TPI question

[TireSmoke420]

so the remanufactured crate engine i put in my 87' 2 years ago has gone to ****. maybe 50,000 miles on it my sister has been driving it and its been running bad so we took it to a shop and well there is no compression of the #7 cylendar. havnt had it apart yet to figure out what happend but i find out the engine is still under warrantty... thank god. but now my question is.. has anyone here swapped a TBI to a TPI. ive been thinking about doing the swap for quit sumtime and i think this is pry the time to do it. now can anyone tell me how ill benefit from the swap. and is it pretty straight forward installing it. aside from the right computer and all. i have seen the whole setup on ebay bfore for like 200 bucks intake, computer, and harness.
thanks for anyhelp

[Russell]

First of all, take your guess of $200 bucks, and add about $600 - $800 to that number to get it installed and running.

Second, you'll want to build your engine up a bit to suit the TPI. You want an aftermarket fuel injection cam that makes power from idle to no more than 5500 RPM (you'll never get it to rev that high anyways), and a compression ratio of about 9.2:1. Your current swirl port heads should actually be alright, as they make big torque down low, but won't flow much past 4500 RPM, just like the stock TPI intake.

You'll want to go with an 1989 - 90 intake (lower intake, runners and plenum) that doesn't have the cold start injector stuff, and has the same intake bolt pattern as your TBI intake has right now.

Then you need to decide if you want to run Mass Air (MAF), or speed density (SD). Personally I'd go with a Mass Air system , its a little bit more complicated in that it needs the wiring for the MAF, and intake ducting that incorporates the MAF, but it is more forgiving with regards to engine modifications, and both the ECMs and memcals are a dime a dozen, while a 350 memcal for SD can run a guy over $100 bucks.

If you go with a MAF setup, you will need to have the prom edited to disable VATS, and the AIR system, if you go SD, you will need to have the prom edited to disable VATS, AIR and change the VSS input the magnetic 40 pulse per driveshaft revolution AC signal to the 2000 pulse per mile optical signal that your current TBI engine uses. I can program these chips to disable AIR and VATS, along with changing the VSS input style, and will do so at the cost of shipping both ways, a chip, and low profile ZIF.

Make sure the knock sensor, TPS, CTS, IAT and IAC are included either way, EGR temp sensor, MAF burnoff / power relays, EST module and MAF itself if running MAF, MAP sensor and 350 memcal if SD. The TBI and TPI CTS are both the same sensor. IAT is the same as a CTS sensor as well. MAP should be interchangeable between TBI and TPI too, though they may have slightly different connectors. Make sure you get the correct EGR solenoid for whichever system you wind up with as well.

Get a setup that has absolutely ALL the electrical and mechanical components included. You absolutely WILL get nickled and dimed to death on this swap if you don't. Make totally sure all the nuts and bolts are included, and that nothing is missing. Individual parts are quite expensive...

You can use your old distributer with the TPI engine, they are identical. If you are running MAF, you can simply leave the TBI distributer where it is, and change the EST module out. Confirm the pinout for the EST module and ECM are the same between the two EFI systems.

Fuel should go fairly easily too. Simply replace your TBI fuel pump with a TPI fuel pump, then get a fuel rail modified so you can hook your stock TBI steel braided fuel lines straight up without moving, exending or shortening them.

Wiring should be a cake walk doing a TBI - > TPI conversion, your truck already has all the fuses, and connections you need to fab up on a carb conversion. If you go MAF, you can replace the TBI ECM with the TPI ECM directly, and use the same ECM connectors. You will have a bit of re-pinning to do, but if you do it one step at a time, it should go fairly well. You will need to add a few wires, remove a few others, change lengths, and change connectors to make it all work.

TPI is more exotic than a TBI, and most certainly has way better throttle response / mid range torque, but don't expect any real mileage or driveability gains doing the swap. You could expect better milage, and better driveabilty over a carb though.

I did my TPI swap over the span of about a year, and it really woke my engine up. I'm pretty happy with it, but I can't say I'd do it again. I'm ready to move onto bigger fish, and try a Gen III engine swap. However, that said, for a first time swap, a TPI is nice and easy, relatively speaking, and if you build the engine to suite, you'll be very happy with it

Check out www.chevythunder.com for more information, wiring diagrams etc. Its the absolute best TPI site I know of on the net.