This writeup has been a long time coming and is sort of a give back for all the info that has been a help to me in the past. Thanks.
This procedure is not for all, but if followed, will fix the “infamous dying while driving” problem that many had believed to be caused by the 2 torx screws or the 3 bad connectors on the PCM.
You will need to know how to solder correctly, so if you decide to take this on, and don’t have any experience soldering, you can practice with just about anything that plugs into the wall now a days. Just about everything has a circuit board in it.
Just to save typing, if you have been successful with getting your Jeep to respond well to the problems of back firing, stumbling, stalling at driving as well as idling speeds, by tie wrapping the PCM connectors to the PCM, all indications are telling you that the soldering connections within the PCM are bad. This is the procedure for reflowing the bad connections that have occurred over time due to the expansion and contraction of the potting compound, that the circuit board is encase in, caused.
I will explain the whole procedure in detail just so you won’t screw up anything as I did on the first PCM I attempted to repair.
If you screwed up the PCM connector pins and need to replace them. The following link has all the info on getting replacement pins, and what you’ll need in order to replace them.
Supplies needed for the repair,
Regular hand tools,
A pocket knife
A thin razor, snap off blade type utility knife
A torch (propane or map gas)
A brass utility brush (a steel one is too aggressive)
A can of Acetone (for removing traces of potting and cleaning up the pins and circuit board)
A soldering iron (25-40 watt) A Weller iron is a decent brand
Solder (.020”) you might get away with .032” gauge, but the thinner the better
Solder wicking (for removing excess solder, if too much has been applied
A tube of silicone chalking (not the latex type)
The first thing that needs to be explained is how the PCM is assembled so nothing other than what is needed to be done is disturbed.
In the picture below, you’ll see that the top cover is actually a circuit board, laminated onto an aluminum plate. The stuff on there is a gel potting compound that is contained in a foam retainer, and acts as the protective coating and also wicks away heat while the PCM is operating. It sticks onto the cover when the cover is taken off. We want to leave it this way. Do not remove or disturb this stuff when you have it apart. There is no substitute that I have found as yet that doesn’t come in 2 one gallon jugs. $$
Don’t do anything yet,
You’ll also notice, on the cover, that there’s a connector bonded to the cover, which plugs into the (MB) mother board, which is totally encased in a much firmer potting compound. When it’s time to remove the cover, you will need to pull up on the right and left sides (torx screw holes) of the cover so you don’t harm the bond that holds the connector to the cover. Don’t worry it’s held on pretty good. Don’t try taking the cover off by pulling up from the bottom end. It might break the bond that holds it there.
So much for the adjectives……
Disconnect the battery
Remove the over flow reservoir