I'm going from TBI to TPI on my 350...here's what I have, and will be getting.....

I have......entire TPI setup (runners, plenum, base manifold, TB, EGR, FPR, fuel rails, w/ all bolts), MAF sensor, Wiring harness, injectors, ECM w/ chip, distributor, TPI fuel pump, thermostat housing, gaskets.

Will be getting....braided fuel lines, throttle cable, TV cable,

I think i'm forgetting a cable (can't remember off the top of my head) anything else? Thanks

 

I used TBI emissions parts in my TPI swap, and found a snag with the EGR solenoid. The TPI and TBI EGR solenoids work in reverse of each other. I was getting SES codes relating to the EGR function until I replaced the TBI solenoid with one for a TPI.

I do not have a clue why, but that was the case. One is normally open, while the other was normally closed, so the TPI ECM was actually shutting the EGR valve when it sent a signal to "open", and the reverse when it tried to shut the EGR. In both cases, the ECMs and hardware were from 1990 350ci models.

I would recommend that you get the solenoid from the TPI donor, or see your friendly Generous Motors dealer for the TPI's EGR solenoid if you plan to use the EGR.

 

When you say EGR solenoid, are you talking about the valve itself? Because if you are, I have that attatched to the intake manifold. Did you have to make the vacuum line running to it longer, or can you use the same one? And how did you like your TPI swap? What kind of a difference did you see? Thanks

 

Do not hook-up the EGR valve directly to the manifold!

You do not want to have uncontrolled manifold vacuum at the EGR valve because then the ECM will have no control over it.
The 730 TPI ECM controls the EGR valve through a solenoid valve.
The ECM cycles the solenoid off/on, thereby turning the EGR off/on. The problem I encountered was that the TBI and TPI ECMs work in opposite ways, and use opposite style solenoids (normally open vs. normally closed).
The EGR solenoid is fed vacuum by a manifold nipple at the Throttle Body (which is turned off at closed throttle). This line should run from the manifold to the EGR solenoid, then another line goes from the EGR solenoid to the EGR valve itself.

Wish I had a photo--

 

anyone else??

 

Are you installing a speed density setup or older type using MAF?

 

MAF

 

Sorry, I don't know much about those.