Help Run away engine

Tsh3po

Member
Joined
May 29, 2021
Location
Pretoria
TDI
Jetta Mk4
Hi smokers... I had a Turbo that leaked oil on my 2002 AHF, today as I was driving it started "running away" (revving out of control) then shut itself down as I was reaching for the key. Was driving between 100 - 120 kilometers. It turns but sounds like it's low on compression. Any ideas what could have happened? Maybe valve float? Or something?
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
"Runaway" is a pretty good search term and should point you to a ton of threads.

The basics are: liquid oil from turbo --> intake manifold --> cylinder(s) --> bent rod(s) --> very low compression --> no start
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
just another case where the ASV didn't help at all to save the engine.
sorry for the loss. time to move on after your compression test!
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
It shut down before the OP could turn the key off, so the ASV didn't get a chance to do it's thing.
Exactly
My point is that it usually does not matter if you have one or not.
 

Tsh3po

Member
Joined
May 29, 2021
Location
Pretoria
TDI
Jetta Mk4
Thanks bros for your inputs. After some time, I decided to turn the key and the TDI started but with a lot of black smoke and low power, then the smoke turned white. I don't have the tools to work on it myself and no proper mechanic around yet... So, since it starts, does it mean my engine is safe?
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
NO
all it means is it started.
bent rods can snap totalling the engine and possibly causing an accident when the engine locks up.
how much is a tow off the road? a few hundred bucks? not worth it IMO.
compression test is #1 priority If it passes, then engine is probably OK. as long as you didn't starve it of oil you should be fine.
the turbo is clearly shot and the entire boost charge system needs to be cleaned and inspected for metal fragments. its best to NOT run the engine until you do both of those at the least. If you DO run the engine, do it with the intake boot OFF so you cant charge the engine with boost and have another runaway.
 

jakej78b

Veteran Member
Joined
Jun 13, 2019
Location
Alamogordo, New Mexico
TDI
2000 Volkswagen Jetta TDI ALH 1.9
Make sure you clean the intake before you start it... otherwise the new turbo will flood the intake with oil which will cause it to runaway again.
 

Tsh3po

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Joined
May 29, 2021
Location
Pretoria
TDI
Jetta Mk4
Update: opened up the engine and thank God it's still intact, except for a piston ring (they were all worn out anyway) and a bent valve/s. I took the head to a machine shop for a full service. Thanks guys, there's not alot of diesel guys where I live so y'all helped me immensely. Keep doing what you do.
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
So your block needs a full hone and oversized rings and pistons.
Imo walk away from it or do an engine swap. It will cost much less than trying to fix what you have because it may not last. You must have at least a hone job on it and you need to remove the rods and pistons and crank if you do and that means dropping the trans. Your 20 minutes from actually pulling the engine anyways.
You can do a diy hone job if your bores are still within spec and not egged. Get a bore gauge caliper tool
Still running about $300 in tooling vs 500 for a used running engine.
Food for thought.
 

Drewser

Veteran Member
Joined
Jul 19, 2002
Location
Mesa, AZ USA
TDI
'04 Jetta TDI Wagon, '04 Passat TDI, '03 Jetta TDI Wagon, several more in past
To be the voice of dissent, I say fix it! First, I don't know how much good used running engines are in Pretoria, maybe they are only $500. But best I found out here was closer to $1000. That being said, it may still be cheaper to do the used engine route. But I love the idea of keeping things running...kind of a romantic for fixing things, almost to a fault. That's why I'm not in the business of fixing things 🤪
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
No harm in doing a dirty hone with a dinglebery hone tool, throw some new rings at it and some gaskets. If you go that brought, spend the least you can incase it's a waste.
 

Mozambiquer

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Mar 21, 2015
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Versailles Missouri
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2004 VW Touareg V10 TDI, 2012 Audi Q7 V6 TDI, 1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
I'm of the opinion that rebuilding your engine is much better than installing a used engine. I'm a professional mechanic, and I've installed used engines, and most of the times they have had problems. Installed an alh that someone brought their own engine for, and after installing it, it ran, but was a bit rough and had a popping sound from the exhaust. I pulled the head and found that it had a broken glow plug at one point and that had dropped into the cylinder and damaged the exhaust valve. Also it had scored the cylinder walls and so then they needed a rebuild on that engine. I know that there, labor is a lot cheaper than here, I have spent some time over there in South Africa.
 

Tsh3po

Member
Joined
May 29, 2021
Location
Pretoria
TDI
Jetta Mk4
So the engine is rebuilt, head was worked with new everything, Block and pistons checked and they are still good, turbo had a full recon (new core, vnt's blah blah blah)... Got a guy, he put it together but there's a few issues:
1. Engine has a loud ticking diesel sound when it drives
2. One injector leaks vacuum (is it due to the copper washer?)
3. Car has little boost from the turbo
Any ideas?
 

Mozambiquer

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Joined
Mar 21, 2015
Location
Versailles Missouri
TDI
2004 VW Touareg V10 TDI, 2012 Audi Q7 V6 TDI, 1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
So the engine is rebuilt, head was worked with new everything, Block and pistons checked and they are still good, turbo had a full recon (new core, vnt's blah blah blah)... Got a guy, he put it together but there's a few issues:
1. Engine has a loud ticking diesel sound when it drives
2. One injector leaks vacuum (is it due to the copper washer?)
3. Car has little boost from the turbo
Any ideas?
Obviously something is wrong with each of those issues...
Ticking sound... Where is it coming from? Upper end or lower?
Could you elaborate on the injector leaking vacuum? There is no vacuum on these injectors, only pressure. If there's pressure coming around the injector, that could explain the ticking and leaking. Seems to be not too uncommon with the ahf, as last time I was in South Africa, a friend had a golf estate with the ahf and it had that same issue, it was the copper washer that was bad. I pulled the injectors and replaced them and that went away. I'd only get those from VW themselves. I know they were pretty cheap, like maybe R6 each? Prices have probably went up since then though.
The turbo not boosting could be a number of issues. First, I'd be sure that the vnt actuator is calibrated correctly and that you have good vacuum.
 

Tsh3po

Member
Joined
May 29, 2021
Location
Pretoria
TDI
Jetta Mk4
Obviously something is wrong with each of those issues...
Ticking sound... Where is it coming from? Upper end or lower?
Could you elaborate on the injector leaking vacuum? There is no vacuum on these injectors, only pressure. If there's pressure coming around the injector, that could explain the ticking and leaking. Seems to be not too uncommon with the ahf, as last time I was in South Africa, a friend had a golf estate with the ahf and it had that same issue, it was the copper washer that was bad. I pulled the injectors and replaced them and that went away. I'd only get those from VW themselves. I know they were pretty cheap, like maybe R6 each? Prices have probably went up since then though.
The turbo not boosting could be a number of issues. First, I'd be sure that the vnt actuator is calibrated correctly and that you have good vacuum.
Yes, the pressure is coming from around. So it's probably the washer.
The noise is coming from the upper part of the engine, especially when I take off, the ticking gets louder
 

Tsh3po

Member
Joined
May 29, 2021
Location
Pretoria
TDI
Jetta Mk4
Obviously something is wrong with each of those issues...
Ticking sound... Where is it coming from? Upper end or lower?
Could you elaborate on the injector leaking vacuum? There is no vacuum on these injectors, only pressure. If there's pressure coming around the injector, that could explain the ticking and leaking. Seems to be not too uncommon with the ahf, as last time I was in South Africa, a friend had a golf estate with the ahf and it had that same issue, it was the copper washer that was bad. I pulled the injectors and replaced them and that went away. I'd only get those from VW themselves. I know they were pretty cheap, like maybe R6 each? Prices have probably went up since then though.
The turbo not boosting could be a number of issues. First, I'd be sure that the vnt actuator is calibrated correctly and that you have good vacuum.
Vnt actuator calibration? Is this supposed to be done at the Turbo shop or by the mech?
 

Mozambiquer

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Mar 21, 2015
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Versailles Missouri
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2004 VW Touareg V10 TDI, 2012 Audi Q7 V6 TDI, 1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
Yes, the pressure is coming from around. So it's probably the washer.
The noise is coming from the upper part of the engine, especially when I take off, the ticking gets louder
Try replacing those washers, that'll rule that out.
The turbo actuator should be adjusted by the turbo shop, but some shops don't know to do that...
 

Mike_04GolfTDI

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Joined
Nov 19, 2003
Location
Richmond, BC, Canada
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Mine: 2019 Golf R DSG, Wife's: 2015 Golf Comfortline TDI
Was the piston protrusion measured to see what thickness of head gasket is required?

The ticking could be a piston lightly touching a valve.

Was any material taken off the surface of the head or block?
 

Tsh3po

Member
Joined
May 29, 2021
Location
Pretoria
TDI
Jetta Mk4
Was the piston protrusion measured to see what thickness of head gasket is required?

The ticking could be a piston lightly touching a valve.

Was any material taken off the surface of the head or block?
Piston protrusion? I don't even know what that is, I bought the same gasket as original
I'll get the washers for injectors just to see if the noise will go away, because few injectors are leaking
The head went to the machine shop and it was skimmed
 

Mike_04GolfTDI

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Nov 19, 2003
Location
Richmond, BC, Canada
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Mine: 2019 Golf R DSG, Wife's: 2015 Golf Comfortline TDI
Piston protrusion? I don't even know what that is, I bought the same gasket as original
I'll get the washers for injectors just to see if the noise will go away, because few injectors are leaking
The head went to the machine shop and it was skimmed
With the head off the engine, you turn the crank and measure how far the pistons protrude above the surface of the block.

You need that information to know if you need a thicker than original gasket, to give the pistons enough space between the block and the head.

Read this:

 
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