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  #1  
Old 07-18-2022, 01:30 AM
BogfordGarage BogfordGarage is offline
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Default Runaway on start up (SOLVED)

Hi everyone
This weekend my brother and I bought a 760 GLE turbo diesel, she been a bit neglected, dry stored for 20 years or so, but with a bit of work should be back on the road in no time. Except for the slight engine problem.
Firstly the starter motor wouldn't engage but after removing it and lubricanting all the part it was then working fine. Trying to start it was difficult with the battery half flat plus jumping off another car but eventually we got the injector lines bled and it ran on all 6. However it then started to runaway immediately. We switched it off and covered the air intake and it died out. Removing the turbo from the situation didn't help as it did the same thing again.
I've read in Anders post regarding the same problem that the governors can get stuck having sat for a long time. Is this a good place to start? And does anyone else have any other ideas what could be causing this?
Thanks in advance
Tristan

Last edited by BogfordGarage; 07-29-2022 at 02:37 PM.
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Old 07-18-2022, 02:53 PM
DrSpanky DrSpanky is offline
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If it's not running on oil then it's gotta be fuel, strip the pump down and give it a Refurb. There are plenty of guides and seal kits are easy to find.
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  #3  
Old 07-18-2022, 06:32 PM
ngoma ngoma is offline
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Don't know which Anders post you're referring to but when one of mine had a broken governor linkage cage it would start (with difficulty) but not stay running. Guess there could be other failure modes.

The main fuel collar is at the bottom of the pump, and if the 20 years of gunk has settled there, it could be impeding the sliding action of the collar. If stuck in WOT position that would for sure cause a runaway condition. Forum member v8volvo had a fuel collar with a broken control knob. The collar migrated to a WOT position and the resulting runaway near ruined the engine.

Presuming the "throttle" linkage, levers, cams, and spools are operating freely and not binding?

Has anyone messed with the fueling ("smoke") screw? Even a partial turn in too far can cause an extremely high idle.

Has anyone removed the throttle lever? Its hole is toothed to mate with the splined end of the throttle shaft (but not keyed), and a common mistake is to replace it in a different clocking position which can cause a high or no idle condition.
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Old 07-19-2022, 02:19 AM
BogfordGarage BogfordGarage is offline
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Thanks for both your replies
DrSpanky: I was thinking the pump would probably need a rebuild at some point its just a shame that i cant at least get it to run before doing so but if it comes to it it might need to be done.

Ngoma: Anders post: http://d24t.com/showthread.php?t=677&highlight=Kibbles

Your first suggestion seems like a good one to investigate, would i have to strip the pump from the head down to get to the main fuel collar or is there an easier way to access and clean it up?

All the throttle linkage seems free and easy to move, no sticking on return from full throttle.

I have very little history on this car however things do seem to have been "looked after" there was a decent amount of oil in the crankcase and I found a garage invoice for coolant flushing which looks to be true as its very clean.
On the pump itself there seems to be yellow markings on the max fuel screw and on the boost compensator nut suggesting to has been set up following a rebuild prehaps?

I wont be able to work on the car for a couple of weeks now but I will check out the throttle lever when I next can.
Thanks again.
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Old 07-19-2022, 10:45 AM
ngoma ngoma is offline
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Quote:
Originally Posted by BogfordGarage View Post
Your first suggestion seems like a good one to investigate, would i have to strip the pump from the head down to get to the main fuel collar or is there an easier way to access and clean it up?
The governor shaft and its flyweight mechanism dominates the space above the main shaft, blocking much of it from view. You may, however, be able to inspect and observe the governor lever and its motion. Remember to matchmark the control lever to its splined control shaft before removing the top cover. I am using the component terminology from this exploded view, good enough for our purposes.


Quote:
Originally Posted by BogfordGarage View Post
On the pump itself there seems to be yellow markings on the max fuel screw and on the boost compensator nut suggesting to has been set up following a rebuild prehaps?
Pretty good assumption. Possible rebuild or recalibration.
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  #6  
Old 07-19-2022, 11:52 AM
BogfordGarage BogfordGarage is offline
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Thanks again Ngoma. I'll look forward to Investigating it soon. I found that image earlier it's a little hard to see the complete assembly of certain parts, but it's a good place to start.
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Old 07-29-2022, 02:35 PM
BogfordGarage BogfordGarage is offline
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Default Fixed!

So...
Having spent the last couple of weeks watching tutorials and reading, all to learn how the VE pumps work and what each component's role is, I now know them pretty well. (I've always found it easier to fix something having first understood it fully.)
This evening I got to work removing the top cover, following Ngoma's suggestion I made sure to mark the throttle shaft. Inside was dirty where old fuel had sat for a number of years so i sucked it out, with the help of a syringe, and got a better look inside. It turns out Ngoma is the man because as he suggested the governor lever was sticking in WOT position, I could also just about see the top of the fuel collar getting stuck on the plunger. I refilled the pump with ATF and worked the lever back and forth until all was freed up. Following reassembly we started it up and it idled perfectly and didn't try to runaway on reving. Thanks again to Ngoma with your help on this one, I hope someone will find my experience useful. Now to get her on the road!
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  #8  
Old 07-30-2022, 09:59 AM
ngoma ngoma is offline
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Good strategy + good efforts = Great Payoff!!!
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