Glow plugs?

[Leakylunar]

Hi our VW T5 is struggling to start once it starts it’s very lumpy. Once we set off it revs freely with good acceleration, only once at tickover does it become lumpy again. Any ideas other than glue plugs?

 

[martin2603]

If it’s lumpy when running it is not glow plugs. Injector or injector pump ?

 

[Leakylunar]

Thanks just trying to work out best scenario

 

[simsy56]

Sounds like injectors.

Craig

 

[Leakylunar]

Looked online and the2.5ltr modelhasa weakness in that the box injectors are you only secured on one side not both if you know what I mean!

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[donkey]

Have you tried a quality injector cleaner? Some report success using it.

Geoff

 

[Leakylunar]

I wonder if by using diesel redex I’ve caused the problem but I’ve always used it

 

[L' Hobo]

I wonder if by using diesel redex I’ve caused the problem but I’ve always used it

I doubt if the Redex has caused the problem if you have used it correctly. You said that the injectors are only secured by one stud, can you not check if these?

Could it be that the tick-over is too slow, most modern vehicle have a fly by wire system and this is governed by a sensor attached to the accelerator, make certain there is no mud etc in that area and why not plug it into a scanner and see what it says. They can be bought fairly cheaply these days and are not complicated to use. Good Luck!

 

[Leakylunar]

It’s a 2009 model, I’m whipping it to my mates garage this afternoon. The revs fluctuate between 750-900 but you can feel it’s very lumpy not smooth as it was previously but does smooth out once you accelerate

 

[Leakylunar]

I enjoy working on my motorcycle but the van is left to the professionals unless it looks like a simple job.

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[pagey]

My guess is heater plugs or the relay

 

[Landy Andy]

Is it always hard to start? Or just first one of the day?
Does it always tick over lumpy, even after a drive?

 

[Bertilak]

In case you don't know, the 2.5 has a known weakness with the injector harness, which degrades as it runs through the cam box. Certainly causes low speed lumpiness, worse when cold and on hill starts. Relatively easy fix, (for a garage).

 

[fifthwheel]

Dont know about your engine but some engines keep the glow plugs hot after the engine has started for a time. As above it could be the glowplugs or the relay. Does it run smooth when up to temp?

 

[Leakylunar]

It started last Sunday got it going took it fir a blast thought it was fine popped into gym for an hour then same again wouldn’t start tried twice when oil light came on. Checked oil all ok, tried to start again eventually it started lumpy again got home and left it. After 3 hours I checked the battery 12.75 so ok then read if you turn ignition leave for 10-15 seconds turn off repeat procedure it stated better but still lumpy

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[Leakylunar]

Even when upto temp at idle/low revs it’s lumpy

 

[fifthwheel]

Can your garage mate read the codes for you, it sounds like the injectors need checking but a code reader might show something.

 

[Landy Andy]

Even when upto temp at idle/low revs it’s lumpy

Then it definitely isn’t glow plugs or their relay.
It will be more likely to be air or fuel related. If it goes well at all other times but just bad at low revs I’d start with checking EGR operations (assuming it has one) then clean the throttle body and MAP sensor. As they foul with age, and are cheap/easy jobs to start with.

 

[Leakylunar]

Thanks, fingers crossed it’s relatively easy to find with no expensive parts required
Yes hopefully code reader will throw up some clues.
Again thanks for all the quick replies, just trying to get a handle on most possibilities.

 

[mitzimad]

try running it with the oil cap removed if that clears the lumpy running its a blockage in the pcr system not sure if deisel have a pcr valve but it could be that glow plugs have no effect on the running and only cut in in very cold weather

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[Leakylunar]

Well quick update, set off to garage and it started 1st time no lumpyness
After 5 miles van just stopped!
Managed to pull after several attempts it started, it then stopped again on Castle street Hull( very busy) again after an age it started eventually getting it to the garage.
He’ll look at it on Monday

 

[Landy Andy]

Well quick update, set off to garage and it started 1st time no lumpyness
After 5 miles van just stopped!
Managed to pull after several attempts it started, it then stopped again on Castle street Hull( very busy) again after an age it started eventually getting it to the garage.
He’ll look at it on Monday

Good news in reality. It’s much easier to sort a current problem, than search for inconsistent one.

 

[donkey]

That sounds like a fuel problem. Filter, filter housing or priming pump (if your vehicle has one).

Geoff

 

[Leakylunar]

Yes agree, fuel. Funny how it travelled around 5 miles then stopped then another 4 miles stopped again!

 

[Leakylunar]

The fuel filter was replaced last year.

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[Leakylunar]

Update, they took it for a run to experience the problem. Checked with code reader and no codes showing, so they've said they will check further today injector/low or high pressure pumps and relays

 

[Leakylunar]

A quick update, tried fuel pump,low and high pressure pumps still having problems they rang Friday to say next will be injectors !!!!!!
This will be costly but really have no choice, fingers crossed this works.

 

[Gromett]

A quick update, tried fuel pump,low and high pressure pumps still having problems they rang Friday to say next will be injectors !!!!!!
This will be costly but really have no choice, fingers crossed this works.

Why don't they test the injectors rather than firing the parts cannon?

Also for it to cut out completely that would mean more than one injector going bad at the same time?

 

[L' Hobo]

A quick update, tried fuel pump,low and high pressure pumps still having problems they rang Friday to say next will be injectors !!!!!!
This will be costly but really have no choice, fingers crossed this works.

If it run okay for about 5 miles, how can it be injectors??

A number of years ago, before common rail, I had a similar problem with one of my work vans. After a lot of investigation, it was trace to fuel starvation caused by debris in the tank blocking the fuel strainer at the end of the intake pipe.

We concluded that the vehicle was using what was in the system, (line, filter etc.) plus the small amount that was getting passed the nearly blocked strainer, but when that was exhausted (a few miles) there was not enough to keep the engine running until the engine had stopped and the electric feed pump had continued to pressurise the system again and we could travel another few miles.

As I say, this was on a non 'common rail' vehicle but with all the talk about blockages cause by the Biofuel algae, it might be worth checking the tank strainer before changing expensive injectors? Good Luck and thanks for keeping us informed.

 

[Leakylunar]

Thanks I’ll give him a call but do imagine he’s exhausted all routes Though

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