[Gmecm] Tracker TBI problem solved!

[Garrett Herning]

Hi Duncan,

Glad you solved your problem. I had a probalem with the TBI gasket on my 
K1500. I would notice at idle sometime it would be a bit rough, other times 
not. Kind of bugged me but with the high milage of the vehicle I thought 
that it was just old. I happened to be doing something else and had the air 
cleaner off and was opening the throttle with the engine off and noticed 
something sticking out into one of the bores farther down. Here the gasket 
had cracked and been partially sucked into the bore on the are with the 
largest distance between bolts and least amount of gasket. (on the typ GM 3 
bolt pattern for a TBI). So I had an intermittent vac leak. From the looks 
of it, it had been like that for a while. I popped off the TBI, scrapped off 
the gasket and put a new one on. IIRC, the old gasket was quite hard and 
brittle. I am pretty sure this was the original GM gasket.

Garrett


>From: Cowen <captain_krill at yahoo.com>
>Reply-To: gmecm at diy-efi.org
>To: gmecm at diy-efi.org
>Subject: [Gmecm] Tracker TBI problem solved!
>Date: Mon, 8 Jan 2007 17:14:08 -0800 (PST)
>
>Hello folks!  First let me thank all of you for your
>suggestions re: my wife's 1992 Tracker.  To recap, it
>was getting poor mileage, failing emissions testing
>because CO was spiking off the scale every time the
>throttle was increased, and hesitating on
>acceleration.
>
>When I asked you guys for advice, I had already
>swapped in known good O2, TPS, MAP, cap/wire/rotor,
>ECM, plugs.  I had set the valves, confirmed the
>timing, cleaned the EGR (which was completely
>plugged)and PCV valves, inspected the injector for
>spray pattern and leaks, and confirmed the purge
>canister worked.
>
>Following your suggestions, I confirmed the fuel
>return line to the tank was clear and confirmed the
>MAP port on the throttle body was clear.
>
>All of this made no difference.  I finally decided to
>do some investigative surgery, so I pulled off the
>Thottle Body... and found the gasket to the intake
>manifold was disintegrating!  The gasket was coming
>apart like wet paper, and the soft chunks were moving
>through the throttle body, plugging ports, although
>there were no external vacuum leaks.
>
>After installing a new gasket for a whopping $3.28, it
>runs perfectly.  I haven't had a chance to emissions
>test it, but the difference in driveability is night
>and day!
>
>I've never seen a failure of a gasket like that, where
>it just started rotting away on an otherwise excellent
>engine.  As far as I can tell it was OEM.  Funny
>though, I fell into the trap of thinking that if the
>car ran poorly, it was likely a failure of some
>complex component.  Thinking back with 20/20
>hindsight, in my limited GM, Suzuki, and Toyota EFI
>experience, I haven't seen a "failure" yet that wasn't
>actually a broken hose, gasket, or wire!
>
>Thanks for the advice folks, thought you'd like to
>know how it worked out.
>
>Duncan
>
>**********************END TRANSMISSION**********************
>
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