pay me now or pay me later...

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SlowLane
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Re: pay me now or pay me later...

Post by SlowLane » Sat Jun 24, 2017 8:41 pm

Amskeptic wrote:
Sat Jun 24, 2017 6:47 pm
SlowLane wrote:
Sat Jun 24, 2017 10:02 am
the OXS relay 3000 RPM threshold where the problem manifests.

Have fun figuring out this puzzle, guys.
Yes, you and I had a front row seat to the mixture shift, it was fascinating. I think it was on gauge 3MNR mid-level on the secondary pod. Or was it on the sub-mezzanine display cluster?

This is a Federal Vanagon with a full throttle switch, but these symptoms occur underneath full throttle as well as at full-throttle. Keep the ideas coming, maybe we have a CA ECU?
Colin
That would need to be accompanied with a CA wiring loom and an absence of external ballast resistors.

Spastic fuel pressure: equally spastic manifold vacuum? Weak fuel pump? Flaky injector chattering under high duty cycle?
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

TrollFromDownBelow
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Re: pay me now or pay me later...

Post by TrollFromDownBelow » Mon Jun 26, 2017 7:42 pm

Okay, I will be the one to post the stupid questions, just to get the obvious out of the way....I'm sure you tested for all of this, but it will help level set everyone else's brains....

- good compression on all 4 cylinders
- good fuel pressure both at idle and under load
- good vacuum as tested with a vacuum gauge
- proper valve lash
- air filter that isn't plugged
- coil that is pumping out proper voltage
- valve timing that looked heuristically correct from watching them open and close
- Temp sensor 2 that tested okay
- AFM mixture settings good
- strong battery
- oil that isn't pure sludge
- plugs/cap/rotor in good working order
- timing and dwell set correctly
- dizzy that advances correclty
- good gas
- AFM wiper (not sure of correct terminology) that isn't worn out
- S boot in good condition (eg no funky cracks that may be partially sealed at idle, but may open up with some harmonic vibration at higher RPM's
- exhaust that is not restricted (although from the post sounds like you tested this)
1976 VW Bus aka tripod
FI ...8 completely solid lifters.... now it's both kinda noisy and leaky, but she sure runs good!
hambone wrote: There are those out there with no other aim but to bunch panties. It's like arguing with a pretzel.
::troll2::

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Amskeptic
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Re: pay me now or pay me later...

Post by Amskeptic » Tue Jun 27, 2017 5:55 pm

TrollFromDownBelow wrote:
Mon Jun 26, 2017 7:42 pm
Okay, I will be the one to post the stupid questions, just to get the obvious out of the way....I'm sure you tested for all of this, but it will help level set everyone else's brains....

- good compression on all 4 cylinders (good enough, I don't remember the numbers)
- good fuel pressure both at idle and under load ( 28-36 )
- good vacuum as tested with a vacuum gauge ( 18-20 overrun damn close to 0 on acceleration )
- proper valve lash ( hydraulic, preload set at 1 1/2 )
- air filter that isn't plugged ( NOOOO )
- coil that is pumping out proper voltage ( good 5/16" purplish spark )
- valve timing that looked heuristically correct from watching them open and close ( didn't check on account of the good idle )
- Temp sensor 2 that tested okay ( didn't test )
- AFM mixture settings good ( it liked to be left alone )
- strong battery ( eventually, yes )
- oil that isn't pure sludge
- plugs/cap/rotor in good working order ( yes )
- timing and dwell set correctly ( why, yes, yes, of course )
- dizzy that advances correctly ( good behavior down low, weak upper end, 40* BTDC vacuum and 28* centrifugal )
- good gas ( I think so )
- AFM wiper (not sure of correct terminology) that isn't worn out ( check and symptoms were same with different unit )
- S boot in good condition (eg no funky cracks that may be partially sealed at idle, but may open up with some harmonic vibration at higher RPM's ( did not check )
- exhaust that is not restricted (although from the post sounds like you tested this) (oh, we TESTED IT )

Good string of ideas . . .
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

TrollFromDownBelow
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Re: pay me now or pay me later...

Post by TrollFromDownBelow » Wed Jun 28, 2017 6:39 pm

Thanks for the response Colin...now we need more subjective clues, like:

- how consistent was the lack of power...was it always abt 3k rpm, or did it vary? did it ever decide to 'clear it's throat' and have a surge of power?
- did you ever have a feeling whether it was running either lean or rich?
- could you get it above 3k not under load, or was it only under load it couldn't get above 3k?
- how close to the stock setting is the current AFM where it is the best of evils? close to stock?
- if I read correctly, you tried a different AFM with the exact same results, so therefore, fair to assume that it isn't the AFM
- was the 3k bog consistent in all gears?
1976 VW Bus aka tripod
FI ...8 completely solid lifters.... now it's both kinda noisy and leaky, but she sure runs good!
hambone wrote: There are those out there with no other aim but to bunch panties. It's like arguing with a pretzel.
::troll2::

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Amskeptic
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Re: pay me now or pay me later...

Post by Amskeptic » Wed Jun 28, 2017 8:10 pm

TrollFromDownBelow wrote:
Wed Jun 28, 2017 6:39 pm
Thanks for the response Colin...now we need more subjective clues, like:

- how consistent was the lack of power...was it always abt 3k rpm,
- was the 3k bog consistent in all gears?


Very consistent.
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

bus71
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Re: pay me now or pay me later...

Post by bus71 » Thu Jun 29, 2017 8:55 am

Possible pinhole leak in fuel line before pump causing pump to suck air under higher load?

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hippiewannabe
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Re: pay me now or pay me later...

Post by hippiewannabe » Thu Jun 29, 2017 7:48 pm

Amskeptic wrote:
Wed Jun 21, 2017 6:56 pm

It is about concrete in Motor City, concrete:

Image
Looks like you found a rare stretch of smooth Michigan freeway. I'm guessing that's the 75/96/94 mixing bowl near the Ambassador Bridge.
When thousands of people believe a made-up story for a month, we call it fake news. When a billion people believe a made-up story for a thousand years, we call it a religion.

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hippiewannabe
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Re: pay me now or pay me later...

Post by hippiewannabe » Thu Jun 29, 2017 7:53 pm

Amskeptic wrote:
Wed Jun 28, 2017 8:10 pm
TrollFromDownBelow wrote:
Wed Jun 28, 2017 6:39 pm
Thanks for the response Colin...now we need more subjective clues, like:

- how consistent was the lack of power...was it always abt 3k rpm,
- was the 3k bog consistent in all gears?


Very consistent.
Colin
I think this is key. If it depended on load, and RPM was incidental, air or fuel would be suspected. If it is only RPM, irrespective of load, must be ignition or something else that only knows RPM, like valve train. .
When thousands of people believe a made-up story for a month, we call it fake news. When a billion people believe a made-up story for a thousand years, we call it a religion.

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Amskeptic
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Re: pay me now or pay me later...

Post by Amskeptic » Thu Jun 29, 2017 8:56 pm

hippiewannabe wrote:
Thu Jun 29, 2017 7:53 pm
Amskeptic wrote:
Wed Jun 28, 2017 8:10 pm
TrollFromDownBelow wrote:
Wed Jun 28, 2017 6:39 pm
Thanks for the response Colin...now we need more subjective clues, like:

- how consistent was the lack of power...was it always abt 3k rpm,
- was the 3k bog consistent in all gears?


Very consistent.
Colin
I think this is key. If it depended on load, and RPM was incidental, air or fuel would be suspected. If it is only RPM, irrespective of load, must be ignition or something else that only knows RPM, like valve train. .

That is what has me baffled. I could easily manipulate the AFM wiper while underway and under load with Wes Simpson Dad driving. There was no evidence that the mixture changes increased power in any way ... in fact, there was only power loss either leaner or richer. The second AFM was run with no air filter, so no filter obstruction. We ran the engine with no muffler and there was no discernible improvement in power.

Valve train, valve timing, over-pumped lifters?
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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asiab3
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Re: pay me now or pay me later...

Post by asiab3 » Thu Jun 29, 2017 11:46 pm

Any noticeable hesitations when revved in neutral? Any interesting diagnostic readings in neutral? (Timing light flashing irregularly, dwell angle changing, fuel pressure reading?)

Or is the problem only replicable under load?
Robbie
1969 bus, "Buddy."
119k miles with me.
296k miles on Earth.

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Amskeptic
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Re: pay me now or pay me later...

Post by Amskeptic » Fri Jun 30, 2017 3:54 pm

asiab3 wrote:
Thu Jun 29, 2017 11:46 pm
Any noticeable hesitations when revved in neutral? Any interesting diagnostic readings in neutral? (Timing light flashing irregularly, dwell angle changing, fuel pressure reading?)

Or is the problem only replicable under load?
Robbie


Only high speed load. Timing light was consistent. Fuel pressure gauge needle danced horrendously.
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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asiab3
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Re: pay me now or pay me later...

Post by asiab3 » Sat Jul 01, 2017 8:10 am

Amskeptic wrote:Fuel pressure gauge needle danced horrendously.
Was the needle smooth at idle and at speed in neutral? Was there an LM1 reading during any of this? I would be curious about a sudden drop off of usable fuel supply.

Faulty valve springs causing some kind of float?

Hydraulic lifter pushrods should be steel... could solid lifter aluminum pushrods be expanding enough to mess with the hydraulic lifter inflation/cam profile/valve timing?

Robbie
1969 bus, "Buddy."
119k miles with me.
296k miles on Earth.

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SlowLane
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Re: pay me now or pay me later...

Post by SlowLane » Sun Jul 02, 2017 12:32 am

Amskeptic wrote:
Fri Jun 30, 2017 3:54 pm
Fuel pressure gauge needle danced horrendously.
Fuel pressure dance; symptom or cause?
Symptom: Is the fuel pressure dance being caused by fluctuating manifold vacuum (caused by something else?)
Cause: Is the fuel pump not able to provide sufficient capacity for stable fuel delivery at high RPM under load? Are the fuel injectors (one or more) not able to maintain the higher duty cycles required for loaded operation? Are the injectors the correct ones?
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

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Amskeptic
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Re: pay me now or pay me later...

Post by Amskeptic » Sun Jul 02, 2017 3:08 pm

SlowLane wrote:
Sun Jul 02, 2017 12:32 am
Amskeptic wrote:
Fri Jun 30, 2017 3:54 pm
Fuel pressure gauge needle danced horrendously.
Fuel pressure dance; symptom or cause?
Symptom: Is the fuel pressure dance being caused by fluctuating manifold vacuum (caused by something else?)
Cause: Is the fuel pump not able to provide sufficient capacity for stable fuel delivery at high RPM under load? Are the fuel injectors (one or more) not able to maintain the higher duty cycles required for loaded operation? Are the injectors the correct ones?



It danced even with the FPR vacuum hose off. Can't answer the other questions because it is too far away now.
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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