HELP WITH IDLE ??? PROBLEM

[jarc1]

jace
I have cleared the fault memory now and will wait to see if any further faults appear. Will check again tomorrow after the wife has used it for work and back. She will do some 15 miles as a round trip.

Lets hope, as you suggest that toolbox does pick up on this problem as it is now looking as though it might be an injector proble.

Cheers, John

 

[Toolbox]

Reading through the post it is possible that there is a problem with injection timing but very strange you only get a problem at tick over.
It could also be fuel starvation or air in the fuel, the injection pump has to draw its own fuel from the tank and it may be when idling it is struggling to do so, try pumping the hand primer on the fuel filter when its running rough and see if it improves. Also check the fuel filter is sealing even change it again to be sure it’s not the problem.
It may even be worth checking the tappets aswell.

As far as the timing issues, the needle lift sensor in number 1 injector senses the exact injection point and this can be tested with a multimeter by unplugging it and checking the resistance through the sensor which should be approx 105 ohms @ 25degC.

The Fuel injection timing solenoid is mounted in the injection pump and is a little more difficult to do anything with it may be that it is sticking, this is turned on and off rapidly by the ecu to maintain appropriate timing, if this is suspect I would advise running a good fuel additive through the fuel system.

The CKP sensor is the crankshaft position sensor in the top of the bell housing and with you only having your problem at tick over probably not the cause.

 

[Glenno]

It might be worth checking that there isn't any particles on the anti-friction plate on the side of the throttle assembly (it's under a plate held on by three screws). I was having throttle problems and the engine check light was coming on until I cleaned up this area.

It might not solve anything, but it fairly quick to do and costs nothing!

Good luck

 

[jarc1]

Toolbox
Many thanks for your interest and suggestions.

Pressing the primer is going to be difficult as the missing ammounts to about one or two beats and then clears itself.

I am now fairly convinced that it is either fuel starvation or air gaining ingress to the fuel system. What is so very confusing is that it is only on idle and then not very regular. It will idle for maybe some ten minutes and then suddenly just have an attack. One attack is usually followed reasonably quickly by another one and then it recovers for a protracted period. (I find it all very confusing).

Will get another fuel filter and fit it.

As for taking readings with a multi meter at No1 injector, this sounds a bit like rocket science or brain surgery to me. Not certain of what I am supposed to be doing on that subject. I will have a look and see what I can do.

The car is now on its second treatment of additive. I am using one bottle to a tank of fuel. Do you suggest upping the doseage and putting another bottle in with the current one. Only a gallon or so gone from the last full tank of fuel.

Many thanks for your time and assistance, will keep you updated, on this post.

Cheers, John

 

[jace]

get the stuff goes in fuel filter from empty filter so its straight into the system asap

 

[jarc1]

Having cleared the faults from the memory (24hrs ago) the car has been used by wife to work and return. Approx 18 miles round trip.
Have just re-read the faults and it is showing 55....NO FAULTS FOUND.
The missing on idle, all be it very intermitently, is still there ???????

 

[jarc1]

get the stuff goes in fuel filter from empty filter so its straight into the system asap

jace
is there a brand name that you would recommend
Cheers, John

 

[jace]

no mate i dont never use them think there waste money some people swear by them though mostly kereosene based!

 

[jarc1]

LATEST UPDATE:
Another new Air Filter and Fuel Filter fitted.
Addative straight into the new Fuel Filter (correct one for the job) and addative into the fuel tank (correct one for the job).

Injector needle lift sensor tested and showing smack on suggested reading of 109 ohms.

Fault codes read again..... 55 No Faults Found

RESULT:
Still exactly the same as before, intermittent misfire on idle.
Little bit more information to add..... if revs are built up progressively the engine does not mis at all. If throttle is floored from idle you get a slight hesitation and then everything runs ok.

Next stage....???????....
Suggestion has been made regards temperature sensor. I can find two, side by side. One with a single wire and one with multi wires. Am I correct in assuming the single wire is for the dashboard temperature gauge and the multi connector sensor is back to the ECU. Presumably the one to replace would be the multipin sensor. The gauge on the dash is working.

Is there any way that I can prove that this sensor is working correctly, or is it a case of replace on the off chance of it being faulty.

Would it not be that if the temperature sensor is faulty, this would show up when either warm/hot or when cold and not as we have with the fault both warm and cold.

 

[Toolbox]

You are correct on the temp sensor it’s the one with the 2 wires.
You can test the resistance at different temperature with it unplugged 20deg C = 2.1 - 2.9 K ohms
50deg C = 0.68 - 1 K ohms and 90deg C = 0.236 - 0.260 K ohms.
This may give you some idea. I would have thought if this was faulty and reading cold then you would have black smoke when driving due to over fuelling for warm up mode, or if it was reading hot it would be a job to start.
You can disconnect it when its running and see what happens but if it does run ok with it off, it will not necessarily mean its faulty. This will put the Mill light on and generate an error code that you will need to clear.

 

[jarc1]

Water Temp. sensors reading OK.
Now I am snookered>>>>>> ?????????????????????

 

[Toolbox]

Do you have an EGR valve?

 

[jarc1]

Jeremy
I believe not, think someone has previously indicated that they are not fitted to the TDi.

Just checked where I seen the EGR refered to on a previous occaision. It was infact yourself advising regards three solenoids or one, under the air filter housing. I actually cannot see one solenoid let alone three.

If you could advise, I will double check.
Thanks, John

 

[jarc1]

Jeremy

Just been and had another inspection.

If I am "barking up the right tree", the answer is no we do not have an EGR valve.
Found what I believe to be the one and only solenoid, that you refer to, in the area of the air filter. It has rubber pipe which I believe to be vacumn pipe and connects back to a metal pipe, one branch of which goes back to the brake servo.

Hope this helps with the diagnosis.
Cheers, John

 

[Toolbox]

If you only have one solenoid then you have no EGR, so thats not the problem for sure.

 

[jarc1]

Really do not know where to go, what to do now.

 

[jarc1]

Anyone have any further suggestions or ideas?
All comments gratefully accepted.
Cheers, John

 

[jarc1]

PLEASE !!!!!!!!!!!!!!!

 

[Toolbox]

Something you can try, just to see if it makes a difference is to swap the wires on number 1 injector sensor.
If you pull the plug apart and remove the coloured plastic tag in the plug you can then remove the terminals from the plug and swap them around. This will save cutting the wire and you can put it back as it was after.

 

[terranokid]

Just reading through the post and as it has just been said by toolbox swap the wires on the sensor and see if it makes it worse or better.
also there is a mini filter on the tdi models its built into the banjo I removed the short steel pipe and blew mine through with carb cleaner and then compressed air