2.1 XUD11 engine surging after start up

[jdevereux]

I have the pre HDI engine that is 2.1l turbo diesel and not that common.
The problem i have is soon after start up(usually when driving)the engine revs go up and down uncontrollably
and if i press the accelerator it often just goes to full revs and stays there(turn off ignition and restart)
sometimes you can drive out of it (the hunting bit anyway)and it is always within the first minute or so of the car starting.
I am sure this will have happened to others and wondered if anyone knows of a solution to this problem?
The full revs thing can be somewhat offputting
Thanks
John

[gumby6371]

Hi John and welcome to the forum,

If it was hunting between 900 to around 1100 RPM I would say fuel filter needs changing but full revs sounds like fuel pump to me.
The 2.1 is a mechanical pump so that iliminates dodgey BSI option.

I'd change the fuel filter first and maybe look at the intank strainer, not sure if the 2.1 has a lift pump but someone will be along soon with more experience of that engine.

Another thought - does it go to full revs without touching the throttle pedal? my last car had a sticky throttle cable and I used to have to flick the pedal back up with my foot or slam it into gear fast. If I was accelerating it would red line when I dipped the clutch for the up shift.
Check for any pinch marks along the cable, or even the pedal itself for play or any sticky spots.

[StevieboyTD]

The 2.1 uses the ecu controlled Lucas Epic system. The throttle is a fly-by-wire job, it could just be the throttle resistor is manky.

[pavlf]

Hi, I had a 2.1, just sold it (and it's now on ebay for twice what I sold it for!!!), and it used to do this hunting business. It was a fuel temperature sensor. Can't remember which one, the garage had to look at the fault codes. But anyway, I was really worried it was going to be the fuel pump but the sensor is a really easy job and a cheap part. Reading the code cost the most!

I''ve now bought an HDI 110 and it's loads slower than the 2.1 ... too early to give a full verdict though!

Good luck fixing yours. They're great those 2.1s.

paul

[midsmike]

hi i have 2 2.1s and never had this problem but have u checked the oil it could be running on its oil

[jdevereux]

The problem is intermittent but always happens not long after start up when driving.
I presume that it is something to do with a check that is happening electronically at this time.
It never does it after this initial start up period of a few minutes.
I think it only goes to full revs when accelerator is depressed while it is hunting and yes the hunting is prob between about 900 to 11 hundred revs.
People must think i am keen to get in that traffic.
Fuel temp sensor is a possibility.any info on which one would be great.
Throttle resistor if it was manky would nt this problem happen any old time? not just on start up?
Re the oil commentmidsmike do you mean the pump oil could be low?didnt understand your comment.
As you can imagine it is quite a dangerous problem in the wrong hands.
cheers and any further help appreciated as it has been years and years
john

[pavlf]

Sorry, I can't give you any more info about which one it was. Probably you'll have to take it to someone who can read the fault codes :-(

[jdevereux]

I think from the research i have done that the sensor you refer to will be a water temp sensor not feul temp?
And therefore it should be the green one on the side of the cylinder head is used by the ECU to control fueling.
So i think i will try that easy option first.
Am not sure how the dealership here would go on finding the fault but i know it would be very expensive.
cheers
john

[marty1979]

The green temp sensor your refer to would certainly be the first thing to check/replace when "self revving" problems occur. The Epic also has a sensor inside of the pump that can cause such issues, and on the top of the pump are some solenoids that control fueling also, but the green sensor is a good place to start. Good luck

[jdevereux]

Cheers Marty,let's hope it is the easy option.
Will report back
john

[jdevereux]

i have not tried any fix but the car is not not starting at all yet has fuel compression etc and timing is fine.
I don't know if mechanics have plugged it in to get a fault but am thinking i will replace the green water temp sensor on the head and
leave battery disconnected for a few days before i retry.Otherwise it will be a lost cause and that is a shame as it goes very well.