More TPI questions
John Hess
JohnH at ixc-comm.net
Fri Jan 17 15:55:10 GMT 1997
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.
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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
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.
Ok, here we go...
>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)
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.
>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)
Any help would be greatly appreciated!
Jeff
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