So this code 27 keeps stalking me.
I've replaced plugs, wires, coil, map, iac, tps, fuel pump and sending unit, battery, both temp sensors, fixed the splice under the fuse relay box, new o-rings on the injectors.
The injectors read 15.2 OHM except for cylinder 4 and 8, which read 13.4, but the manual states 13-15 OHM is acceptable. The fuel pressure is a solid 40 psi whether idling or revving in park. When the check engine lights, the truck starts to misfire badly, but fuel pressure is still 40 psi. It holds 40 psi in the rails for one hour, then drops to 10 psi, but I've read that aftermarket fuel pumps are designed to only hold pressure for a few minutes sometimes. This is an airtex pump, which I also read that are horrible and won't work in weather over 90 degreesf, which makes sense since I can burn the tires when its cool outside and can feel 300+ horses, but when it's 110 degrees outside, it feels like its running on four cylinders; maybe 60 horses until rpms are over 2800, reeks of gas like massive fuel is dumping into the cylinders and mpg goes from 18 to 4.

The truck doesn't have a catalytic converter, but Thursday I will be replacing the o2 sensor and possibly the fuel pump back to the old one, which worked fine; just not the sending unit.

 

PCM is shot, again. I'll be taking this POS into the desert on Saturday and having at it with a Bushmaster Chaingun, maybe any other Dodge on the way

 

I feel your pain there. Just went through the same thing on my 92. Fan clutch died without warning but still kind of spun. Temps here hit 100* last month and melted the stock PCM and the first replacement one till I figured out what was causing the truck to overheat. New fan clutch, 2nd PCM and a custom made heat shield and she was good as new again

 

I bought a reman Cardone this time. It appears that the Mopar $700.00 units still use electrolitic capacitors, which can blow within a few days, while the Cardones updated the software and capacitors with ceramic, which never fail.

The tachometer was pegged past 7000 rpms when I swapped out the PCM's, but the first gen dakota has a bolt on plastic shield. Just removed the four tamper proof torx and flicked the needle counter-clockwise, and it reset itself. No need to crack the glass.

Runs better than it did when it came off the floor in 1996.

How long does it take to train/learn the new pcm? 50 miles at 45mph, 45 miles at 50mph?

 

I was very careful after the second PCM fried. For the third, I drove the truck 50 miles from 0-75mph (what I consider highway speed) with absolutely no accessories on as sort of a break-in for the new computer. I've heard people say as little as 2 hot/cold driving cycles at or above 45 mph and I have heard as long as 20-50 key-on/off driving cycles. I have almost 400 miles on since my 50 mile break-in on 4 driving cycles and haven't had any issues (knock on wood). Also noticed a good gain in fuel mileage too now that the ignition system knows what the hell is going on again lol

 

It took me 10 miles of city (well, desert where I live) driving to learn (45-60mph). I will swear by Cardone computers from this day forward.

I seem to have a major increase in mpg with the new parts. Usually it would take $20.00 to get to Walmart and back. Today, the fuel gauge needle barely moved, so I would guess a 600% gain in fuel economy.

The sad part is that my degree is in Computer Science, and the computer is the one component I refused to care for. Que Sera, Sera.

New Water Pump
New Plugs
New Ignition Wires
New Ignition Coil
New Oxygen Sensor
New Engine Control Module ECM PCM $400.00
Rebuilt Fuel Injectors
New Fuel Pump and Sending Unit
New Optima Battery $260.00
New Driveshaft U-Joints
New Seal and Gaskets, Transmission
New MAP Sensor
New IAC Sensor
New TPS Sensor
New Temp Sensors, Both
New Thermostat 180 Degree
Gear Indicator Replaced (common replacement with these trucks)

That put it right at $5k invested. I think these trucks are like a bipolar woman; they judge their own self worth by the dollar sign compiled against themselves.

 

Gonna hijack the thread for a little bit. I had a small engine bay fire on the drivers side fuel line connectors failed long story short I'm now popping a 27 code I had an injector get melted on the connector. I replaced the engine bay wire harness. So do you guys think it got hot enough to fry the PCM?

 

Airtex fuel pumps are great. I actually prefer to install them on customers vehicles due to their low failure rate. By the sound of your conclusion, it wasn't the fuel pump at all and you're besmirching a quality part for lack of diagnostic skills.

You can't blame the truck for your lack of diagnostic skills. My '94 Dakota is a great truck and not bi-polar at all. I have spent less than you even with my performance upgrades but I only fix what's broken. I'm not a parts thrower.

 

Hey just a thought. did you ever check your crank position sensor. I understand its a little different, but I ran into this same issue with a 98 Jeep Cherokee 4.0. I was just trying to help a guy out. he did MAP Sensor, Plugs, Coil, Everything he could think of in the autozone parking lot. Ended up being the crank position sensor. ran like a champ after that.