Will I was wondering if anyone has ever used and OBD !! on a 5 speed manual. What i did was dropped in a 3400 LA1 engine from a 2000 Grand AM into my 98 sunfire and i have a 5 speed isuzu manual (built up). And i was wanting to know if anyone had a way to overide the stock PCM into thinking that the auto tranny was running OK so i could use my 5 speed. I know Digital horsepower inc. can reprogram my PCM but i am wanting to drive the car now and save up for the DHP PCM thanks for the help.

Would you mean ECM and not PCM?

Darn, listening to SACD (DSD) discs and how great they sound compared to even the best DVD Audio (PCM) has made me rottenly oversensitive to some terms.

That would be an interesting development if the ECM worked that way.

Beno

The correct term is PCM for a 2000 engine. The 2000 Grand Am uses a Powertrain Control Module (PCM) and a Body Control Module (BCM) instead of a single Electronic Control Module (ECM), like the Fiero uses.

But yes, the OBDII PCM can be made to work. You have to make the PCM think the transmission is in either Neutral or Drive at the appropriate times. DarthFiero has come up with ways to do this for a 3800SC. I don't know if it's the same for the 3400, though.

edit: I just found this link for Darth Fiero: http://dtcc.cz28.com/fiero/transbypass.htm
and http://dtcc.cz28.com/fiero/fmods.htm

[This message has been edited by Formula88 (edited 03-06-2004).]

Thanks for the info i'll email him. thanks again

If the 2000 PCM is like the 1997 PCM for a 3400 in an Olds Silhoutte, you'll have a tough time. The PCM compares the engine speed to the road speed based on the gear selected. If they two aren't in the correct ratio, the PCM will throw a trouble code. What I mean is that there is a table in the PCM that says the car should be going 40 mph with the engine turning 2000 rpm when the PCM has commanded the transmission to be in third gear. If the actual numbers vary, the PCM thinks one or more of the transmission shift solenoids has failed and trips the Check Engine light. I don't know if the PCM goes into limp home mode at this time. I finally had to give up on using that PCM as my Fiero won't pass emissions with a Check Engine light.

As reprogramming an ODB II PCM is expensive, I'd go with an ODB I ECM.

There is a car out there that has the SFI 3100 but still used the ODB I standard. I think it was the 1993 Beretta or Lumina (car). If you can find out exactly which one it was, you can run the SFI in the 3400 but be able to reprogram it with a pop in PROM.

quote Originally posted by Formula88: But yes, the OBDII PCM can be made to work. You have to make the PCM think the transmission is in either Neutral or Drive at the appropriate times. DarthFiero has come up with ways to do this for a 3800SC. I don't know if it's the same for the 3400, though.

The information I have about bypassing the trans controls in the OBDII PCM's is pretty universal across GM. Of course there will be exceptions, but for the most part that info should help you work around the stock PCM programming obsticle. However, I need to make one thing clear. The information I have up on my site is merely a suggestion. You don't have to do everything that I spell out in order for the car to run and drive. Rather, the information I have up is intended to make your PCM more compatible with the combo you are using as well as improve drivability and functionallity of the stock PCM programming. Ultimately, a PCM reprogramming would be the best option but it can be very expensive and depending on what company you have do the job, they may not do everything you want done or may not be able to fix every problem you have.

In my opinion, my solution to the 3400 5-speed problem would be to do away with the OBDII PCM altogether and wire in an early 90's Beretta 3.1 V6 ECM and then just get an inexpensive custom chip burned. However, if you have emissions testing in your area, this may not be an option your local testing stations could live with.

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