Error code P0251
 

I have a 2003 xtype - 2.0 D

I've been getting this error code (P0251) recently - it happens after I accelerate hard over 2500 rpm - I've searched the internet and it seems to be a common problem, but no-one ever updates their post on how they fixed it.

To explain a little more....

When driving around under 2500 rpm the car drives normally but does put out a lot of black smoke if I accelerate. If I go over about 2.5k RPM the glow plug light flashes and it goes into it's safe mode. It still drives fine after this. If I restart the car its all fine again until I accelerate over the 2.5k again.....

From what I have found it's something to do with the fuel system, possibly injectors of fuel pump - both expensive to fix so don't really want to try something that may not work.

It's averaging 30mpg down from its usual 50mpg so I don't think it's the fuel pump as it's getting through so much fuel and then there's the big black plumes!! - but it's my first diesel and I know very little about them.

Could anyone suggest how I could isolate the problem or what testing I can do?

Has anyone ever resolved this issue?

It's done about 108,000 miles and has a FSH - last service about 6000 miles ago.

Any ideas/help would be very much appreciated.

Most people here are not from the UK so wont have diesels (diesel never sold in USA/Canada)
Somone on the co.uk forum had this and it was a blocked fuel filter causing that code and the same issues
When was the fuel filter last changed?
Try changing it and see if that cures it

OK thanks - I'll give that a go too.

I did some investigating and the intercooler pipe was split so waiting for a new one to be delivered. So fingers crossed it's just that :-)

You could try wrapping some duct tape around the intercooler pipe while youre waiting for the replacement as a temp fix and I think you may well have hit the nail on the head with the problem.
Taped a split with duct tape on a pipe on my 3.0 X type which cured juddering and not being able to rev over 3k and problem went away.New pipe fitted a few days later.

Did you ever get to the bottom of this problem as i have the same but my car cuts out whilst driving and P0251 is the code this throws up?

Welcome to the forum billdrives,

You've posted to a five year old thread so starting a new one for your P0251 code issue is likely to get a better response.

When you get a minute, please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see.

In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

did u get a reply? same with my 08 x type? help
 

Did u get a reply, cant find this Q on new members!, and same with my 08 x type, Engine Management> cut out > code P0251 & P1211 - help!

Hello everyone, let me start with this I had also P0251 and I fixed it, but how I got is more interesting. I was driving my Jag x-type 2.0d 300k km out of town, when I got battery warning light on my dashboard. I stopped and opened the hood and what I saw pieces of my auxiliary belt and pulleys everywhere ( later on I found one of the pulleys had broke a bearing and rest is history, but no indications of this .... ) so the car was fine and decided to continue driving on battery power. I reach a city near by, I have relatives there, they borrow my 2 other batteries and started to move on to my home town 150 km away (135km on highway) I reach the highway start driving with 130km/h so far so good. But when I wanted to accelerate the car limp and I check engine and flashing glow plug light. While driving power off the car then power on and everything back to normal. This happened few more times so I decided it is related to the low battery power or something like this. So I reach home, buy everything needed replaced everything, clear all errors on the car ( without checking them, because pretty much everything was affected due to low battery power) with Launch and leave the garage. Accelerate and again limp mode and low power....when car was on idle it was different there were more vibrations inside. I checked the car and I have only P0251 nothing else. I read a lot in the next few days, I found spare(second hand) fuel regulator valve, I prepare bottles for injectors return fuel test and new fuel filter. My EGR was cleaned 2 weeks ago so I was confident it is good. I replace the filter start the car and it sounds perfect I take it to a ride and no more p0251. So 1 week later still perfect, I was sure it is related to the blow of the pulley and belt, but at the end my filter was clogged.
So start cheap repairs first and verify the new conditions... good luck

Update on the case, car was good for 3 days then back to limp mode and blinking glow light. I drain the fuel replace the filter and same issue again. Check with diagnostic and what I saw is sometimes car has steady idle 230 bar, but sometimes is 170-200-250-300 bar and constantly moving. I replace with cheap spare sensor the one of the fuel rail - no change then I replace the fuel pressure regulator on the fuel pressure pump and success car working fine, perfect idle !

Update on the case, the resolution was temporary, I mean when the engine is cold I don't put so much pressure on it so no limp modes. When it is hot 1,2,3 gear pedal to the metal and limp mode again.... I do a new leak off test in cold engine the result are even better, equal levels of fuel of the 4 injectors (I can attach pics even) So far:
1. Replaced Fuel pressure sensor *second hand - no change
2. Fuel filter 2 times bosch and mann - no change
3. Fuel pressure regulator valve *second hand - no change
4. EGR - clean - no change
5. EGR repalced *second hand - no change
6. Catalyst converter - removed and clean (it was in very good condition) - no changed
7. ECU reset ( if the videos in internet are valid - jump cable between positive and negative terminal of the battery of course with battery disconnect :D )
8. MAF replaced *second hand - no change
9. Camshaft possition sensor replaced with new one - no change
10. Fuel tank opened and cheked for anything that can obstruct the lines - no change very clean ...
11. Obtain fuel pump from crashed jag second hand looks good final point to repalce the pump I am looking for good manual how to do it, espacialy the timing chain.

some remark my turbo doesn't have actuator fully mechanical and EGR is only with vacuum pile no sensors

You mentioned a belt and pulleys breaking, did you fix that and make sure the alternator is charging properly???

You can get with a faulty battery or a poor charge from the alternator, many different codes appear because of this. Make sure the batter is OK and charging at the correct voltage before you start looking for faults from codes which don't exist, caused by electrical issues

Get the new intercooler pipe first and see if that helps.
then get loads of oil like wd40 and spray it all over the turbo actuator to loosen it up, mine got stuck a bit before and the car goes into limp mode (safe mode) when you accelerate hard. The oil will loosen it. If you could get someone to rev the car while you spray on the oil even better.
if the new hose doesn't help the black smoke then your EGR valve could be going.
my car had a lot of black smoke when mine was failing and used to jerk the car at a constant speed. Other times the car would hesitate and blow out loads of black smoke when the power came back.

I ended up blanking off the egr valve until I got a new one and then the new egr valve went too after a week , it must have been poor quality lol

Hi guys I forgot to update you on the story:

at the end I gave up and went to Bosch service - they weren't exactly specialize in Delphi but they know the right guy so long story short - fuel pump was wear and small
metal debris to the injectors.

So the pumg got new "head", realease valve and one more thing I don't remember , Injectors were recycled also and after 1200Euros the car is good as before.
It seems this issue did came slowly because now the acceleration is very smoth and the start is how we called it here "half key" very fast ...

So I am happy with the car again. The car is around 190K miles I have it from 6 years(73000miles) and except that no other major failures.

One of the first things I done was to check the pipes and they were looking good, after one month after I fix the car, suddenly I lost power and black smoke start- the hose beneath the
EGR got a crack, after replacement all good.

My turbo is the old one with the vacuum valve and it was moving fine all the time. I am using fuel additives all the time and I can say that the pipes and turbo were very clean, just a thin layer of soft carbon.

Other than that during the years I done 2 carbon cleanings of the engine with Hydrogen and the results were very good ( here is very cheap around 30euros)