7 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHTachometer "jumping" up and down
Leading reported evidence
Check connector onto the sensor too
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
They should check the connector onto the sensor too and clean the contacs while they're at it.
Leading evidence: 'Check connector onto the sensor too' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check connector onto the sensor too' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
They should check the connector onto the sensor too and clean the contacs while they're at it.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
How does it run, does the tach work when running..?
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
if it was while running then i would suspect the crank sensor
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
7 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
Unfortunately, that didn't solve the problem, and the
This morning when turning the ignition on my 996 4S the techometer started "jumping" up and down.
See the attached movie clip...
What can be the reason and cause of this?
Strange, never seen exactly that before. But with a tach problem like that, makes me think of the Crank Position Sensor.
Just to be clear, does this happen when cranking engine over or with just key to on position...?
Depending on your answer to above question, I'd unplug the CPS and see if the tach still jumps....
How does it run, does the tach work when running..?
jmo
Most likely not the Crank sensor, I would check for Fault codes, I would be looking at the instrument cluster, grounding issues and of course the infamous ignition switch. if it was while running then i would suspect the crank sensor
My first guess was also the crank position sensor.
In September last year while driving on the freeway, the car lost power and I got it of the road with the car limping forward.
While waiting for the tow truck, I turned the ignition on and the tachometer did the same thing like it did today.
After getting home I parked it for the winter and today was the first time starting it since then.
The engine runs ok the first start up and I reversed out of my garage and turned the engine of, quite relieved actually but after turning the ignition on (not starting) the second time the tachometer got jumpy again.
It also resulted in lighting ABS and PSM warning lights.
Sounds like I hear some "clicking" at the same time the Tach jumps......I'm thinking a relay turning on and off....
If you can locate the source of the noise, it will give a much better clue as to what is causing this weird issue...
The workshop I hired to service my car and fix the problem
called back today informing me they got an error code on
the Crank Position Sensor and therefore replaced it.
Unfortunately, that didn't solve the problem, and the
error code on the Crank Position Sensor remains and the
engine runs on and off really bad.
Now they think the error may be in the wiring to the sensor
and they will therefore try to measure whether the signal
is going through as it should.
Could this be the cause of the problem and has anyone else
experienced similar problems?
Yes, that is plausible, though I've not experienced it myself and hope to never do so.
Rodents can cause this sort of wiring damage.
The shop should check at the connector into the DME and also at the big 25-pin round connector where engine wiring loom connects to body wiring loom, to narrow down the location of damage. Latter is probably less time consuming.
They should check the connector onto the sensor too and clean the contacs while they're at it.
This is a source reference. Confirm exact model applicability in the original material.
