VW T4 Forum - VW T5 Forum banner

1 - 20 of 43 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter #1
Hi all, I've been madly reading this site basically nonstop since I got the van - a 2003 t4 2.5tdi AJT. I do not really know the history of it and mainly bought it as it was a steal - 350k on the clock.... :)

I have now replaced all filters and put 2 new (to me) alternators on (the original and replacement had knackered diodes). I've replaced both temp sensors and spliced new wires in to the loom where they had split by alternator. Replaced oil filler o rings, replaced all vacuum and pressure hoses and replaced N75. Replaced N109 relay in fuse box. (funnily went to do EGR blank and found a 2p coin hammered in to valve side :)). Checked all inlet pipework and no leaks and jubilee clips where necessary. Max turbo pressure is 1.8atm.

The remaining issues I have are that:
MAF sensor is a bit dodgy (vagcom jumping all over when at 100% throttle) so have ordered a replacement.
Inlet manifold is mingling (any hints on removal for cleaning appreciated - other than struggle).
Low power (well I think so - not much experience with vans tbh) and top speed is it eeking up to 60 maybe 70.

So I was wondering if any of you bright sparks have any hints or suggestions other than clean inlet, replace MAF. Thoughts on injectors? If so recommendations for reasonable priced decent ones?

Oh, only code I have had persistently is about intermittent short to ground on fuel shutoff. If anyone can tell me how to fix?

More than happy to post pictures and or take any advice anyone has
 

·
Premium Member
Joined
·
27 Posts
Hullo Dan
I have been having a similar-ish problem with my van and after replacing similar bits to you I pulled the fuel tank sender out from under the seat and found a gooey slug like thing lurking in the bottom. luckily the filter looking bit just unclips and is easy to clean out. Give it a go - it can't do any harm.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #3
Okay, excuse my ignorance, I am assuming you mean there is an access port under one of the seats? Which one? Haven't actually had the carpet up yet...
 

·
Premium Member
Joined
·
27 Posts
You will need to remove the passenger seat and the easiest way that I have found is to cut the mat from the back to the handbrake and then roll the mat forward releasing it from under the LH doorstep plastic. You will then see a black metal cover held on by three screws take this off and 'voila' there is your inlet and outlet pipes etc.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #5
I've just stripped it down and it's clean as a whistle. Well now I've wiped my blood off it (the pipes must have never been off so as the screwdriver slipped a mashed my hand into the nice metal edge :))
 

·
Full of Cr*p....
Joined
·
8,876 Posts
Make sure you get a GENUINE Bosch MAF...the cheap ebay ones don't last (even if they work at all!).
 

·
Premium Member
Joined
·
27 Posts
I've just stripped it down and it's clean as a whistle. Well now I've wiped my blood off it (the pipes must have never been off so as the screwdriver slipped a mashed my hand into the nice metal edge :))
I take it that you have already changed the fuel filter?
 

·
Registered
Joined
·
23 Posts
Discussion Starter #9
Uh oh.... I just ordered one with a 1 year warranty - figured I could return it and it will get me to the bottom of the issue. Have to see what it says on vag I guess.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #11
When did it last run ok?
Well I've o ly had it a month or so and it has always been low on power. It is getting better with each repair. Hoses, n75, all filters, but is still struggling up hill a lot and doesn't get past 60 without a mile or so of road... (if you tell me that's normal then I'll just take it but I can't have something not working right)
 

·
Registered
Joined
·
23 Posts
Discussion Starter #13
Cat blocked at the sort of mileage?
I have read about this option but am not sure how to test, should add it has an aftermarket exhaust but I'm not sure if it has a cat or not - anyone who can give me an idiots guide would be appreciated.
 

·
Premium Member
Joined
·
27 Posts
Well I've o ly had it a month or so and it has always been low on power. It is getting better with each repair. Hoses, n75, all filters, but is still struggling up hill a lot and doesn't get past 60 without a mile or so of road... (if you tell me that's normal then I'll just take it but I can't have something not working right)
We have two AJT's both with over 200,000 on the clock and they go like the clappers uphill or downhill and fully loaded so it could be the mileage - you say 350,000? Have you tried getting compression checked? Although if you are getting a fault code on the fuel shutoff - maybe try replacing that, I have a spare one that I know is ok if that helps? If that is not working well it could be shutting off your fuel supply intermittently - having had weeks of similar issues with fuel supplies but getting fault codes on boost pressure etc.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #15
We have two AJT's both with over 200,000 on the clock and they go like the clappers uphill or downhill and fully loaded so it could be the mileage - you say 350,000? Have you tried getting compression checked? Although if you are getting a fault code on the fuel shutoff - maybe try replacing that, I have a spare one that I know is ok if that helps? If that is not working well it could be shutting off your fuel supply intermittently - having had weeks of similar issues with fuel supplies but getting fault codes on boost pressure etc.
This is sound advice and just what I wanted to hear. I have replace the N109 relay but thought that if shut off was truly not working then the engine wouldn't fire - that's what most people seem to report? happy to be wrong and change it though if it can have a limit/limp effect? What would you want for it?
 

·
Premium Member
Joined
·
27 Posts
The fuel shut off is just a solenoid and is just an on/off device but if it is producing a fault code (intermittently) maybe there is an intermittent fault which would presumably cause poor running, Just pm me with your address and if it works it's yours - if not send it back.
It could also be the wiring and it just so happens that I have just produced a coloured wiring diagram of that part of the loom, most of the wires from the pump connections go to the small connector on the ECU (It's not complete but I can send you a copy). One of the advantages of all this spare time.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #17
The fuel shut off is just a solenoid and is just an on/off device but if it is producing a fault code (intermittently) maybe there is an intermittent fault which would presumably cause poor running, Just pm me with your address and if it works it's yours - if not send it back.
It could also be the wiring and it just so happens that I have just produced a coloured wiring diagram of that part of the loom, most of the wires from the pump connections go to the small connector on the ECU (It's not complete but I can send you a copy). One of the advantages of all this spare time.
You sir are a gentleman and a scholar - this sounds ace. I'll send my address over. Bugger is that when I got it the ecu was gaffeted up in a bin bag, I reorganised the after market light wires and that and secured it with some bloody good cable ties, looks like that's coming apart... :)
 

·
Registered
Joined
·
6 Posts
Hi all, I've been madly reading this site basically nonstop since I got the van - a 2003 t4 2.5tdi AJT. I do not really know the history of it and mainly bought it as it was a steal - 350k on the clock.... :)

I have now replaced all filters and put 2 new (to me) alternators on (the original and replacement had knackered diodes). I've replaced both temp sensors and spliced new wires in to the loom where they had split by alternator. Replaced oil filler o rings, replaced all vacuum and pressure hoses and replaced N75. Replaced N109 relay in fuse box. (funnily went to do EGR blank and found a 2p coin hammered in to valve side :)). Checked all inlet pipework and no leaks and jubilee clips where necessary. Max turbo pressure is 1.8atm.

The remaining issues I have are that:
MAF sensor is a bit dodgy (vagcom jumping all over when at 100% throttle) so have ordered a replacement.
Inlet manifold is mingling (any hints on removal for cleaning appreciated - other than struggle).
Low power (well I think so - not much experience with vans tbh) and top speed is it eeking up to 60 maybe 70.

So I was wondering if any of you bright sparks have any hints or suggestions other than clean inlet, replace MAF. Thoughts on injectors? If so recommendations for reasonable priced decent ones?

Oh, only code I have had persistently is about intermittent short to ground on fuel shutoff. If anyone can tell me how to fix?

More than happy to post pictures and or take any advice anyone has
Mine is same van and had similar issues. Many of the same parts have been changed on mine too. The big difference was getting the diesel timing belt checked and tweaked. This has sorted most of the limp issue but I am still left chasing why it’s grumbling about starting. Good luck 😬
 

·
Registered
Joined
·
6 Posts
Mine is same van and had similar issues. Many of the same parts have been changed on mine too. The big difference was getting the diesel timing belt checked and tweaked. This has sorted most of the limp issue but I am still left chasing why it’s grumbling about starting. Good luck 😬
Actually it may also be worth me mentioning that the start of my vans long winded problem hunt, was finding at some point the air filter pipe had not been securely attached. It was on enough not to be noticed but other work in that area dislodged it further and became evident. It’s a long shot but I know this same issue has been plaguing me for months...so want to offer up what I know of.
 

·
Full of Cr*p....
Joined
·
8,876 Posts
As Peppi just mentioned....notorious problem that the intake pipe to the turbo is a "loose fit".....warm the plastic pipe with boiling water, and use a Jubilee clip to hold it tight.
Loose fit allows "un-metered" air into the system and results in incorrect fuel injection.
 
1 - 20 of 43 Posts
Top