1998 Mer. Gm Dies At Idle Won't Start - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

ron1942 · 11-02-2009, 05:19

'98 Merc Gm Will Die At Idle And Will Only Start If You Wait A Few Hours Or Shoot Starting Fluid In Intake. It May Run For A Few Months Or A Few Minutes. Have Replaced The Fuel Pump, Filter, And Fuel Press Reg. Have Had It In The Garage And Can.t Make It Shut Down. It Has A Mind Of Its Own. Does Anyone Have Any Ideas. No Codes Come Up.

'98 Merc Gm 4.6 150000mi
Ron1942

**Bert** · 11-02-2009, 07:29

It's probably the crankshaft position sensor. They do have a problem once in awhile. Maybe even a crroded connector. The fuel pump is what I would have first thought, but you covered that.

jsuthers · 11-02-2009, 08:42

iv seen this pop up alot lately.... what exactly is the crankshaft position sensor and what does it do...

iv been wondering about that

thx

**Bert** · 11-02-2009, 09:18

From the Ford manual

Crankshaft Position Sensor
The crankshaft position sensor (CKP sensor) is a variable reluctance sensor triggered by a 36-minus-1 tooth trigger pulse wheel located inside the engine front cover.

The sine wave type signal generated from the crankshaft position sensor provides two types of information. One is the position of the crankshaft in 10-degree increments. The other is the crankshaft speed (rpm).

The ignition control module (ICM) uses this information with the spark advance information from the powertrain control module (PCM) to determine ignition coil turn ON and turn OFF time.

Base ignition timing is referenced to the position of the crankshaft position sensor and is set at 10 ± 2 degrees before top dead center (BTDC) and is not adjustable.

jsuthers · 11-02-2009, 11:09

ahhh ok thx....

ron1942 · 11-02-2009, 14:12

Thanks. That will probably be my next project. Hope my manual shows me just where its located. The Merc. otherwise runs just great, and my gas milage is 28 to 30 on the road and low 20's just jacking around. Will let everyone know if it does the job.
Ron

**Bert** · 11-02-2009, 15:06

It's on the right side of the engine near the A/C compressor.