Tricking 3800 PCM into being in park? (Page 1/2)
Additivewalnut OCT 18, 04:33 PM
I have a 4spd 3800, I can't go WOT without it falling flat on it's face and all the timing gets taken out of it. It feels like a rev limiter and the only thing I can think to do is a CASE learn since it's a different PCM than what came with it. I've seen the post that says to jumper pin X to ground and whatever but I can't seem to make heads or tails of my harness connector + the guy who did the harness pulled the pins that weren't being used out so I don't have any colors to go off of. Does anyone have pictures or a guide that explains it like I'm 3 years old? I also have an O2 sensor code for the one coming out of the manifold but even after replacing it and clearing the code, it still persists. Wiring checks out so all I've got left to go off is maybe my PCM is shot.
olejoedad OCT 18, 05:06 PM
Any wiring harness guy that knows what he's doing would have included the proper wiring and full instructions on how to trigger the PCM for a CASE learn with a manual transmission.

I guess you get what you pay for, heh?

Sinister Performance has the instructions on his website.

[This message has been edited by olejoedad (edited 10-18-2023).]

Additivewalnut OCT 18, 05:16 PM

quote
Originally posted by olejoedad:

Any wiring harness guy that knows what he's doing would have included the proper wiring and full instructions on how to trigger the PCM for a CASE learn with a manual transmission.

I guess you get what you pay for, heh?

Sinister Performance has the instructions on his website.




Ugh yeah. I mean everything else is really quite nice. All wrapped up and tidy, the tune is decent enough. It was done by Danny Mcllmoyle, he had nothing but great reviews on Facebook.

Other than that, the one on sinister's site mentions pin locations but they don't seem to line up with what's on my ecm connectors. Which is why I was hoping someone had a pic of the exact spot I need to add wires.
Additivewalnut OCT 18, 05:32 PM
for what it's worth, the car runs fantastic until you give it more than 3/4 throttle. It takes a fair amount of cranking to start though. It idles a little high too but does eventually settle. I really wonder if my PCM is junk. I have another one that isn't tuned to have emissions or any auto trans stuff turned off. If I plug that in would anything be harmed?
olejoedad OCT 18, 07:45 PM
The PCM should have the same part number, as all 3800 PCM's are not pinned the same.

I doubt the PCM is junk, they are very reliable.

What PCM # are you using?
What year engine?
Additivewalnut OCT 19, 12:24 AM

quote
Originally posted by olejoedad:

The PCM should have the same part number, as all 3800 PCM's are not pinned the same.

I doubt the PCM is junk, they are very reliable.

What PCM # are you using?
What year engine?



Its out of a 2004 monte carlo. I think Danny is going to send me a new one and see if it's a PCM issue. But it's still not out of the question that it could just need a case learn
ericjon262 OCT 21, 12:08 PM
how are you tuning the PCM? if you don't already have it, download a copy of tiny tuner, and get PCM hammer and an OBD pro VX interface, in the transmission parameters, there's a subsection titled "Gear ratio" under that is "trans type" set this to "0" for manual transmissions. the P04 PCM was used with a manual with the 3800 F body.

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I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.

Additivewalnut OCT 23, 12:31 PM

quote
Originally posted by ericjon262:

how are you tuning the PCM? if you don't already have it, download a copy of tiny tuner, and get PCM hammer and an OBD pro VX interface, in the transmission parameters, there's a subsection titled "Gear ratio" under that is "trans type" set this to "0" for manual transmissions. the P04 PCM was used with a manual with the 3800 F body.




I personally haven't even attempted to tune anything on it. It has been tuned by the same guy that made the harness. So honestly I have no idea what any of the things that you said to get actually ARE. I didn't think there would be any crossover for an N/A F body PCM and a FI W body car
Darth Fiero OCT 25, 08:42 PM
I've never seen a situation where the CASE Learn NOT being done caused the engine to fall flat on its face above 3/4 throttle. Will the engine rev above 4000 rpm if you are giving it less than 3/4 throttle?

If you are not getting a code P0315 or P1336, then a CASE Learn is not required by the PCM.

If the PCM requires a CASE Learn, and one of the above codes are set, this can cause extended crank times before the engine will start.

-Ryan

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More is more. Less is not enough.

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

Additivewalnut OCT 25, 11:07 PM

quote
Originally posted by Darth Fiero:

I've never seen a situation where the CASE Learn NOT being done caused the engine to fall flat on its face above 3/4 throttle. Will the engine rev above 4000 rpm if you are giving it less than 3/4 throttle?

If you are not getting a code P0315 or P1336, then a CASE Learn is not required by the PCM.

If the PCM requires a CASE Learn, and one of the above codes are set, this can cause extended crank times before the engine will start.

-Ryan



With 1/2 throttle I can all the way to redline with zero problems, any gear, any speed. I'm not getting any of the crank sensor codes but it does have to crank for a while to start. Probably about 4-6 seconds before it catches and then starts idling at 1400, comes back down to 850 after a minute