Re: At my wits end... HELP!!!!

From: Bob Tom (tigers@bserv.com)
Date: Fri Nov 17 2000 - 15:51:11 EST


At 12:30 PM 11/17/00 EST, you wrote:
>Ok, I am at my wits end with my friends 97 Dakota. We thought the coil was
>the culprit but after replacing it, we thought it was fixed, but it wasn't.
>We are still getting hard starts and the occasional die on the road. The
>same code 43 is popping up again. "Peak primary circuit current not
achieved
>with maximum dwell time." He has a Jet stage II chip, a MSD 6A, Autolite
>3923's. We thought maybe the jet was going out, so we took it off, no
>change. We can reset the comp and it will do better for about 3 cranking
>cycles and then screw up. Any ideas? TIA Will

I can supply some information but not a solution.

Code 43 in the '97 FSM says that misfire is being detected. If you could
pull the OBD-II codes (Pxxx codes), it would tell which cylinder. It also
shows that this code should trigger the MIL on.

The PCM monitors for misfire durning most engine operating conditions
(positive
torque) by looking at changes in the crankshaft speed. If a misfire occurs,
the speed of the crankshaft will vary more than normal.

The PCM does NOT monitor the following circuits.
Fuel pressure
Secondary ignition circuit = inoperative coil, fouled/worn plugs, cross
firing,
                             open spark plug cables
Cylinder compression
Exhaust system
Fuel injector mechanical malfunctions
Excessive oil consumption
Throttle body air flow
Vacuum assist
PCM system ground
PCM connector engagement

Without the DRB scantool diagnostic procedures, it's a guessing game.

My best guess would be to examine the crankshaft sensor and its circuitry.
The engine will not operate if the PCM does not receive a crankshaft sensor
input. Possibly it's receiving a faulty input. On the 3.9/5.2L, the sensor
is bolted to the top of the cylinder block near the rear of the right cylinder
head. Access requires removing the right front fender liner. Check that
the wiring is firmly attached and clean the crud around it (may want to
put dielectric grease on the connectors). The sensor is a hall effect device
combined with an internal magnet so that it is sensitive to steel within
a certain distance (?) from it.

That's all I can find. Good luck.

Bob. Burlington, Ont., Canada.
'97 Dakota CC, 5.2L, 4x2, 3.92 SG, auto., 4265 lb.
Dyno: 231.2 rwhp 340.0 lb-ft rw torque
PB: 14.737 @ 91.75 9.364 @ 72.95



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