TD4 Injector advice needed please

Well the saga continues - They asked me to bring in the car which I did - the plugged it into their Diagnostic and said all was ok!!! A little difference in Cylinder 4 but not enough to make it miss. HOWEVER they cannot see what happens under load!!! Doh! Why ask me to bring it in then.

So it's out with the injectors yet again and back to them for a test again.

I went to Strathstone Landrover and the Service Manager was great and checked my car in the computer for any recalls needed etc - made suggestions but I had already tried and then said that a T4 test would not show up anything that would help here - he said go the take the injectors back to the service that did the diagnostic route. I was impressed by the amount of help when he knew I was not going to get them to do the job.

So at the end of the week I will get them out and retested.

Anyone know how to do a compression test on a TD4 through Injector holes?

er no sorry angeloc done plenty on petrol engines

teddywood1 said:

er no sorry angeloc done plenty on petrol engines

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Same here and I have the kit for that.

City are giving me a bit if a run around I think - don't think I will use them again unless things improve. I have taken out the 4 injectors ( got it down to less than 1 hour now!!!) and am taking them in for testing again tomorrow.

You need a diesel compression tester! It has "fake" injectors to fit and connect your gauge to!
The thing that's getting me is that you said the lumpy running moves cylinder with the injector. So surely that's where the problem lies??? Or is it sooo slight that they're in denial? How do you measure the missfire? How do you know which cylinder it's on?
If it was a compression issue it wouldn't change cylinders!

They are in denial - well said. You echo my thoughts exactly.

To me it's clear - there is a miss under initial load - it shakes the engine and then clears. There is overfilling at Rick over one the cylinder that has the injector they sold me - they cannot test under load on the car do I have taken all injectors out and am going down again today!

The techie is saying the tick over difference is small and then started saying it could be a hole in the piston (I ask you!) - he said I should do a compression test - I don't have Diesel kit but I have two testers one of which is one that has a rubber taper that you just hold down while cranking - that might work but what about ECU faults as no injectors would be connected?

Anyhow it looks to me that as they have not done any of the work on the car they are sceptical and so are not admitting that they may have cocked up. The car on diagnostic is to quote them "perfect" I think what has happened is that they sold me a duff recon injector - I took the car back they tested and no load test did not show fault - I took injector out they supposedly tested it (but could not give me a print out because they had a computer printer problem!) - this may have been a fob off. I refitted in another cylinder and the overfilling at tickover followed it (this was diagnosed by a local independent LR specialist). I went back to them - they did on car diag - no load fault and do blamed everything except the possibility of a duff Injector. They then said in a not very supportive way - we need all the injectors to test on the Delphi. So today I am doing that.

It's a shame I thought they were good and they may be but their customer service needs a bomb under it! I don't expect unnecessary niceties but a bit of help wouldn't go amiss - its a 65 mile trip each time!

Anyhow thanks for the replies it all helps with confirming my thinking and alerting me to things I may have missed.

Compression testers for petrol engines generally don't read high enough to do a diesel. Plus I doubt you'd be able to push hard enough to seal the type you have on a diesel. A hole in a piston would give a definite problem on one cylinder! It wouldn't move! Suspect you're talking to the wrong person you need someone that has a clue

I recently had 4 injectors refurbed by Diesel Bob. - Diesel Bob Tuning - Home ; good service and all seems well. Afterwards, I did have a very similar sounding wobble on mine....it would stutter very slightly at 2200 - 2800 RPM under certain throttle positions, and was worse with the Synergy module running. Turning down the synergy settings reduced the wobble, and switching it off reduced it further but it was still slightly noticeable. When towing a heavy trailer up a hill, the stuttering got suddenly worse then it just suddenly crapped out in the middle of the road. It restarted and got home OK, although the EM warning light has been lit up since. I found two problems - despite the nuts being tight; the battery terminals were a bit loose. I cleaned them up and bent the clamps a bit to grip properly, secondly, the plug to the AFM was not making proper contact; The caveman that owned the car previously had snapped off the retaining clip and it was a bit loose. I gave it some contact cleaner and a zip tie and it has ran fine since with no missfire. The EM light is still on, but I have not had the time to get a diagnosis done (nearest equipped garage is a bloody long trek from me) but its running perfectly and giving good MPG even with the synergy on max.

Ok they swapped out the injector and gave another plus tested my other 3 - I refitted today and the miss or wobble was significantly reduced - much softer BUT it has returned - not quite as bad but noticeable.

I don't know what else to try!

have you looked at your tyres and wheels I know it sounds a bit daft but you could have kirbed it and bent the whel slightly always worth a check glad you got those injectors sorted there is nothing worse than a fault that can not be sorted

There are a few observations I would make here.Firstly a positive or negative compensation of up to 3.5 is acceptable - someone should have told you this as T4 will show the value as being out of range by making the value go grey rather than black.So your diesel specialist is quite right in saying that their injector is not faulty.You should also have been told that the values only read at low engine speed/load situations - most of the time this is good enough to see the problem.One of the companies I do diagnostic stuff for had around 15 TD4's a while back,one of them had lumpy running and smoke problems.It didnt log any faults and live data didnt show any big variations in cylinder balancing.It was cured completely with 4 new Bosch injectors.(After a compression test)
Lastly, any serious garage now does an electronic compression test,not a mechanical gauge.Its quick,accurate and needs no dismantling etc.It uses a current clamp around the battery lead,this is fed to an oscilliscope to view the current peaks as the starter pushes the pistons up on the compression stroke.It doesnt give an actual pressure reading,but it will show any variations - which is what you need.
Common rail injection is known in the trade as "Common Fail" .....

teddywood1 said:

have you looked at your tyres and wheels I know it sounds a bit daft but you could have kirbed it and bent the whel slightly always worth a check glad you got those injectors sorted there is nothing worse than a fault that can not be sorted

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We had the car up on a ramps with all wheels off the ground and ran it - no signs of bent wheels or out of true Tyres - the wobble is only on acceleration and really noticeable in 2nd gear. It stops if I lift off the accelerator.

All Tyres were new and balanced and matched - been on 18 months nearly worn out the front now.

I asked Rover Ron for any advice - I am sure he won't mind me pasting his comments as they may help others - I have done most of these but not all so more to try.

Hi Angelo,

Have you checked the turbo vnt mechanism, the vacuum pipes to the vnt actuator and solenoid, and removed and cleaned the map sensor? (stiction can cause boost pressure variations, as can dirty map sensor.

Also worth removing the high pressure regulator and replacing the seal and checking the needle for scoring.

Remove and clean the fuel pressure sensor (the one on the end of the fuel rail).

Remove and clean the injector plugs with switch cleaner and also the crank sensor connector.

Is there any exhaust smoke as it is now, and with the Synergy 2 fitted, with the power switch off and on?

Some faults are hard to pin down but the TD4s do suffer from turbo / boost pressure faults due to the vnt mechanism sticking or control system faults. In one case the actuator was loose causing erratic performance. It affects the lower gears more because the pressure is changing more rapidly, or should be..

Regards
Ron

eightinavee said:

There are a few observations I would make here.Firstly a positive or negative compensation of up to 3.5 is acceptable - someone should have told you this as T4 will show the value as being out of range by making the value go grey rather than black.So your diesel specialist is quite right in saying that their injector is not faulty.You should also have been told that the values only read at low engine speed/load situations - most of the time this is good enough to see the problem.One of the companies I do diagnostic stuff for had around 15 TD4's a while back,one of them had lumpy running and smoke problems.It didnt log any faults and live data didnt show any big variations in cylinder balancing.It was cured completely with 4 new Bosch injectors.(After a compression test)
Lastly, any serious garage now does an electronic compression test,not a mechanical gauge.Its quick,accurate and needs no dismantling etc.It uses a current clamp around the battery lead,this is fed to an oscilliscope to view the current peaks as the starter pushes the pistons up on the compression stroke.It doesnt give an actual pressure reading,but it will show any variations - which is what you need.
Common rail injection is known in the trade as "Common Fail" .....

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Thanks this is helpful - I really don't want to buy 4 Bosch injectors as the cost is a bit much for an older vehicle. I think the LR indie checked compression on an Autologic unit. Here is a photo of the readings before the latest Injector swap. In this case my suspect recon injector was cylinder 4.

If compression was down wouldn't I feel low power, smoke, roughness throughout?

Re photo in previous post - I just realised you may have thought that I thought these were compression readings - I know they are not and they are compensation fueling readings at tick over.

The EDC ecu will try its very best to compensate to get effectively what it regards a 4 separate engines to do the same thing - generally very successfully,even with poor compression on one or more cylinders.TD4's are not generally prone to compression loss even at higher mileages.Its much more likely to be an injector.You can never say never,but its more likely fuel.VNT problems usually result in a lack of low down power or loss of top end if they overboost,but not lumpy running or misfire.Low or high side fuel pressure problems will log faults and normally show up as poor starting and/or low power.
I would be giving all 4 injectors to a trusted fuel shop - by recommendation locally, NOT by adverts.Good fuel techs are few and far between now.....
As an aside I notice your photo's show an Autologic unit the same as mine,one of its downsides is that the live data values dont show as out of expected value as T4 does - which is why I still use mine for jobs like that.

To be fair to the company I used they are well respected and have significant businesses in both Cardiff and Swansea. They did test all my injectors again and gave me print outs - there are some fails in the sub categories but they explained the significance of these and said they were in effect a on spec and very good injectors - now they could have said I needed new ones and sold me some but they didn't - even the one they sold me and I thought was faulty they changed for me.

To clarify the Autologic pic is from the Indie LR guy - all he did was a diagnostic and a full check of possible mechanical problems - ones that you can see and listen for.

The one thing that I believe the diesel service cannot do is test an injector under lower mid load.

I am going to do another leak back test but realise that it is limited in what it can show. Rover Ron has suggested I look at the vnt - turbo stuff and vacuum hoses incase there is a split - long shot but easy to do.

I suppose ideally a complete set of good injectors would prove the problem but getting hd of any that I can trust is impossible apart from buying new - big bucks for me. I am tempted to get one and start a process of swopping it out one at a time.

Here is part of a print out of one of my injectors - the company testing say they are good but I notice there are some fails - does anyone know if these have any significance?

Just done a manual leak back test and it seems fine - small amount from each nicely matched

Been back down to the diesel company because the owner wanted to drive it. He was very good in feeling it right away but at a loss to identify what it is. He did say it is not beyond the realms of possibility that I have had two injectors off them that have a fault not showing up on their test machine but it's unlikely.

So he is going to do so e research and we meet up again in a couple of weekend when I will go down and take my Injectors out in their place to keep cost down - then he will get another that is know to be working on a vehicle and we will do a compression test and then swop out injectors and plug into a diagnostic.

Don't give up on any ideas you all might have - I am open to any possibility.

Sounds like they're trying to sort it. I'd let em go that route and see what happens

Yes if they follow up great. Rover Ron has been great as have people responding here. Special thanks to eightinavee for a very informative response.

They won't do anything for a few weeks because of holidays do watch this space.