Flywheel Position sensor- (long)
02-12-2002, 05:58 PM
#1
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Flywheel Position sensor- (long)
Kevin asked me to start a thread on my experience w/ flywheel pos sensor:
First a bit of background- PO owner had had starting problems intermittently since the car was under warranty. The dealer threw parts at it: new dist, dist caps, rotors, battery- all kinds of things. When I got the car I also bought the problem. Very hard to start about 1-3X per year. Last year the car had been sittin a couple of weeks, so I thought I'd take it out and blow out the cobs. Got to end of my lane, and when I stopped, so did the engine. Terrfic effort to get restarted; I had to gag it. Finally, it started, and it bucked like a cheap w**re. Like someone was turning the key on-off-on. I got it back to the garage, coaxed it warm, thinking that the head sensor would change someting. Nothing. The car started instantly, would run 10-50 seconds and die. Here is what I did (all to no avail)
1. replaced fuel pump relay
2. checked fuel pump pressure and volume
3. checked plugs/ connectors
4. checked injectors
5. Had Porsche rebuild my DME
6. checked cylinder head temp sensor
7. Checked all grounds I could find
8. checked dist belt
9. checked batt & alt output
10.checked ait cleaner
11.Took apart air regulator box ( NOT user serviceable-ha) found a bit more resistance, some oxidation on variable resistor track. Cleaned with Wurth contact cleaner & re-sealed
12.Assured that the electrical connector at the rear of the air regulator box had been modified per Porsche recall. It had.
Finally in despair, I took it to a local shop where they had a Hammer.. Two days. $990.00 labor. The fix?
"Impulse sender" #02p99660610500 $66.00. The 90 964 have only one, 92 & up have two, and the new, upgraded part requires some modification of the plu/connector.
Also: "replace shorted intake side coil" 02055 $77.00
Expensive at $1,050.44 (w/ PCA discount). That was over a year ago, but the car has run perfectly since <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />
First a bit of background- PO owner had had starting problems intermittently since the car was under warranty. The dealer threw parts at it: new dist, dist caps, rotors, battery- all kinds of things. When I got the car I also bought the problem. Very hard to start about 1-3X per year. Last year the car had been sittin a couple of weeks, so I thought I'd take it out and blow out the cobs. Got to end of my lane, and when I stopped, so did the engine. Terrfic effort to get restarted; I had to gag it. Finally, it started, and it bucked like a cheap w**re. Like someone was turning the key on-off-on. I got it back to the garage, coaxed it warm, thinking that the head sensor would change someting. Nothing. The car started instantly, would run 10-50 seconds and die. Here is what I did (all to no avail)
1. replaced fuel pump relay
2. checked fuel pump pressure and volume
3. checked plugs/ connectors
4. checked injectors
5. Had Porsche rebuild my DME
6. checked cylinder head temp sensor
7. Checked all grounds I could find
8. checked dist belt
9. checked batt & alt output
10.checked ait cleaner
11.Took apart air regulator box ( NOT user serviceable-ha) found a bit more resistance, some oxidation on variable resistor track. Cleaned with Wurth contact cleaner & re-sealed
12.Assured that the electrical connector at the rear of the air regulator box had been modified per Porsche recall. It had.
Finally in despair, I took it to a local shop where they had a Hammer.. Two days. $990.00 labor. The fix?
"Impulse sender" #02p99660610500 $66.00. The 90 964 have only one, 92 & up have two, and the new, upgraded part requires some modification of the plu/connector.
Also: "replace shorted intake side coil" 02055 $77.00
Expensive at $1,050.44 (w/ PCA discount). That was over a year ago, but the car has run perfectly since <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />
02-19-2002, 02:12 PM
#2
Hi,
Interesting post actually, because mine seems to have just died. On Sunday it suddenly started jerking - the same as your bucking I would guess - as if it was completely losing power for a split second, but fairly repeatedly. I pulled over to the side of the road and it died. Would happily turn over but wouldn't fire.
It went to the garage yesterday and they've told me that the flywheel position sensor seems dead - it doesn't output anything. Since DME doesn't know where / how fast the flywheel is turning it doesn't generate any sparks and it doesn't inject any fuel.
Dave
90 C4
Interesting post actually, because mine seems to have just died. On Sunday it suddenly started jerking - the same as your bucking I would guess - as if it was completely losing power for a split second, but fairly repeatedly. I pulled over to the side of the road and it died. Would happily turn over but wouldn't fire.
It went to the garage yesterday and they've told me that the flywheel position sensor seems dead - it doesn't output anything. Since DME doesn't know where / how fast the flywheel is turning it doesn't generate any sparks and it doesn't inject any fuel.
Dave
90 C4
