While turning the corner from a traffic light my SSE just died. I threw it in
neutral and coasted to the curb.
Tried to re start and nothing. Popped the hood wiggled the coil wires nothing.
Then I unplugged the crank sensor then plugged it back on and it fired right up.
I drove it to the dealer who put the crank sensor in 20k miles ago and said what gives?
They didn't know and said it could be an intermitten fault. There are no codes.
I mentioned how I unplugged the sensor and it started and they said it could be the sensor again.
I don't believe its the sensor as when the first time it wen't the car wouldn't start but
it never just died while driving.
What gives? This is very frustratiing.........

could have been crap on the connector, see if it happens again, if it doesn't, could have just been a fluke. maybe put some die electric grease on the connector..


-justin

When my sensor was gone ( gone since I bought it) as it would get to running temp it would stall. Then would not start up again till it cooled off a bit. So yeah it is very possible that your sensor caused it to die.

the ECM doesn't do any of the firing, the Ignition is stand alone. Crank Sensor -> ICM -> Coils -> Wires -> Plugs.


-justin

I have to disagree with you

exactly, even though not directly linked, the crank does affect all the other factors in getting a car running. So no fuel pulse...no ignition, no spark...no ignition, bad crank sensor.......no running bonneville, hehe.

wwwwwwwwwwaaaaaaiaiiiiiiiitttttttt.. so the ECM controls timing? So if I do the eprom programming I can adjust the timing??


-justin

The dealer did use a Delco part I watched him pull it from their parts shelf.
They also told me if you throw water on it to cool it off and it starts it probably is the sensor.
But I had just started the car and went one block my temp gage didn't start to move yet so I don't think the sensor was hot.
I did clean the connector and put dielectric grease on it hoping it won't happen again.
Also flushed the whole sensor out with engine degreaser, a brush, and water.
If the Delco only lasts 20k miles I think I'll try another brand if it happens again.
I'm also thinking of changing the computer as I have a spare on the shelf from the bone yard. I don't know if this will be worth the bother though.

Trouble with simple answers is that they leave a lot out.

Ignition has three phases:
1) Below about 400 rpm (cranking) spark is controlled entirely by the ignition module
2) Above 400 rpm and while cold, control of spart timing is takem over by the ECM operating in open loop (no O2 feedback).
3) Closed loop (full PID) timing begins after a specific delay time and when the coolant temp exceeds about 146F. This makes little difference rom a spark advance standpoint but major differences in fuel management

Basic spark reference is provided by the crank sensor to the ICM. This is passed to the ECM which "adjusts" the spark advance based mainly on LV8 (load variable #8 ) which is a combination of TPS, MAF, rpm, and some other components.

There is also a rudimentary "get home mode" that will keep the engine running (sorta) in the event of a catastrophic failure. If the engine is stopped in this condition, it will not restart.

Electronics often fail when hot and recover when cool, this is why in the bad old daze every good tech carried an aerosol of freon in their kit to selectively cool parts.

The ignition module interaction is particularly complex. I finally built a breakout box so I could connect an O'scope to the ignition module harness and run diagnostics.

And yes, you can adjust the timing by changing the values in the UV-PROM (a 27C256) but the factory settings for spark are pretty good and optomised for unleaded regular (87 PON). Put premium in and it is liable to run worse.

For this specific instance *which* part did the dealer replace ? Does sound like a part that is failing when hot and that can happen within a block - OTOH usually takes about three minutes from a cold start to reach 146F & go into closed loop - and on the gripping hand my temp guage does not move much even at 180. Only way to know is with a scan tool or a connected laptop on the seat.

I'd love to have a scan tool on it when it stalls.
Problem is:
A) You don't know when it will happen. - So far so good today.
B) I need a scan tool. My ECU never stores a code?