VW T5 won’t start

[DerryW]

A bit of a long shot I know.

Is there anyone with a depth of knowledge of the mechanics (specifically the ADX engine).

My BIL has a T5 California conversion which will not start. Even the local VW garage having spent in excess of £5k still can’t sort it.

Would appreciate any pointers which may just resolve it.

Thanks

 

[Tombola]

What's happening ? Any specifics?

 

[Landy Andy]

I assume turning over but not fire up.

Also assume they have used some brake cleaner, or easy start in air intake to indicate fuel, or other problem.

 

[ChrisL]

Even the local VW garage having spent in excess of £5k still can’t sort it.

If they can't diagnose the issue after spending £5000 on the job, they are clearly not fit to be working on vehicles, I sincerely hope your friend hasn't paid them that.

 

[DerryW]

What's happening ? Any specifics?

Last Dec yes nearly 12 months ago, he started it as normal, left it running 15mins on his drive to clear the screen, switched it off. 45mins later when to start it to attend a funeral, and it wouldn’t start. It was towed into a specialist Deisel garage, who checked the timing, fitted a new ECU, fitted a new cam shaft sensor. but could not get it to run.

He had it collected and delivered to a genuine VW commercial dealership. They have had it for 5 months. fitted a dual fuel pump, checked and cleaned the inline fuel pump, fitted another ECU they managed to get it to start using a brake cleaner aerosol, but only for a short time. Last week fitted a full set (5) refurbished injectors, still won’t start. They did manage to get it to start using brake cleaner, but only for a short time.

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[DerryW]

Last Dec yes nearly 12 months ago, he started it as normal, left it running 15mins on his drive to clear the screen, switched it off. 45mins later when to start it to attend a funeral, and it wouldn’t start. It was towed into a specialist Deisel garage, who checked the timing, fitted a new ECU, fitted a new cam shaft sensor. but could not get it to run.

He had it collected and delivered to a genuine VW commercial dealership. They have had it for 5 months. fitted a dual fuel pump, checked and cleaned the inline fuel pump, fitted another ECU they managed to get it to start using a brake cleaner aerosol, but only for a short time. Last week fitted a full set (5) refurbished injectors, still won’t start. They did manage to get it to start using brake cleaner, but only for a short time.

Even though it’s a 06 plate it had a genuine VW replacement engine fitted 4 years ago and had since covered less than 40k miles.

 

[ChrisL]

I'm afraid I don't have any information that might help you, but I find this attitude of let's just keep changing parts until we stumble onto the solution to be disgraceful.

 

[pappajohn]

It's obviously a fuel problem but with new injectors, new fuel pumps, timing checked and an ECU but starts with ether sprayed down it's throat that only leaves one thing ... .blocked fuel line somewhere between tank and engine......but that won't show on a "technicians" computer so they won't think to check that whereas a proper mechanic would.

 

[pappajohn]

If they can't diagnose the issue after spending £5000 on the job, they are clearly not fit to be working on vehicles, I sincerely hope your friend hasn't paid them that.

If it doesn't show on a diagnostic computer they are clueless.
They wouldn't know what a ring compressor, for example, is or does and certainly won't have one

 

[DerryW]

It's obviously a fuel problem but with new injectors, new fuel pumps, timing checked and an ECU but starts with ether sprayed down it's throat that only leaves one thing ... .blocked fuel line somewhere between tank and engine......but that won't show on a "technicians" computer so they won't think to check that whereas a proper mechanic would.

Apparently they’ve removed and flushed out the fuel tank, cleaned and checked the inline pump at the tank end, cleaned the fuel line from tank to the new duel fuel pump. It was after fitting the new duel fuel pump they managed to get it started with brake cleaner and their diagnosis was to send all 5 injectors to be tested, they were informed 3 failed all together and 2 had a low resistance. So recommend a complete set of new injectors. This were duly fitted but it still will only start with a spray of brake cleaner

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[DerryW]

It was a new tandem fuel pump they fitted, not a Dual fuel pump as I previously said.

 

[Electraglide]

He needs to join some VW forums. John Givens and Darren Wright seem to know their stuff.

 

[L' Hobo]

I know nothing about the T5's but have had T25 Diesels for the past 50yrs and replaced most parts while travelling from North Sweden to the Algarve over that time.

Why has no-one rigged up a separate fuel tank and spliced it into the pump and eliminated a fuel line problem?

I'm also not happy about the use of ether as, although it will start an engine, it also expands and puts excess pressure on the cylinders.
Once used in excess, it's like a drug and the engine always needs it to start. Far better to correct the original problems correctly!

PS. IMO, For £5000 a brand new engine could have been purchased!

 

[Bertilak]

People have said cam sensor, how about the crank sensor?
Mine had a complete failure to start, and I believe it was damp in the sensor plug somewhere down the front of the engine... Bit of a rub and dose it with WD40 and was good for another 120k when I sold it. Needed a laptop guy to locate the error.

 

[DerryW]

I know nothing about the T5's but have had T25 Diesels for the past 50yrs and replaced most parts while travelling from North Sweden to the Algarve over that time.

Why has no-one rigged up a separate fuel tank and spliced it into the pump and eliminated a fuel line problem?

I'm also not happy about the use of ether as, although it will start an engine, it also expands and puts excess pressure on the cylinders.
Once used in excess, it's like a drug and the engine always needs it to start. Far better to correct the original problems correctly!

PS. IMO, For £5000 a brand new engine could have been purchased!

It had a full factory recon engine 4 years ago. We spoke about the separate temp tank idea this evening.

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[Landy Andy]

It’s simple to rule out things like tank with basic tests if you / they have the correct equipment. It should be very easy to find the fuel pressure coming from the pump, with a basic fuel pressure gauge. Just by breaking down the system it should indicate where the problem lies. Sounds like you need a decent garage, not a parts selling place.

Are you sure it doesn’t have some form of immobiliser on it.

What codes does it show?

 

[ChrisL]

Something that's just sprung to mind, what kind of voltage drop does it have when starting is attempted, is it dropping so far that the ecu can't function?

 

[DerryW]

It’s simple to rule out things like tank with basic tests if you / they have the correct equipment. It should be very easy to find the fuel pressure coming from the pump, with a basic fuel pressure gauge. Just by breaking down the system it should indicate where the problem lies. Sounds like you need a decent garage, not a parts selling place.

Are you sure it doesn’t have some form of immobiliser on it.

What codes does it show?

Andy. Thanks for your response


It does have an immobiliser fitted, which apparently has played up in the past, both the the first specialist garage at Cambridge and the VW Commercial garage where the vehicle currently sits were informed of this and both say there are no current problems with the immobiliser.

Apparently the technician who has been working on it has over 20 years VW experience and the overall workshop manager close on 40 years experience.

They are treating it has an hospital job, pushing it in and out the workshop as and when they have a space in the workshop diary. It’s been with them since 18/06/24.

The whole purpose of taking it to a genuine VW garage (one of, if not the biggest in east Anglia) was we were told they will have equipment that only a true VW dealership will have.

I am in the process of arranging a meeting with them including the technician for sometime next week (we’re away at moment) and will ask them to prepare a detailed invoice for all work carried out to date.

Thanks once again

 

[gus-lopez]

He had it collected and delivered to a genuine VW commercial dealership. They have had it for 5 months. fitted a dual fuel pump, checked and cleaned the inline fuel pump, fitted another ECU they managed to get it to start using a brake cleaner aerosol, but only for a short time. Last week fitted a full set (5) refurbished injectors, still won’t start. They did manage to get it to start using brake cleaner, but only for a short time

I wouldn't be paying them as if it started on brake cleaner & the fuel system has been ruled out as clear, the fault would be electrical.

 

[rod_vw]

DerryW are you a member on the VW T6 Forum? If not I would suggest joining, yes I see that yours is a T5 but there are some members on there that know far more about these vehicles than most dealers. A competent person with VCDS and good knowledge of modern VW diesel engines should have solved your BILs problems months ago.

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[DerryW]

I wouldn't be paying them as if it started on brake cleaner & the fuel system has been ruled out as clear, the fault would be electrical.

Thanks Gus.

Apparently they’ve ruled out electrical.
I will try and copy and paste their last email (Thursday) which sets out everything they’ve done since fitting the new (factory refurbished) injectors last week.

But they are saying have spoken to senior technicians from their passengers car division they still can’t get it running, and are now stumped. Anything else they do from now on would be a calculated guess.

 

[gus-lopez]

Apparently they’ve ruled out electrical.

If they have a clear fuel system, & they have started it on brake cleaner with the original injectors in, they have fitted a set of new injectors & it still doesn't start but will start with brake cleaner again it has to be something electrical or a sensor.
Fuel pressure sensor,
common rail pressure sensor. crank or camshaft sensor

It could even be a blocked fuel filter if the fault code shows no pressure & you have changed the sensor but you'd assume that they had ensured fuel was available right to the actual injector?

 

[DerryW]

Something that's just sprung to mind, what kind of voltage drop does it have when starting is attempted, is it dropping so far that the ecu can't function?

I will ask the question.

Thanks Derry

I know nothing about the T5's but have had T25 Diesels for the past 50yrs and replaced most parts while travelling from North Sweden to the Algarve over that time.

Why has no-one rigged up a separate fuel tank and spliced it into the pump and eliminated a fuel line problem?

I'm also not happy about the use of ether as, although it will start an engine, it also expands and puts excess pressure on the cylinders.
Once used in excess, it's like a drug and the engine always needs it to start. Far better to correct the original problems correctly!

PS. IMO, For £5000 a brand new engine could have been purchased!

had the BiL thought for I minute it was going to be this trouble and expense, that’s what he would have done.

She it first wouldn’t start he had a chap who by all accounts is the go to diagnostic brains in the county. He diagnosed “non electrical fault. Possible timing issue” the timing was checked by the specialist diesel engineers at Cambridge, however after having the vehicle for 5 3/4 months and fitting various parts including ECU and an ECU with the immobiliser removed, and only able to start with a spare of easy start. They gave up and the vehicle was collected and taken to a fully fledged VW commercial workshop where it’s been since 18th June. And it now looks as though they have exhausted all attempts to identify the problem and fix it.
We really are at the end of our wits. Hence me turning to all you fellow Funsters.

 

[ChrisL]

I'm not sure exactly which engine your BIL has but this chap appears to be very knowledgeable, I hope it's helpful.

 

[L' Hobo]

Something I don't understand is, if it starts and runs OKAY on ANOTHER form of fuel, it HAS to be something connected with the fuel doesn't it.
It can't be timing surely?


Just as an aside, about 15 years ago, I bought a £300+ UNIVERSAL Cylinder Pressure Check set made by Tool makers, Laser It has all the different fittings to fit all different types of older type injectors.

It has never been used BUT if it's any help to this situation, you are more than welcome to borrow it.

(Afterwards, if anyone wants to make me a reasonable offer for it, get in touch.)

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[Landy Andy]

If it runs on brake come cleaner then that indicates it to be a fuel issue. So next step it to put a mechanical pressure gauge on the fuel rail and see if you are getting the required fuel pressure also checking that the pressure hold for a while after cranking.

It could be a “secret switch” that a previous owner has installed somewhere. But if it’s fuel. Easiest place to start is fuel pressure.

 

[jockaneezer]

I'd be getting the fuel rail pressure tested or failing that, crank it over with the injector feeds slackened off to at least make sure the diesel is actually getting to them, if it is, it must be a sensor/timing fault or not enough pressure from the pump ?

 

[DerryW]

I wouldn't be paying them as if it started on brake cleaner & the fuel system has been ruled out as clear, the fault would be electrical.

 

[L' Hobo]

Out of curiosity as I have never heard it used before, could the use of brake cleaner have caused any problems?

 

[DerryW]

I'm not sure exactly which engine your BIL has but this chap appears to be very knowledgeable, I hope it's helpful.

Chris

Thanks very much for the link. Unfortunately the engine in BiL vehicle is a VW 2.5 AXD these don’t have a timing belt of chain, instead have have timing gears.

Interesting video all the same. Shows how easy it is to set of on the complete wrong track if you rely solely on the diagnostics reading. I would like to think a trained VW technician would know this.

Thanks once again.

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