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Recent content by red_georgia

  1. R

    8.1 GXi-f conundrum; power under load

    Resolved. Here are the details in case it helps anyone searching this problem in future. Recap: 1. Volvo penta 8.1L experience power loss over a period of weeks culminating in the inability to accelerate past about 1K rpms/9-10 mph at basically idle. Severe misfire and backfires when trying...
  2. R

    8.1 GXi-f conundrum; power under load

    So just used the spark gap tester and it is definitely sparking. The one I got is adjustable and it would carry the spark all the way out to 3.5cm. Spark is a single solid white line. Very hard to see the line/color when tester is closed to normal spark plug gap. Just to reiterate, have...
  3. R

    8.1 GXi-f conundrum; power under load

    Plugs are 2 years old and have about 10 hours run time on them. Wires I tested are about 18” long so definitely low. Wires are 20 years old.
  4. R

    8.1 GXi-f conundrum; power under load

    Looked up that spark gap tester..... have one coming from amazon.
  5. R

    8.1 GXi-f conundrum; power under load

    I'm still working on it to verify. I already swapped coils and plugs from good to bad cylinder with no change. I did test signal to coil this morning and both good and bad cylinder were 12.2V. One thing I haven't tested or swapped was wires. on a good and bad cylinder, only getting 2.03K...
  6. R

    8.1 GXi-f conundrum; power under load

    Ok, breaking out the multi-meter next but using a timing light and a noid light for the injectors, I've verified one of the dead cylinders is getting both a spark pulse and an injector pulse. Doesn't that have to mean that it is a plugged injector that isn't spraying or spraying correctly...
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    8.1 GXi-f conundrum; power under load

    And, ran both injector kill test and spark kill test with same results. No change on the four dead cylinders. As for compression test, there are almost zero internal failures on the 8.1l block before 259-300k miles. I’m no where close to that and oil changes/etc have been annual. The...
  8. R

    8.1 GXi-f conundrum; power under load

    Thanks, will do and report back. Need to get crank sensor back in tomorrow and working on eliminating rest of fuel system right now. Struggling to get pick up tube /fitting out of tank. Soaking in PB blaster right now.
  9. R

    8.1 GXi-f conundrum; power under load

    Have the crank sensor out and waiting on replacement.... then noticed something. On the injector balance test (results below), the cylinders with the low pressure drop across the rail, happen to be the same cylinders that are dead (1,3,6,7). Is it possible that the injectors aren't dispensing...
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    8.1 GXi-f conundrum; power under load

    Since I’m running out of “obvious things to check” I’m going to try the crank position sensor as there are reports of it causing these symptoms without throwing a code. Open to other ideas. Have inspected all the harness, connectors, grounding block, etc and find nothing concerning
  11. R

    8.1 GXi-f conundrum; power under load

    I had the connectors off the coils but since the 12v is only present when key first turned on, then was going away I was struggling to confirm I was making a connection. Finally stabbed one wire and cycle key and figured out the 12v goes off if motor doesn’t start. What is the 5v signal for...
  12. R

    8.1 GXi-f conundrum; power under load

    On both a dead cylinder and a working cylinder the pink wire at coil plug is getting 11.7 v upon key on (a little low due to connection I'm guessing as getting a probe in those mini fittings required some creativey). The voltage drops to zero about same time fuel pump shuts off even thought...
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    8.1 GXi-f conundrum; power under load

    One additional thought on condition is that the symptoms seemed to get progressively worse from morning to afternoon (had more power in morning than afternoon) which makes me think it is not a bad ground or bad wire. Is that logical thinking?
  14. R

    8.1 GXi-f conundrum; power under load

    So…..I have a saying: “It can never be easy”. This challenge seems to be the case. Swapped coils on good/bad cylinder and no change. #1 cylinder still dead. I’m going to check plugs next but since they are fairly new, I doubt that is it. Seems to be upstream of coils. Not sure where to...
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    8.1 GXi-f conundrum; power under load

    Thank you….had to watch some football today, will continue the adventure tomorrow morning. Killing me today, while I was on ramp testing, probably 25 boats launched around me at 10 am to spend day on lake. I pulled out to make room and guy asked me….”why pulling out? U r supposed to be...
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