Run an ALH naturally aspirated ? (+sketchy dump valve fix)

Fosco

New member
Joined
Apr 27, 2017
Location
Le Mans, France
TDI
1Z, AHU, ALH, BKC & AXE
Hey guys, long time lurker here, I'm 25 yo from France, been reading stuff & troubleshooting cars with help of this forum for awhile now.

I often get to work on TDI's (even tho I'm not a mechanic), it's about 10+ cars I often work on which are TDI powered (1Z, AHU, ALH, BKC and even 5cyl AXE engines).


So let's get started with my current subject :

My company owns a worn out VW Caddy TDI from the 2000's with ALH engine.

The car is falling appart from each and every side but lately, the VNT turbo started to get stuck and the ECU went to limp mode ... pretty annoying.

Since we don't give much f*** about it, we're not going to fix it, but instead of throwing it in a junkyard, we went for a temporary crappy fix : add a "non automotive" dump valve before the boost sensor.

So here it comes, we picked up a 7 to 11 bar (100-160 psi) safety valve, replaced the original spring with a softer one laying around and began setting it



0.9bar (stock pressure IIRC), boom it's done



Then comes the piping process, the plumber way :lol:




Fitted in the car


I went for a test run, it whistles so hard, it's so much fun, then goes the boom, hose went off, oil everywhere :D


We added some retaining springs for the hose not to fly (yet, mostly for fun, we know this wont last), and I went for another, longer testrun and well ...



Success(ish*), the ECU won't go in limp mode. The sensor still shows some pressure peaks, yet the valve blows everything away quite quickly (a bit too hard tho, pressure goes down very fast).
* : Hoses still tend to fly away :D

It's a lot of fun hearing the (way too) loud whistle over 3k RPM ... now we wait for the turbo to blow (judging by the oil in the hoses, it's coming soon) :lol:



Now here comes the questions about the next step :

We'd like to keep this Caddy beater. It runs once a week to get cardboard & other garbage to recycling center and definitely won't need a turbo for that. We don't want to replace the turbo on this turd, or spend too much time/money working on it ... but at the same time, it would be a bummer to send this thing to the junkyard since the engine / brakes / drivetrains are perfectly fine ...


I had thoughts about going the N/A route on this one, like bring the maf before the inlet manifold, let the turbo blow nowhere (well atleast in some kind of box to retain the oil lol) and boom done.

Problem we had before fixing it with the ghetto dump valve is that limp mode is way too low power, I know this ALH can achieve more power while N/A than in limp mode but I don't know the in and outs of doing this.

My biggest concern being the current turbo ... we don't want to remove it ... but at the same time, it will probably blow and spill oil everywhere ... and we don't want to damage the engine.

Maybe shunt oil feed / return and let it blow ? :)D)

Anyways thanks for reading all this crap,

Fosco
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
How do we know the oil is from the TC and not the crankcase vent?

I would speculate that limp mode is as much power as you'll get with no TC. The ECU is setting the fuel based on no boost.
 

VeeDubTDI

Good Ol' Boy, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Here in the States, companies are offering a "stage 0" tune that is designed for turbo-delete. I'd expect something in the neighborhood of 60 hp.
 

\/\/0J0

Veteran Member
Joined
Apr 27, 2010
Location
Knoxville, TN
TDI
Sadly, none anymore
I would say that if you continue running it like that, your chances of having the the turbo puke all of the engine oil into the intake are great. Best case scenario here is that your engine runs away. Worst case is hydrolock and smashed rods.
1. Take the turbo off, cut the vnt housing off and weld a replacement pipe in place to join the manifold to the downpipe.
2a. Replace etdi injection pump with mtdi injection pump and throttle cable.

-or-

2b. Go with stage 0 tune as mentioned above

3. Enjoy having plenty of time to take in the scenery on your drives along with the relaxed lifestyle that life out of the fast lane will bring.


Sent from my mobile look-at device
 

need4speed

Veteran Member
Joined
May 4, 2004
Sick build.

And it inspired me to write a poem:
Rock a by turbo in the engine,
When the vanes seize, the boost wont give-in,
When the shaft breaks, the turbo will fail,
and into your valve train, shrapnel will sail.

:D
 

AnotherPerson

Veteran Member
Joined
Oct 24, 2015
Location
New Orleans
TDI
1999 Beetle
Here in the States, companies are offering a "stage 0" tune that is designed for turbo-delete. I'd expect something in the neighborhood of 60 hp.


I suspect with good injectors it can be more. First hand experience in limp mode on worn and new injectors is night and day.


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Fosco

New member
Joined
Apr 27, 2017
Location
Le Mans, France
TDI
1Z, AHU, ALH, BKC & AXE
How do we know the oil is from the TC and not the crankcase vent?

I would speculate that limp mode is as much power as you'll get with no TC. The ECU is setting the fuel based on no boost.
Well so far I removed every hoses and before the turbo it's not THAT oily and crankcase vent looks alright. And even tho it wouldn't be an accurate way to know, considering the vast amount of oil in the lines, the engine would probably be dead by now if that was from the vent. 99% sure it's the turbo


Here in the States, companies are offering a "stage 0" tune that is designed for turbo-delete. I'd expect something in the neighborhood of 60 hp.
Ye I saw something like that existed here aswell, that would be a nice idea once we figured how to do the proper "turbo delete mod", I mean physically.

I would say that if you continue running it like that, your chances of having the the turbo puke all of the engine oil into the intake are great. Best case scenario here is that your engine runs away. Worst case is hydrolock and smashed rods.
1. Take the turbo off, cut the vnt housing off and weld a replacement pipe in place to join the manifold to the downpipe.
2a. Replace etdi injection pump with mtdi injection pump and throttle cable.

-or-

2b. Go with stage 0 tune as mentioned above

3. Enjoy having plenty of time to take in the scenery on your drives along with the relaxed lifestyle that life out of the fast lane will bring.


Sent from my mobile look-at device
Hahaha, that's exactly what's in my mind.
I'm buying the "cut the turbo and weld a tube inside", it would match the degree of f***s given to this beater :D

I even thought of a sketchier way to mess up things :
- block air intake & cold side while the turbo still fitted in the car (I still have to figure how)
- remove the oil lines, let it blow / clear itself (idk how oil is supplied on this engine/turbo tho)
- profit (It's good to be dreaming nah ?)

Sick build.

And it inspired me to write a poem:
Rock a by turbo in the engine,
When the vanes seize, the boost wont give-in,
When the shaft breaks, the turbo will fail,
and into your valve train, shrapnel will sail.

:D
Sir, you really made my day. :D :D :D :D
 

Nevada_TDI

Veteran Member
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
The oil supply is on the oil filter housing on a banjo bolt. I had to run my car w/o a turbo for a short amount of time so I made a short bolt to thread into the housing , sealing with one copper washer. I left the piping the way it was and she did not have much power, but she did smoke a lot even with the IQ somewhere around 11.
 

Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
Hi,

How about brazing a band around the copper pipe to help retain the hoses and run the turbo...The reason the hoses are slipping off the copper connecting pipe is because it has no "ridge" to help hold the hose on....I wish I had a pic I could post to illustrate what I mean, maybe somebody else here could help with that).

Hope this helps

Andrew
 

n1das

TDIClub Enthusiast, Veteran Member
Joined
Jun 11, 2002
Location
Nashua, NH, USA
TDI
2014 BMW 535xd ///M-Sport, 2012 BMW X5 Xdrive35d, former 3x TDI owner
Why not correctly diagnose and fix the limp mode cause?? It may not need a new turbo and probably has a stuck actuator or stuck vanes in the VNT mechanism. The vanes in the VNT mechanism can get stuck from soot buildup from poor TDI driving habits or other problems causing lots of soot from running with no boost for long periods. Consult the stickies at the top of the forum section for more information.

Good luck.


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Fosco

New member
Joined
Apr 27, 2017
Location
Le Mans, France
TDI
1Z, AHU, ALH, BKC & AXE
Everyone loves watching a train wreck.
:D

The oil supply is on the oil filter housing on a banjo bolt. I had to run my car w/o a turbo for a short amount of time so I made a short bolt to thread into the housing , sealing with one copper washer. I left the piping the way it was and she did not have much power, but she did smoke a lot even with the IQ somewhere around 11.
That's good to know for the oil feed. We'll dig into that later.

So far, the only long term, "easy fix" will probably to swap the car with a 1.9D and get rid of all the issues we're experiencing.

Hi,

How about brazing a band around the copper pipe to help retain the hoses and run the turbo...The reason the hoses are slipping off the copper connecting pipe is because it has no "ridge" to help hold the hose on....I wish I had a pic I could post to illustrate what I mean, maybe somebody else here could help with that).

Hope this helps

Andrew
That would've totally helped Andrew thanks but we did bent the edges of the copper tube to act like a retainer or a ridge. In addition we replaced the hose which was a bit too short and the problem got solved.

In addition, the copper tube & the hoses were oily, that's why it failed !:D


Why not correctly diagnose and fix the limp mode cause?? It may not need a new turbo and probably has a stuck actuator or stuck vanes in the VNT mechanism. The vanes in the VNT mechanism can get stuck from soot buildup from poor TDI driving habits or other problems causing lots of soot from running with no boost for long periods. Consult the stickies at the top of the forum section for more information.

Good luck.
Hey, at first that was what I thought. I went through all of the process of diagnose for this issue.

The result is :
N75 does its job.
Boost pressure sensor reads ok all along the boost magnitude.
ECU "knows(/read) what's going on"
VNT actuator is ok / holds vacuum etc

But yeah, mechanism is stuck when the engine (turbo) is cold, it can't move all the way down or up, I can't remember.

If it was the only issue, we could've fixed it the proper way (atleast try), unfortunately, the turbo shaft has a lot of play and spills oil everywhere in the hoses ... it's really near from death right now. It isn't (yet) touching the body, but it's getting close ...



However, so far, the Caddy has been running great, no limp mode, we just drive it easy for the engine/turbo's sake, yet it still makes boost and the valve dumps the excess when the turbo is cold/mecanism is stuck.


Unfortunately, a new problem showed up and the ECU sometimes doesn't respond / the car acts like if there was an issue with the immo (starts & stop within a second).

I already replaced the immo with an immo emulator but the problem remains. I've ring'd (is it the accurate word ?) the wiring to the ECU with a multimeter, suspecting an issue with the harness but I haven't found any issue so far.

I opened the ECU, a little moisture invasion and a dry weld but nothing changed, the ECU will still randomly "lose" his mind, preventing him to start the car and the RossTech Cable to communicate.
However I can still diagnose the immobilizer, key is recognized, engine start autorized, etc but "no response from ECU" so ...:(


That's why, we're considering throwing the ALH away and get a mere 1.9D just to get it reliable -without any power- :D
 

\/\/0J0

Veteran Member
Joined
Apr 27, 2010
Location
Knoxville, TN
TDI
Sadly, none anymore
Check your grounds(earths)--especially under the wiper cowl--and your 109 relay to help diagnose the dodgy ecu communication.

Sent from my mobile look-at device
 

casioqv

Veteran Member
Joined
Aug 18, 2015
Location
California
TDI
2009 Touareg TDI
I'd guess you have either a vacuum leak, or failing vacuum pump causing your boost spike- not quite enough vacuum for the system to work. There are many places for a vacuum leak, and small ones seem to still read a strong vacuum on a gauge, but still cause overboost.
 

flee

Veteran Member
Joined
Sep 19, 2011
Location
Chatsworth, CA
TDI
2002 Jetta GLS wagon
Here in the States, companies are offering a "stage 0" tune that is designed for turbo-delete. I'd expect something in the neighborhood of 60 hp.
If you get ~90hp at the crank with 15psi of boost then expect no more than 45hp at atmospheric.
A specialized tune could maybe squeak out a few more but with what air?
And don't they have enough diesel smoke in France already?
 
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