2000 Chrysler T&C, Random Surging, Stalling
97K15004WD
02-13-2008, 05:08 PM
2000 Chrysler T and C
110,000 miles
3.8L, Auto
LXi model
The random no start condition has not reoccurred for quite some time. Now the situation has changed somewhat; the vehicle randomly starts surging and almost stalls. Here are the conditions:
Idle; (750 to 1000 RPM), engine warm or moderately warm - When placed in gear rpm's swing by up to 400 rpm both ways. Engine almost stalls, then races. Timing swings from 7 degrees to 23 degrees.
Getting onto the on ramp the other day, after a moderate amount of time for engine cool down (approx 30 minutes from normal operation temp) the engine had intake backfire two or three times, then ran fine.
90 Percent of the time, it runs fine. Other times, does this randomly. Using an Actron scanner and looking at rpms and spark advance PID's is where my info comes from. Need a better scanner, the frame rates are too slow....
Shows no codes in the Actron Scanner, set or pending....
My thoughts are: fuel pump, crank/cam sensor, ECM.
Since the problem is intermittent, this would seem to rule out the plugs, wires, fuel filter, and vacuum leaks. Might be the EGR though, but it seems odd this would occur randomly at idle conditions. Idle air controller would throw a code.....
Fuel pump might be intermittent, but I have no TSB's that show failure occurring at this mileage. Will check with an installed gauge, but it's hard to get the vehicle for that long....
==============================================
Okay, here's what we found. The original diagnosis was correct. The vehicle began the missing and running rich immediately upon start-up, while cold. This meant the ECM was in open loop mode, and as such, ruled out the HO2S. This left the ECM, the CMP, the CKP, the MAP, and the TPS as the intial culprits. We had already ruled out the fuel pump and the filter with the pressure test set.
Upon further scanning, we narrowed it down to the CKP / CMP. We replaced the CKP first (swore it would be the one!), and this did not fix the problem. We then replaced the CMP, and this solved the problem.
The vehicle started up and exhibited the same problems initially, but only for a short time. It got better quickly; the plugs may have been fouled by the overly rich mixture.
The vehicle now has 45 miles drive time on it, and the problem has not reappeared.
We intend to Seafoam it, and replace one questionable vaccuum line. We will continue to post info here as we get more on this vehicle.
110,000 miles
3.8L, Auto
LXi model
The random no start condition has not reoccurred for quite some time. Now the situation has changed somewhat; the vehicle randomly starts surging and almost stalls. Here are the conditions:
Idle; (750 to 1000 RPM), engine warm or moderately warm - When placed in gear rpm's swing by up to 400 rpm both ways. Engine almost stalls, then races. Timing swings from 7 degrees to 23 degrees.
Getting onto the on ramp the other day, after a moderate amount of time for engine cool down (approx 30 minutes from normal operation temp) the engine had intake backfire two or three times, then ran fine.
90 Percent of the time, it runs fine. Other times, does this randomly. Using an Actron scanner and looking at rpms and spark advance PID's is where my info comes from. Need a better scanner, the frame rates are too slow....
Shows no codes in the Actron Scanner, set or pending....
My thoughts are: fuel pump, crank/cam sensor, ECM.
Since the problem is intermittent, this would seem to rule out the plugs, wires, fuel filter, and vacuum leaks. Might be the EGR though, but it seems odd this would occur randomly at idle conditions. Idle air controller would throw a code.....
Fuel pump might be intermittent, but I have no TSB's that show failure occurring at this mileage. Will check with an installed gauge, but it's hard to get the vehicle for that long....
==============================================
Okay, here's what we found. The original diagnosis was correct. The vehicle began the missing and running rich immediately upon start-up, while cold. This meant the ECM was in open loop mode, and as such, ruled out the HO2S. This left the ECM, the CMP, the CKP, the MAP, and the TPS as the intial culprits. We had already ruled out the fuel pump and the filter with the pressure test set.
Upon further scanning, we narrowed it down to the CKP / CMP. We replaced the CKP first (swore it would be the one!), and this did not fix the problem. We then replaced the CMP, and this solved the problem.
The vehicle started up and exhibited the same problems initially, but only for a short time. It got better quickly; the plugs may have been fouled by the overly rich mixture.
The vehicle now has 45 miles drive time on it, and the problem has not reappeared.
We intend to Seafoam it, and replace one questionable vaccuum line. We will continue to post info here as we get more on this vehicle.
veedubmechanic
02-13-2008, 09:45 PM
lower intake gasket leaks are common. The little rubber gasket at the valley of the block blows out and leaks.
97K15004WD
02-15-2008, 08:26 AM
Just a short note on the price of the two sensors from the Chrysler Dealership: both together was just over $100.00 (CKP-$48.50; CMP-$53.10). These are the list prices so this is probably the highest you will see them.
Could have gotten them for less from Advance, but we would had to wait a couple of days for them to come in....
Also, changing the CKP sensor from the top is the easier way to go with this vehicle. Just remove the air resonator box and air filter box top. Much easier and makes more sense than the Alldata way (raise the vehicle, reach around blind, etc.)
Could have gotten them for less from Advance, but we would had to wait a couple of days for them to come in....
Also, changing the CKP sensor from the top is the easier way to go with this vehicle. Just remove the air resonator box and air filter box top. Much easier and makes more sense than the Alldata way (raise the vehicle, reach around blind, etc.)
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