Impossible idle and spewing gas, Need help from the V8 guys Options

[John G]

OK guys, I'm mechanically challenged but willing to learn.

My wife's V6 car (chevy 4.3L V6) starts, but sputters and blows smoke. I can keep it running for a minute or so, but it's idling very rough, smoking, and acting like it's misfiring.

There's a lot of moisture blasting out the exhaust pipes, and the moisture smells like gas (though could be exhaust).

The car was running fine until a few days ago, when it would not start suddenly.

I did kick out all the fuses by accident when I was getting out of the car to troubleshoot the starting prob, but I think I got them all back into the right spot.

Any ideas?

Thanks mucho,

John

[SpecialK]

Black, blue, or white smoke coming out the tailpipe?

[John G]

Black, blue, or white smoke coming out the tailpipe?

More of a gray color, so I would opt for blue. Not black, not white.

Here's a pic of the garage floor directly below one of my tailpipes after the wet puddle dried up. (IMG:style_emoticons/default/barf.gif)

[SpecialK]

Hmmmm....Pull the plugs, and see what they look like (meaning: oily wet, wet smelling like gas, etc). Did this happen all of the sudden? Or has it been running crappier, and crappier over a period of time?

Here's the basic smoke color breakdown:

Black = running rich....injector stuck open, plug(s) not firing, bad plug wire, or anything "gone south" in the ignition.

Blue = oil getting into the combustion chamber....something mechanical worn/broken, i.e. worn valve guides, stuck/broken ring(s).

White = Coolant getting into the combustion chamber via cracked head, blown head gasket, warped head from overheating. Pull the radiator cap and check for oil (floaties) in the coolant.

The crap left on the floor might just be carbon deposits from the exhaust pipe washed out "hopefully" from a super-rich condition.....Blue or white smoke are usually bad news.

Start with the simple/cheap stuff.

[John G]

SpecialK

Thanks for the quick reply!

This happened all of a sudden.

The car did overheat recently about a week ago. The PO didn't have a coolant overflow bottle, and it appears over a period of time the coolant leaked out. Hopefully we don't have anything cracked or warped. As you suggest, I'll check the plugs.

That smoke list is great and very helpful to a pathetic noob like me. :-)

John

[SpecialK]

If you get a chance, throw a couple of pics of the plugs on the board when you get them out. Plugs can tell a lot about what's going on with it......keep track of which plug came from which cylinder to help pin point the trouble.

Good luck!

[John G]

Dang... the fun continues.

OK, here's a pic of one of the plugs. Sucker SNAPPED OFF when I took it out.

Other than the fact that it is BROKEN, let me know what you think of the plug itself.

I checked the coolant, and no floaties or evidence of oil.

Think I should try replacing the plugs and plug wires next?

John

[John G]

If you get a chance, throw a couple of pics of the plugs on the board when you get them out. Plugs can tell a lot about what's going on with it......keep track of which plug came from which cylinder to help pin point the trouble.

Good luck!

Thanks, Kevin. Not sure how to tell which cylinder number is which. The one I've removed and pic'd above came from the center position on the driver's side (chevy 4.3L 6).

I can take them all out and post pics if that would help, and label them accodingly.

John

[LS6/914]

AHHH yes the number 3 plug. Its going to break, steering shaft binds against the plug socket. During my years at the dealership I used a short socket with a 5/8 head and a short 5/8 open wrench. Socket from Matco tools. As far as the no idle concern it is VERY common for the 4.3 central injected motor to stick the EGR valve open due to a hunk of carbon or binding shaft. The valve can be removed fairly easily with a 1/4 drive 10mm wobbly on a LONG extension. Look for a chunk of carbon holding the pintle open. This will cause a false MAP signal to the ECM, thus a overfuel condition. A updated EGR valve gasket with a mesh grid is available. Good luck Lar (IMG:style_emoticons/default/beer3.gif)

[LS6/914]

OOPPPSSS I spoke before confirming make model year. Sorry Lar

[John G]

OOPPPSSS I spoke before confirming make model year. Sorry Lar

Thanks, Lar. Unfortunately, the PO installed the motor, so I am not sure of the model year. Any place to pull that off the motor itself that might help? the car, of course, is a 73 914. (IMG:style_emoticons/default/biggrin.gif)

The motor is carb'd. I can provide a pic so you can see the setup if that would help.

I will buy a Haynes manual for this particular motor, if available, to help me find the EGR valve. I'm a real dunce when it comes to this kind of stuff, but I am not afraid to dive in if necessary. The only way to learn, I guess!

Where is the best place to buy the updated EGR valve, and what kind of info would the parts place need to get me the right item?

Thank you for the idea!

John

[SpecialK]

Definitely a little sooty looking (carbon fouled), it should have a light tan color to it if all was working correctly. If the rest look similar, you might try going to a hotter plug, but I kind of doubt that's the problem. You're looking for one or more plugs that look significantly different from the rest. Did you ever find out what caused the car to overheat? Got any friends that have a compression tester (for checking/comparing cylinder pressures when the engine is cranked over)? That'd be my next test while the plugs are out. Depending on the cars mileage, I'm guessing that 150 to 160 psi would be good. It's not really the pressure, but that the cylinders are all close to the same pressure (give or take 10%). One or more significantly low pressures will mean the heads will be coming off.....might be more than you're willing to tackle. If all of the pressures are relatively close to one another (crossed fingers), I'd check the fuel pressure (also requiring a gauge) to insure that the fuel pressure regulator is functioning correctly (check the manual for the correct pressure). If the fuel pressure is correct, it's time to insure that the cap (a hairline crack can cause all kinds of rough running), rotor, and plug wires are good. It looks like you'll be replacing the plugs anyway...if in doubt about any of the ignition components, replace them.

Does it have MPFI (one injector per cylinder), or TBI (kind of an electric carb type deal)?

Well, there's a bunch of stuff for you to check, and I need to get my ass in bed, but I'll be watching your thread.

P.S. - Just about all of the gauges (fuel pressure, compression tester) can be rented/borrowed from AutoZone, or whatever FLAPS is near you.

[LS6/914]

Sorry again, The info I gave would be for a 93 to 03 chevy or gmc 4.3 with fuel injection. (IMG:style_emoticons/default/headbang.gif)

[SpecialK]

Crap!...I was so busy writing, I missed what vehicle the engine was in (for some reason I was thinking "the family sedan", not 914 (IMG:style_emoticons/default/slap.gif) ). Ignore all of the FI crap I brought up.....except for the fuel pressure, no more that 4-5psi for a carb.

Good point on the EGR LS6! (IMG:style_emoticons/default/beerchug.gif) Didn't think of that one.......bedtime for me!

[andys]

John,

I'd suggest starting with the basics; from easiest to most difficult.
Did the fuse panel you kicked cause damage/shorts?
Plug wires all connected? Broken plug wire(s). Spark? HEI, or? Yup, read all the plugs; that one plug looks pretty darned rich; at least in the pic.
Stuck float? This can easily cause a very excessive (and possibly sudden) rich condition. Excessive fuel pressure (though not likely, since I assume it's the same pump)?
Compression test. Blown head gasket? Etc......

Anyway, that's the idea.

Andys

[914fan]

grey smoke is fuel. The fact that there was a puddle tells me water. You said you overheated a week ago. I'm thinking 1 cylinder is getting coolent and screwing with everything else. I hope I'm wrong and its just bad gas.....

[GWN7]

Did you ever find out what caused the car to overheat?

Mine would do the same till I added the overflow tank. It spits a ounce or two on shutdown out the overflow. Over time this adds up and causes overheating.

Not having oil in the water still dosen't mean that a head gasket is not leaking. Check the water level. If it's dropped...problems. You can check if it's water by cranking the engine over with all the plugs out (pull the coil wire). If you have a leak into the cyl the water will leak in and be pushed out when your cranking it over. If this is the problem it will also be part of the cause of the overheating. The leaking cyl preassurizes the coolant system forcing more water out when the car is running.

[sixnotfour]

The motor is carb'd. I can provide a pic so you can see the setup if that would help.

ya that would help
choke stuck? manual or electric type choke ?

[John G]

Update:

I had a mechanic friend of mine come over for a quick look, and we quickly discovered that the carb is dripping gas.

Looks like a serious flooding problem with the carb. Possibly a stuck float or problem with the needle.

Since I'm a complete mechanical doofus, I think I'm going to just tow the car in and have the carb rebuilt (or take the carb off and take it in somewhere.

FYI, the carb is an Edelbrock (Weber) performance series 1406 with (I believe) electric choke.

I can't wait to get this sucka fixed so I can drive it again! (IMG:style_emoticons/default/sad.gif)

John

[GWN7]

Update:

I had a mechanic friend of mine come over for a quick look, and we quickly discovered that the carb is dripping gas.

Looks like a serious flooding problem with the carb. Possibly a stuck float or problem with the needle.

Since I'm a complete mechanical doofus, I think I'm going to just tow the car in and have the carb rebuilt (or take the carb off and take it in somewhere.

FYI, the carb is an Edelbrock (Weber) performance series 1406 with (I believe) electric choke.

I can't wait to get this sucka fixed so I can drive it again! (IMG:style_emoticons/default/sad.gif)

John

Same carb I have on mine. If you need it, I have the Owners manual with the Calibration Reference Chart and the secondary metering, float adjustment, ect. I can scan and post...

* found it online @ http://www.edelbrock.com/automotive_new/mc...ners_manual.pdf

also here's a site for sparklug reading http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html