Injector leak

Hi on the TD4 could an injector be leaking even if a full diagnostic showed no faults and all tests well within tolerances?

I have had the injectors removed to get the cam cover off to repair a broken injector collar stud - all done well and injectors refitted to the same cylinders they were removed from.

Driving it seems great - loads of power and no smoking BUT I get a sense of what seems like an out of balance wheel on load acceleration - new Tyres just fitted and balanced well so kind of dismissing this - would a dirty injector do this?

Fitted BMW crankcase breather and an EGR

Diagnostic done by a Automotive Lecturer in a college I work at and he is one of those good ones from industry.

Can you just tap the injectors down to see if it helps? New copper washers were fitted.

Any help appreciated. Thanks Angelo

angeloc said:

Hi on the TD4 could an injector be leaking even if a full diagnostic showed no faults and all tests well within tolerances?

I have had the injectors removed to get the cam cover off to repair a broken injector collar stud - all done well and injectors refitted to the same cylinders they were removed from.

Driving it seems great - loads of power and no smoking BUT I get a sense of what seems like an out of balance wheel on load acceleration - new Tyres just fitted and balanced well so kind of dismissing this - would a dirty injector do this?

Fitted BMW crankcase breather and an EGR

Diagnostic done by a Automotive Lecturer in a college I work at and he is one of those good ones from industry.

Can you just tap the injectors down to see if it helps? New copper washers were fitted.

Any help appreciated. Thanks Angelo

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Leak back is only one fault, there could be sticking needle valve or fouling. The only way to assess is to remove and test by a specialist. Try some cleaner/additive first though

Yes I am putting cleaner additive through now - it seems to be improving but I will wait and see.

Thanks

angeloc said:

Yes I am putting cleaner additive through now - it seems to be improving but I will wait and see.

Thanks

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Do you get on steady throttle a slight surge or drop in power for a second then all seems fine?

mjrimmer said:

Do you get on steady throttle a slight surge or drop in power for a second then all seems fine?

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No it pulls well and it powers all the way through. To be honest if I hadn't balanced the wheels I would point to that - it's like a shimmy at a point through the acceleration. I am on my first tank with cleaner in and prior to that all the injectors were removed to fix a broken stud on the collar that holds each on in. I suppose it is possible some rubbish has been picked up and is clogging an injector but it runs so smoothly and powerful otherwise I lost as to what it might be.

mjrimmer said:

Do you get on steady throttle a slight surge or drop in power for a second then all seems fine?

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Mine does this, but only since I stopped using millers. Haven't done anything with injectors since stopping millers, just stripped and cleaned EGR, top boost pipe(plastic one), and the inlet manifold.
What do you think it could be?

Well the cleaner doesn't seen to be working and if anything it's getting worse - almost a miss at about 2500 rmp.

I have notice an oily residue on the bigger intercooler hose which comes back after wiping it clean within 50 miles. Could this be part or all of the problem?

angeloc said:

Well the cleaner doesn't seen to be working and if anything it's getting worse - almost a miss at about 2500 rmp.

I have notice an oily residue on the bigger intercooler hose which comes back after wiping it clean within 50 miles. Could this be part or all of the problem?

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If there's no improvement after a couple of tankfuls of fuel with additive then your going to have to consider having the injectors tested.

Some oil residue inside is normal, I've never found one without. If there is oil sweating through to the outside it's best to replace the hose.

Chaser said:

If there's no improvement after a couple of tankfuls of fuel with additive then your going to have to consider having the injectors tested.

Some oil residue inside is normal, I've never found one without. If there is oil sweating through to the outside it's best to replace the hose.

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Yes the oil on the hose is on the outside so a replacement it is methinks.

Well a bit of an update - still got the shimmy type thing going on as I accelerate through - I have done the following
EGR Blanked off
Ultrasound Cleaned the Injectors
New Intercooler Pipes
Checked and replaced any other pipes looking suspect
Fitted Synergy 2
Put it on a diagnostic - no faults showing
Tried another MAF - no difference
New air cleaner
Changed the Crankcase breater for the BMW one
No significant black smoke , only when hard on acceleration and turbo boosting
No grey or white smoke
Ticks over absolutely steadily at 750rpm
Quite engine and cruises well

Lots of power okish mpg (35mpg mway and city driving)

New tyres all round

VCU a tightening so going to change - could it be this creating a kind of tension shimmy?

Anyone had a CV Joint go? Do they do this?

Things not tried - Injector test other that a diesel mechanic drove it and said "They ain't gone mate!" he thought it was MAF but tried another same problem - tried switching it on and off as well on synergy no improvement on shimmy.

The shimmy is as though the car was shaking it self in defiance of acceleration through about 2500 to 3000rpm! fine below fine above and if I am gently almost fine all the way through - hence my now thinking its drive train stuff.

Help appreciated

Ahh, so by shimmy you mean you've got a bad vibration?

mjrimmer said:

Ahh, so by shimmy you mean you've got a bad vibration?

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I wouldn't call it a vibration as this is soft and feels like a good hand shake!

I get this too so be interested to hear the cure if and when you finally find it!! Its just like an out of balance wheel but as you are accellerating, rather than cruising at a set speed!

I also currently have the surging mentioned at low revs. Going to try some injector cleaner too.

The front driveshaft CV fault on FL1 is normally noticable on hard acceleration in a straight line. Its not so much a shimmy on the steering wheel like you would get with out of balance wheels, but just a feeling of a shimmy on the vehicle.

Jack the front end of the vehicle up, check for play in track rod ends, its not uncommon. with the wheels straight ahead , spin them check they spin smoothly and there is no issue with IRD. Turn the wheels from full lock to full lock , spin the wheels by hand again , check there isnt a notch or tight spot during rotation. If that checks ok , straighten the wheels up and from underneath applying force to the shaft near the cv joint, moving it up and down. If you find significal difference in the movement, then you may well have found your issue.

The issue you describe is more likely to be siezing / damage than excessive play though imho.

If all checks ok , look elsewhere And as guidance only

Hope that helps.

Now that sounds more like it - yes the shimmy is as you have both described - I will investigate