Re: Throttle body backfires

From: Jon Steiger (stei0302@cs.fredonia.edu)
Date: Fri Apr 07 2000 - 10:48:02 EDT


On Fri, 7 Apr 2000, Bob Tom wrote:
[...]
> I had something similar happen just after installing the 24# injectors
> and firing up for the first time. It did not happen again while the
> 24# were in.
>
> My guess is that an extremely rich mixture was dumped in initially,
> resulting in some pudding down in the combustion chamber, ignited in the
> high temp. heat when the exhaust valves were closed or almost closed.
> Subsequent running probably gave the computer enough time to adjust the
> mixture.
>
> Also, initial fire-up with the 24# shot enormous black smoke out of
> the exhaust tips (ask Bill about his experience). Mine resulted in
> two huge black spots on my daughter-in-laws '94 white Spirit around
> her two fog lights (00ps) ... looked like her fogs had started a fire.
> A couple of subsequent start-ups let loose less and less black smoke
> until there was none at all.

   
   Interesting. That sounds similar to when I started it up with the
4bbl. I could smell the gas in the air, there was smoke coming out
of the exhaust pipe, and the A/F meter was trying to bust the needle
right out the "rich" side of the gauge. :-) After maybe 20 seconds
or so, the needle started moving back and forth and everything seemed
normal. I wonder if it will do that every time I reset the computer?
  
   I'm hoping you're right about the gas puddling. Running that rich
may have left lots of gas in the intake; maybe I just need to run it
a while and let it warm up too.

   Oh, another thing I forgot to mention, when I shut off the engine,
if I open up the throttle body blades, smoke comes out. Not real thick
or black or anything, just a constant flow of thin smoke. There are
also traces of oil in the intake. It did that with the 2bbl TB also.
Is this a normal thing? (Truck has 70,000 miles.)

  Thanks for the info, and the rather humorous visual of your daughter-
in-law's Spirit! Hee hee hee! :-)

                                              -Jon-

  .--- jon@dakota-truck.net -- or -- stei0302@cs.fredonia.edu ------------.
  | Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
  | '92 Ram 150 4x4 V8, '96 Dakota V8, '96 Intruder 1400, '96 FireFly 447 |
  `---------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'



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