im swaping my 92 LO3 engine for a 88 350 TPI engine. i know the 88 is a MAF.. if that what i have to stay with? or do i have to go SD? im kinda confused.

 

You have the option of swapping in whichever you want...as you will need to alter the wiring harness to match, but since you have a 91 car, you may want to find a 91 SD harness to make it simpler.

You could also put in the MAF setup, but since your car is SD, it probably would be easier to do the swap with SD...

HTH,

 

Ahhh... since your getting a 88 engine, why dont you just stay with MAF? The TBI PROM isnt gunna work well with the TPI. You also still have to worry about the "9th" injector or cold start injector. You can take that out, and have it capped off. Go get a 88 computer with the right PROM and wire harness for MAF. Nothing of the ecu from your 91 tbi is gunna work with the new 350 tpi. You really have 2 options
One is get a 88 ecu and just go MAF.
The other is get SD, Which you need to get a 90-92 ecu and whatever parts for that. Like i said, you have an 88 engine, get the ecu for it. MAF isnt bad... i really dont understand what the big deal is? What, you wana mout the cone filter right on the tb?
You dont have to go SD. your cars age has nothing to do with it. Its what powers it that dictates it. if you had a SD 350, then i would get the SD ecu...Just go MAF and dont worry.

 

I've ran all 3 systems, and have had the best luck tuning with the $8D stuff..

You could repin your harness to run SD, or get another harness.

I'd stick with the MAP personally. You already have the map sensor, all you need now is an ECM and a harness, or repin your harness.

You have no idea what your talking about..

You _can_ go with the 88 setup, and run $32 code, or 89 and run $6E code. You'll need harness, ecm, maf sensor, maf relays, esc circuitry, etc.

-- Joe

 

If budget is a concern then SD wins hands down IMO. Less parts to buy and break and less stuff to change.

You don't need a new wiring harness for SD, all you need to do is repin the ECM connector, change the injector connectors on that side, and run a direct wire to the ECM for the knock sensor. If you do a search this has been covered in detail many times. Off the top of my head i think Dyno Don posted some good info on this a whiloe back when he changed his 91 RS to SD TPI.

If you want to run MAF you'll need to add wiring for that stuff and probbaly some alterations to the ESC circuitry compared to TBI as well.

I think there will be VSS differences no matter which way you go. I think a late TBI car has a buffer box off the VSS for the speedo and ECM. SD TPI runs the VSS by itself and sends a signal to the speedo. MAF uses a different VSS signal altogether, complicating things a bit.

 

Im sorry, but how does a TBI harness even come close to working on a TPI car? I really wana know now... im not tryin to be sarcastic, but i really dont understand how a TBI harness can work fine for the TPI system? Am i understanding you guys right? I dont know a lot about the ecm and proms and what not, but i thought that it was just easy just to get a 88 ecm, harness, and maf with all the sensors. I dont see what is so bad? He could do a SD too, wouldnt he need a TPI harness anyway? i dont understand how the 2 injector TBI harness fits on a 8 injector TPI system? I guess theres a lot of cutting and splicing. OH well... sorry... just didnt think it was possible.

 

You just need to repin the ecm connectors, and then provide some injector plugs. 99% of the wiring is allready there..

-- Joe

 

bigal, i'm not making this up. Think about it. What is so different between a SD TPI and a TBI engine? I'll tell you:

8 injectors vs. 2
ESC on-board the memcal vs. seperate box.

Minor:

VSS - driven by ECM vs. driven by buffer box. (requires running VSS to ECM rather than box and changing a switch in the PROM.)

The rest:

TPS - same connector
dizzy - same
MAP - same
CTS - same
IAT - same
IAC - same
EGR solenoid- same
canister purge - not sure but never heard it mentioned as an issue. most likely the same.


Oh yeah, and you'd want to disable VATS unless you felt like adding that $$$ ignition lock and VATS module + wiring.


With MAF you'd have to add MAF wiring as well as for the associated relays. And a little more work for the VSS.


EFI is EFI daddy-o. Don't make things more difficult than it needs to be.

 

Wouldnt it be easier if you got a 87 harness with 87 ecm? You guys know more about modding the computers then i do, i just thought that if he could get a 87 set up, then he would be fine... 87 doesnt have VATS or any of that stuff. and wouldnt he already have the knock sensor, TPS, IAC, etc with the engine? just think he would need something to hook it up to, a MAF (if it didnt come with one) and hes off and running? sorry, i just thought that for a guy that doesnt know much about comptuers, that getting a old harness and ecm just sounds easier to me, then cutting up the old one.. sorry.

 

I assure you, swapping harnesses is 500x the job that repinning for SD would be.

 

If the 199x RS TBI has the buffer box, I fail to see why it's required to run the speedo off the ECM. Is it because the `746 ECM using a 2002ppm input? Seems like you could use the signal from the trans. to feed the buffer, and the `730 ECM.


If the VATS module in the RS and key are undisturbed, merely wired into a SD swap like a stock Z28, I again don't see why a SD swap would require disabling it. Please elaborate.

Matthew

 

Knock sensor is different. The swap to SD is easy on a TBI car; I believe the pinouts to the dash harness are the same. Change the ESC setup, change fuel pumps, mod harness, and go.