alright - i bought TBI for my 350 but it doesn't come with a computer, which model do i need? Sorry i don't know shit about TBI so if you need anymore info just ask. thanks for the help

i think all the computers are all the same, just the chips in them are different. i would get one that your motor came out of. ie a pu w/350 auto or what every it was hooked to. mike

i think it came out of a van but i am not the one that took it out. I'm sure that whatever it came out of probably had an auto tranny and there is a manual behind the motor it is going on. I know the parts store is going to want a model number for the computer or a make/model/year and maybe a vin code to look up the proper computer and i was hoping someone here already knew the part number. Thanks for your help

This site DIY EFI (http://www.diy-efi.org/diy_efi/) should have the answer. I think you want a 1227-747, but I'm not certain. Thats what I used for my 4.3 tbi conversion and I think the rest is in the PROM.

the one you want has the last digits of 7747

- jack

contact howell, they can provide you with a computer and a chip. As far as I know the tbi computers were the same from 87-91 or 92, just buy the correct prom. the 92 and later tbi have red and blue connectors, and they are set up for a computer controlled trans.

Originally posted by SpaceGhost
This site DIY EFI (http://www.diy-efi.org/diy_efi/) should have the answer. I think you want a 1227-747, but I'm not certain. Thats what I used for my 4.3 tbi conversion and I think the rest is in the PROM.

What Mike said. The 1227747 is the most common of computers. Be prepared. When you go to the parts house to get the computer, you will have to pay for it twice. Once for the computer and again for the core. Actually on mine, the core was more expensive :confused:

Do you have a laptop? If you do, download WinALDL. It will help tons in pulling the info. http://www.winaldl.webhop.net/

Go to the salvage yard.... I could spend all day out there pulling nothing but '7747s. The go for less than $25 a pop here. Just replace the EPROM with one that matches the configuration you're wanting to run.

thanks for all the help. So basically the eprom is all that is important and the number on the computer, such as 1227747 , designates how the eprom is programmed. And the most common is the 1227747, which will work for both the v6 and v8.

TORC - how much would you want to ship a core to San Luis Obispo? Thanks

Originally posted by TRD
thanks for all the help. So basically the eprom is all that is important and the number on the computer, such as 1227747 , designates how the eprom is programmed. And the most common is the 1227747, which will work for both the v6 and v8.

TORC - how much would you want to ship a core to San Luis Obispo? Thanks

Close, but not quite. There are different chips for the same puter. The numbers on mine are 5463 on the Large Chip and 8905 on the small chip. They can have different burns however to make up differences in the motor. A 350 TBI DOES use the 1227747 ECM though.

If all else fails, you can snag the ECM and then get a chip burnt to match what you do have or find a place local to you that does custom chip burning, they are sure to have some old stock chips laying around.

Check Ebay, I have seen them in the $25 range, several at a time. If you go to a pick n pull and snag one from a similar vehicle it WILL run. However they may also set codes and not be optimized. Howell will hook you up based on your set up, I think ATS will too.

Stock they used VSS's, knock detectors and controlled the ignition, does your setup have these? If so you might be surprised how well it runs with a stock prom from the right vehicle.

I run a stock prom in my 1227747.

Works fine, I nave NO complaints. No codes either.

No codes depends mainly on what is hooked up in the harness. Wiring the Park / Neutral switch together makes the enigne always think it is out of gear. THings like VSS and EGR will not set because the computer always thinks the vehicle is not moving .... BTW, this is what Painful (painless) and other "DIY" harnesses do to help you :flipoff2: In all honesty, for a trail vehicle, as long as it has all the basic engine stuff and the O2, you are set :beer:

any 4.3L or 350 tbi computer will run it.. most people have the best luck with factory ecu's.. ecu's go for about $50 at the junkyards here..

thanks for the replies. I am going to get the 1227747 prom and see how it works. I don't want to spend the money on a custom chip (otherwise i would have gotten TPI). This is not a trail only rig - it will see street driving around town and to and from the trail. Again thanks for the help and I'll let you know how it works.

Like everyone else mentioned, any computer with the 1227747 number on it will run most TBI motors. The important thing to do is make sure you've got the right "Cal Pack" or calibration pack in it. If you remove the cover plate on the computer (its a small plate held on by two screws) the Cal Pack is located underneath it. It's a small chip that plugs right into the circuit board.

GM can sell you a Cal Pack (I think I paid around $60Can for mine). The calibration packs tell the ECM how much fuel to give the motor etc. There are different Cal Packs for every motor and for various types of vehicles. A Chev 1500 pickup with an automatic runs a different cal pack than a Chev 3500 with a 5spd.

I picked up a Cal Pack for an '88 Blazer with a TBI 350 and a SM465 4spd. It a perfect match for my CJ with a TBI 350 and SM465.

Edit - Just to clarify - So long as the Cal Pack in the ECM is one for the same size motor it will run fine (don't run a V6 cal pack with a V8). It just might not be giving you 100%. The fuel curve could be off etc. GM also released upgraded Cal Packs for some years to cure performance problems etc.

THAT IS EXACTLY WHAT I WILL BE RUNNING - THANK YOU VERY MUCH

The calpack also has the limp home mode, that is not part of the actual 27c128 "chip" or eprom. These are specific to each type of combo, so tell the dealer what is was out of and thye can setup you up with a P/N go to a discount GM parts house and order away. Should be about $60...

TRD just throw that junk together and lets go wheelin already. UR TAKING FOREVERRRRRRR. :flipoff2: :flipoff2: :flipoff2:

Dude, I think the problem is, that YOU are working on it. Stay outta the garage, and go back to the classroom, biatch!