Stalling

[jodiz]

My 98 Caravan has been doing something weird. The "Service Engine" light comes on sometimes the whole day and then it turns off. The problem is that sometimes when I press the accelerator it doesn't really respond. It stalls and then I take my foot off and slowly starts moving until it reaches 50 and up, then it runs smoothly.

I also hear some small explosions during the stalling phase.

Your input is appreciated.

[murph7727]

The problem sounds like it is your catalitic converter. Or possibly your muffler. If the muffler is old replace it first as it will save you alot of money. If it is in pretty good shape, then I would not hesitate to replace the catalitic converter. If not sure you want to replace it then u could try a couple of things first.
1.)Try drilling about three holes in the bottom of your converter. The holes should be between 3/8" to 5/8". This will let the "BB's" fall out opening up your convereter. This will not harm your van in any way except make it sound a little louder, not that noticeable though!
or:
2.)If this does not solve your problem, you may want check your oxygen sensor and/or mab sensor. The mab sensor would be the next likely candidate. Try the catalitic converter thing first if it works then u can actually run it like that for a while, prob between 6months to a year before it will clog up again, or u can replace it. Good Luck! Hope this helps!

[yogi_123rd]

When the check engine light comes on, a fault code is stored in the computer memory for diagnostic purposes. It should lead you to the sensor or engine control system having the problem. You will need an ODBII reader to get it. If an AutoZone is nearby (and perhaps other parts stores do this too), they will read the code for free. You other alternative is to replace perfectly good parts guessing.

[Cobra_Sam]

Originally Posted by yogi_123rd

When the check engine light comes on, a fault code is stored in the computer memory for diagnostic purposes. It should lead you to the sensor or engine control system having the problem. You will need an ODBII reader to get it. If an AutoZone is nearby (and perhaps other parts stores do this too), they will read the code for free. You other alternative is to replace perfectly good parts guessing.

I agree with murph7727 and yogi both have good points, I went the replace route not realising how many sensors these vans have.
You said you heard explosion noises, this is typical when the timing goes out .... related to that is 2 more sensors, the cam sensor and the crank sensor. You can also get miss firing when the engine gets eregular spirts of gas, so you may have a fuel pump breaking down or clogging fuel filter... you see there are too many factors. A quick check you can do is to start the engine at night with the hood up and see if you don't have some plug wires shorting out (sparking) ...If you don't see anything, check the codes ...

[jodiz]

I sure appreciate all your responses. I don't know much about mechanics and I am impressed with all of your advice. It seems I have plenty to work on so I'll start doing my part and I'll let you all know what the findings are.

I forgot also to mention that the problem gets worse as I drive for a while and the engine warms up. When I first start there is no problem it is only after a few minutes that I accelerate and the van doesn't seem to respond...and the explosions...and the rest...well you know already.

Thanks again!

[mrrpm]

If the problem gets worse as the van warms up, I would be sure to check the temp gauge to see if it might be getting too warm. The ECM controled timing is affected in part by the coolant temperature sensor. If this part is defective, the ECM reads incorrect engine temp, and therefore will send incorrect timing signals. I've seen this problem a number of times in my shop. Just something else to consider...

[jodiz]

Happy 2005 to everyone! I finally get a chance to share the outcome of my troubles. Yogi 123rd is the winner. I followed your suggestion and visited Autozone and bingo! The code revealed that it was one of the spark plugs cable. I know I know guys...I sound stupid for not having checked that first but I know little about cars. Isn't it obvious by now? Anyway, thank you for all your helpful responses and I wish you a wonderful 2005 from sunny Miami.

[RM-TECH]

Originally Posted by jodiz

I sure appreciate all your responses. I don't know much about mechanics and I am impressed with all of your advice. It seems I have plenty to work on so I'll start doing my part and I'll let you all know what the findings are.

I forgot also to mention that the problem gets worse as I drive for a while and the engine warms up. When I first start there is no problem it is only after a few minutes that I accelerate and the van doesn't seem to respond...and the explosions...and the rest...well you know already.

Thanks again!

You have two basic areas of concern with a problem like this; ignition and fuel delivery. A simple thing to check is the ignition coil. A defective coil can cause these problems, as it warms up and it starts breaking down. Change te coil to eliminate the issue.
These symtoms can also be caused by a lean fuel mixture. A clogged fuel filter, specially the inlet strainer on the in-tank fuel pump can do this. As you drive the car, the inlet filter collapses and fuel pressure drops below the required minimun. The injectors can't deliver enough fuel and the lean mixture causes backfiring and loss of power. See if you can get a fuel pressure gauge attached to the fuel release port (I rigged a gauge from an old R12 AC charging manifold to it) and drive around with the gauge attached to see what happens to the pressure when the problem occurs. The gauge looked weird taped up on the outside of the winshield but it diagnosed the problem right away!
Hopefully this will help. Happy New Year!

RM-TECH