raven350

Okay Prom experts I need some advice.

I would like to take my TPI off of my 89 firebird (going to miniram) and put it on my 93 C/K pace truck(silverado) that is currently a TBI. I can create jumper harness's from the stock fuel injectors and sensors to the new sensors. (real easy since the TPI is batch fire already).

My question is I don't remember if the truck has a prom or not. and if it has a prom, can I use the stock one, or will I have to go custom? I am not sure of the on time or or cycles it has for the fuel injectors.

Has anyone here done this conversion before or know someone who has? What problems have they run into?

Thanks for all your help....

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Sportsman II 72 CC heads, Pete Jackson gear drive, Performance Resources chip, Edelbrock 1 5/8" headers and Edelbrock cat back exhaust, hi-flow cats, Trans-go stage 3 shift kit, Vigilante 9.5" 2800 stall convertor, SLP cold air induction, SLP roller camshaft, 24lb ADS injectors, AFPR, 3.45 rear end gears, and other goodies...


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gdkng

Raven, I have been thinking about swapping my 93 C/K to mpi but haven't got around to it yet but here is some information. The truck most likely uses a 16168625 pcm (E6) which takes a 27c512 eprom. I use Tunercat to modify the bin. It is my contention that you might be able to simply wire each set of (4) injectors in parallel off of one of the existinf injector leads- Do this for each bank. Then change the injector constant in the .bin to reflect the total flow of the (4) injectors instead of the single TBI Injector. I am sure I am making this too simple, but if somebody else would like to jump in--Please do!! I am all Ears!

gdkng

87/88Firetruck

I just completed a conversion of a 1988 C1500 from 4.3L TBI, and the ECM and PROM have been the last great hurdles in the installation. As far as ECM compatibility goes, I was wrongly given 1227747, which is a truck ECM, with the L98 TPI unit I purchased. It came with PROM 0024 ACSU, which is from a 1987 Suburban with a TBI 350, automatic transmission, 3.73 rear axle, and air conditioning. My engine was not very happy. With no MAF input (my system should use 1227165), and fuel tables for a 2-injector TBI system, it was running extremely rich, and would not hold any RPM steadily. I will tell you that in stock configuration, at least on the 7747, there is left bank injector output taken from D14 and right bank injector output taken from D16. TPI systems use D15 and D16 on the 7165, but there seems to be left bank output on D15 with the 7747, as well. Output is probably the wrong term, since the ECM only actuates the injector ground. Since it takes two revolutions for all eight cylinders have an intake stroke, and since each cylinder has a dedicated, isolated injector which can only fire with every other injector in that bank, I would assume that each bank of injectors pulses four times every two revolutions so that fuel is dispensed, heated, and atomized uniformly. It would seem that if the injectors delivered the full quantity of fuel necessary for the complete cycle of one cylinder in one pulse, that the cylinder receiving the fuel during the intake stroke would perform differently than the cylinder whose fuel remained in the intake passages for three of its four cycles. Of course, I could be entirely wrong. It just seems to me that in an MPFI system the injectors would pulse differently. The most I know for sure is that my engine ran, though not very well, on a computer that thought it was a TBI.

Grumpy

93 is that a pcm or ecm?.
If it's the 8625, then there are several different modes of operation.

If you want any *easy* way to do it if ecm'd then use a 1227165 but run the Australian 808 calibration, that will let you run MAP with a 165. BUT, it has the lousy slow scanner rate and needs the AU Diacom to run on it. My 2 cents is graft a 730 into it, if not a PCM.

Guy on the Sy list ran the PCM for controlling the tranny and a hac'd ecm for the engine controls

gdkng

What would you say if it is a pcm and the 4l60e is to be retained?

thanks, gdkng

raven350

I am not to worried about switching over the throttle cables, vacuum lines, or the sensors. Most sensors TPS, IAC, MAP, and such are basically all the same. So I shouldn't have a problem with those.

I am more curious as to what the difference will be between what a TBI computer tells the injectors to do than what a TPI can do.

All i was going to do was make a connector to fit into the original one that went to each fuel injector, then splice it off to four different ones.

I am looking for an easy fix, not pulling all wires and the computer and putting in an aftermarket one.

Has anyone looked at the difference between what the computer commands between a TBI and TPI.

What is normal fuel pressure for a TBI?

What is the normal cycle time for TBI and TPI?

raven350

bttt