Having problems with your 1998 Dodge Caravan ?

1998 Dodge Caravan. Random misfires and fans don't work

\015 1998 Dodge Caravan. I had the Transmission rebuilt around 145000 miles. As soon as I got it back it had a check engine code for random misfires. The tranny shop claims it can't be their fault because "misfires happen in the engine" Um, no duh... Also noticed a bit later that the radiator fans do not come on unless the A/C is running. Since the tranny shop was no help I have since replaced the spark plugs, plug wires, distributor cap and rotor, both O2 sensors, coolant temp. sensor, fan relay, and the fuel pump(because it died). I have also put in a jumper switch at the coolant temp. sensor to trick the computer into running the fans. I live in the Sonoran Desert and in the last few days i've had to use the jump switch and have the heater on full blast just to keep the engine under 190 degrees. Crossing my fingers that its not the PCM that's going bad. Any ideas?\015 Posted / edited by AnonymousUser on : 26-02-2018

Answers :

You could have a crack in the flywheel/flexplate where the crank sensor reads. This crack can cause random misfires as it passes beneath the crank sensor but it is fairly rare and hard to find with the transmission bolted up. The cranks sensor is also prone to being damaged or not being properly spaced where it mounts above the flywheel. Do you know if there are any service codes other than for a random misfire which is usually a P0300? The cooling fans on these were designed to stay off until either the A/C was on [like yours is working now] or until the engine temp reaches about 220 - 228 degrees at which point the fan[s] would run until the engine temp drops back to about 210 or so and shut off again. At a true engine temp of 190 to 210 theu should stay off. The best fan test is to start the engine, leave the a/c and defrost off, and allow it to idle in your driveway until the gauge reaches about th 3/4 to 7/8ths of the way up and somewhere in there the fan should finally come on. If not then you need someone with a scan tool to command the computer to turn the fans on and off to see if it is capable of doing so but I'm betting it is since it will turn them on for the a/c. I have both a 94 and an 02 caravan and when I'm sitting in traffic they'll hang at the 210 - 228 degree point all day long [actual temp as read on a scan tool] which is ok because the cooling system is pressurized and the coolant can't boil over. Once I'm moving over 35 mph the temp willd drop back down the the thermostat set point which is about 198 degrees on both. Hope this helps a bit with your problem and good luck!
The main wiring harness is getting hot, if you reach behind the upper plenum, and unplug the connector to the injectors, you wil 9 times out of ten notice that the insulation on the wires are missing, therefor causing them to arch across, wich will give the misfire code, also not alowing the fans to come on, because it is tricking the pcm on its own. Fix this issue, and have the pcm reset, and 90% of the time, this will fix youre problem.
Repair Help & Product Troubleshooting for 1998 Dodge Caravan

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