Fouling spark plugs

[89sportside]

Hey guys, been a longtime lurker, this is my first post. Tonight after I get a photo I'll post on the new member board.



My 1989 Chevy K1500 5.7l 350 has been running great for 276000 miles now, but a couple of weeks ago I made the grave mistake of dropping it off with a shop for a brake job. When I got it back, it was running rough, smoking, and smelled like an ocean of gasoline. A quick check at my spark plugs revealed that the shop had taken them off and mixed them all up. Putting them back in their homes remedied my issue, but just to be sure i replaced the cap, rotor, plugs, and wires. Truck ran great for 3 days, then I started smelling fuel and the rough running came back. Pulled out my plugs and was disappointed to see my new NGK 2771's covered in black soot. Threw the old plugs back in and it ran good for about 10 minutes until it fouled them up and choked itself out.



My ignition and fuel system appear to be working fine and OBD through the ASDL doesn't throw any codes, except for a thermostat code about 20% of the time.



Anyone got any ideas where to look for this problem? Strange that I don't even get a code for running rich. Scared to take it back to a shop at this point.

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[shorepatrol]

They did a brake job and for no reason switch your plugs around? Am I reading that right?

 

[89sportside]

They did a brake job and for no reason switch your plugs around? Am I reading that right?

Yeah, that's about how I feel typing it. Apparently, they were having trouble starting it and called me saying they flooded the engine (yes, they flooded a TBI, you read that right too), so they spent two hours pulling the spark plugs to dry them off. But don't worry, they were only going to charge me for 30 minutes of it.

Needless to say they didn't get the money.

 

[GarrettGmc]

It be telling that shop to fix it. You drive it there running fine an get it back screwed up. They should be responsible for something they most likely caused

 

[shorepatrol]

It be telling that shop to fix it. You drive it there running fine an get it back screwed up. They should be responsible for something they most likely caused

Especially since they started ******* with things not related to the job you brought it in for. I'd be going high up that chain until I got it taken care of. That is inexcusable

 

[89sportside]

Well, here's the thing. Somebody was working on it the night before, and maybe they forgot to tighten the lugnuts all the way on when they were done. And maybe that somebody lost a wheel right in front of the shop , and when the drum hit the ground a lot of their brake parts went tumbling out.

The folks in the shop see the accident and run outside to jack me up and spare me a few lugnuts, so I start it up (without a hitch) and park it there to leave it with them to repair the brakes. Well, the next morning they call me and say they can't start it up to get it into the shop. It had never had any problem starting before, and since then the problem has got worse.

Obviously them screwing up my spark plugs didn't help the issue, but is there a chance the impact of the drum hitting the road knocked something loose and that's causing my fuel problem?

 

[GarrettGmc]

I would doubt it but I've got the front wheels off the ground out muddingonce and had some loose connections.

 

[jsnow36318]

If your thermostat is stuck open running your engine cold it will run rich and fowl your plugs.
But if its hard starting after sitting your fuel system is bleeding down. May be time for a new pump/filter, FPR, leaky injectors, all sorts of things. Could also be your ignition coil failing

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[89sportside]

I'm expecting my new thermostat to show up Monday, so I'll be sure to mention how that goes. I have read about the thermostat being open causing a richer fuel mix, but it does hard start after sitting. When I coax it into running, it backfires and runs rough when idling and even more when under a load. I have ruled out the injectors leaking, and the fuel and air filters are brand new. From what I can tell (which isn't much) the fuel is coming out of the injectors normally, besides the pressure seeming fairly erratic.

Another thing I noticed today is a buzzing, electrical short sound coming from near my throttle body. Makes me wonder if my electronics are the suspect...

Any tips on how I can narrow down the possibilities?

 

[jsnow36318]

I'm expecting my new thermostat to show up Monday, so I'll be sure to mention how that goes. I have read about the thermostat being open causing a richer fuel mix, but it does hard start after sitting. When I coax it into running, it backfires and runs rough when idling and even more when under a load. I have ruled out the injectors leaking, and the fuel and air filters are brand new. From what I can tell (which isn't much) the fuel is coming out of the injectors normally, besides the pressure seeming fairly erratic.

Another thing I noticed today is a buzzing, electrical short sound coming from near my throttle body. Makes me wonder if my electronics are the suspect...

Any tips on how I can narrow down the possibilities?

My first test would be to check the ignition system. My 98 chevy ran like **** because the spark plug wires were all leaking. Smelled rich. Burned the paint off my cherry bombs. Open the hood in the dark and Have someone put it in gear and hold the brake and look for sparks. Check your rotor and cap for wear or moisture water in the cap will cause a no start/long crank


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