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Sluggish then heavy black smoke from tailpipe?


dottnmd
06-30-2007, 07:45 PM
First I like to say Hi and I am so thankful for finding these forums. The mechanics are seeing less and less of our money.

We have a 94' S10 4.3 Votec. Every couple months it has a major breakdown. This time hubby was about a quarter of a mile from the house and he said he the truck got real sluggish and heavy black smoke started coming from the tailpipe. The truck has been parked once again for a few days and hubby has started it and the same heavy black smoke comes pouring out of the tailpipe.

From what I have read this usually means the truck is running rich. Can anyone inform us where to start first to find the problem?

Thanks
Dott

MT-2500
07-01-2007, 10:20 AM
First I like to say Hi and I am so thankful for finding these forums. The mechanics are seeing less and less of our money.

We have a 94' S10 4.3 Votec. Every couple months it has a major breakdown. This time hubby was about a quarter of a mile from the house and he said he the truck got real sluggish and heavy black smoke started coming from the tailpipe. The truck has been parked once again for a few days and hubby has started it and the same heavy black smoke comes pouring out of the tailpipe.

From what I have read this usually means the truck is running rich. Can anyone inform us where to start first to find the problem?

Thanks
Dott


Welcome to AF

Yes black smoke is a good indication it is running rich.
Any check engine lights or codes?
Can you smell raw gas?
Check map sensor and for good vacuum to it.

On big problem on that model is the fuel pressure regulator on the injector unit and the nut kit lines inside the upper intake.

You need to get a fuel pressure gauge on it and watch fuel pressure and check for a fast leak down on fuel pressure when engine is shut off.

If a fast pressure drop check for that pressure leak.

Post back fuel pressure readings and how fast pressure drops down.
MT

dottnmd
07-03-2007, 06:56 AM
MT,

No engine lights or blinking codes.
I din't really think to check for smells but will do this evening when DH gets home.
We changed the mapping sensor about a yr ago but I will have him check.

I need to get a hold of a fuel pressure guage to check. It may take a couple of days. I'll come back and let you know. Thank you for taking time to help. I'll let you know.

Dott

MT-2500
07-03-2007, 08:34 AM
You are welcome and let us know what you find.
MT

dottnmd
08-05-2007, 08:03 PM
MT,

I'm sorry I haven't been able to get back to you as fast as I should have. We have 3 vehicles and house repairs that are all going on at the same time.

We never did get a hold of a fuel pressure guage. DH and SIL just went ahead and and took the intake apart to see where the fuel smell was coming from. Here's what we found. The side where the Fuel Pressure Regulator is located in the intake is dry but the other side is just skirting out fuel all over the place.

old_master
08-05-2007, 09:30 PM
That would be the "nut Kit" MT was talking about that is leaking. It is available through any GM dealer. For the cost involved, it might be beneficial to replace the fuel pressure regulator as long as you're in there. After the leak is repaired, change the oil and filter. The excess fuel runs into the crankcase and dilutes the oil.

dottnmd
08-12-2007, 08:09 PM
Welp were back up and running. We went ahead and just replaced the whole Spider Assembly. Thanks for all the wonderful help. Your guys are awesome.


Dott

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