1996 Voyager - No Power/Backfiring/Fault Code 43

Hi all,

I have a 1996 Plymouth Voyager 2.4L, 4 cylinder with 176,000 miles.
During a trip, it began to lose power when put under load (e.g.
accelerating from a stop, climbing). My initial thought was the fuel
filter so I had that replaced. (The fuel system did have very low
pressure before the replacement.) This seemed to help the problem only
a little and only for a few days.

The problem has slowly gotten worse over the last couple of thousand
miles or so. Now...

* Difficult to start when cold. Backfires. Odor of raw gas present
around rear of vehicle (exhaust).

* Idles only slightly rough.

* Almost no power when accelerating from a stop. Sometimes backfires.
(When it gets up to speed it does okay unless it's forced to climb.)

* Almost no power when climbing. Backfires some.

* Problem is sporadic but present more often than not.

I tested the charging system and found it to be normal so I checked
the fault codes. It returned 12 (battery disconnect), which I
expected. It also returned 43 about four times before flashing 55
(end).

Code 43 deals with the ignition system. I purchased a new coil which I
will install today over lunch. However, I tested the resistance of the
old coil and compared it to readings I'm getting from the new coil and
they are pretty much the same so I'm not too confident this will
remedy the problem.

Here's the recent service history:
* Clock spring replaced at dealership (over 10,000 miles ago).
* Throttle body, injectors, and cylinders washed at dealership (over
10,000 miles ago).
* A gasket replaced at dealership (over 10,000 miles ago; was causing
a misfire on Cylinder #4).
* Fuel filter replaced by my father (under 1,000 miles ago).
* PCV valve and related cracked vacuum hoses replaced by me (under 10
miles ago).
* Oil changed and oil filter replaced by me (under 10 miles ago).

Thanks in advance for any advice. After I replace the coil, I'll post
a follow-up.

-- Christian

 

Need to look into the possibility of the power module (SMEC) driver
transistor being bad. Easiest to replace entire module.

 

Thanks. Is this something I can do myself or do I need to take it to a
dealership or mechanic? Where do I get the power module driver and
about how much does it cost?

Again, thanks!

-- Christian

 

Replaced ignition coil as planned. Runs without problem. Starts well.
Idles well. Good power.

Now, onto the transmission problem (but that's another post).

Thanks for the help.

-- Christian

 

My first suspision would be secondary ignition, plugs and wires, Under a
load backfiring, that would be the first thing to replace and i didnt see
that anywhere on your list that you have done?Also make sure there is no oil
getitng into the spark plugs holes, that could be a problem
Glenn Beasley
Chrysler Tech

 

I did test the resistance of the plug wires and found them within the
acceptable range. I also pulled and checked the gap on all four plugs
(which had been replaced when the other work was done at the
dealership). They were pristine (no carbonization, oil fouling, or
other problems).

Thanks for the advice.

-- Christian