Sunday, March 22, 2015

Engine dies at low speed around 20-25

Question:
I have a 1994 Dodge Caravan 3.0 litre dies at low speed around 20-25 mph and especially it seems on turns in shopping centers. Just shuts off with no warning, no hesitation, starts right back up again. It does it sparatically. My Mechanic again today says it may be wiring? He changed previously the TPS which showed on codes as bad. Today I had him replace the in-line gas filter. He also today pulled and plugged a vacuum line next to the EGR valve to test for a few days? By the way, this started right after they pulled and and replaced the rebuilt trans.

Answer:
There are a couple of things that come to mind,
First is the crank shaft position sensor may be going bad or may have been improperly installed, these sensors require a paper spacer be placed on them during installation, if the spacer was not put on when they reinstalled it in the bell housing and it was resting on the flex plate when they started it up it would have made a noise and then they may have backed it out until the noise stopped, if the flex plate hit it, it is bad, if the spacer was not used the air gap setting may be incorrect causing an intermittent read, the crank sensor should be inspected and replaced if needed
Next the engine harness may have been pulled off of its tabs and be touching or very close to the exhaust crossover pipe and shorting out on corners, or being partially melted by the pipe, this harness is under the flexible hose that connects the top of the air cleaner to the throttle body and should be clipped or wire tied in place up near the throttle body, if it is down on or near the crossover pipe it should be inspected for damage and repaired as needed
also next to the battery near the engine controller is the harness that comes off the engine controller, this harness wraps around the corner of the battery and if the battery is oversize or loose it will damage this harness causing any number of issues.