SMEC - Plymouth Voyager

Awhile back, I posted regarding some probelms I was having w/ my 1996
Plymouth Voyager. It was doing poorly upon initial accelaration and
when under load (very little power). It was also showing Fault Code
43. Someone suggested it may be a problem with the SMEC.

I replaced the ignition coil and the vehicle ran much better. However,
the same fault code quickly returned and performance is again poor
upon initial accelaration and when under load.

So, I'm going to replace the SMEC but had some questions...

1) Is this something I can do or is there some kind of calibration
that must be perfromed by a mechanic?

2) Can a bad SMEC damage the coil?

3) Is there anything else I should consider before/while doing this?

Thanks!

-- Christian

 

Is this a 3.0 or 3.3? If you are going to replace the module it is easy to
do and you dont need any special equipment. Normally the coil would damage
the module if a plug or wire was arching and left unattended

 

Your van hasn't got a SMEC, it's got an SBEC. The SBEC is extremely
dependable and seldom fails; it is probably NOT causing your problem. And
Code 43 doesn't indicate a problem with your SBEC, it indicates a cylinder
misfire.

Probably because you didn't replace the rest of the secondary system *at
the same time* (cables, spark plugs and, if applicable, cap and rotor).

Waste of money unless/until you have tested it and it is *known* to be
bad.

No, you can do it, but it almost certainly won't fix your problem.

Yes: Test and diagnose, don't just throw parts at the problem.

DS

 

2.4L -- the 4 cylinder.

I've checked and cleaned the plugs. They all looked good and are
fairly new. I did a visual and resistance check on the wires. I didn't
see any damage and resistance is within the acceptable range.

-- Christian

 

What's the difference between a SMEC and an SBEC?

Also, I see that Fault Code 43 can be either a problem with the coil
or a cylinder misfire, as you stated. I gather the code indicates one
thng for certain years and something different for other years? (I
might need to find a better reference book.)

The plugs are fairly new. I did clean and regap them but they were in
excellent condition. As there are no cap and rotor, that leaves the
plug wires. Visually, I don't see that they are damaged and their
resistance tests within the acceptable range.Would you still recommend
replacing them?

What's the method to test it?

Thanks for the advice.

-- Christian

 

SMEC: Single Module Engine Controller, has a 60-pin and a 14-pin connector
and multiple circuit boards inside. Used through 1989.

SBEC: Single Board Engine Controller, has a 60-pin connector and only one
circuit board inside.

Requires a scan tool.

A very common cause of persistent misfire is as follows:

Misfire occurs due to secondary voltage leak down spark plug insulator to
ground. First component replaced is spark plugs, but plug wire boots have
also been affected, so affected plug boots continue to allow voltage
leakage. Misfire persists, so spark plug wires are replaced, but plugs are
left alone since they were just replaced. But, faulty plug boots caused
leakage path on plug insulators. Back and forth and back and forth. Often
a persistent misfire of this nature will go away when plugs AND wires are
replaced at the same time.


DS

 

You have carbon tracking on the spark plugs and plug wire boots
as Daniel has described.

Go buy 4 new spark plugs and a quality set of spark plug wires,
install them, throw the spark plugs and the wires in the trash,
even though they look okay, they're not.

 

Aw, I donno, maybe he installed the wrong brand of spark plug, which
caused his logic module to change the ignition timing! ;-)

 

Yeah that's probably it. I knew I should have never used foreign plugs
on a domestic car! {P

-- Christian

 

Which foreign plug did you use?

 

Didn't he claim it was the power module?

 

He probably claimed as follows:

if u INSTALLL THE RONG SPARK PLUG'S ONLY USE CHAMPION'S THEN THE TIMING
WILL CHANGE IN THE LOJIK MODJUL

 

Actually, that was a bit tongue-in-cheek.

I was using NGK. As part of a tune-up the dealer changed them to
Champion when I took it in for service.

-- Christian

 

Seems like I would remember that...

-- Christian

 

Nothing wrong with NGKs in a Chrysler as long as they're the
correct heat range.

 

Daniel is referring to someone else's comments from a different
thread...

 

Naw, don't pay any heed, I was mocking someone else from a different
thread. Nothing to do with your van.

 

Do yourself a favor and change back to NGKs.

 

I've always had good luck with them. Probably will change back.

-- Christian

 

Yeah, I figured that out after I posted.

-- Christian