6 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHAnyone ever seen a P1374 code?
Leading reported evidence
Use cutting torch
Performed · outcome unconfirmed
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 performed work without a confirmed outcome
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
(Although one machinist bragged he only did jobs that required he measure with a yardstick, mark places to cut with chalk, and then he used a cutting torch to make the cuts.
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 the difference between the two cylinder bank O2 sensors is less than 4%, one valve may be faulty on both cylinder banks and then the fix consists of replacing *all* flat-base tappets of intake valves on both banks.
Leading evidence: 'Use cutting torch' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace *all* flat-base tappets of intake valves' (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
If the difference between the two cylinder bank O2 sensors is less than 4%, one valve may be faulty on both cylinder banks and then the fix consists of replacing *all* flat-base tappets of intake valves on both banks.
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
Thus, if you are confident of the test results, if you believe the test was executed properly, then the fix is to replace all flat-base tappets of the intake valves on the failing bank.
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
In this case, you want to test twice and remove, open up the engine and replace tappets just once.
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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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.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Replace *all* flat-base tappets of intake valves
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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 the difference between the two cylinder bank O2 sensors is less than 4%, one valve may be faulty on both cylinder banks and then the fix consists of replacing *all* flat-base tappets of intake valves on both banks.
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
Thus, if you are confident of the test results, if you believe the test was executed properly, then the fix is to replace all flat-base tappets of the intake valves on the failing bank.
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
Thus, if you are confident of the test results, if you believe the test was executed properly, then the fix is to replace all flat-base tappets of the intake valves on the failing bank.
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
(Although one machinist bragged he only did jobs that required he measure with a yardstick, mark places to cut with chalk, and then he used a cutting torch to make the cuts.
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
The diagnosis/trouble shooting requires the use of a PST2 diaagnostics computer which the tech uses to command the valves remain in large lift mode during running the engine and at the same time monitoring the O2 sensors of the two banks to determne if one or more valves fail to switch over to large lift.
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.
6 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: 20261027T000231Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Would be nice to have more details on car: model, miles, etc.
I don't find a P1374 code in my sources.
I do find a P1354: valve lift control, cylinder 4 above limit.
Diagnosis conditions: Speed between 5280 and 6520 rpms. Load between 125 and 190%. Acceleration with wide open throttle. Possible fault causes: a valve does not switch from small lift to large lift. Several valves (various cylinders) do not switch from small lift to large lift.
The diagnosis/trouble shooting requires the use of a PST2 diaagnostics computer which the tech uses to command the valves remain in large lift mode during running the engine and at the same time monitoring the O2 sensors of the two banks to determne if one or more valves fail to switch over to large lift.
I am not familiar with the Durametric system but it may offer access to or support this test.
Sincerely,
Macster.
Well, if you have access to PST2 you should have access to the very specific steps necessary in order to perform the tests properly/correctly and the 02 sensor readings that are used to determine the presence of a valve lift fault.
Just to cover some high points:
It is possible if one or more intake valves do not remain in large lift mode the engine can run rough mimicing a misfire condition.
Several cylinders may be flagged as bad even though just 1 valve on one cylinder is bad.
Thus, if you are confident of the test results, if you believe the test was executed properly, then the fix is to replace all flat-base tappets of the intake valves on the failing bank.
If the difference between the two cylinder bank O2 sensors is less than 4%, one valve may be faulty on both cylinder banks and then the fix consists of replacing *all* flat-base tappets of intake valves on both banks.
Replacing these are expensive. (I bought one to disassemble and study and IIRC it cost me around $75. But it is a marvelous piece of hardware!) There are 2 flat-base intake valve tappets per cylinder, 6 per bank, 12 per engine, which I'm sure you already know. Flat-base intake valve tappets parts cost alone can be nearly $1000.
In the machine shop we had a saying: Measure twice. Cut once. (Although one machinist bragged he only did jobs that required he measure with a yardstick, mark places to cut with chalk, and then he used a cutting torch to make the cuts. No close tolerance work for this guy!)
In this case, you want to test twice and remove, open up the engine and replace tappets just once. And my sources - for DME 7.8 -- don't give any but you want to be darn sure nothing else can account for the test results. That is that the test results point conclusively to the flat-base intake valve tappets and nothing else.
Best of luck!
Sincerely,
Macster.
Holy cow Macster, awesome! I just like reading every single one of your posts, regardless of the problem. It's like reading a manual with every answer conceivable. I hope I never have any hard core issues, but if I do, I hope you're still on the forum to help diagnose mine!!!
OP, keep us posted. I'd like to know the final outcome to your problem.
