Hey all,

I started a wanted thread last year where I was looking for Mopar Performance PCM p/n P5249546, but I thought I was start another one with a better title. Here's my old one for reference: https://dodgeforum.com/forum/2nd-gen...n-s-teeth.html

I wanted to check in here again to see if anyone has the PCM I'm looking for. I'm still looking! If you read the other thread you'll see there were a few available this time last year, but there was actually only two: one for $610 and another for $650. The $650 dollar one that was on eBay in September 2021 is STILL there today. I reached out and offered $350 for it last year but didn't get a reply. At $650 he might as well put the thing in a frame and hang it on his wall because I don't think it's going to sell. But aside from that one I haven't seen any on eBay or Craigslist since last year, and believe me, I have been looking.

Since my last post I installed a Mopar Performance M1 intake, which is great, but it moves the power band up so I could really use the extra RPM the Mopar PCM would allow. I also installed a set of roller rockers and just completed the holy grail of muscle car upgrades: overdrive transmission. (I know, I know, this is the truck forum and I'm posting about a muscle car. But I'm posting about the truck powertrain!). The trans is a 46rh, so exactly what was behind that engine from the factory in 1994. I put in a 2500 stall torque converter (with lockup) so the car gets up and goes pretty good. Right now the overdrive and lockup are controlled with pressure switches that are fed from the governor port, but I'm going to change it so it uses the PCM to control OD and LU. For those that don't want to go look at my other thread on this topic, here's a list of the rest of the setup:
- 1994 Magnum 5.9
- Long tube headers into 2.5 inch exhaust
- Hughes cam SER0814ALN-14 and spring kit (https://www.hughesengines.com/Index/...4&partid=30212)
- Super mild porting on the heads. I only removed the most ridiculous bumps and restrictions.
- Lapped the valves, they all sealed beautifully.
- Removed the EGR and EVAP system (I probably would have kept it if it wasn't such a mess of tubes and vacuum lines).
- 3.23 gear in an 8.75 Sure Grip diff with 27" tires.

Here's a couple pics I just took.

 

The 46RH came behind the 5.9 magnum in 94..... your current PCM should control it, I would think.

The performance PCM is getting REALLY hard to find... if not impossible. Haven't made 'em for a couple decades, and those that are still working, are generally in use. I really don't wanna think about how many of them went to the scrap yard, when folks didn't know what they had......

 

Yup, I just have to get a speed sensor in the trans so the PCM will know when to shift. Right now I have the old school mechanical speedometer drive in there, so I was thinking I would have to give up my analogue speedo. But then I found out the 93 Dakotas used a speed sensor AND a mechanical speedo. They were Magnum engines, so the sensor should work fine for me You can see below that the sensor has a pass-through for the speedo cable.

Your comment about MP PCMs having gone to the scrap yard is so true. I know they didn't sell a ton of them back in the day, but there should be more of them out there right now!

Oh well, if I don't find one then I'll live with the factory tune (car runs great, tbh) or I'll do the OBD2 swap. Then I'm back to pressure switches to control my 46rh, or I would have to swap it out for a 46re.

 

Ugh... it's looking like OBD2 might be my only option to get a tune into this thing. Does anyone have any advice on which year of OBD2 I should go with? Something early like 96 / 97 or something later like 2002 / 2003?

 

A fair bit changed between 97 and 98, so, the 96-97 electronics will make for the easiest conversion.

 

Well, looks like I won't be going to OBD2. I got the PCM controlling the OD and lockup on the trans this past weekend, and it works SO GOOD I'm not going back to the pressure switches. If I went with OBD2 I would have to swap out my 46rh for a 46re to have the PCM continue to control the transmission.

Here's how I made it work: I installed the 2 wire speed sensor that would have been used on the earlier TBI engines (the one I posted previously). One wire goes to the 1994 Magnum PCM, the other wire to ground. The 3rd wire used in the Magnums was for an 8 volt feed from the PCM, which I think is required for the digital hall effect sensor whereas the older style sensor is a reluctor type (I think). I wired up the OD solenoid to the PCM, and like magic now the PCM is controlling OD and lockup.

The pressure switches were fine, but they would engage and disengage at the set speed regardless of whether I was at full throttle or accelerating like granny. Plus it didn't allow for kickdown when I stepped on the throttle, and the lockup wouldn't unlock when I let off the throttle (it would only unlock once I got to about 53 mph).

Having the PCM control the transmission is so much better I'm not going back to the pressure switches. So I'll hold out hope that I can find one of those old Mopar Performance PCMs, or I'll just live with the factory PCM and know I'm giving up a bit of horsepower.

 

Nicely done. That is a cool workaround. Anybody with a Gen I looking for a Magnum, stuck with auto, might be able to use this.

 

Thanks! It's a lot of fun / rewarding to make stuff work that was never intended to work.

Hey, wait a minute, what do you mean "stuck with auto"??? Some of us are pretty damn lazy and happen to like it 🤣 🤣 🤣

 

Getting back to the original intent of the post, there are now three of those PCMs on eBay. The one that has been on eBay forever at $650, another one popped up about a week ago for $600, and something very interesting: one that appears to be NOS for $950 just a couple days ago.

They're all way more than I'm willing to spend for the 20-ish horsepower I would get out of it, especially considering the car works so well as it sits. But I'll hold out hope that someone is willing to give one up for a reasonable price one day.

 

I bought the last two Mopar Performance units SummitRacing had for the '95 V-10. Maybe 100USD ea. Had the others available at the time for similar prices, might have been a good investment.
Can't say anything, all my trucks vehicles except the '85 W350 are auto shifted.