ALH TDI Timing

drseth

Well-known member
Joined
Sep 15, 2014
Location
Moon, VA
TDI
2001 Jetta TDI Automatic
Hi,

I have been using a OBD2 reader and TORQUE on my smartphone, and really like all of the data that it displays. I also have the readers on my other cars: 2009 GMC Yukon (It also reads Ethanol %), 2001 Corvette, 1997 Lexus LS400, and my 2002 Jetta TDI automatic.

I can watch the transmission temperature, MPG Instant, MPG Average, Intake Temp, GPS Speed, Engine load%, Boost Gauge, Fuel Flow GPH, and Intake Air CFM, among others. There is also a Timing Advance, which is usually -1 to 1 degrees advanced, but I have seen it as high as 4 degrees advanced with some cetane booster. The PO said it had a chip (not sure of brand), and some high flow injectors, and stock turbo that I had rebuilt a year ago. The mechanic who was a factory VW mechanic for 20 years before opening his own shop did the timing belt service for me, said that it was the fastest TDI he had ever driven.

I know spark timing advance in gas engine really helps the engine rev up, but with a diesel, the only timing that can be adjusted is the fuel injector pump. What is normal timing variation in an ALH TDI engine?

Seth Anderson
Moon, VA
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
You have 10 or so start of injection maps by temperature from -20 C to 86C. IIRC they run from about 20 deg when very cold, high revs, low fuel, all the way down to -2 deg (2 deg after TDC) when hot, low fuel, low revs.

The pump controls dynamic timing through the cold start valve. This used to be used long ago on mechanically governed engines to provide maximum advance for cold starting, thus the name of the solenoid.

Your base timing is set at the pump, on older engines by twisting the pump in its mounting, and on newer ones by moving the sprocket on the hub. This is the absolute least advance your engine will see, at 0% duty cycle on the cold start valve.

There is no fuel sensors (other than temperature) or ignition sensing at all, so cetane booster will not change what the computer reads out to you.

I've been running mine lately at 8 deg base, 10 deg slightly above idle, 16 deg full fuel and speed.
What your engine likes the best will likely be a lot higher as you're running a smaller pump and nozzles. What your catalyst will like is a lot lower, as it increases EGTs and keeps the cat lit up.

In general, more timing is better for fuel economy (got mine from 42 to 48 with no changes in my driving, or hardware changes) too much timing at lower fueling levels will have your economy drop off, too much timing at high fueling levels will lift the cylinder head enough to fart coolant out.
 

Enabled

Veteran Member
Joined
Apr 23, 2013
Location
Houston, TX
TDI
2003 Jetta TDI Manual, BMW 328d SW
drseth, keep in mind that you are viewing spark ignition timing in your gasoline cars, which is written in ECU and controlled by knock sensor signal,

while your diesel car has injection timing, which is again written in ECU as mentioned above, but no direct feedback is provided from the engine, so cetane boost will not influence the timing values.
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
drseth, if i may ask, which OBDII reader are you using? Do I really need v1.5 or did I just purchase the wrong ones? Thanks in advance.
 

Hasenwerk

Vendor , w/Business number
Joined
Nov 28, 2003
Location
Quesnel, BC
TDI
1982 Cabriolet (BEW|VNT17|Stage4), 1989 VW TriStar Syncro soon-to-be CR TDI (CBEA), 2001 Ford Ranger Edge 4x4 (ALH|VNT17|R520|Stage4)
Here's a question for the avid wrench spinners out there!

I want to set the timing on my ALH, which is as we all know, loosening the three bolts on the pulley and moving the sprocket.

For me, it tighten everything down, start the vehicle, open VCDS, check timing, stop vehicle, loosen bolts, re-adjust and repeat until happy.

Let's say I want exactly 8 degrees base timing on my pump and for the sake of this example, it is currently at 4 degrees. Besides trial and error and multiple starts to get things dialed in, is there a "one shot" procedure to adjust? It is possible to put the pistons and cam at TDC and then look at VCDS while moving the pump to get it dialed in without running the engine?
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
Rig up a vernier degree wheel. Reference to what you know, e.g. locked at TDC.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Here's a question for the avid wrench spinners out there!
I want to set the timing on my ALH, which is as we all know, loosening the three bolts on the pulley and moving the sprocket.
For me, it tighten everything down, start the vehicle, open VCDS, check timing, stop vehicle, loosen bolts, re-adjust and repeat until happy.
Let's say I want exactly 8 degrees base timing on my pump and for the sake of this example, it is currently at 4 degrees. Besides trial and error and multiple starts to get things dialed in, is there a "one shot" procedure to adjust? It is possible to put the pistons and cam at TDC and then look at VCDS while moving the pump to get it dialed in without running the engine?
SOI "actual" box is data from third injector needle lift sensor

Vernier scale like you find on adjustable cam timing pullies is really the only way to do it stationary. I just guess and check until its somewhat close. There's 20+ degrees in the pump, and I'm only using about 10 degrees of that range. More base timing will help startup, but anything over a couple degrees pops right over with any factory compression (18.5:1 on mine)
 

drseth

Well-known member
Joined
Sep 15, 2014
Location
Moon, VA
TDI
2001 Jetta TDI Automatic
drseth, if i may ask, which OBDII reader are you using? Do I really need v1.5 or did I just purchase the wrong ones? Thanks in advance.
I am using a cheap EBay ELM327 Reader. Some older cars they will not work. My 2001 Corvette would only work with a OBDLink LX. It costs more, but it has more stuff programmed.
 

vtpsd

Veteran Member
Joined
Aug 15, 2013
Location
Vermont
TDI
03 jsw TDI, audi 90 AHU swap
Here's a question for the avid wrench spinners out there!
I want to set the timing on my ALH, which is as we all know, loosening the three bolts on the pulley and moving the sprocket.
For me, it tighten everything down, start the vehicle, open VCDS, check timing, stop vehicle, loosen bolts, re-adjust and repeat until happy.
Let's say I want exactly 8 degrees base timing on my pump and for the sake of this example, it is currently at 4 degrees. Besides trial and error and multiple starts to get things dialed in, is there a "one shot" procedure to adjust? It is possible to put the pistons and cam at TDC and then look at VCDS while moving the pump to get it dialed in without running the engine?
I've wondered the same thing, but I assume the trial and error method still proves to be faster than setting something up. It can be frustrating when you keep over/undershooting your mark though!
 

im570rm

Veteran Member
Joined
Jul 11, 2005
Location
Romania
TDI
Audi a6 avant 2.5 tdi quattro
i don't know if there is a way of adjusting the timing the way you want it with engine off.I guess everybody does the trial and error thing.
 
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