Cyclone Mechanics - Opinions Needed

[cstrunk]

Alright, so I have a '97 GMC pickup with the 5.7L engine. It has been running fine, until last week when I put a can of STP fuel injector cleaner in it. Almost right away, my engine began running worse. I figured it was due to a bunch of carbon crap getting spit out of it. The check engine soon light came on. I have been driving it, thinking it will eventually work itself through, but after a couple hundred miles (I drove home) it still doesn't run right and the check engine light is still on. The engine feels rough at idle and around 1500 rpm's. It also spits out black stuff out of the exhaust.

I have put in probably more than a tank's worth of fresh gas since this has started. My guess is that one or more of the injectors or spark plugs has a piece of gunk on them that is causing it to run bad. Any ideas on where I should go from here to get this resolved? I checked with my local mechanic and they are booked until next Tuesday.

Any help or information is appreciated... thanks. :sad:

 

[BugDoc]

Not that this helps much, but you could try Click and Clack this weekend from Cartalk. If nothing else, it will be a fun conversation.

 

[djcubby]

I would start by taking it to someplace like O'Reilly's. They should have a handheld computer that can pull the code for you as to why the 'Check Engine' light came on. That should give you a place to start.

 

[4429 mcc]

Sounds like the fuel filter.

Q: is it very sluggish during exceleration?


edit: black stuff out the exhaust sound more like oil is being burned off in your engine.

 

[cstrunk]

Thanks for the replies so far...

I also just go talking with a friend and we are going to drive it into town and see if our local O'Reilly's can scan it and give us any information. He also thought that if I unhooked my battery, it might reset my oxygen sensor and when I restarted the truck it might run differently and/or better. The black stuff shooting through the exhaust might be getting picked up by the 02 sensor and therefore changing the fuel mixture making it run differently.

I'm going to start there and see what I can find out.

 

[Stewo]

There is a good chance you fouled one or more plugs. If they are the stock plugs and you have higher miles, this would most likely be the case. You could also test this by starting the engine and giving her a few revs and smell for raw fuel. Fouled plug(s) will allow raw fuel to move through the engine and will get burned of in the catalytic converter giving you the black smoke. Oil will burn with a blueish tint.

 

[jumbopackage]

Fuel filter should probably be changed at any rate. It's not a bad job on that style truck. I think it's along the passenger side frame rail.

Other than that, it's either fuel or ignition. Fuel could be caused by a messed up sensor (likely an O2 sensor that got fouled from crap burning through it), or a plugged injector (you've got TBI injection on that guy I think, so there are just a couple of injectors in the throttle body as opposed to direct port into each cylinder).

Ignition is likely fouled plugs.

Or it could be a combination of both. Fouled up plugs could have put raw fuel through to the exhaust which could have messed up your O2 sensor.

Get it coded and see what it's thrown.

 

[tube1]

Perhaps you guys need a refresher course. It's all ball bearings now-a-days.

 

[usedcarguy]

Black smoke is fuel. Blue smoke is oil. Sounds like carbon wedged in a spark plug gap. I'd start there before I bunch of money elsewhere. Fuel filters are good to replace because most people forget about them. The result is burning up a $400 fuel pump which on that vehicle is inside the gas tank.

Regardless, I'd be giving Richard Petty a piece of my mind.........

 

[cstrunk]

Alright, my friend came over with an engine code reader and it spit out these codes:

P0300 - Random/multiple cylinder misfire detected

P0151 - O2 sensor circuit, low voltage, bank 2 sensor 1

P0151 - O2 sensor circuit, no activity detected, bank 2 sensor 1

P0174 - System too lean, bank 2

We then cleared these codes and took it out for a short spin. In a short time, the check engine light came back on and P0300 and P0151 codes came back.

What do you guys think?

 

[cstrunk]

Black smoke is fuel. Blue smoke is oil. Sounds like carbon wedged in a spark plug gap. I'd start there before I bunch of money elsewhere. Fuel filters are good to replace because most people forget about them. The result is burning up a $400 fuel pump which on that vehicle is inside the gas tank.

Regardless, I'd be giving Richard Petty a piece of my mind.........

The truck doesn't smoke, but spits out small pieces of black stuff that you can see plain as day on the snow where the truck sits for any period of time.

 

[chadm]

The truck doesn't smoke, but spits out small pieces of black stuff that you can see plain as day on the snow where the truck sits for any period of time.

If your friend can check the codes, I am sure you can pull the plugs and check them?

 

[cstrunk]

If your friend can check the codes, I am sure you can pull the plugs and check them?

Yeah I will be doing that probably when I get back from my short Christmas trip to see family. Should be able to do that on Friday. I'm wondering if I screwed up an O2 sensor... sure hope not.

 

[cstrunk]

Well I talked with my uncle who is a mechanic, he said it sounds like I screwed up an O2 sensor which is now making it run bad. Crap. I guess I will have to replace that and see what happens. I hope that fixes it.

 

[cstrunk]

In case anyone was still wondering... I ran a bottle of Seafoam through the truck to get more crap out, then replaced the faulty O2 sensor. Problem solved.... almost... the old O2 sensor was rusted in pretty well and removing it stripped the threads. I put the new one in halfway before it stripped again. I could not wiggle it at all at it's current state, so I just left it in. It works for now, should work as long as it does not fall out. At least I know what it is this time.

 

[Dave19642006]

I say change the plugs @ 1.59 a plug thats pretty cheap

 

[Lenny25]

I say change the plugs @ 1.59 a plug thats pretty cheap

Might be the fetzer valve or you might need a new Johnson rod.

 

[cowboycurtis]

Might be the fetzer valve or you might need a new Johnson rod.

it could be the blinker fluid or the carburetor chain. i would check that for sure. then get some new air for your tires. :wink:

 

[cyson]

muffler bearings