Re: Re: Throttle body backfires

From: Shane Moseley (smoseley@ix.netcom.com)
Date: Fri Apr 07 2000 - 11:35:44 EDT


Jon Steiger wrote:

> The MAP I'm not 100% sure of. I have a tube running from the TB to the
> MAP sensor, which isn't quite the right size. (I'm going to have to extend
> the wires of my MAP sensor, but I didn't feel like hacking up my wiring
> harness just yet... I'll get the proper sized tube or bite the bullet and
> actually completely install the MAP sensor to ensure that connection is good.
>
> The TPS is reading about 25% at idle, just under 80% at WOT.

Jon,
   Here's some tips for the MAP issues you mentioned: First as far as the tube
from the TB to the MAP - try putting in a "tee" in order to allow you to hook up
a vacuum gauge to find out just what the MAP is seeing. It should see full
manifold vacuum - the FSM spec is "at least 16in-hg" and out of the last 3 trucks
I measured - they were 17.5, 18.5, and 19in-hg which exceed the spec (more is
good!). As far as the MAP harness connector - go to PepBoys and look in the
electrical connectors section. Dig around and you will find a large selection of
weatherpak connectors that allow custom fitting just about any vehicle's harness
without cutting any wires.

Keep us posted on what you find out - some of us like all the boring (NOT)
details 8-)

Shane

ps - I've talked to a parts manager down in FL who has some experience with the
4bbl TB. He said his customer put one on and complained about driveability.
Mostly that while easing the throttle plates open - it would compensate fine.
But, when stabbing the throttle - the truck would stumble due to all the extra
air. I'm pretty sure that thing flows at least 1000cfm. Sounds like the factory
delta-TPS enrichment tables need to have their pulsewidth values increased a
little to compensate for the extra air. Unfortunately, custom computers are not
only very expensive but also very illegal.

Good Luck!

--
'96 IndyRam-HisIndy-MPI/TB/Pulleys/Coil/Wires/CompTAs
'96 IndyRam-HerIndy-numbered(#142)"Track Truck"
'74 Triple-Black Dodge Challenger Rallye 360 home-brew EFI R&D vehicle
'68 Black Corvette Convertible 427 (For Sale)



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