limped it around a few back streets and it got better, not 100% but 85% at least. Drove it around about an hour and was doing good. I figure I'll add some more gas in the morning before work. The next morning, started, idled well, drove around about 30 minutes and then all of a sudden it started missing again. Stopped at a red light and thought it was going to die, then noticed the truck filling with smoke and the smell of gas. Uuugg, this is bad, white vapor was pouring out the exhaust like a concert smoke machine. Drove it about 10 miles like this to work, then 10 miles back home after work.


Didn't get better or worse, starts up, some times a bit of cranking, but starts and idles (rough). White smoke out the pipe, and a constant drip along with a bad gas smell.


Scanner hooked; bank 2 O2 sensor, nothing else.


Data; Bank 1 flickerd between LEAN/RICH, Bank 2 RICH, misfire #3 - #7


Going to dig more in tomorrow as I am finally off work. Unless told otherwise I plan to pull the intake and look for signs of raw fuel dripping somewhere. Inspect injectors...




Is it common for the injectors to go bad and have Lean running to flip to a overly rich running condition?


What does it sound like?

73shark

Welcome to the forum.

White smoke might indicate a bad head gasket. Try doing a compression test with the throttle wide open.

lilwhitesub

Its not coolant, no bubbling in the radiator, coolant level hasn't changed, smells like fuel. Liquid coming from the exhaust has a very low flash point, won't stay burning, but does flash over when putting a flame to it. No water in the oil.


Going to limp it over to a friends shop and going to tear into it.

73shark

Dirty injector maybe?

lilwhitesub

Well, found #3 injector was stuck open, replaced with a new injector and problem fixed. However I just hope I didn't hurt anything driving it like that, it had to have washed the cylinder. Changed oil, but it seems my oil pressure is down from where it was. about 25psi at idle and ~40psi under acceleration, ~30psi cruising.