3400 buggy install

[dezertrat]

I am relatively new to posting on the site but have been visiting for info on my swap for a while.

I have a "sandrail" with a rear mounted 3400 v-6 out of a 99 pontiac montana. The motor is installed with custom full length headers, a manual transmission (vw type), power steering, and the stock OBD 2 pcm.
The motor has the following sensors/systems intact: DIS, cam/crank sensors, IAT, MAF, coolant, MAP, front O2 sensor, IAC valve, TPS, knock sensor, oil pressure sensor, stock injectors and pressure reg.,
The motor has no egr sensors or valves, no a/c compressor, no 2nd o2 sensor, and no vss. I may have missed something, but its hard to say without seeing.
The motor starts and idles well. The car does not run well in the mid range through top end. I sent the pcm to pcmforless where they supposedly modified it to work, but I have my doubts as to whether or not they accomplished what they said.

I need advice as to how to best manage the engine.
I can buy software from dhp to do my own programming, but will it work without the vss/egr/etc.?
Should I change to a OBD 1 setup? If so, from what car?
Can I run either setup without the vss?
If not, does anyone have experience with an aftermarket pcm?
And, as a last ditch effort, is there anyone out there that has made a manifold to put a carb on this bad boy? It seems that it would be a one off custom item, but I have alot invested in this thing...
I have access to a complete L67 with a standalone pcm, but that goes against the grain...

Any help/advice would be greatly appreciated....

Its dune season and I don't want to scrap the whole enchilada...

Thanks,

Frank

[WhiteRaider]

You can go about it a bunch of different ways. Your most painless would probably be to get the engine harness and ECU from a late 80's/early 90's car with a 3.1l engine. The preferred ECUs are 1227730 or 1227727 ECU because they are widely hacked and programmable. You are just MPFI instead of SFI that way, but it works well and is easy to program. You should be able to find them all over the place. If you find one from a manual xmission, you can pretty much just plug and play. Otherwise, you can have your transmission controls disabled with a new burned chip from a bunch of sources. The ODB1 controllers can be reprogrammed to turn off EGR. Or, you could buy a chip burner and do it yourself.

I got my 7730 ECU from a Chevy Corsica. Cavaliers are pretty easy to rip the wiring harnesses from I hear. If you go to a junkyard, just look through the GM small-midsize cars from that era until you find a 3.1 manual and take the harness and ECU from that car. You should be able to find one in any decent sized yard.

There are some people who have built adapters to add an older EGR from the ODB1 era to the newer engines if you wanted to make it functional. For a buggy though, I wouldn't bother.

Alternately, if you are handy with a soldering iron, you could go the Megasquirt route. You can build your own ECU and program it using the stock GM sensors that are already on the engine. For DIS type ignition, a lot of the Megasquirt users convert their cars to use Ford's EDIS. However, they have started to be able to use GMs DIS recently. You can check it out at http://megasquirt.info .

If you've got money to burn, you could always get an aftermarket controller like a Haltech.

My preferences would be in the order that I listed.

[dezertrat]

thanks for the advice. I appreciate the quick response.

So, going the first route, do I need to somehow have a vehicle speed sensor? This is the only sensor that I could not easilly install...

Are the numbers you gave me off of the pcm?

Are those old cars DIS? If so, I assume that I will have to get the module/coil packs from the old one..?

Also, are those old cars MAF, and if so, should I get the MAF from the donor as well?

I assume I'll have to use the older style (unheated) o2 sensor?

And last, but not least, where do I find the software/hardware that I need to reprogram the computer?

Thanks again for your help!!!!


Frank

[WhiteRaider]

Are the numbers you gave me off of the pcm?

Yes, there is a sticker on the top of the computer that gives you the number.

Are those old cars DIS? If so, I assume that I will have to get the module/coil packs from the old one..?

The FWD cars are DIS. Your coil packs from the Montana will work just fine so don't bother swapping them.

Also, are those old cars MAF, and if so, should I get the MAF from the donor as well?

Good point. It depends on the years for the MAF. Mine was a map car. If you do a search in the forums, or it's possibly on the family tree link, it will tell you. You can always update the ECU to just use the MAP which is easier if you get an older one.

I assume I'll have to use the older style (unheated) o2 sensor?

I don't think it would matter, but I never looked into it. I know that some people have wired in heated O2 sensors in exchange for their unheated ones so it would just be a question of researching the wiring. Easiest would be to buy a non-heated as I doubt it would matter for a buggy.

As far as the VSS goes, I'm not sure what adverse effects it would have not being hooked up. Perhaps one of the ECU gurus can chime in on that.

Software and hardware to reprogram are all over the place. Moates.net is one and tunercat.com is a place that I know of. If you google for "programming the 1227730", you'll find a lot of information. Also, there is a lot of great information on this site and forum.

[dezertrat]

Thanks a million...

I will research the vss thing on the computer forum...

Awesome info...off to the junkyard I go!!!




Thanks again,

Frank

[geoffinbc]

Keep the heated sensor. Thay keep the ECM in close loop during idle because they do not cool down when the exhaust flow is low. The VSS is an extremly important sensor on stock ECM's. If changed properly then you would be a ble to run without it. You shold contact the company you used and get more info on what they have done and see if a VSS is required. It sounds like it may be. EGR wont cause running issues. It is easily removed.

[dezertrat]

Great...maybe I won't have to re-wire the whole system!!!

So it is possible to run without it?

What does "changed properly" entail?

I have a spare stock PCM in my hand, and was going to order the dhp software to tune my OBD2 unit, but was wondering if in fact the lack of vss would put me back to square one.

I would rather not deal with pcmforless anymore. They told me that they could program the computer no problem, and when they received it they told me they had no programs for a 3400. They supposedly sent a program for a 3800, hence why I don't trust it.

It may be a question best left to dhp. Do you guys have any experience with the software?

Thanks a bunch for the info.

Frank

[geoffinbc]

Ouch yea that really blows. Fuckin company sounds like alot of shit we come across.

Anyway the VSS could be removed from the PCM's math calculations. Especially on a manual trans it is really not too important. I dont know how I have never reporgrammed any computers.

[bu01]

so what hgappened

[dezertrat]

sorry i had not checked in in a while....

I gave up on the obd 2 and am trying an aftermarket controller.

[dezertrat]

That was an understated response...

I decided to try and run a carb with a distributor I made using a 2.8 distributor and extending it about 5 inches. I simply cut a hole on the 3400 manifold and welded an aluminum four barrel adapter to the top. Needless to say, fuel distribution was the demise of this setup. It did pull like gangbusters from 4k to 7k rpm, though.

In november i ordered a custom wiring harness with a delphi mpfi controller from a local buggy shop and am still waiting for the mapping to be done. Mapping is done in Phoenix and out of the hands of the local guy. The wiring harness is very nice. It could be summer again before it gets done. I'll let you know.

Meanwhile, now that I have a distributor, I am persuing a third option. The buggy shop had a Link Systems fuel only control that was geared more towards retrofitting old vw's with distributors. It is a very simple system that batch fires the injectors, but it will get me running before the end of the seaon. I'll let you know how it performs. I hope to have that going by this weekend and on the dyno on Saturday.