EST Distributor

[Shannen Durphey]

The MAF/165 TPI cars use an external knock sensor module.  The MAP cars do not.
VIN F is a 305, VIN 8 is a 350.  In 1991 F cars both use a 1227730, which is MAP.
The VIN 8 engine is used in both the Corvette and F car.
Corvettes used the large cap distributor, F cars use the small cap style.
Large cap distributors designed to use with EST systems are functionally
interchangeable with small cap style.

Parts guys are generally no better than the information they have.  Just because
you don't understand what he meant doesn't mean he doesn't.  Remember that the
dealership parts man's main job is to look up parts based on year, make, and model
and get those parts to the technicians quickly.  His job is _not_ to know the
differences between parts, or even what the parts do.  The good parts guys do go
beyond this.  

Ya know, there's a few of us "professionals" on the list.  Prolly not a good idea
to start laying blame yet...
Shannen

Bob Wooten wrote:
> 
> I see.  I think that you are right, it is time that I get another source of
> information.  what I was using was the print in the manual & an educated
> guess @ how it works.  the description that Keith quoted makes perfect sense
> to me now.
> 
> the reference to the 8 engine code is to the VIN.  there were two TPI engine
> codes in 91, one was 8 & the other F.  I think that the difference was one
> was MAF & one MAP.  the distributor diagrams in the manual that I have are
> different for them as well.  It appears that the 8 Engine code is the "HEI"
> style of distributor with the Coil in cap & the F is the tall thin
> distributor that I have that has an external coil.  but as I said, I don't
> have that one so I don't know what it really is.
> 
> a fried of mine has an Iroc that is a MAF car.  His computer died & the GM
> dealer told him that there are two ECM's for his car.  one has the coil
> driver in the ECM & the other has another "module" that goes between the ECM
> & the distributor.  this has always perplexed me as I don't recall having
> ever seen a GM "Module" that was not either in the distributor or in the
> ECM.  any thoughts or is this just another "parts guy" that doesn't know his
> ECM from a hole in the ground?
> 
> Tanx, again to all.
> BW
>
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