10 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH1999 3.4 cranks but won?t start
Leading reported evidence
Use before and may have added
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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1
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Performed · outcome unconfirmed · Original poster
The car runs on easy start although I did backfire through the throttle body after a few seconds it�s not a product I�ve used before and may have added to much or little also not sure it�s recommended on these engines.
Leading evidence: 'Use before and may have added' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check ...ilter-and.html' (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.
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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.
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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.
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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.
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Suggestion · Original poster
The car runs on easy start although I did backfire through the throttle body after a few seconds it�s not a product I�ve used before and may have added to much or little also not sure it�s recommended on these engines.
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
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Suggestion · Original poster
It is very hard to tell if I�m getting tach bounce the needle goes to the first notch on the scale when cranking both before and after replacing the cps.
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 · Original poster
The car runs on easy start although I did backfire through the throttle body after a few seconds it�s not a product I�ve used before and may have added to much or little also not sure it�s recommended on these engines.
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 · Original poster
It is very hard to tell if I�m getting tach bounce the needle goes to the first notch on the scale when cranking both before and after replacing the cps.
Discussions that performed work without a confirmed outcome
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.
Performed · outcome unconfirmed · Original poster
The car runs on easy start although I did backfire through the throttle body after a few seconds it�s not a product I�ve used before and may have added to much or little also not sure it�s recommended on these engines.
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.
10 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.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T225432Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hi folks, I have newly acquired a non running 1999 996 carrera 4 manual 3.4. This is my first 996 after many 944s with engine and bodywork rebuilds.
After a Porsche hiatus of a few years this car came up unexpectedly. The PO had it for a long time but it has been sat up for several years an extended by covid. He assures me it went away running.
It cranks freely but will not start.
So far I have replaced the fuel filter, drive belt, battery (Bosch) and crank shaft position sensor.
It is very hard to tell if I�m getting tach bounce the needle goes to the first notch on the scale when cranking both before and after replacing the cps.
I pulled a plug and cranked and get a spark.
The car runs on easy start although I did backfire through the throttle body after a few seconds it�s not a product I�ve used before and may have added to much or little also not sure it�s recommended on these engines.
I have drained the tank using a fuel relay jumper but it still says 1/2 full!? I�ve tried to crank the car with the said jumper in. I don�t here the engine priming when I turn the key to notch 2 but the pump is audible with the jumper and drained the fuel via the filter feed.
I have pull all the relays (no 53s) in the rear bulk head and cleaned them but none in the front foot well.
I have durametric and get 2 codes one P1124 167 fuel pump output stage below limit and
P0102 115 mass air flow sensor below limit both I assume because I unplugged these items?
so any suggestion where to go from here?
Did you check fuel pressure valve ? If no fuel sprays out would look to fuel pump, it is an in tank pump with sender above it. I did one just recently not to bad a job just takes some time and care.
Rich
Any evap codes/charcoal filter? My 2000 Cab threw this code when I first got it. I'd have to crank it for about 30 seconds to get it started after getting fuel. There are some other threads on it here that go into detail.
Thanks for the replies so far, the codes I got are mentioned above but I think only because I unplugged those items.
How do you test the fuel pressure?
Ive ordered some noise lights to see if the injectors are getting a signal.
2 of the brown earth wires have broken off / corroded off the bracket on the engine that holds the cps connector not sure what these earths are for and if they are an issue no idea how I would fix them - strip back to good wire splice and take the earth to a bolt nearby?!
how hard is the fuel pressure regulator to access? Keep in mind I drained the fuel tank by running the pump and connecting a hose to the feed into the fuel filter in the engine bay!
On the right side fuel rail there's a cap over the valve, remove it - nasty way to check is to push it in with something and see if fuel sprays out, or hook up a pressure gauge like mine -
http://www.dtmtune.com/2021/07/check...ilter-and.html
I'm chasing down a problem with my 996 too, starts up no problem but idles like a pig. Compression tester is on the way.
This is a source reference. Confirm exact model applicability in the original material.
