Hello members of thirdgen! My names Mitch, this is my first posting, although im pretty familiar with the site, ive followed many threads that have helped me out majorly with projects.

A dilemma im having at the moment is wiring an engine that im preparing to swap. Its a corvette 350 with an 88' GTA tpi intake system on top. The guy i bought it from Had it running in his corvette. When he pulled the harness he cut all the main jumble of wires heading through the firewall. Now I was looking over the intake and the Runners do not have a cold start valve hole, which i understand that a cold start is for the early MAF tpi systems, but he gave me a MAF sensor along with everything. I am assuming the previous owner just got new runners?

My question is this, does anyone know the wiring harness difference between the MAF and MAP harnesses used in the later tpi systems? and does the MAP harness connect to the MAF computer? Reason is that i have access to a MAP harness at a friends, i was thinking of swapping a couple sensors on it from my set up and trying to run it with the ecu. Would this work or am i blowin smoke? thanks in advance!

 

165 to 730 not just a plug and play.

https://www.thirdgen.org/forums/dfi-...730-749-a.html

 

Thank you, all I needed to know!

 

As far as your tpi now, 89 tpi maf went away with the csi in programing. The 89-92 runners block the vacuum po on the runner. If the car is hard to start cold more than likely the memcal in the 1227165 ecm is $32b 87-88 programing. the tpi speed density will use a different memcal you cannot use the one you have now and will have vats enabled. the plenum will need to be tapped for a additional vacuum port sharing a vacuum signal to the map sensor does not play well with it being accurate and causes running issues.
You will also need to use retrofit 4k vss if you have a speedometer driven speedometer to get the correct signal to the ecm. The memcal can be reprogramed to accept the optical signal like your 165 ecm instead of a magnetic pulse.

 

Ok so basically with the MAF sensor I can not run it without issues because its lacking a vacuum port? The guy said it ran fine the way he has it wired but he cut it going to connect into the computer and fusebox. I just want to know the easiest way to get the damn thing running, should I buy a crappy wiring harness and use the continuation to my existing ecu?

 

If you are staying with tpi maf you should remove the harness and determine if its worth repairing. if not look for one in the classified section or ebay. Maf uses air flow grams per second to determine engine air flow to base fueling and will need to be mounted to the throttle body bellows. Tpi speed density will require manifold vacuum within a foot of the plenum and not off a T.

 

You seem confused
Just to clarify TP's comment , the MAF sensor is a big black thing that goes on the intake ducting ahead of the TB
and has nothing to do with a vac port that the MAP sensor requires.

 

If so ,it would be much easier and simpler to just buy a '730 computer and convert it to MAP.
They typically go for $50 -75 in the parts for sale Dept
Most of the MAF sensors will interchange ,
you would need a MAP TPI knock sensor and obviously a 350 MAP memcal ( chip ) which TP can arrange.