Sudden black smoke

fturner

Registered User
Heading to work this morning and slowed right down for some tracks and the guy behind me wasn't paying attention and was going to hit me, so I gunned it. Got up to the lights and turned then the car started bucking and wouldn't hold idle very well so I had to keep my foot on the gas a bit. I was able to drive it home barely.

I noticed alot of black smoke coming out behind me and when I sat in the driveway alot of black soot formed up at the exhaust exits on the driveway.

I've recently replaced the stock fuel pump with a 255lph pump, fuel filter, I resealed all my IC tubes and changed out all the pullies except the SC's for aluminum ones. From doing searches the following possible things could have happened.

- The fuel pressure regulator failed
- One of the IC's tubes blew their seal (to me that would cause a very lean condition not rich though)
- HB went (stock).
- Headgaskets went (done 2 years ago)
- PCV valve became disconnected.

I have no CEL light.

I'll be checking the above, but any other suggestions to track this problem down would be appreciated. The car has been running beautifully except a few weeks ago when all the symptons of a failed cam sensor showed up, but after cleaning everything up and reseating the DIS with fresh heat sink gel the problem went away. BTW The tach is still working.

Anyways.

Idea's?
 
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Sounds like the DIS module. I had similar experinces and it started out as intermitent and gradually became worse and worse over the period of a few weeks.

David
 
at one point my car would stall out now and then at low speed - with a bouncing tach - no CEL -also, once stalled, would not start for quite a while ( until things cooled down) - replaced the DIS and all was fine. - But i never saw any black smoke.
 
I would re-check the cam sensor. This sensor believe it or not controls the timing of the fuel injectors, not ignition, ( crank does that ).. Therefore the bucking, and the richness producing the black smoke could very well be the cam sensor.
 
Guess I didn't talk to her nice this morning. I went out after work and it stumbled at idle pretty bad then started to clear up :eek: . I reset the computer and it just slowly got better till it was purring smoothly again.

I replaced the cam sensor anyway with a new one and threw on another DIS I had sitting around. I drove into the city and also filled up on Sunoco Ultra 94 as I only get 91 out here. I'm also going to run sea foam through the gas tank as well for good luck. I check the fuel pressure and it was just under 40 psi before start up, and hung around 31 I think it was with the bad idle, so I don't think it was the FPR. Once I shut the car off, the fuel pressure stayed at about 40psi for at least the 10 minutes I kept the gauge hooked up. Once everything settled down again I was sitting at 20" vacuum as well.

Brand new DIS module on order and should be here tomorrow.

I am confused here. It acted just like the old 351W that was in my dads '74 jeep wagoneer once in awhile and to fix it you just drove the snot out of it till the carbon all blew out :cool:

I have a new crank sensor to install, but I was waiting till I got myself a new balancer first.
 
Ok 3 DIS modules (last 1 being new) and 3 cam sensors (again last 1 new) and now I'm driving along happily and bam!

Slight shudder, CEL comes on, and NO power.... just barely enough to keep moving and judging from the black exhaust, the car is running rich. This I assume is the computer putting everything in limp home mode. Stop the car shut it off, restart right away and I'm fine again, all power and everything.

This happens regularly now and at random times. Despite the CEL comes on, I have no codes with KOEO and KOER tests. Idle vacuum is smack on 20.

Could an intermittent crank sensor cause this? There is no wobble on the crank pully and all the bolts are there. I've looked as best I can and I don't see any crack showing the harmonic balancer being done for.

Anyways, the ole girl is parked for now until I figure this out :(
 
I had a bad crank sensor one time when somebody forgot to tie strap the wires and a belt cut right through them. I vote for bad wires or a bad cam sensor
 
I used to lose the tach about a month ago, but that problem went away once the DIS was reseated with fresh heat goop and another cam sensor.

Since I have a new crank sensor sitting there, I might as well throw it on to see what happens.
 
Ok... the wierd scenario is over as I believe the problem had been solved.

Fortunately the parts I replaced earlier where planned anyway, but it did turn out to be an intermitent crank sensor. It doesn't look like anything has hit it. I checked the H/B and I did not see any cracks etc.

So the ole girl is back on the road till the next issue :D .
 
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