I spoke to the OTC tech. He was very discouraging because the unit is so old and they do not support it or make replacement parts any longer. He did say they would help me interpret any codes or sensor readings I got.
He recommended I get an Actron CP9087 because they do still support it. He figured I could do what I needed to with it.

The guy who is selling it has been working cars since the 70's so he knew how to use the readings but couldn't really explain it. I have decided not to buy it so it is all yours.

I have to decide whether or not to pay the dealer for a diagnosis I do not trust or to just buy a new PCM since I have seen a few posts with the same problems in my searches and that was the fix they landed on.

 

Your best bet is to find a local independent shop that you can trust. Ask your family and friends who they use. The dealer isn't all they're cracked up to be. If you get a fairly new technician who's never worked on an OBD I vehicle could just end up being a parts thrower because they don't have the experience to diagnose it properly. Don't think that because it's the dealer, everybody's got factory training on '94 Dodge Dakotas.

 

Good advice. Thank You.

 

Here are a few bits of information for thought:

• The OBD1 system isn't overly complicated and I haven't run into any that have a built-in security system in them, so replacing 1 ECU for another is usually not a problem as long as you get an ECU that's for the same general generation and engine configuration.
• You can read OBD1 codes through the flashes and reset them manually by disconnecting the battery, but, the OBD1 systems do have a "learning" algorithm and do store parameters that they use to average out various calculations & when you disconnect the battery, you bring the ECU to it's "first time on" state and it will need to relearn some things. This isn't all that critical, but sometimes you'll notice a performance change or a mileage change after doing this.
• You can get a combo OBD1 & 2 diagnostic tool that will be able to read and reset your codes so you don't impact the "learning" aspects. These diagnostic tools can do a lot more than just read and reset, they can give you real time information as your vehicle is running and this can be very useful in diagnosing and confirming any problems or even just trying to tune it for the best the ECU can give to the engine. Usually, there's a bit of a manual with these diagnostic tools and You-tube is also handy in giving tutorials on how to use the real time mode.

 

Thanks Alfons.
It seems to be stuck on idling high now like it did before the EGR code when I first bought it. I'll wait a while as I do not drive it much.

 

If it's idling high, it could be a couple of things, but I wouldn't say the ECU is the problem. Here's what I'd look for:

• Intake vacuum leak - this would be my #1 guess. This is usually the most likely cause of a high idle and this could be related to any leaking vacuum hose including the power steering hose, a leaky intake manifold gasket, or a leaky throttle body gasket.
• Malfunctioning Idle Air Control motor. This is the little unit on the throttle body that many people call an idle sensor - it's not a sensor, but a little precision stepper motor that sets idle based on a voltage signal that's fed to it by the ECU. The other thing on the throttle body is a sensor, it's the Throttle Position Sensor (TPS) and from my experience, when it malfunctions, you get a lot of weird symptoms where the engine will run rough and die - sometimes it won't even start. There are some tests for both of these units.

 

Good info. When I changed the EGR I sprayed throttle body cleaner all over the area around each injector and the egr generally while it was running, as this is a poor mans way to check for vacuum leaks. I'll definitely look into those issues as it makes sense it would be something like that since the motor is so clean and apparently well maintained.

I haven't look yet but since i had the tranny fluid changed there seems to be an oil leak on the passenger side about the level of the wheel. Is the filter near that spot?

I'm waiting for the unusual snow fall to melt away before I dig back into it.

 

Did you happen to check if someone messed with the throttle plate angle?

 

No. I'll add it to the list after I read about it.

 

In relation to your Q on the oil leak, I would check to see if that's oil or transmission fluid - if you don't know the difference, pull out the engine oil dipstick and put some on your finger, feel it, look at it, and smell it (transmission oil is pink and will have a unique odor). Do the same with the transmission dipstick and with the drops of "oil" on the ground. You should be able to tell which it is. If this started after the transmission fluid change, (I'd suspect that's it - look under the truck and see where it's coming from, that would be the biggest indicator) take it back and have them do it up right, don't accept a shoddy job.