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Old 12-11-2020, 03:05 AM
Admiral Ahani's Avatar
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Join Date: Sep 2003
Location: San Francisco
Posts: 291
1986 VW golf diesel won't stay running

I'm posting this for my brother. His car is a 1986 Golf diesel, 4-cyl non-turbo. It was totally fine before, it would start normally, idle, run, drive normally. But he would never drive it - it was being stored, and we'd just start it and drive around the block once every few months.

So last month he decided to drive it home to start fixing it up, and on the way home it developed the issues. He lost accelerator control - it just went full "throttle" on its own. He made it home, thankfully it was only 2 miles. Once home and parked, it doesn't want to run anymore. It will crank, and start, but it dies immediately.

He spent hours trying to bleed lines, he removed the fuel return banjo and poured seafoam into the IP, and I think he even used a Mitivac to pull seafoam from the new filter into the IP. He says the accelerator is working again, but it still won't stay on. In the 2 weeks of sporadic tinkering, he did get it to stay running for a few minutes once, and several times it would stay on for a few seconds and then sputter and die. My brother's current theory is bad fuel in the tank, because the only times it ran was off of a jerry can of fresh diesel next to the engine.

It's not the shutoff solenoid because when we unplugged it, the engine wouldn't start at all. With it plugged in, it will start but just dies immediately afterwards.

Any other things we should look at? We're both veteran mechanics but rookies when it comes to diesels.

'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo
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Old 12-11-2020, 08:14 AM
oldsinner111's Avatar
lied to for years
Join Date: Nov 2008
Location: bristol,tn
Posts: 6,166
look up run away diesel, drain old fuel ? is timing rubberband ? might have jumped during run away
veteran, hippy, will always be, but will fight for the under dogs
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Old 12-11-2020, 08:44 AM
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Posts: 186
Cover the basics first.: compression IP timing, and air. If you experienced a true runaway the compression will be poor and your engine will need a rebuild.
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Old 12-11-2020, 09:38 AM
Diesel911's Avatar
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Location: Long Beach,CA
Posts: 42,697
Was the Fuel Fuel Filter changed? I am assuming it also has Fuel Tank Screen.

The Filter should have a drain at the bottom. Drain some fuel out of it into a glass jar so that you can see what it looks like. Is there Water in it?

The runaway could have been the throttle linkage stuck but there is sort of a sliding block inside of the fuel injection pump at is moved on the plunger to adjust the Fuel. Not sure what happens if that sticks and does not move.

My Volvo Diesel uses the same Fuel Injection Pump but a 6 cylinder. I decided to change the Fuel Injection Pump Drive Belt (on mine there is as separate belt for the Fuel Injection Pump) teeth cam off of the Belt.

Also there is VW Forums concerning the VW Rabbit type engines and so on.

I have a Bently VW Rabbit service manual but I am not sure where it is.
84 300D, 82 Volvo 244Gl Diesel
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Old 12-11-2020, 10:54 AM
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Join Date: Nov 2010
Location: TX
Posts: 3,905
What you experienced sounds like a stuck gummed I/P or your engine ran away on its engine oil.

How did the engine shut off after this incident? - a runaway diesel only shuts off when its engine oil is finished. If you were able to shut off with key then the problem was not a runaway.

I would start with removing the cam cover to see the timing. Also remove the injection pump solenoid and inspect its internal plunger if its gummy.

The lifters on this engine are hydraulic, so they usually collapse when left for long, but they dont cause a run away. runaway is usually due to a missing baffle plate on on the camshaft.
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)
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Old 12-11-2020, 05:13 PM
dkr dkr is offline
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Join Date: Oct 2009
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I would be looking at fuel pressure and even trying to connect a plastic line into the fuel system to see if there are any bubbles.

After that, I would start looking at the IP.

You could also try running the car from a temporary tank to rule out fuel issues.

Also, the VW diesels are very particular about IP timing.

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Old 12-12-2020, 01:09 AM
Admiral Ahani's Avatar
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Location: San Francisco
Posts: 291
Thanks guys

It's not running away. That one time the accelerator stopped working and the engine was revving, he was able to shut off the engine with the key. Also, that problem went away and then came back in the opposite way - no way to Rev.

Now the accelerator seems to work. He spent some time cleaning something in the IP, I don't know what.

This weekend we're going to flush the tank.

The filter is new, and full of fresh diesel as it was drawing from a Jerry can.
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Old 12-12-2020, 07:55 PM
rrgrassi's Avatar
mmmmmm Diesel...
Join Date: Jun 2006
Location: Royse City Tx
Posts: 5,122 has a lot of VW enthusiasts there. They even have help for the 1.6 liter diesels.

Do check IP timing and also timing belt for skipped teeth.

70's Southern Pacific #5608 Fairmont A-4 MOW car

06 VW Jetta TDI 133K miles-replaced the other '06 that quit after 300k miles. (did not catch the bad cam in time)

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 195K

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Old 12-14-2020, 01:59 PM
μολὼν λαβέ
Join Date: Nov 2020
Location: USA
Posts: 92
Originally Posted by oldsinner111 View Post
look up run away diesel,
Not likely on a non-turbo engine.

Current fleet:
1998 E300 turbodiesel
2008 E320 bluetec - leaky oil cooler seals replaced
2012 S350 bluetec
2015 GL350 bluetec

1996 Passat TDI
1997 E300 diesel
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