9 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHCompression test results
Leading reported evidence
Fill due
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
The test was crippled by a lack of chamber filling due to this.
Leading evidence: 'Fill due' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Fill due' (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
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Suggestion
I can look at the values, and see that the highs and lows are classic examples of the intake characteristics, and how they effect chamber filling with a closed throttle plate.
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.
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Suggestion · Original poster
I asked the owner for compression and leak down test results.
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
I can look at the values, and see that the highs and lows are classic examples of the intake characteristics, and how they effect chamber filling with a closed throttle plate.
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.
9 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: 20261026T174436Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I�m looking at buying a used 1999 3.4 engine with about 45k miles. I asked the owner for compression and leak down test results. Here is what I received:
1. 135 / 4%
2. 130 / 4%
3. 130 / 6%
4. 150 / 2%
5. 140 / 6%
6. 150 / 4%
Leakdown numbers look ok to me, but compression values look low, particularly in bank 1. I was expecting numbers in the 175 range.
Comments welcome.
From what I�ve read, compression PSI figurescan have a lot of factors that cause variables and are not necessarily accurate or always provide much value, unless you see something like 50psi. I would be way more comcerned if leakdown was bad.
The shop didn't lock the throttle plate open during the compression test. The test was crippled by a lack of chamber filling due to this.
I can look at the values, and see that the highs and lows are classic examples of the intake characteristics, and how they effect chamber filling with a closed throttle plate. Cylinder 1 always has the lowest compression on these tests when the throttle plate is closed.
Air that doesn't enter the chamber on the intake stroke, can't be compressed.
It amazes me what shops don't know about the basics of engine operation. (well, actually it doesn't these days)
