TPI Questions

[James Boughton]

Jeff,
	It wouldn't surprise me if the EGR wouldn't work if you
ground the P/N switch since this usually is a signal to the ECM
that the car is idling.  EGR is not used at idle due the desire to 
have good idle quality and EGR tends to increase the variation
in combustion to the point that the driver can feel it.  Also, as
mentioned regarding large cams, the residual fraction at idle is
quite large anyhow.

You shouldn't have to change any of the calibration since the
ECM is not turning on the EGR and it knows this.  Since the
ECM is aware that it is not using EGR it should never attempt
to correct for it.  I am not sure what the effects will be of driving
the car with the engine controller always thinking you are at idle
will be however.  It is possible that it is no problem, then again...

Jim Boughton
boughton at bignet.net

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From: 	Jeffrey R Muehl[SMTP:JRMUEHL at mail.delcoelect.com]
Sent: 	Thursday, August 14, 1997 8:14 AM
To: 	diy_efi at coulomb.eng.ohio-state.edu
Subject: 	RE: TPI Questions





I apologise - I feel like I'm beating a dead horse.

It was mentioned a while back that with a standard transmission I should
ground the P/N pin on the ECM - done.
Someone told me that if you do this, the EGR valve will never work anyway.
  Is this true?

And if it is, do I still need to change the timing (or fuel), when the EGR
should have been working (part throttle)?

Jeff