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89 Chrysler Voyager, SMEC Gurus Please Help

Hello everybody,

some weeks ago I've posted problems I had with my 89 Voyager. It reported code 54 (although the signals from the distributor looked great at the oscilloscpe screen), it was hard to start and tended to stall at red lights when warmed up to full operating temperature. It also engaged the a/c compressor every

10 seconds (but just for a single second!), even when I pulled the cable from the low pressure switch! I finally gave up searching for cabling and / or contact problems. I went to a second hand parts dealer and bought a used SMEC from another 89 Voyager. The SMEC I bought did not have a Chrysler sticker with a parts number on it, so I was unable to verify that it was exactly the same SMEC as the one in my car, but these computers are extremely difficult to find in Germany, so I just decided to drop $100 and give it a try.

Back home I swapped the SMEC.

Now the car is running great! No more "code 54", no more a/c trouble, no more hard start procedures, no more stalling! Last weekend I drove the car for 500 miles, fuel economy is good.

There are just two issues left: with the "new" SMEC I have a little bit higher voltage than with the old one. Can this be adjusted at the dealer? What is the maximum allowed voltage when the engine is idling? Second: I'm getting code 23 now, which should tell me that the charge temperature sensor is malfunctioning. Well, my engine (a 3 litre Mitsubishi) does not have that sensor! Is it possible to "tell" the SMEC (using the dealer's computer system) that there is no such sensor, or should I just let it live with that error, or should I try to add that sensor to the car to complete the system? If so, how can I connect a wire to the 60-way SMEC connector, I do not have a connector for that sensor in my wire harness?

Thanks for your help,

Markus

Reply to
Markus Klama
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I remember this report, yes.

On the other hand, this means your likelihood of getting the correct one when you *do* find one is higher!

Terrific. Problems solved.

It cannot. The voltage regulation is fully integrated with the SMEC and is nonadjustable. If voltage regulation fails or becomes problematic (e.g. overly temperature sensitive such that your fernlichtgluehlampen act like blitzlampen if you switch them on immediately after starting the engine in very cold weather), then you either get a replacement SMEC (factory fix) or you cleverly install an external voltage regulator -- THESE can be had in adjustable form.

It is temperature sensitive. Factory spec is as follows by ambient temperature =B0C at battery:

-18 to 10=B0C : 14.95V 10 to 38=B0C : 14.45V 38 to 66=B0C : 13.85V 66 to 93=B0C : 13.75V

I cannot confirm or correct this with the literature available to me at this time. That is what is listed in several of the online code lists, but codes differ from year to year, and unless you have got this equation from Chrysler's own 1989 FWD service manual, do not be sure it refers to the air intake temperature sensor (or "Charge temperature sensor" as you call it). P

No. SMECs cannot be reprogrammed by the dealer's computer system.

Probably the easiest route. It's running well, getting good fuel economy..

=2E..zie gesundt!

DS

Reply to
Daniel J. Stern

Reply to
Marvin Cohen

AHA! Now checking that with a voltmeter it turns out that right now with the "new" SMEC I have the right voltages; so I must have had a low voltage system with that original broken SMEC, because the dash panel voltmeter showed about 0.5 volts less before the swap. Also my "Fernlicht" is quite normal (Hey, where did you learn German?).

Hmm, the thing about code 23 is "what they say on the net" and what my Haynes manual says. I don't have CC manuals available. I was just wondering if anybody knows that it is normal that within the model year of 1989 Chrysler made 3.0L engines with and without the intake air sensor. Is it possible that this is a difference e.g. between California and Federal engine versions? I'm just asking because it was around 1989 when CC really started selling the Voyagers in Germany. Nevertheless at that time half of all the vehicles registered in Germany were self-imported, that means we have a beautiful mixup of Canadian, Federal and California versions and usually the German Chrysler mechanics do not even know that these cars were different!

The Haynes manual says that 3.0L and 1991 and earlier 3.3L engines have that "charge temperature sensor". They even supply a drawing about where the sensor is located (passenger side of the intake air plenum, right above the vacuum hose connector). At that very spot my Voyager's intake plenum does not even have a blocked hole or something like that. I also don't have an unused connector in that area.

That code 23, BTW, does not light up the "Check Engine" lamp.

Best regards,

Markus

Reply to
Markus Klama

Most of what I need to know I learned from my friend Peter:

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It will pay you many times over to send to North America for the genuine Chrysler Corp. manuals -- or watch for them on

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. The Haynes book is dreck!

DS

Reply to
Daniel J. Stern

Incorrect. It is perfectly normal that the original poster's '89 Voyager uses a SMEC. The SBEC was first used in 1990-model vehicles.

DS

Reply to
Daniel J. Stern

Yes, of course my vehicle takes a SMEC. But that they went from dedicated sensor (at intake plenum) to extrapolation from another sensor, that's new to me. If this is the case, they must have done it in 1989, because the dealer who sold me the replacement SMEC gave me the VIN of the vehicle from which my replacement SMEC was taken out. So I could verify that both cars were 1989 models (if the info was correct, however).

I would not mind to buy a sensor and connector, drill a hole into the intake plenum to screw it in, but how should I attach the wires to that

60-way connector? I'm afraid I would need special crimp-on contacts to snap the wires into the connector body...

See Daniel Stern's post. Turns out that I'm having the correct voltages now and that I've had a low voltage condition with the broken SMEC.

Best regards, Markus

Reply to
Markus Klama

According to my CC service manual for the 89 Caravan, the code 23 applies to the throttle body temperature sensor which is used on the four cylinder engine only.

Code 23 is not listed in the 3.0 engine code list.

Reply to
eldred30

Some more information

The SMEC in both of my 89 Dodge Grand Caravans with the 3.0L engine are marked with the CC part number - 5235097. If the part label is missing, the part number can be obtained from inside the SMEC by using a scanner such as the OTC System 2000.

The eBay auction had a new SMEC of this part number up for auction this summer. The starting bid was $90 but there were no bidders.

Reply to
eldred30

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