PDA

View Full Version : sputters & pops on start? stalls? then won't start? Crank Pos. Sensor? NOT always...



c55m8o
04-06-2008, 07:59 PM
Thought this might help some folks. Probably not the 1st one who encountered this and I may have found it with a search. But honestly, I'm so spoiled knowing my mechanic who did my engine swap and who takes such good care of this stuff and me so well.

Within a two week period the car went from
a) had a little bit of difficulty starting one morning. Start, then stall... then started and kept running.
b) came out from the place we were hav'n breakfast, got in the car, and it wouldn't start. Seems like it wanted to, but was sputtering & popping bad and would die. I was really worried the battery would run down, as not driving it over the cold winter the battery had run down a few times and i took to keeping the trickle charge on it. It literally took about 20 tries to start it. But it finally kicked in and I got home.
c) Called Jeffery who did my engine swap, and he was sure it was the rear crank position sensor (the front cam pos sensor would only give a rough start; not a stall) I was hoping to get to him this weekend to change it.

But yesterday, I couldn't get the car started, period. And battery was running down to nill fast. I'd wait for the charger to build up power a little and try 3 or 4 more times; probably about 50 times total. It kicked in once about 1/2 way, but died in about 10 seconds.

So I asked Jeffrey if he'd be willing to make a "house call". ;) And he did. A quick change out of the crank position sensor .... and ... nothing! Stilll won't start.

So he started looking @ the fuel system (that was my 1st thought actually). He pulled the relay and with ignition in the ON position, was using a wire to trigger the fuel motor. But it wouldn't run. So this was the great part. He pulled the pump power plug out, used a jumper cable from my battery, and ran the pump in reverse. And low and behold, it ran. Did that a bit. Then ran the pump in the forward position. And sure enough, it now ran too. And finally, the car would start and kept running.

Frigg'n dirt in the fuel tank got stuck in the fuel pump, hung it up, and stopped it from turning... !!!

82K mile... Just to be safe, I'm going to get a new fuel pump, relay, and filter.

OzC36
04-09-2008, 11:58 PM
One bad ignition coil gave me the identical symptoms.

On my C36, I went through two new crank position sensors, new fuel pump relay, fuel pump pressure tests, two new overvoltage protection modules, two new sets of spark plugs, a new ignition wiring harness, an engine wiring harness wiring repair and finally a replacement engine wiring harness first.

One lousy intermittent ignition coil can cause a lot of grief, especially when the weather turns cold, humid or wet.

I have a friend whose C36 suffered loss of power and finally engine failure after a longish drive. Turned out that his mechanic installed his fuel filter back to front, thereby causing fuel starvation.

So, I guess your experience of a blocked fuel pump would add to the list as well.

c55m8o
04-10-2008, 05:59 AM
Good grief! I consider myself lucky in this case! Thanx for sharing.
-steve