sakattack28

If I had time I would have been spending more time here, but due to life (you know, class, work, flying etc) I haven't had the time or money to do anything to my car. But now, I think I have a project I can do. So like always, before starting something big that could keep my car from running and me getting to work to make money, I figured I would ask the experts.

Right now I have the wonderful 305 TBI engine in my car. I found an 87 up TPI kit on Thirdgen Ranch for $400 and I was thinking to myself, "Self, this might be fun project, get rid of that stupid TBI and put a proper fuel injection system onto my car." After I realized that I was talking to myself I got to thinking about what I would need to do. This is where y'all come in.

The TPI system is off a 350. It comes with everything, the harness and ECM and MAF sensor. Since its off a 350 and I have a 305, I want to know if I will have to change anything in the ECM, or would changing the injectors to the right ones get my fuel air mixture right? If I do have to change some computer parameters, is it hard to do, and can I do it myself? I have a OBD scanner that I think can reprogram computers, but since I just got it, im not entirely sure how to use it yet.

Also, if I have the intake off would it make sense to change out the cam to something better than stock? I am more looking for fuel economy right now than power. (power comes when I have the money and time for an LS1/T56 swap. )

Basically what I would like y'alls input on is this:
1) Would this be a worthwhile project (gas mileage gains, and general less suckyness)
2) Besides swapping out injectors do i have to change anything else, computer parameters, fuel pump, etc.
3) Would anyone advise replacing the camshaft at this point as well
4) Am i rambling on about something that was already answered, but managed to miss when i was looking through the boards?

Anyway, if I could get y'alls input that'd be great.

~Dan

vetteoz

iTrader: (13)

You need a prom for a 305 MAF TPI and the correct injectors
86 - 89 TPI MAF computers are all the same ; only the tune on the prom / chip / memcal
differs to suit a particular engine

wyochimneysweep

iTrader: (1)

Also dont forget the fuel pump in the tank will probably need to be change. when I convert my 305 in my pickup I had to get a tpi pump and also you need a prom for a 305 and if you can program the chip you could change the fuel injector size on the prom and run 350 injectors. I gained mileage and power in the lower rpm's. I'd do it again. I'd go with a cam also. I think 88 or 89 the proms started with vats so if you get that year you will need to have vats removed.

wyochimneysweep

iTrader: (1)

I'd use the money that you would spend on injectors to by a prom programmer from moates.net

sakattack28

Ok, so what I would have to do is burn a new PROM chip, but thats all I would have to modify to have it work right? I've been looking at the DIY PROM board and trying to wrap my head around it, sounds fun, but possibly expensive. wyochimneysweep, you mentioned a new fuel pump, is that because the TPI needs a different fuel pressure? Because I really don't want to have to drop the fuel tank right now....
Oh, and I should have mentioned that my car is a 91, is that going to make any difference in this? Or just in how I would have to program the PROM?

wyochimneysweep

iTrader: (1)

I'm sure the tbi pump is good for like 8-12psi and tpi is 43.5psi. so yes you need a pump. You would need to make a custom prom so you can run 22lb injectors on a 305. 305 came stock with 19lb. If I was you I would also up to the 90-92 ecm for tpi and just run Speed density. That will safe you the money of a MAF sensor.

wyochimneysweep

iTrader: (1)

The prom is on whats called a calpak and you either have to remove the eprom and install a socket into the calpak to use flash chips or buy a adapter. Craig moates site has the programmer and adapter. I had the apu1 and it worked awesome. now I run obd2 and use hptuners.

utilityguy2

iTrader: (1)

you need the computer (they are different) the harness. A TPI high pressure fuel pump and either reprogram your memcal for higher lb. injectors or replace the injectors with 19 lb. 305 injectors. The donor car was probably a automatic so may have to re-program the memcal anyway.

utilityguy2

iTrader: (1)

the computer on his TBI car is a 01228746 with a DIP prom. Different from a 01227165 which is a TPI computer with a memcal.

sakattack28

http://thirdgenranch.com/-strse-863/...tem/Detail.bok

I figured that I would post the link to the ad on Thirdgen Ranch. I don't really know anything about PROM. So right now when I have time I'm looking into learning as much as I can about everything. Between class and work. Woo. Airplanes are so much easier to work on... no computers.

utilityguy2

iTrader: (1)

As long as you transferred the harness and ECM from the donor system into your car plus add a higher pressure fuel pump you should be good to go. EXCEPT the harness and ECM is out of a 89 or earlier car. So, your speedo may be a problem. I think being a TBI car you have the buffer box so that may work out. You will also want to get the memcal reprogramed for the larger 22 lb injectors. Remember if the the injectors have been dry for awhile you may need to replace them or at least get them tested. maybe better to just replace with new 19 lb. One other thing, your car has VATS and depending on the year of memcal that may be a problem. Seems like a fun project. Good Luck.

92RSTPI

Just an FYI, I did this last year (to an L98), and I would highly recommend buying a donor car.. you will get nickel and dimed on the little things (throttle cable, fuel pump, fuel lines). Upgrading to TPI will not yield any power with the LO3 swirlport heads, and putting in a new cam will not help either, unless you do both.

You need the heads, cam, and tpi in order to make it worthwhile. The TBI is 170HP, and the LB9 is probably 195 HP, so you can determine if the cost is worth it...

You can find everything you need on this site (TPI, heads, cam,ECM, MEMcal, fuel pump) if you decide to go with it.

VATS won't matter, as the 87 ECM doesn't have an input. The TBI cars do run a buffer box, so no issue there either.

You should look into repinning the harness in your car and use the speed density (90-92) Tpi (you can convert MAF 85-89 to SD easily). There is a sticky for repinning in the TPI forum.

sakattack28

Well, I'm not really looking for more power right now. I plan on doing an LS1/T56 swap after I graduate and have the time and money. I was hoping that I could get better gas mileage right now until I have the time and money for an LS1.

And actually it looks like Denny sold the intake before I made up my mind on if it would be worth it or not. If I see another one I might pick it up. Thanks for the advice guys!

~Dan