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Old 02-25-2001, 01:13 PM
Registered User
Join Date: Nov 1999
Location: Matthews, NC, USA
Posts: 133
We have spent the weekend playing diagnostician and are completely stumped.

The the car has always had a minor problem of occasionally stumbling when you first pull away from a stop and would occasionally cutoff when pulling quickly to a stop or slowing for say a u-turn. Due to its lack of frequency, this we have given up on and I have learned to live with it.

However, lately it has developed a phenomena that I cannot live with. The car runs fine under moderate load and below 2000 rpms. Under moderate to heavy acceration or anything above 2000 rpms, it stumbles terribly. Engine analyzer reveals that #2 cylinder is dropping our intermittently as it approaches 2000 rpms and drops out COMPLETELY at 2000 rpms. Above 2000 it is dropping out intermittently.

We found a cracked distributor cap with a hairline fracture which seem to start at the #4 terminal and radiate to the #2 terminal. Replacing the cap did not change anything.

We replaced the #2 plug wire, the #2 plug, and still no change.

I understand that there is a pickup sensor inside the distributor. Could the pickup sensor or something else in the distributor be faulty or worn out, or would it affect all cylinders?

While it does not feel loose, is it possible that there is
some wobble in the distributor that is causing the rotor to hit the cap at #2 and #4 (nearly opposite sides)resulting in
both intermittent ignition and cracking of the cap?

Could the ignition amplifier(CD box?) be bad, or would it affect all cylinders?

The local shop is stumped!
Any ideas are welcome, we will resume our efforts on monday.

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Old 02-25-2001, 01:45 PM
Registered User
Join Date: Dec 2000
Location: ny
Posts: 119
my 500 sec has the same problem . i also found all the same symptons that you have .i have also replaced the cap and rotor no avail problem is still there .car also does not start in the cold. cranks fine has gas no spark.will start when weather gets warmer.have no idea how to check hall sensor in dist or the crank sensor or spark are very expensive donot want to gamble with my money....any one have any ideas or testing procedures....any help is gretly appreciated...thank you all in advance
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Old 02-25-2001, 03:09 PM
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
Does your tech have the ability to post the secondary pattern during the misfire. If not he should, if he can I would like to see the what it looks like.

Both the "pickup sensor" and the amplifier have no reason to cause a single cylinder misfire. It is possible that if the secondary voltage need is higher for one cylinder (due to a lean mixture for example) that a weakened potential caused by either the amp or the coil would not keep up under load.

It is possible that the fuel flow on that cylinder is only enough for low flow conditions.
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician
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Old 02-26-2001, 12:17 PM
Registered User
Join Date: Nov 1999
Location: Matthews, NC, USA
Posts: 133
Just a status update. Problem has momentarily disappear as suddenly as it appeared. Drove 20 minutes to work, 15 out to lunch and it pulls cleanly up to 3000 without a miss.

Could it be that 65 degree weather is masking a cold weather problem?

If, When, problem returns, Ill let you know.

Thanks again for the prompt response.

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