Re: Throttle body backfires

From: Shari & Marty (msdng@netzero.net)
Date: Fri Apr 07 2000 - 12:12:28 EDT


Did the lower pan on the 2bbl have a leak before, Jon? Do you have the pcv
from the valve cover routed to the intake or in the filter housing? What
gasket came with the intake? Is there a possibility that the gasket slipped
and is exposing the lifter galley allowing oil to enter the passages? I know
you have had the intake on for a while, maybe the pattern needs to be re-
torqued. I am unsure of why your truck would be running rich at first
because ever Tb I ported in Atlanta (granted not as big as the 4bbl) started
life running lean and bogged for 20 miles, till the pulse width opened up
and delivered more fuel. If there is a vacuum leak either in the intake
gasket or TB gasket, or the surface of the TB is not flatttttbbbbbbbbbbhh,,
sorry, the baby started typing to you. If there is a chance of a vacuum
leak, the MAP and IAS will freak out. The IAS will be plunging back and
forth like a mad plumber on a clogged toilet. I don't believe I have ever
had a TB swap that started life immediately rich. Adding #24 injectors will
do that at first real bad with a stock cam. Good luck, and too bad my super
duper Space Center Transporter isn't up yet, until then, get a remote camera
for your PC.
Kuk

> > 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/ ---'
>
>

_____________________________________________
NetZero - Defenders of the Free World
Click here for FREE Internet Access and Email
http://www.netzero.net/download/index.html



This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:50:37 EDT