Well, I received my "new" Mopar Performance PCM yesterday. Jetted off to the gas station to tank up with hi-test (93 octane) ... on top of about 1/4 tank of regular (87) ... should be high enough to start off with. Installed the new computer (yes, disconnected the battery first). Started right up ... first turn of the key. Idles nice ... ok, lets see what the big deal is all about.

First impressions were pretty poor. The truck felt ... heavier ... like it was running in sand ... or water. This is similar to what I experienced when I tried a tank full of super when the truck was new. Oh, well ... probably just needs a few start cycles to map the motor.

After a while (today), the first difference I noticed was on a certain hill, I was able to maintain speed without having to drop out of overdrive. Nice. There's a longer hill I have to hit tonight that I usually have to drop into 2nd to maintain speed ... we'll see what happens there.

The truck seems to want to accelerate in the gear it's in ... I have to FORCE it to kick-down by flooring it. Makes the truck FEEL slower and heavier.

With the old PCM, the 360 made a lot of power ... on regular gas. The jury will be out for a while (2 or 3 tankfuls, at least) on this PCM to see if it's worth the extra $5 a fill-up.

... I wonder if I can get by on mid-grade ... ?


Oh ... and I've got a constant companion with me. The "Put Your Seatbelt On" guy won't go away. You're supposed to burn your VIN and mileage into the unit (when new). This one's used so it's already been done by the previous owner ... except they don't match my vehicle. The research I did claimed that it can cause all kinds of odd indications ... one of which is the one I'm experiencing. The consensus is that once the VIN is burned-in, it cannot be altered. I don't know ... anyone here know? I'd hate to have to pay the d-d-d-dealer to mess with this thing.

 

You won't be able to get by on mid-grade...not in the Texas heat

The dealer should be able to change the VIN on your truck.

Give the computer a while to learn.

 

I experienced a similar reaction as you when I first installed my Mopar performance PCM. But after I let it go longer, it seemed to get better and better. This seems consistant with about any mod I install. It usually takes 200-300 miles before I notice the full effect of a mod. Same seemed to be true with this PCM install, except I think it was from it having to detect and adjust to all the changes coming in from my already installed mods. I can definelty say without a doubt that my truck runs stronger today then it did when I installed the PCM almost 2 weeks ago. So give it some more time, then report back to us about if it has gotten any better.

I am somewhat disappointed with off-the-line acceleration improvements with my PCM though. It is about the same as it always was. But once I get into higher RPM ranges, escpecially if i'm in second and third gears, it pulls stonger then it ever has. For that alone, it was well worth it in my opinion, escpecially considering what I paid for it on eBay. I'd say it is one of the best performance gain for the price mods I have done. Just wish I didn't have to run premium. I think in the winter I might try to get by with mid grade, and just run premium in the hot months when I ping easier.

 

I ordered a 180 degree thermostat and am digging around for an affordable CTD 3-core radiator ($229.00 on eBay). My radiator developed an 8x1/8" crack in the left tank about 4 months ago and I've been running around on a "Bill-fix" ever since. Consists of epoxy, stop-leak and two modified hose clamps. Survived the 105+ we hit here a week ago but I think it's time to face reality.

I could drop down to a 160 if I had to ...

 

Don't do a 160. If your still pingining with a 180, try some Autolite 3923 plugs. Their one temp range cooler, which usually helps eliminate pinging.

 

Oh, I'm not pinging now ... even on a 195. Of course that's running something around ... well ... let's see ... it was closer to 2/3 tank of 93 on top of 1/3 tank of 87 ... 91 octane or so. The mid-grade around here is 89. We're leveling out at over 100 degrees on a daily basis, running a 195 degree thermostat on a leaky 2 core radiator.

I wonder if a bumbling dealership re-flashed this PCM to standard configuration when they installed the VIN. I read some stories like that when I was researching the "seatbelt guy" thing.

What's wrong with a 160? Why do they make them if they suck?

 

On these engines, it will cause you to stay in open-loop mode which means it will run rich, and will throw code p1281, engine not reaching operating temperature.
Also, they say running that cool causes build-up that would normally be burnt off at higher temps. I can't say for sure on that as I have never done an analysis of buildup on engine internals comparing engines with different thermostats. HankL has some good info on this though.