12mm pre stroke head timing.

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
Hi
I have 2004 1.9 tdi 81kw Seat leon.
I have problem with timing on 12mm pre stroke head.
I replaced my 10mm zero pre stroke pump head to 12mm pre stroke head. At first I set injection timing using vcds to blue line on a timing graph. But it was to retarded, so I advanced it 7-8 degrees (vcds shows 8 degrees BTDC). But it is still hard cold start (-20 degrees) it takes 10-20 sec to engine stop stuttering, after that engine runs very smooth.
Now I advabced it 14 degrees, I will see in morning how it is.





Is that right when timing is out of the graph then ECU does not advance timing on driving?

Does injector number 3 measures needle lift from zero? So it shows pre stroke not main injection?

Can I make delay in to the needle lift zensor?
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
I don't know what you mean by "pre stroke"

There is no advance curve built into the pump, the computer doing PWM on the cold start valve (n108 iirc) is 100 percent of the timing control. It will try and follow the maps as best it can, meaning if you have 8 degrees at the pump, it'll be flat at 8 degrees when the maps are calling for 0-8 deg, but when the maps call for 8+ degrees it'll bump the timing up to whatever it wants. I remember the stock maps call for up to something like 18 degrees, so you might see some movement with your 14 deg initial timing, but I doubt it as that is only in the very coldest maps, high RPM and low injected quantity.

You might get the engine kicking back against the starter with that much advance, I'm running 7 degrees right now and I'm thinking about backing it off to 6 or less as there is white smoke from the fuel being injected before there is enough heat to ignite it.

You will get codes for an over advanced timing condition, you can disable these codes in winOLS, search the code numbers on ecuconnections to find exactly how.

Oh, one more hard-earned nugget of wisdom on the timing control scheme, sometimes at hot idle with very large injectors you will notice the G80 needle lift sensor registers no timing numbers, and the cold start valve defaults to 44% iirc. This is from the injector not being opened hard enough by the tiny amount of fuel going in and not rattling the piezoelectric needle lift sensor.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Oh right, be careful with that 12mm pump head, if you are not running large enough injectors you will cause it to sieze. My 12mm/de110 pump siezed with pp764 injectors which are .234mm hole size iirc?
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
Here is a little bit of pres-stroke (pre hub, preload) plunger:
http://forums.tdiclub.com/showthread.php?t=472359
http://howcarpartswork.blogspot.com/2016/03/distributor-fuel-injection-pump.html
My plunger has quite big area before pre-stroke groove( bigger/ longer than Alleslowbuged posted picture)
Today was -10C. Engine started good (no engine kicking back) Tomorrow wold be -25C
Best way to get spot on mechanical timing is cold weather, for TDI I use as cold as possible and for mechanical pump is good some degrees down from zero.
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
Yes I got codes for an over advanced timing condition.
I have only VCDS to play with (I am more mechanical type, computers are not my strongest side)
I advanced timing with VCDS as much as possible (under Adaptation, Channel 4) got it 5.5 BTDC. At least now there are some timing advancing by computer when I am driving. But still there are 9 degree difference between static and dynamic timing.
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
Can it be that fuel quantity is to big for my nozzles/injectors?(stock .205 220/300 bar nozzles, I have guite minimal fuel, there are no black smoke, no ecu tuning) When there is pre stroke then fuel pressure is rising too quickly for my nozzles and it is moving a little bit main injector spring so needle lift sensor registaret movement, same what is happening with turbo boost.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
I'm shocked your injection pump head is not siezed with that small of injector
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
Yeah sorry, I know they are to small, but I hoped if there are really small fueling from the pump (hammer mod, a little bit more fuel then stock head) then they will handle it, but look like they don't.
Is .240mm nozzles reasonable size?
My goal is not max out everything. I bought 12mm head because mu stock head was damaged by rust in side the pump and 12mm head was same price as 10mm head. Yes I have tuning plans in future but now I need this car as cheap (fuel economyand) and durable as possible.
 

p0wer

Veteran Member
Joined
May 21, 2009
Location
Jyvaskyla, Finland
TDI
Golf 3 -94 1Z 377hp, Golf 3 Cabrio 4-Motion 1.8T 620hp, Golf 3 Syncro 2.9 VR6 HX52, Bora AJM 4-Motion 2260vk +120% Firad, Passat 3B Syncro AFN 2260vk
0.280-0.320mm is good for 12mm+de110. 2-4 degrees would be good timing for your engine. If you have problems on cold start, you should look that your glows work.
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
Thank you for advice.
I decided to use 0.240mm nozzles. Engine where this 12mm head came from (I use new head) uses 0.230 nozzles, but uses less rpm.
I am planing to rise nozzle pressure to.
I hope this will solve my problem.
 

p0wer

Veteran Member
Joined
May 21, 2009
Location
Jyvaskyla, Finland
TDI
Golf 3 -94 1Z 377hp, Golf 3 Cabrio 4-Motion 1.8T 620hp, Golf 3 Syncro 2.9 VR6 HX52, Bora AJM 4-Motion 2260vk +120% Firad, Passat 3B Syncro AFN 2260vk
It will not solve that problem.
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
It will not solve that problem.
Why do you think so?
Am I missing something?
My static timing is good (good cold start at -20C) but needle lift sensor are registreiting pre stroke not main stroke as it should to.
 

p0wer

Veteran Member
Joined
May 21, 2009
Location
Jyvaskyla, Finland
TDI
Golf 3 -94 1Z 377hp, Golf 3 Cabrio 4-Motion 1.8T 620hp, Golf 3 Syncro 2.9 VR6 HX52, Bora AJM 4-Motion 2260vk +120% Firad, Passat 3B Syncro AFN 2260vk
Nozzle size will not affect for cold idle. I cant see your problem. Set your timing somewhere like it should originally be (0-2btdc). What problems you have then?

Are your all glows ok and 100% sure they are proper model, and they are getting electricity ?
 
Last edited:

Markus L

Veteran Member
Joined
Feb 12, 2015
Location
Finland
TDI
Caddy (14D) 1.9TDI 2-stage 400+bhp, Passat 3BG 4motion AVF
OP, so you have machined a circular groove on the plunger that allows the fuel to flow back to the low pressure area at the beginning of stroke? Now you wonder why you need to advance static timing so much to get the dynamic timing to the setpoint?
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
Nozzle size will not affect for cold idle. I cant see your problem. Set your timing somewhere like it should originally be (0-2btdc). What problems you have then?

Are your all glows ok and 100% sure they are proper model, and they are getting electricity ?
When I set my timing as originally (0-2bdtc) then it is really bad cold start and other symptoms for retarded timing but ECU is happy, showing all reading as it should be. (Look my first post)
How there can be problem in glows, after advancing timing 14 degrees there are no cold start problems?


OP, so you have machined a circular groove on the plunger that allows the fuel to flow back to the low pressure area at the beginning of stroke? Now you wonder why you need to advance static timing so much to get the dynamic timing to the setpoint?
I have not done this groove myself. I think this head uses one spring nozzle and plunger shape are making 2 stage pressure increase and then one spring nozzle will make two stage spray as two spring nozzle.
 

WarmStart

Well-known member
Joined
Aug 24, 2016
Location
Estonia
TDI
TDI
I finally figured out where was problem.
Pump inside pressure was too small.
When I started engine there wasn't enough pressure to advance timing enough.
But I still don't now why there were not enough pressure.
Now I set timing to 2 BTDC, everything works find but there isn't still enough inside pressure. Over 2500 rpm timing starts to drop.
When I get time I'm going to mount pressure gauge to monitor pump inside pressure and add lift pump.
 
Top