Back After a 'Work Induced' Hiatus....

TommyLT

Member
Joined
Dec 2, 2012
Messages
61
Location
Liverpool
Timing the pump when it's installed is easier done from the front - hands through to the back and eyes on the guage.
Been thinking about the fact that it's actually ran for a few seconds which would mean timings are ok, this makes me think more of a fuel supply issue. If it is a supply issue then you'd be looking at things like the:

Fuel filter....when was it last changed or water drained? Also meant to say the the little valve on the filter is a regulator not a non return valve, in cold weather it'll allow warm returned fuel from the pump back into the filter and then back to the pump, warm weather it's fuel straight back to the tank.

When you said the wiring for the fuel pressure solenoid I think your referring to the commencement of injection valve (front underside on pump) which can be tested with a multimeter at the connector plug. Do you have the 7 pin connection or 10 pin connection pump? I can post the specs.

Fuel cut off solenoid......You could try a live feed direct from battery (should hear it click) and give it a try.

Worst case scenario the pump is mechanically fubar.

Or even the 'worstest' case scenario...... the fuel tank is empty!!!!!

Another thing you mentioned was the wiring for the needle lift sensor injector no.5 (and this has only just come to me.... the old grey cells aint what they used to be sorry) I had a starting issue a while back and it was the wiring on the sensor injector (VCDS told me) another reason why it's so important to have, it can save so much time troubleshooting. I was having to give the wiring a wiggle when it wouldn't start. I vaguely remember reading that unplugging it will cause the ecu to use a default map so the engine will still run (a kind of limp mode) although I never actually tried it I just swapped it over when I had time with one of my many many spares I'd refurbed.
That's got me curious now, I might try unplugging it in the morning and let you know if it still starts.
 

MollyNomad

Member
Joined
Oct 19, 2017
Messages
50
Location
NE Fife, Scotland
Timing the pump when it's installed is easier done from the front - hands through to the back and eyes on the guage.
Been thinking about the fact that it's actually ran for a few seconds which would mean timings are ok, this makes me think more of a fuel supply issue. If it is a supply issue then you'd be looking at things like the:

Fuel filter....when was it last changed or water drained? Also meant to say the the little valve on the filter is a regulator not a non return valve, in cold weather it'll allow warm returned fuel from the pump back into the filter and then back to the pump, warm weather it's fuel straight back to the tank.

When you said the wiring for the fuel pressure solenoid I think your referring to the commencement of injection valve (front underside on pump) which can be tested with a multimeter at the connector plug. Do you have the 7 pin connection or 10 pin connection pump? I can post the specs.

Fuel cut off solenoid......You could try a live feed direct from battery (should hear it click) and give it a try.

Worst case scenario the pump is mechanically fubar.

Or even the 'worstest' case scenario...... the fuel tank is empty!!!!!

Another thing you mentioned was the wiring for the needle lift sensor injector no.5 (and this has only just come to me.... the old grey cells aint what they used to be sorry) I had a starting issue a while back and it was the wiring on the sensor injector (VCDS told me) another reason why it's so important to have, it can save so much time troubleshooting. I was having to give the wiring a wiggle when it wouldn't start. I vaguely remember reading that unplugging it will cause the ecu to use a default map so the engine will still run (a kind of limp mode) although I never actually tried it I just swapped it over when I had time with one of my many many spares I'd refurbed.
That's got me curious now, I might try unplugging it in the morning and let you know if it still starts.
Wow Thanks Tom. Fuel tank is FULL. Less condensation. Fuel filter was changed before I drove to Spain (6,000miles ago approx) but I will drain a bit off the housing as I’ve not done that in a while. Was staring at it s couple of days back and was thinking that very though. Cut off solenoid works perfectly. The commence of injection valve I have tested for resistance AFAIK it was within specs which elude me at the moment. They may be incorrect specs BTW as everything else seems to have been incorrect it seems? The wiring to it is damaged right where it connects to the round housing although I have effected a repair which makes me think it actually works. Have tried to source a replacement of the same spec but no luck. I actually bought an old Pump off a turbo van for shits and giggles out of mild curiosity the part number on the commencement of injection valve is different (obviously considering). When I get back I will do as mention regards rechecking timing and have a go before again the specs of +\- 17 needs to be explored. Although I disassembled the pump to reseal it I’m convinced it’s reassembled correctly. 276,000 miles it’s probably within its ‘own’ specs.. not so much within factory/brand new pumps specs… and it functioned okay before disassembly.. it will work I am sure if we could get the timing correct. Fickle as it may be. Some great info and advice.. lying on my truck bed at Bathgate, back home Wednesday I feel re energised by the advice given.. despite not sleeping more than three hours in 30+ degree heat yesterday and a 400 plus mile drive last night. Many thanks again It’s much appreciated…💪🏻💪🏻👍🏻
 
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MollyNomad

Member
Joined
Oct 19, 2017
Messages
50
Location
NE Fife, Scotland
And it’s a 10 pin connector.. 🤦‍♂️

I have a decent MAHLE filter on the shelf and new valve thingy (Bosch) so may just bite the bullet and swap the filter etc out. Hated that job the last time did it from underneath but since I have ‘learnt’ that the front is relatively easy to remove(aside radiator/coolant etc) I will do it from the front…. if the feeling takes me..
 
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TommyLT

Member
Joined
Dec 2, 2012
Messages
61
Location
Liverpool
I'd just sat down and started typing then realised I'd forgot to check the needle lift sender...... just tried it and it starts fine with it unplugged. So there is a quick test for you.

Another thing which came to me today was, if you had the pump apart for a rebuild then you will have disturbed the fuel injection quantity setting/position. This can be adjusted with vcds or the rough arse way to do it is, loosen the head of the pump and smack it backwards with a hammer to increase fiq. (search tdi hammer mod or fuel injection quantity hammer mod)

Anyway, heres the specs for the pumps electrical parts and the needle lift sender:

Commencement of injection valve (N108):
Commencement of injection valve N108.jpg

Metering adjuster (N146):
Metering adjuster N146.jpg
Modulating pistom movement sender (G149):
Modulating piston movement sender G149.jpg
Needle lift sender (G80):
Needle lift sender G80.jpg
 

MollyNomad

Member
Joined
Oct 19, 2017
Messages
50
Location
NE Fife, Scotland
I'd just sat down and started typing then realised I'd forgot to check the needle lift sender...... just tried it and it starts fine with it unplugged. So there is a quick test for you.

Another thing which came to me today was, if you had the pump apart for a rebuild then you will have disturbed the fuel injection quantity setting/position. This can be adjusted with vcds or the rough arse way to do it is, loosen the head of the pump and smack it backwards with a hammer to increase fiq. (search tdi hammer mod or fuel injection quantity hammer mod)

Anyway, heres the specs for the pumps electrical parts and the needle lift sender:

Commencement of injection valve (N108):
View attachment 8679

Metering adjuster (N146):
View attachment 8680
Modulating pistom movement sender (G149):
View attachment 8681
Needle lift sender (G80):
View attachment 8682
Hello Tom when you say the ‘pump head’ do you mean where the fuel outlets are on the ‘pump head’(as referred to in Bosch official manuals) or the ‘pump head’ on top of the pump that contains the electrically (ECU) controlled ‘gizmo I have no idea what it’s called thingy’ that resides inside then aluminium housing held in by 4 Torx/any tamper bolt that’s on the top of the pump…?
 

MollyNomad

Member
Joined
Oct 19, 2017
Messages
50
Location
NE Fife, Scotland
Hello Tommy and Crasher

Very quick update....maybe...

Spent all day in my bed yesterday after finishing work, got up this morning early (ish) for me on a day off...went to visit a mate who was sat on by a cow Several months ago as not seen him for a wee while...anyhoo on returning via Tescos for some chocolate eclairs and cat litter.......I decided to have a quick fiddle with the van...No plan just went up to it and after checking that I hadn't locked the pump after resetting stuff last time connected the batteries and turn it over...hadn't done anything to adjust the pump timing...it turned over and fired up and ran for a couple of seconds.... after about 8 to 10 seconds of cranking...did that twice just incase the LT35 angel was watching and did me a favour but she just have been watching Love Island or summin' similar. Now it was time to take positive action and follow any instructions to the letter...but wait the 'Hammer thing' hadn't been tried etc...so I went and got the appropriate tools and started 'fiddling'...after some swearing and a couple of trips back into the garage for the correct tools I had the 'pump head' (governor housing on the old pumps) loose enough to tap the head backwards..how far? ALL THE WAY!! retightened everything and turned the key...plenty of crank but no firing of any kind...a step backwards...a bit miffed I reversed the process but pulled the 'pump head' forwards with my hand until it stopped and resecured all the 'fasteners'.............................

Thought I'd turn the key to ensure we had restored the previous crank, fire, not run for more than a few seconds situation....

FECK ME IT FIRES UP STRAIGHT AWAY AND RUNS.........UNTIL I TURN THE KEY OFF........than restarts IMMEDIATELY on the key...no extended crank of any kind...runs a bit rough though, sounds like there is a hole in the exhaust but that's because there was..(EGR outlet from manifold)

To say I was bit shocked, well.....is an understatement...But I'll take that ANYDAY of the week... I have reassembled everything just need to get some distilled water as I have 'concentrated' Whatever is the new recommended coolant ...once I fill the cooling system I will get it onto VCDS and dynamically tune the pump....

Although not exactly scientific 'stuff and things' have worked.

You can't know how happy I am..

Thanks for your help up until now I will continue to let you know how things develop. WELL CHUFFED
 

MollyNomad

Member
Joined
Oct 19, 2017
Messages
50
Location
NE Fife, Scotland
Further to last instalment...Well this week I was hoping to get the engine up to temp and put VCDS onto it...well that happened..VCDS says that the pump timing to too far advanced to be adjusted on VCDS. So I am assuming that I will need to 'retime' the pump again and go from there.

Before I did this (when I got home yesterday) I started the van (for encouragement more than anything else) and I had a fuelling issue as the 'bulb priming pump was letting air into the system(I had fitted that a while ago FYI). After fiddling with that I started the engine and almost immediately it started to build revs in an alarming fashion...kind of like a 'runaway' engine. Switched it off....then went into the garage and got myself an appropriate piece of wood to blank the intake should it happen again.. Well, I thought that's odd...so started it and the engine again started to 'runaway'..Checked the TPS and pedal etc incase they had got snagged up...all was good. Decided to do a 'reverse hammer' modification' and eventually got he engine to run in a 'almost' normal way by 'tippy tapping' to the top housing on the pump. One thing I noticed if I brought it too far forwards then it immediately started to increase revs rapidly....Funnily when I did the hammer mod originally' thats where I 'set it' and got the engine running..albeit it badly.

Anyhoo, I am just waiting for the engine to cool enough(I had put coolant into it thinking I wouldn't have to re time the pump but I will have to drain some at least to remove alternator/vacuum pump for access) so I can 'fiddle' with the DTI 'et al'.. Worse case I will have to remove the front end/radiator if I can't reach/see the pump drive wheel or DTI...I am blind and have T Rex arms...the front end has been off many times...Its actually a 5 min job for me...

I would attach some photos but have no idea how to reduce their size (I have done it before but a long time ago...). I have removed the horn and currently re painting it whilst things cool off a bit..

Cheers.
 

TommyLT

Member
Joined
Dec 2, 2012
Messages
61
Location
Liverpool
Did you use the TDI Checker graph on vcds? Only ask as I've never checked the AGX section on it to see if there is a choice for the different years (35mm or 55mm), and did you get your fuel injection quantity?
I use ms paint for resizing pics.
 
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