2.0 hdi Lumpy idle / slow pick up

Kieron G · 2024-01-23 22:28:20

Hi all. Been a spectator on this site for a few years now.
Hope someone can direct me in the right area with our problem.
We've had our 2005 enterprise 2.0 hdi for maybe 8 years and has been very reliable.
It has developed a fault where it starts and ticks over lovely until the accelerator is pressed then the tick over becomes lumpy.
Stop the engine and start it again and everything reset to being fine.
Try driving it especially when cold and it has a massive turbo lag which becomes a bit dangerous sometimes pulling onto busy roads,
Once engine speed has eventually increased the van is off like a scalded cat.
I've read as much as I can find on similar faults with variants of this engine in different vehicles.
I disconnected the maf sensor and EGR vacuum pipe but these make no difference also added diesel treatment last fill up.
There are no warning / management lights coming on.
I don't mind getting any faults downloaded at a garage, but thought I would ask here first.
Was wondering if it might be the fuel rail pressure sensor.
Thanks

kenbw2 · 2024-01-23 22:39:48

I don't know as much about the HDi (JohnDragonMan will be your guy) but could it be the in-tank pump not running? There are two fuel pumps on the HDi - one in the tank, and the high pressure one in the engine.

So with the in-tank one maybe not running, the high pressure pump is able to drag fuel from the tank at low RPM, but when demand is higher it suffers fuel starvation.

I gather you should normally hear the priming pump as a little whirr before you start the engine. Maybe you could take a fuel line between the tank and the high pressure pump off and see if it pushes fuel out?

Kieron G · 2024-01-23 23:07:01

Thanks for that.
I guess starting at the tank and working from there makes sense, I wasn't aware that there is a pump in the tank.
It's the stopping the engine running Lumpy, immediately restart running smooth that baffles me.
Like something has reset when it's switched off.

JohnDragonMan · 2024-01-24 01:02:18

hey there, when was your fuel filter last changed? yes it can be your in tank pump but if that does not work, the engine just wont run. you should be able to hear the in tank pump running when you turn the ignition to position 2.

its possible it can be a fuel rail pressure sensor but its not common for them to fail on a HDI.
how is your temperature gauge behaving? a faulty temperature sensor can cause all kinds of fun.

see unlike the 1.9 (XUD and DW8) with NO lift pump, the HDIs fuel system is being pressurised constantly while running by the lift pump, you never get air leaking into the fuel system with a HDI. its one thing you can rule out. you can however get low fuel delivery flow to the high pressure pump due to a blocked fuel filter. so its worth checking or at least doing a flow test on.
you can do a flow test by following the high pressure pumps feed (the pipe with no other pipes connected to it coming from the fuel filter) back, unplugging it from the fuel filter, sticking a pop bottle over the outlet from the fuel filter and get someone to turn the ignition to position 2 (glow plug mode).. or disconnect the battery, switch the ignition to position 2, set the pop bottle in position and just touch the battery connector to the battery terminal. (best battery terminal design ever)

the flow rate should be quite a lot.

see how it goes and report back with the findings big_smile

Last edited by JohnDragonMan (2024-01-24 01:11:57)

Kieron G · 2024-01-24 11:09:33

Thanks, I'll do a flow test today.
The fuel filter was changed a few months ago, I did have an issue with the sealing ring once but it's not leaking now.
Temperature is good, when van is driven for a long period it settles around 80 degrees from memory.
Will report back

Kieron G · 2024-01-24 12:05:13

Yes flow test was a success. High flow / volume out of the filter from the housing outlet to high pressure pump.
Battery terminal clamp is nifty but even better got a trusted passer by to help.
Relieved to know that I don't have to delve into the diesel tank.

JohnDragonMan · 2024-01-24 20:41:47

hmm without live data diagnostics i guess we wont know if its the fuel pressure for sure.. so yes i would suggest swapping the fuel rail pressure sensor.

i have not had much experience with the high pressure fuel side of the HDi DW10 engines (its always been pretty reliable!). so it would be guesswork from me now hmm sorry.. maybe i will think of something though.

Kieron G · 2024-01-25 00:41:04

Well thanks Ken & John for taking the time to reply and sharing your expertise, you've helped me rule out some possible causes.
When I find out exactly what the problem is I'll update this post.
It might be some time as read that Wynns Formula Gold sorted a Citroen C5 hdi with a similar problem so going to run that through the system in the next fill up before spending on diagnostics or parts

AlvyLad · 2024-01-25 16:10:29

Kieron G wrote:

Well thanks Ken & John for taking the time to reply and sharing your expertise, you've helped me rule out some possible causes.
When I find out exactly what the problem is I'll update this post.
It might be some time as read that Wynns Formula Gold sorted a Citroen C5 hdi with a similar problem so going to run that through the system in the next fill up before spending on diagnostics or parts

It is rather frustrating without good-helpful-experienced mechanic advice or even diagnosis, but I'm in the market for a MK2 and already annoyed mechanic with all sorts of questions, like, one van I inspected and it was as per what symptoms you say, especially on HDI models

1- Injectors blocked, warned out possibility of 3/4 chances
2- Head whopped possibility of 1/2 the cases
3- Sensors burned, faulty etc- 2/3 possibility

All or either above are only possible to find out by lengthy and expensive process of elimination

Sorry to be the messenger of bad news

(Not sorry), as I nearly drove the van like it back home..

Kieron G · 2024-01-26 00:09:50

Ha. I'm not scared. Honest.
I know this is a good van, really kept on top of the jobs as things have arisen.
I've seen these with massive mileages for sale so at 150,000 I don't think the engine is even half way through its life.
The van is a 6 seater and been a family car for my sister for the last 8 years.
Money and time spent on this one is definitely an investment and intend to keep hold of it as long as we can afford the ever increasing road tax.

Mixerfistit · 2024-01-28 02:13:21

May be worth swapping the 2 solenoid valves around in case one (the turbo valve) is causing problems. Check none of the pipes are split too.
I don't think your symptoms match but it's a free shot in the dark.

Kieron G · 2024-01-28 10:45:58

Thanks. Has to be worth a try.
Not sure where these solenoid valves are located, maybe will become clearer when I look for them.
I can certainly check the rubber pipes and clips

Mixerfistit · 2024-01-28 22:32:01

On the 2.0 HDi, there are 2 identical valves sort of hanging from under the scuttle between the the throttle and the coolant tank. There'll be 2 rubber pipes going in to each of them. One pipe will be pulling a vacuum - or should be, when the engine is running.
The left one is for the EGR and the right one is for the turbo.
On my van the turbo one would get very hot as it had failed, so I removed it and put the Egr one in its place.

Rather than put the faulty one over for the EGR, I may or may not have stuck the loose egr pipes on the end of my windscreen wiper motor mounting bolts and cable tied them to seal them up (not to lose any vacuum). Of course, doing that would disable your egr valve and that's very naughty tongue

As I say, I don't know if any of this will help you but I know split hoses can be problematic, and I'd imagine if an EGR was constantly open, the engine wouldn't run very well.

Last edited by Mixerfistit (2024-01-28 22:33:36)

Kieron G · 2024-01-28 23:34:55

Ah ok thanks. I did already try taking vacuum pipe off the egr solenoid and blanked on a bolt end, I think I followed a YouTube clip.
I didn't know the other was connected with the turbo.
The turbo itself seems to work really well, when that kicks in the van is away.

BogEyes · 2024-02-26 15:04:05

JohnDragonMan wrote:

you can do a flow test by following the high pressure pumps feed (the pipe with no other pipes connected to it coming from the fuel filter) back, unplugging it from the fuel filter, sticking a pop bottle over the outlet from the fuel filter and get someone to turn the ignition to position 2 (glow plug mode).. or disconnect the battery, switch the ignition to position 2, set the pop bottle in position and just touch the battery connector to the battery terminal. (best battery terminal design ever)
the flow rate should be quite a lot.

Are you saying that the lift pump will pump Diesel before the the engine has been started?

(Apologies for the thread hi-jack @Kieron_G)

JohnDragonMan · 2024-02-26 22:40:55

BogEyes wrote:

Are you saying that the lift pump will pump Diesel before the the engine has been started?
(Apologies for the thread hi-jack @Kieron_G)

yes on HDI versions of the Dispatch the pump will prime for a few seconds when you switch the ignition to the 2nd "on" position.

im not sure but i think some DW8 engines had a lift pump but they were quite rare. usually they are a manual prime on the fuel filter.

Kieron G · 2025-02-28 21:36:08

Update on this running issue.
I bought a fuel additive called Hydra Maximius off ebay and it seems to have solved the running problem.
It was a good few months ago but thought I'd wait a while incase it was a coincidence.
I did try a different additive liqui moly before with slight improvement.
Maybe combination of the two sorted it
But the Hydra definitely made a noticeable difference.
It was embarrassing as I'd pull out and hardly accelerate then the van would back fire and tear off like I was deliberately holding the traffic up

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#1 2024-01-23 22:28:20

2.0 hdi Lumpy idle / slow pick up

#2 2024-01-23 22:39:48

Re: 2.0 hdi Lumpy idle / slow pick up

#3 2024-01-23 23:07:01

Re: 2.0 hdi Lumpy idle / slow pick up

#4 2024-01-24 01:02:18

Re: 2.0 hdi Lumpy idle / slow pick up

#5 2024-01-24 11:09:33

Re: 2.0 hdi Lumpy idle / slow pick up

#6 2024-01-24 12:05:13

Re: 2.0 hdi Lumpy idle / slow pick up

#7 2024-01-24 20:41:47

Re: 2.0 hdi Lumpy idle / slow pick up

#8 2024-01-25 00:41:04

Re: 2.0 hdi Lumpy idle / slow pick up

#9 2024-01-25 16:10:29

Re: 2.0 hdi Lumpy idle / slow pick up

#10 2024-01-26 00:09:50

Re: 2.0 hdi Lumpy idle / slow pick up

#11 2024-01-28 02:13:21

Re: 2.0 hdi Lumpy idle / slow pick up

#12 2024-01-28 10:45:58

Re: 2.0 hdi Lumpy idle / slow pick up

#13 2024-01-28 22:32:01

Re: 2.0 hdi Lumpy idle / slow pick up

#14 2024-01-28 23:34:55

Re: 2.0 hdi Lumpy idle / slow pick up

#15 2024-02-26 15:04:05

Re: 2.0 hdi Lumpy idle / slow pick up

#16 2024-02-26 22:40:55

Re: 2.0 hdi Lumpy idle / slow pick up

#17 2025-02-28 21:36:08

Re: 2.0 hdi Lumpy idle / slow pick up

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