[Gmecm] 305 TBI Hesitation

[Programmer]

There's a lot of possibilities:

1. False triggering from RFI
2. Incorrect TPS voltage
3. IAC problems
4. Incorrect loads indicated to the ECM
5. Incorrect base timing
6. Faulty ECM--improper PROM.

If you had a scanner--it'll tell what's going on. If the IAC counts are 
close to "0"--basically, the computer can't control idle. It's a vacuum 
leak--whether wrong PCV valve, physical baseplate leak, IAC stuck, intake 
gaskets or brake booster problem--anything 'false air related'.

If IAC counts are also high--look for a commanded load (P/N switch), A/C 
input, low alternator charging rate, or high operating temps.


----- Original Message ----- 
From: <matthew10_5 at netzero.net>
To: <gmecm at diy-efi.org>
Sent: Tuesday, July 04, 2006 2:42 PM
Subject: [Gmecm] 305 TBI Hesitation


> THis one has plagued me for a year now and like a man it is finally
> time to ask for help.
> The Project:
> 305 CID Small block TBI  7747.
> I'M  trying to figure out two things still. I have a high idle problem
> that cannot be lowered by altering convention cell settings for the
> idle. Something in another area is holding the idle up to 1100 RPM no
> matter what is done, it is not mechanical. The computer wants to
> increase the idle in gear at a stop sign.
> This might be related as well .If the throttle is opened up slowly
> under load, the engine hesitates or stumbles as though it is going
> lean. If you let off the throttle ( around 1100 RPM ), it hesitates and
> the engine surges back as though it went suddenly went rich.   Now if
> you step on it Hard, the engine jumps with all kinds of power and runs
> as it should. My question is has any run into this before and which
> cells are responsible or maybe over riding the others? I need some more
> heads on this one....Fred
>
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