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Re: TPI '165 pulling timing after Cold start



When I disconnected the Knock sensor my stumble between gears went away, I also
noticed that I had a lot of part throttle knock around 1800-2200 RPM, as a
temporary fix, I took out a couple of degrees of timing at the distributor
(remembering that I was out of EPROMs at the time with no eraser).  So I'm under
the impression that the ECM is clueless to the fact that the knock sensor is not
connected and it was functioning properly when connected.

The Truck had cold start problems before I disconnected the sensor as well,
although I had not verified what the problem was at that time.

Right now I have not adjusted any parameters, only disabled VATS, so it would
start.  I have been trying a couple of different stock .bin's.  Right now APYN
seem to be the best (has the closest timing curve when warm).

BTW, if it makes any difference this is an internally stock '85 TPI 305 that's
been converted to a '165 in a full size 2wd truck.....


Steve, when I first started this project, I noticed that sometimes I would have
to crank the engine forever before it would start when cold.  I traced this down
to a bad connection at the FP relay, the engine would (after cranking for a
while) build oil pressure, which would in turn, trigger the oil pressure switch,
feed the fuel pump with power, starting the truck like nothing was wrong.

Thanks
Gabe

"Marteney, Steven J." wrote:

> Knock sensor has a certain impedance the ECM can detect (4.7kohm?).  When
> not connected, it won't find that and should set a code.  Does the ECM
> remove timing if the knock sensor isn't detected?  I would think it would,
> but have no knowledge.
>
> What are you doing to adjust cold-start?  My 89 165-based (soon to be
> 730!!!!!) 350 TPI has a terrible time starting when cold.  Acts like not
> enough fuel.  I have played with the PW correction vs. battery voltage in
> Tunercat and can make it much worse on hot and cold starts by lessening the
> PW.  Increasing the PW (so far) has had little effect.  Doesn't seem like an
> air problem either.  Doesn't matter whether my foot's on or off the gas.
>
> Anyone know if the 165 ECM controls the 2 second fuel pump enable when no
> oil pressure is present?  where that may be in the code?
>
> Steve (pulling 730 this weekend 8^)  <-- note: grin bigger than Texas)

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