VW T4 Forum - VW T5 Forum banner

1 - 20 of 31 Posts

·
Registered
Joined
·
65 Posts
Discussion Starter #1
Around crimbo my 2000 T4 2.5 TDI AJT began to struggle to start. I had fuel pump timing checked in early December and two weeks later went on a 800 road trip. On the morning we left the starting issue began - I hadn’t driven the van for two weeks since getting the timing checked & gear linkage freed up. On the trip it took about three long cranks each morning to fire up. The res5 of the day it was fine and actually got better mpg than ever before. When I got back I took the van back to the same VW Indy to get them to double check the pump timing and they say it’s band on. the van now hasn’t started for six weeks...

I've had this van for almost two years and it’s always started on the turn of the key.

In an effort to solve the starting issue I checked the leak back pipes (dry), clear tube (no bubbles) and decided to changed the glow plug fuse in the little box at the battery in case it had a crack etc...I fitted an 80A strip fuse.

On first turn of ignition I get 1v power drain on battery so it appears glow plugs are getting juice.

Two weeks ago I fried my old starter motor from all the cranking, so I’ve just fitted a new 2.2kw one. Cranks but no fire. Back to square one.

I’ve changed or checked the following roughly in this order:
  • none of the leak back pipes are wet
  • no Bubbles in clear tube from fuel filter
  • replaced relay 103
  • replaced relay 109
  • changed glow plug fuse at battery
  • jumpered the fuel stop solenoid
  • checked black wire across engine bay, no breaks or damage
  • all fuses are good
  • pressed in all the connectors on back of fuse box
  • auto electrician did diagnosis and found only a few intermittent faults short to ground, nothing that would explain the non starting problem but he did suspect the ECU wasn’t sending correct signals. So I bought another ECU with same part number (thought immobiliser was disabled in it but maybe not) - after a few goes engine started ran for a few seconds then died. Immobiliser Faulty???
  • swapped back my ecu (that’s when I fried my starter motor)
  • fitted new starter motor
  • replaced all vacuum lines
  • still doesn’t start...
so I’m going to:
  • fit new fuel filter today
  • use Jerry can direct to fuel pump
what else can I try while it’s not raining for a few hours?
 

·
Full of Cr*p....
Joined
·
8,202 Posts
Try contacting Rake.
AJT with more than 100,000 miles most likely needs new injectors...
The Stanadynes fitted are pretty cr*p, and don't last.
 

·
Registered
Joined
·
557 Posts
I don’t know what your pump timing has been set at. If it’s been set to 55 like it should be as per specs, that may be the problem. I’m going off what the mechanic said to me who did my belts the last time. He said, 55 is ok when the T4 was new, as most are high mileage obviously the pump will have wear and he said what he’s found is some he sets at 55 struggle to start from cold. He mentioned setting some at 65 for them to start and run correctly.
I may be talking out of my hat here but it might be worth an adjustment perhaps and see if it improves?
He did also say that each van is usually different and he does a fair few.
Just a thought.
 

·
Registered
Joined
·
65 Posts
Discussion Starter #4
I’m not sure if my injectors are original @Or_GazM - is there a way to tell visually what I have?

@type4matt ill need to get it running to check pump timing tho. I don’t have a dti gauge and the mobile mechanic I contacted won’t do it manually.
 

·
Registered
Joined
·
65 Posts
Discussion Starter #6
Well... after submerging the inlet pipe into a container of fresh diesel it started - didn’t run it for long as the return line started pumping diesel out of the filter (which I removed the inlet pipe from). So that meant the issues were further up stream: filter, take off for the eberspacher or the fuel tank sender unit.

In the process of removing the old filter the T connector for the diesel heater broke off. On closer inspection it appears to have had a little crack although it never leaked. I left it off when I fitted the new filter.
176994



When we then tried to started the van with the new fuel filter it became apparent that there were air bubbles in the inlet pipe! Checked the connectors and no evidence of leaking on the new diesel filter, so that got me wondering about the sender I read about elsewhere on the forum.

before you know it we’d pulled the seats and floor from the cab...

176995


No big deal as I want to install more sound deadening any way...

Pulled the inspection hatch and saw this:

176996


Notice the small piece of clean plastic and the hole at the return pipe? That’s why i get diesel smells and spillage when I brim the tank.

But nothing prepared me for this!

176998


176997


This unit can’t possibly have been mangled during manufacturing could it? Doubt it.

Which means some idiot of a “mechanic“ must have forced this unit into the tank without a thought for bending the inlet pipe. Its unbelievable how mangled it is and we’ve done numerous trips into France, Spain and Portugal without issues until recently. Tank levels have always been accurate too. Amazing it’s worked so long And didn’t leave us stranded 1800 miles from home on a beach in a Portugal...as good as that sounds.

I can’t say for certain this is the culprit but I’m sure glad I pulled this out and will have a new one in there next weekend!

:oops:
 

·
Registered
Joined
·
1,112 Posts
I had something similar, sometime before I bought it my T4 had obviously been in an incident where the bottom of the fuel tank had been punched up bending the pick up.

Fot ages I thought the tank only held 50 L because the fuel light was coming on just after half the tank had been used!!+

Futher checking showed bodged repairs to the pick up and tank unit which only revealed themselves much later when it started to run rough as a badgers back end.

Really had me going for a while did that one!!!

It also had me wondering how on earth anyone could claim 600 miles to a tank!!

Rhys
 

·
Registered
Joined
·
65 Posts
Discussion Starter #8
That’s very interesting Rhys, it wouldn’t surprise me if mine suffered the same fate. I’ve only got 600 miles to the tank recently no matter how I drove it. Probably wasn’t using all the fuel ⛽
 

·
Registered
Joined
·
65 Posts
Discussion Starter #9
I’ve fitted the new VDO sender unit in the tank, as well as a new Bosch fuel filter and white return valve on top of the filter - no bubbles in the fuel lines after a couple of cranks but still not firing up!
 

·
Registered
Joined
·
65 Posts
Discussion Starter #10
I’ve cracked the nuts on the injectors and completely removed the fuel line to injector 1 - cranking the engine and there is no fuel coming out of the fuel lines!

Does the fuel pump need priming or is my fuel pump disabled?
 

·
Premium Member
Joined
·
2,537 Posts
Okay,

I've had a quick skim through the thread & I suspect the root of the issue is the timing.

You say you have changed the ECU - you need to change the immobilser reader module & key chip as well.

Looking at the fuel sender I would say that it was a long standing issue & had been hit from above.

You need to install the original ECU, replace the ECU earth return (black/white wire in loom across cam cover, just run another wire as visible inspection isn't good enough).

Purchase a DTI & pump adapter (cheap) & a registered copy of VCDS Lite to set the timing as 99.999999999% of VW 'specialists' as utterly clueless when it come to setting the timing.

Do these things & come back with your findings.

HH
 

·
Registered
Joined
·
65 Posts
Discussion Starter #13
i managed to get hold of an old Windows XP laptop like I had when I used to be able to connect to the ECU when I bought the van. I have the free VCDS and Vag.com software - neither are registered.

Yesterday I could read & clear some fault codes. I cleared the immobiliser codes (one was ECU not authorised which was probably the replacement one I tried but the Original is back in) and they did not return, neither did the instrument fault codes.

i tried cranking over the motor but still don’t have diesel coming out of the injector fuel lines.

i fitted a new ignition switch.

Tried the vag com again - no codes for immobiliser or instruments.

BUT These are the engine codes that keep coming back if I click clear.


18027 - P1619 Glow plug relay open or short to ground intermittent
(glow plug is new! so will try old one)

17957 - P1549 boost pressure control valve N75 open circuit / short to ground
(found this article to test it today HOW TO - Test Charge Pressure Solenoid Valve AKA N75)

17946 - P1538 Fuel Shutoff solenoid N109 open or short to ground
(this is the one I give a direct 12v feed from battery and it clicks - could that be why I get this fault and could this be why there’s no fuel at the injectors when I crank over?)

17571 - P1163 fuel temp sensor G81 open or short to plus - intermittent
(where is this ?)

17849 - P1441 EGR valve N18 open or short to ground - intermittent
(will try test this, I assume the resistance is similar to N75 check?)

??
 

·
Registered
Joined
·
65 Posts
Discussion Starter #14
Right, an update from today so far.

i did all the tests from this excellent post: Trouble shooting tips on relay 109 engine not starting

The results are:
  • 109 relay PASSED, it clicks on ignition and clicks a second time when trying to start. Clicks when bypassed too.
  • R3 connector 4 has 12v
  • continuity of the fuse board from front relay R3 connectors to back of G1 connector socket PASSED
  • continuity of white/black wire from G1 white connector block pin 7 (removed from back of fuse box) to large ECU plug PASSED - so this confirms my visual inspection on the black/white wire as being solid.
  • continuity of black/yellow wire from G1 white connector block pin 10 (behind fuse box) to ECU terminal 2 PASSED
  • ECU earth PASSED
  • ECU 12v passed
  • N75 resistance passed at 26.4ohms (within 25-45 range)
  • N75 has 12v on ignition
  • N75 all new silicon vacuum lines are routed correctly
  • EGR bypass checked (all vacuum lines routed as before to N18. My EGR did not have a solenoid)
Still no fuel at loosened fuel lines at the injectors.

i removed the cover for the Cambelt driving the fuel pump and it appears good with idle pulleys looking pretty new. Belt is turning with cranking. But still no fuel getting through to injectors.

Does this mean ECU is at fault?
or
Does this mean fuel pump is not working?
 

·
Registered
Joined
·
65 Posts
Discussion Starter #15 (Edited)
On someone else advice I removed the fuel stop solenoid from the top of the fuel pump.

The plunger remained behind... which I’m fairly certain isn’t supposed to happen?!

177396

177397

177398



I hope this is something significant.

?
 

·
Registered
Joined
·
65 Posts
Discussion Starter #20
@Pickledog i used a ring spanner with an open end, laying underneath. To shift it I gave it a a few light tabs with a rubber mallet. It an awkward reach with the hoses under there but you can get enough room.
 
1 - 20 of 31 Posts
Top