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#15
by
fatmobile
on 07 Jun, 2024 21:31
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Because it's just one injector acting up, I don't think that could be caused by timing.
I'm not sure what the local bosch service center would charge just to test them.
Probably wouldn't be much.
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#16
by
ghostrider2
on 26 Jun, 2024 01:22
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Following up here for future reading. Turns out the injector closest to the transmission was seized. I took the time to rebuild them all and was nervous to do the work but it turned out to be fairly easy and straightforward. Here’s a great video on the topic:
https://youtu.be/EJa7l3ntWSo?si=HoIagN0LAViZNcwkSo it’s now running way better but still smoking a bit of white smoke at high RPMs and the oil pressure light is strangely on all the time even though my pressure gauge is showing at least 1bar at all times. Anyone had that issue before?
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#17
by
ghostrider2
on 26 Jun, 2024 01:24
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Unfortunately I didn’t get to test them properly as the injector tester I ordered had imperial adapters 😒 I’m hoping the pressure is good with the rebuilt insides.
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#18
by
fatmobile
on 26 Jun, 2024 23:35
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Glad you got that part of the problem figured out.
Hagar had a way to make sure the injectors are somewhat matched.
When tightening the injectors back together, make note of when the spring starts to compress and when the injector stops turning.
If the degrees of turn are near the same, the spring pressure should be near the same along with breaking pressure.
I've never tested this method but it should get you close.
White smoke at high RPMs could be air in the fuel. At higher RPMs more fuel is being pulled from the tank
and that can create more of a vacuum at the front of the pump.
I have a dash-mounted vacuum gauge to tell how hard the pump is pulling.
It could also mean the timing isn't getting advanced enough at higher RPMs.
Internal pump pressure drives the timing advance piston.
There are a couple ways to make a tool that will display the internal pump pressure on a gauge,
by making a pedestal that screws into the top of the pump, that the OUT bolt screws into.
The gauge is attached to this pedestal.
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#19
by
ORCoaster
on 27 Jun, 2024 18:26
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Ahh the mention of the man, Hagar. What a riot it was to read his stuff. And he was nearly a local to me. I never found the time to drive up the coast to meet him. My loss for sure.
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#20
by
fatmobile
on 27 Jun, 2024 19:46
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I think Hagar was also the one who first mentioned internal pump pressure and how to check it.
In a way.
He measured the pump output in liters and the pressure was relative to the amount of fuel that flowed from the pump at a given RPM.
he might even have hooked up a gauge too but my memory of where I first heard of it is vague.
Might have been something libby built.
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#21
by
ORCoaster
on 28 Jun, 2024 20:47
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At the time I was reading Hagar on the forum of the time I took the liberty of capturing some of the fun facts that Hagar would throw out every now and then. I think I have them archived in a Word document on another long dead computer. But the hard drive is a solid state one and may yield the file if I would find the time to do so.
But, in my memory of the volume at RPM to get proper pressure I believe that Hagar would state that you should get 900 ml at 1000 RPM in one minute. If less then you were to tap down the regulator button at the front of the IP. By chance you were pumping more you were to remove the button, tap the regulator all the way out and reinstall it, tap it down some, and retest, tap, and test until you came to the magic numbers he prescribed.
I even tested his numbers by building a pressure gauge take-off as you state. Under the OUT bolt and I would tap and test by two lb increments and I think his 900 ml was spot on at 43 lbs. of internal pressure. More gets you advance sooner and less, which is what we generally see gets you later timing advance. That weak fuel as Hagar called it was the bane of the IP pressure and timing issues. No amount of dialing in the right mm of advance would cure thin fuel. He always added some sort of airline oil with no ash content I believe.
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#22
by
fatmobile
on 28 Jun, 2024 21:38
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Yep, that sounds about right.
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#23
by
ORCoaster
on 29 Jun, 2024 18:43
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And I have people telling me I don't remember anything correctly anymore. HA Showed them.
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#24
by
fatmobile
on 29 Jun, 2024 23:29
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Amazing what we chose to remember, what we consider worth remembering.
And what we forget.
Many of my posts are for future me when I forget something.