More TPI questions

[John Hess]

Anything I have to say is from my experience with the Corvette 
engines.  Much of it relates to all of the pre '90 TPIs;  but, you 
correctly stated that some may be irrelevant to the Camaro/Firebird.


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From:  Steve Ravet[SMTP:steve at imes.com]
Sent:  Friday, January 17, 1997 12:03 PM
To:  diy_efi at coulomb.eng.ohio-state.edu
Subject:  RE: More TPI questions

At 09:56 AM 1/17/97 -0600, you wrote:
>Many of the tuners don't really recognize the existence of the '85.
> The major difference is the use of a different ECU and harness and
>the addition of VATS with the '86 model year (from the '86-89). 
 There
>are other changes; but, these one significant in that the ALDL data
>rate is 160 bpS rather than the 8192 of the later ECUs.  This may
>sound insignificant until you try to take real-time readings of the
>engine parameters for performance mapping purposes.
>

Sorry to jump in late with questions...  I've been following this 
thread of
85 vs 86-89, and I was wondering if you guys are talking about a 
particular
motor or GM v8s in general.  I think the vette was the only car that 
had
VATS that long ago, so are you talking about the vette motor (L98)
specifically?  TPI motors in general?  TBI motors also?

--steve

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>From:  Jeffrey R Muehl[SMTP:JRMUEHL at mail.delcoelect.com]
>Sent:  Friday, January 17, 1997 7:22 AM
>To:  diy_efi at coulomb.eng.ohio-state.edu
>Subject:  RE: More TPI questions
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>Many of the aftermarket people don't even treat the '85 as a TPI in
>their discussions.  To start with, it uses a computer (ECU) unique to 
>the model year.  Trying to get information on that particular
>computer/assembly are largely fruitless.  From what I understand (and 
>I am not certain that I understand everything I know about the
>subject), you start with a different ECU, no pre-cats, VATS added in 
>'86, and different ALDL data rate.  There may (probably are) more
>changes;  but, this is all I have heard about.
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>Ok, here we go...
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>>What is the difference between the 85 vs. 89 system.
>>>
>>> Too numerous to describe.  It was the first generation TPI system
>>> and
>>> was significantly changed for '86.  The '86 through 89 is pretty
>>> consistent (some mapping and other variances to basically the 
same
>>> system)
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>It was stated that the 85 -vs- 89 differences were "numerous".
>Were these differences just in the ECM or were sensors, TB, etc
>changed?
>I want to convert an 85 system to the 89 ECM.  What's involved?
>If it's just a harness conversion, I'm not worried.
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>>Ok - lets say that I have an '87 TPI - basically stock.  Can I
>>just swap out a PROM for the '89 TPI to eliminate the cold-start
>>injector
>>on my '87??  IOW, is there a hardware(wire harness) difference
>>that would prevent this (other than the cold-start injector wiring)
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>Any help would be greatly appreciated!
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>Jeff
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