TPI Questions

[George M. Dailey]

It appears that by not having the EGR system (with a stock ECM and engine),
you will not be able to advance the timing to get the part throttle economy
you deserve. Full throttle is unaffected by the EGR, but if you don't have
the proper timing advance to begin with, you will not have it at WOT. The
EGR system seems critical in setting the proper spark advance to begin with.
Without it, you could run into detonation and as a result, have the timing
retarded even futher. 

Has any one ever herd of an GM TPI EGR valve squeaking? My mom's car had
this problem (Dodg K-car). Sounded like premature puppies yelping.  I traced
it to a resonance in the EGR valve. You could actually see it vibrating. My
TPI engine (complete with defective EGR valve) makes a very simular sound.
Dosen't seem like the EGR valve, especially since it's disconnected.

GMD

At 09:03 AM 8/12/97 -0500, you wrote:
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>I was hoping someone would jump in here.
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>Do you have any evidence of the engine knocking without EGR?
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>I have the same question - do I want it or not?  I'm also not concern with
>economy, only power.
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>>I'm lost, for a performance engine, do you want egr or not ?  When I built
>my tpi 350, I pulled the egr valve and stuck >a blanking plate over the
>hole instead, oh, I also put the little metal plates in the manifold
>gaskets where the egr is >meant to breathe through.  Was this a mistake (I
>don't care about economy, only power)?>>
>>
>>
>>Dan     dzorde at geocities.com
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>>The EGR valve is still present and connected, but doesn't actually do
>>anything since there isn't a supply of exhaust gas to the valve.
>>
>>Grounding the EGR feedback wire will set off the SES light (it simulates
>>the EGR being stuck in the open position)
>>
>>Leaving it disconnected will also occasionally set off the SES light
>(there >are a few cases where the ECM will command the EGR to actuate, then
>look to >see what happened.)  Fortunately, temps down here are high enough
>that this >doesn't happen often.  (been about 4 months since the last time
>the code >went off) It will also clear itself within a few minutes of
>driving.
>>
>>Someday I'll have an EGR flange welded to one of the exhaust headers to
>>supply external EGR.. but it's a low priority.
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George M. Dailey
gmd at tecinfo.com