pain in the wallet

[94caravan]

I have a 94 Dodge caravan which is having costly repair problems. I have replaced an engine computer, distributor cap, rotor and wires, and most recently two sensors. the car is back in the shop and the mechanics seem clueless.

HELP - car stalls out in good and rainy weather.

[unite@af]

Well The problem is that you own a Caravan. Sorry

[texan]

94caravan- Could you explain the problem in more detail? For instance, does it stal out only when cold or only when warmed up? Does it stall when idling or only whne you depress the gas? Does it ever stumble at idle or at part throttle?

Also, what sensors have you thus far replaced?

[94caravan]

the majority of the time the car stalls when the engine is warm, after each repair it will perform 3 -5 days and then demonstrates the same behavior. the car starts to stall and will cut out, sometimes it will restart most of the time not.
it was a "crank" sensor that was replaced

[texan]

I would say it has to do with fuel delivery then, in which case (as usual on modern cars) it could be a hundred things. Here's a possible clue to the problem...

In automotive applications, closed loop refers to the mode of operation where the ECU monitors input from all sensors and trims fuel delivery and timing maps to optimize engine performance. During open loop operation, however, all but a few critical sensors (TPS, MAF, coolant temp and Crankshaft Position Sensor on your cars) are ignored, and fuel delivery and timing are based on pre-programmed maps. So if your car only stumbles, hesitates or stalls once warmed up, it's doubtful the sensors monitored for open loop operation are ever the cause. In closed loop operation MAP sensors, O2 sensors, and often a host of other sensors are hard at work trying to keep engine operation optimized, and it should be one of these that is causing the problem. Unfortunately you didn't say that the engine only has problems when warmed up, and on top of that it works fine after leaving the shop for a few days. All I can say is now I understand why they are having difficulty pinpointing the problem, but then again the ECU should be generating codes to help them identify where the problem lies. And of course they can actually look at the car and hopefully get the problem to surface under controlled contidions, so it's not very confidence inspiring that the mechanics can't fix it. Have you tried taking the car to another shop? And is this the dealership service department that's been looking at it?

[JD@af]

I too have experienced and wondered about cars running with these types of problems. Could it due to clogged fuel injectors, a spent fuel filter, or a blockage in a fuel line?

[texan]

JD- It could have something to do with any one of those things, but then again the most common effect noticed from poor fuel delivery is having a hard time starting the motor. The fuel pump cycles over before ignition in any fuel injected motor to create adequate line pressure for starting, in the case of a partially clogged line it takes longer to build this pressure at the fuel rail. Hence the engine usually needs to be cranked over a few times before it fires right up, and also the upper RPM ranges tend to get a lot flat power wise from inadequate flow. If this engine will rev freely and start easily, I doubt it's a flow problem, more likely it's some damn electrical or sensor based issue that is going to be really hard to track down. Sometimes I think it would just be nice to go back to the days of low fuel pressure carbs and mechanical timing advance, since at least these systems allowed easy diagnosis of problems.

[JD@af]

Wow. That diagnosis seems dead on correct. I'll take note of this, thanks a lot for the info.

I'll check into AF later to report on my "trip" for today: the NY Auto Show opens in about two hours!! Can't wait to see the new Acura RS-X, Civic Type R, Nissan Z, Mazda RX-8, and a few others. Have a great day tex-

-JD

[94caravan]

94 Dodge Caravan has been to two different mechanics. we are now getting ready to take it to a dealer and hope for a miracle that they will correctly diagnose the problem. each time we are in the car its a nerve racking experience.

will post to sight after the dealer takes a look.

thanks for suggestions.

[94caravan]

to Texan:

well its been 3 days and so far so good.
dealership replaced oxygen sensor, thermostat and gasket AND distributor system(?). total $960

the thermostat was replaced because the engine temp gauge never got beyond C and even though I had replaced the distributor cap and wires - more related components where replaced. once the dealer got it the diagnostics went quickly - and expensively. so if the car continues to run for more than 7 days we will declare this a success.

thanks for you feedback.:sun:

[CorvetteMan]

Dodge is an expensive make no matter what the problem is, all dodge parts cost a lot of money.

[cgin59]

You think Dodge is expensive, try buying Honda and Toyota parts....not just the simple plug wires or dist. cap. $$$$$$$$$$ I do my own work on Caravans. After 30 years of fixing cars, only 1 out of 5 mechanics has any idea what's going on!

[Dtech42]

Nissan suck too. Thier early 90s cars have bad distributor oil seals (might have been the problem with the 94 Caravan too) that fouls the Crank sensor and causes a stall. Replacement--$200 part, $300 install if you take it to the dealer. Add another $200 if you want them to diagnose a no-start problem