Never had a serious engine problem, but this started yesterday. The smoke in the rear view is so bad you can't see anything and it's off the road. I don't want the dpf filling up with soot either.  All the VCDS scans show no engine fault codes and there's no MIL light on. My thinking is there must be a really bad fuel injector, because diagnostics only monitors the electronics and won't tell you if the nozzle has burned away??

 

I made a slide hammer to lift them up, got 1,3 & 4 to lift up but number 2 is stuck fast. I tried getting the engine hot but it makes no difference. Before I'm forced into the nuclear option to remove the cyl. head and punch it back out, has anbody got any ideas? It's the worst system of injectors I've seen. The only lifting point is under the fuel inlet port and that's off centre.  I've seen the service tools, made those and a slide hammer but it's stuck fast. Because they use a bridging fork to hold down 2 injectors, I can't remove the other one tied with the same bridge.

 

If they had designed the hold down bridge and injectors with some common sense, you would under the center bolt which would pull both injectors up. Common rail diesel injector removal ideas welcome!

Edited 25 May, 20224 yr by voxmagna
typo

I removed a Golf injector couple of months back & found, cleaning up the area with brake cleaner first.

Sprayed some WD40 round the shaft of the injector. Spanner onto the hex part & gently kept moving back & forth.

Started moving & lifted both 1 & 2 injectors. Thorough clean up of injector hole & replaced. 1 hour job. 

28 minutes ago, voxmagna said:

The smoke in the rear view is so bad you can't see anything

1. What colour is the smoke?
2. If it's white, what's the oil level like?

The smoke (LOTS of it) is definitely diesel and even makes the car interior smell as it was drawn in through the heater duct. If I hold the throttle at 30mph I can see behind the smoke thins, but take my foot off for deceleration and day becomes night.  On an immediate cold start there's a small amount of smoke, but I can still smell more diesel in the exhaust than usual.  When the engine is hot it gets worse. I should have taken a video because I'm not talking a small amount of smoke, but so much you see nothing behind! The HP fuel pump pressure seems ok as is the turbo boost.

 

My theory is something bad has happened to a fuel injector because that's the only place diesel fuel can enter the engine. If it was a piezo control fault I would expect no fuel past the injector or if it was open only the fuel amount up to the size of the nozzle jet. Since this smoke is so huge, I think more fuel is coming through than what I would expect from a fully open conventional pintle nozzle jet, but then I don't exactly know how the piezo injector controls fuel? I do know if I replace one I'll have to adapt it with vcds and I'm not mixing them up!

 

I shall try again to get number 2 injector out. If I have to remove the head I'm stuck getting parts off around the injector which means cutting through and destroying the bridging clamp and possible the plastic cover? I think I need liquid nitrogen on the injector body which I don't have, but I do have a CO2 fire extinguisher to try which I took the horn off.

 

If I can't see any obvious signs of burning or damage to the injectors, I will put them on my airline at 150psi and dunk the tip in diesel fuel to see if there's any leak, then it's pay to have them tested if I can't see anything obviously wrong.

Edited 26 May, 20224 yr by voxmagna

Quote

Spanner onto the hex part

There is no accessible hex part on these common rail injectors. There is, but the connector is fixed over the top as part of the return flow. Correction whilst replying: There is a hex part but you can't get anything on it whilst the bridge clamp is still attached and you can't get that off unless both injectors are lifted together , So that gives me an idea: Cut the bridge clamp (which I think they say should be replaced anyway, then try to twist the injector with a wrench on the hex?

@voxmagna That's what I was double checking is that this was diesel smoke and not lubricant smoke. So it's either injector(s) or throttle position.

OK thanks. It's not throttle position. RPM smooth and holds, drives like it did before. Injector 4 came out covered in black gunge, the O ring seal had disintegrated. 1&3 were oily but not as bad as 4. I've not leak tested them yet. I'm assuming whilst these piezo injectors aren't serviceable, the O ring (s) can be replaced? Although they look bolted together like others I've seen, if I confirm definite leak past I might have a go at tearing it down.

 

I've destroyed a clamp plate now (a tenner each) but it's still stuck. I suspect the O ring seal has gone and carbon is locking it in?  I can get a 29mm open end spanner on the top nut but you can only turn it clockwise tighter and since its not a nut with much width metal, I wouldn't put a lot of force on it. The best way to turn  the injector a couple of degrees at a time is to hit the side near the union with a steel bar and hammer. It's virtually impossibe to get the upwards force, even with a slide hammer.  I'm tempted to make a fitting, attach it to a lifting beam and lift the whole damn car up on then wallop the side with the bar and hammer.

Well I finally got them all out with No 2 being the PIG. I had to break the bridge clamp holding 1 & 2 to release 1 and give more room to work. Tap a chisel down the sides between the forks and the injector body and the brittle forks break off. Still couldn't extract No2. so decided to sacrifice the cyl. head cover (£60) to get more extraction options. Didn't use the angle grinder to cut the cover as it would spew far too much plastic over the camshafts. I used a soldering iron with plastic cutting knife bit to create a hole about 50mm around the stuck injector, then lifted the cover over it.

 

More huff & puff and before trying the stillsons, I made the slide hammer heavier and took more care to align the impact shock central to the injector. Also removed trhe HP union and used that to hold my slide hammer fixture solid to the injector body. Each slide hammer blow raised the injector about 5mm until it was clear. Checkout the Laser tools injector remover if you want to copy theirs.

 

Visual condition: Injector 1 oily but clean, O ring still in the groove. Injector 2, Hardly any oiling up, good O ring. Injector 3 oiled up and O ring fragmented. Injector 4 a total mess. with lots of black gunk and hard bits of carbon/O ring outside the injector body, O ring seal gone and groove filled with gunk. The OE seals are 16.2mm ID x 1.5mm. I think they were Buna-N. I shall replace them with 16mm x 1.5mm Viton rings and replace each injector with injector grease.

 

Parts lists shows O rings at the end of each nozzle and some sell kits with 2 O rings per injector. If there's an O ring on the nozzle, It must be way down at the bottom of the cyl. head and I haven't explored how to get to it yet.

 

Off to the diesel injector man tomorrow to have them all tested.

 

Everybody tells me these CR engine injectors aren't serviceable? Not sure what they mean because the black electrical connector body can be removed by the large 29mm nut - watch for the small spring, washer and bypass jet pintle!  After that everything is mechanical.  It looks as though the lower half of the injector body can be separated? I suspect they can be disassembled but you can't get Bosch small parts and more important, measure and qualify the flow calibration.

 

Onwards & Upwards!

Update on parts: The stock O ring fitted to the injector stem is Buna-N size 16.2x1.5 wht 000 884. I've sourced some Viton O rings 16 x 1.5 and I'll use those. I may even fit a second O ring on the bottom groove, even though it's not machined with square sides for an O ring. The 'Seal' at the bottom of each injector isn't rubber but a copper washer left sitting in the cyl. head which you can hook out. Mine measured 13.36 OD, 7.7 ID x 1.45. There are plenty of Bosch common rail copper washer sets on Ebay, but most are the wrong size. I've found some 13.85 x 7.3 x 1.4 which I think will be ok. Fingers crossed this is an injector problem and nothing more serious needing an engine teardown. The Yeti 4WD diesel is a pig for rear engine access.

I learned how to become a Common Rail diesel Expert!

 

MY12 Yeti SE 4WD Tdi is now healthy and smoke free. Fault finding was a journey of patience with some wrong turns and a few self inflicted mistakes. I'll contribute my rough notes in case anybody else has similar diesel engine problems:

 

1. Working on a 2l common rail diesel isn't easy. Removing parts can be difficult and expensive if things don't go to plan. Start by understanding the possible problems, causes, and plan to do checks and tests which avoid removing parts.

2. Smoke can be one of 3 kinds or a mixture: Black smoke = Excessive diesel or insufficient air, Blue smoke = Oil burn, white + blue smoke = oil + coolant water burn.

3. Smoke can have several causes. Severe black smoke (rolling coal) can be caused by faulty (open) fuel injector(s), low compression,loss of turbo boost pressure (insufficient air) or EGR problems may also affect air supply.

4. Oil burning blue smoke can come from bad piston rings, valve seals, excessive crank case pressure, bad turbo seals, faulty EGR operation, or blocked up and gunged EGR, pipes and inlet manifold. Also check the PCV.

5. Most of these possible causes are hard to prove,  but doing the least invasive checks first will eliminate many possible causes.

 

6. Check 1: Run diagnostics and check there are no engine malfunction codes. If no, then smoke problems arise because the cause isn't measured and reported by diagnostics.

 

Check 2: Check for Excessive crank case pressure/blowback on idle by removing the oil cap and feeling with your hand. I actually measured my crank case pressure. You cannot do it at the dipstick because the tube is below the sump oil level. I used a spare V.W oil cap, drilled a centre hole for some pvc tube and connected it to a Monument Gas water gauge - but you can just use a long tube formed as a 'U' and put in some dyed water. I measured a partial vacuum of 3-4 inches WG on idle (Good).

 

Check 3: Do a compression test on each cylinder via the glowplug aperture (M10 x 1mm). N.B Most Chinese compression test tools are for petrol engines up to 300 psi and don't have the pressure or long reach adaptors required for diesels. I found a cheap 0-1000psi diesel comp. test set.

 

Check 4: Test each fuel injector connector with a multimeter: All 0.5 ohm = solenoid type = Good.  All >200k ohm= piezo=Good.

 

Check 5: Injector leak off test. This requires plastic hoses connected to each fuel injector leak line. The amount of fuel leaking back is measured on idle for 30 seconds, then at about 2K rpm. There isn't an exact science, but the leak off volumes should be similar from each fuel injector and there should be some. The purpose of this simple test is to identify unusual fuel injector operation before trying to remove it. Warning: Bosch injectors code 03L/130/277J (0445 110 369 B004) are strange because the injector leak off connection is done with a nozzle and push fitting internal plastic retaining clip. Cheap Chinese test kits for Bosch injectors using external clips won't fit this type. They are also damn dangerous, because it's too easy for the plastic retainer to not engage and fill your engine bay with diesel!!

 

Check 6: Dynamic injector pressure test: Risky but some do it wearing gloves and safety glasses: Reverse the injector link to the common rail and tape the injector into a clear plastic tonic water bottle. Remove injector plugs to other 3 injectors to stop firing and have a second person crank whilst looking at  the spray pattern. These injector nozzles have 4 outlets. You can only see them on the tip with a magifier or microscope.

 

Check 7: Eliminate the turbo as far as possible. Turbos passing oil causes blue smoke, particularly during acceleration. Remove a large clip on the turbo intercooler hose and check inside for any excessive oil pooling inside. The turbo is fed with high pressure oil which drains through gravity back to the sump. Check the turbo oil drain isn't blocked. The crank case back pressure (should be a vacuum!) is important because positive pressure prevents oil draining from the turbo and forces it past seals. Many good turbos are replaced when these are the real problems.It's more difficult to check turbo seal oil leaks on the exhaust side without removing the DPF and pipes - a horrendous job on the 4x4.

Even if these tests as much as you can do all look o.k, that is confirmation to look elsewhere.

 

7. I didn't do an injector leak test first (I should have). My test conclusions led me to fuel injectors. A diesel specialist will test 4 injectors for £80. If MY12 Yeti had done over 120k instead of 75k, I wouldn't have bothered testing the injectors, just go to a German firm that will supply a set of 4 re-conditioned and re-calibrated with test certificates. Another option I didn't do was buy a used injector for about £70, take a chance it was good and use it as a swap to check the others. After testing I was told injector 2 was so bad it shouldn't go back. But removing injector 2 gave me so much grief I could have damaged it? I was still uncertain and went ahead to buy a used injector with the same part codes from a Passat.

 

8. Removing a fuel injector from this CR engine: Easy is gently lift up with a flat screwdriver blade using the ABS rocker housing as a fulcrum point. That didn't work for me. Next option is a slide hammer. There are some Ebay injector removal kits using a slide hammer. The first type require the large nut holding the solenoid to be removed in the car. Frought because the solenoid pin, spring and spacer washer can jump out. Safest is the removal tool (Laser) that attaches to the side of the injector body using its fuel inlet nipple. The most important thing is impact must be absolutely vertical on the mounted centre line of the injector. I made a removal tool that clamps to the side with the fuel inlet nipple.

 

9. When injectors are removed you can check if their stem O rings are still in situ. Mine were burned away. This O rings prevents oil from inside the rocker casing falling down and welling close to the hot injector nozzle, it isn't the primary seal. There's an important copper sealing washer underneath each nozzle, this often drops back into the hole as the injector is removed. Remove the ABS rocker cover because you can then see lower down and inspect the PCV diaphragm.

 

10. In my case, some injectors had significant black gunge around their nozzles and copper washers were scored. The worst had a part of the surface blown away! The consequence of this is compression leaks inside the valve cover adding dieselto oil blow back and being fed into the exhaust. Remember I said check the compression leak readings for each cylinder! I replaced the copper nozzle washers and even lapped them smooth. I checked the cylinder head nozzle surfaces and gently cleaned them up a little with a 15mm flat cutter. The Chinese seat cutter set was flawed. Their smallest 15mm cutter head fits on a 17mm mandril which I had to turn down to 15mm.

 

11. Diesel Fuel injectors: I assumed they were piezo, I found no local or online firm that would recondition them. I should have measured them first with a multimeter. Mine were about 0.5 ohms each. Therefore they are solenoid type. A piezo injector will measure very high resistance. Bosch are very clever at making it difficult to do any servicing. The nozzles are coded and you can find parts, but the hex head they put on the nozzle won't fit any wrench. You can remove the insulated solenoid head with a large spanner, but small parts and a spring can leap out and get lost!!

 

12. Fuel injectors are coded: Before removing any fuel injector you should note the unique serial number code (7 digits) and its corresponding cylinder. If you have previously scanned the car, check the serial numbers and their position tie up. If they don't, somebody has been messing with injectors, replaced them or mixed them up! The 7 digit Bosch injector code incorporate a calibration value of tested fuel volume which the ECU stores. Using vcds and their 'Security access code' popup you enter the injector serial number. When this is done the ECU is supposed to learn and adapt to the new calibration. In practice, I think this means your engine will run smoothly without much diesel knocking? If you didn't recode an injector, I'm sure the engine would still run.

 

13. On the home straight I replaced the ABS rocker cover which I destroyed to get access to a stuck injector, fitted 4 injectors with new Viton O rings and copper sealing washers, fitted all the diesel pipework and got ready to purge the fuel lines using diagnostics. That done and after some prolonged cranking with a fully charged battery, the engine ran with NO SMOKE. It runs a lot smoother than it did before and I haven't had to replace a turbo, pistons, valves or piston rings.

 

CONCLUSION: Rolling coal black smoke was probably caused by poor injector nozzle sealing and a faulty injector.
 

 

Edited 11 June, 20223 yr by voxmagna

Well done you and thanks for the great write up, I'm sure it will help others in the future.

 

It looks like your hunch was correct, at the time I thought you might be rushing in and inflicting damage due to the stuck injector that may have turned out to be fruitless, I'm pleased yout instincts were correct.

 

One question. With the benefit of hindsight what if anything could you have done differently that might have avoided some of the difficulties you encountered or told you definitively where the problem lay?

 

Another question, could there ever be any benefit in re-entering the injector serial numbers and allowing the ECU to recalibrate or does it only work in conjunction with new calibrated injectors?

3 hours ago, voxmagna said:

Check 6: Dynamic injector pressure test: Risky but some do it wearing gloves and safety glasses: Reverse the injector link to the common rail.....................

 

I'm struggling to visualise what it is you are trying to describe, can you explain it in other terms?

 

Aha, maybe I have had a lighbulb moment , do you mean remove the injector to be tested and turn it 180° away from the cylinder?

1 hour ago, J.R. said:

Well done you and thanks for the great write up, I'm sure it will help others in the future.

 

It looks like your hunch was correct, at the time I thought you might be rushing in and inflicting damage due to the stuck injector that may have turned out to be fruitless, I'm pleased yout instincts were correct.

 

One question. With the benefit of hindsight what if anything could you have done differently that might have avoided some of the difficulties you encountered or told you definitively where the problem lay?

 

Another question, could there ever be any benefit in re-entering the injector serial numbers and allowing the ECU to recalibrate or does it only work in conjunction with new calibrated injectors?

What I would have done differently is less hunch and more tests before removing parts!  Paying for workshop repairs and parts on diesels is expensive. The cost of buying or borrowing some key tools like a leak back test kit (cheap) and compression tester is relatively cheap compared to labour charges. Measuring crank case vacuum is a cheap bit plastic hose and an oil cap. Having and being able to use a digital multimeter is essential for most DIY car work. When you do remove injectors I explained by visual inspection that you can find a lot wrong with them. Having a spare known good injector allows you to swap it with each of 4 and save you injector testing costs.

 

I also wondered about re-entering the injector numbers.  If you think how they work, the ECU only knows about pulsing the injector in time units and the EFi loop is the feedback to control fuel to air ratio. I think the calibration is only relevant with a new injector where in addition to the air fuel setting, the ECU is being told in advance what volume of fuel corresponds to an injection stroke at constant fuel rail pressure. If you buy a set of recond injectors e.g from Germany, they come with a test report done on a Bosch tester and a new serial number = calibration.  The ECU 'learns' to modify the data after the injector code has been entered which I think is just a tweak of the starting reference point? If the injector is worn then I think the ECU will have monitored that and re-learned. If it hasn't then re-entering the original code starts the ECU learning over again. The advantage of checking your injector codes with the cylinders using diagnostics is if you or somebody mixes them up, diagnostics will tell you which cylinder they go back in.

2 hours ago, J.R. said:

 

I'm struggling to visualise what it is you are trying to describe, can you explain it in other terms?

 

Aha, maybe I have had a lighbulb moment , do you mean remove the injector to be tested and turn it 180° away from the cylinder?

The short steel fuel lines have the same unions each end and are reversible. Used Golf lines are compatible and bendable.  But you and anybody else should know that injector nozzle pressure for these CR engines is 1800 Bar or 26,100 psi and there are serious safety issues and hazards which would be unacceptable in an industrial workplace environment. When fuel injectors are tested in a Bosch automated tester, they sit inside a clear polycarbonate safety box protecting the operator.  If you search the internet you will find some DIY methods done at your own risk.  The Bosch test kit generates the same working pressure as the HP pump, but in a much safer way. An important test on the Bosch machine is nozzle leakage.  There should be no leakage from the nozzle of a solenoid injector when the injector is at rail pressure and there is no power to the solenoid.  Not wanting to suggest unsafe procedures, I think you can work things out for yourself. 🙂

Edited 11 June, 20223 yr by voxmagna

Thanks for the warning re pressures.

 

Regarding the coding if injector leakage or performance and the engine adapting to the wear of injectors over time, having thought about it (you spurred me on) I dont believe it can tell from the lambda sensors etc which individual injector may need more or less time, all it can do is to change the parameter for all of them, from your experience I dont think it does this (for good reason) as with all your excess fuel it would have reduced the fuelling to all of them, or the individual one it it really can (I think not), this was not the case with your car.

 

I reckon they should be changed as a set (probably the VAG and bosch recommendation) and when that is done the individual figures are used to trim the duration to the individual injectors, that would be why you have to tell VCDS what cylinder each individual injector is fitted to.

 

So I reckon swapping the position of injectors is a no-no, if you fit a new one is it worth coding it? If the others are still behaving exactly to the original coded parameters then probably yes, I would like you fit it and see how it behaved before deciding if coding would be a worthwhile risk.

 

It's been very usefull for someone else to have tackled this problem rather than putting it in a garage, it gives me the opportunity to think it through, something that usually only happens when my car is failing and then there are other pressures at play, better to be prepared!

 

Thanks again, I hope I don't have to put your knowledge to use but I'm sure others will.

9 hours ago, voxmagna said:

Not wanting to suggest unsafe procedures, I think you can work things out for yourself. 🙂

 

Understood and filed in the memory bank!!!!!!!!!!!!!!

Quote

Thanks again, I hope I don't have to put your knowledge to use but I'm sure others will.

I write notes to myself because it's sometimes not about what to do, but what not to do and fall into a hole next time. I can contribute polished write ups with photos or a video, but there's a tendency for beginners to follow step by step as a problem solver without thinking things through. Problems like these can follow several different paths which may not all apply and there's plenty others have posted on each. What I've tried to do is post my notes and thoughts and it's up to the reader to try and work out what may apply to them.

 

I did fit and try the used Passat injector without re-coding it first and the engine started up and to my ears appeared to run smooth and fine (with no smoke).  It actually came from a later 2013  CF series engine but not my CFHC. That's why I suggested the 'calibration' is likely to be fine tuning. Since the ECU plays a part in re-learning some values after you enter a new code, I can only guess what these are and they must come from the Bosch automated injector tester which rebuilders use to allocate a new serial number code? These are the variable characteristics I think each injector may have: Mechanical, e.g How the solenoid responds in time to lifting the jet needle (delay?) and how fast it can pulse for higher rpm, volume of fuel let through the injector nozzle from the time the solenoid is triggered to when it turns off.  This would include any lag due to the mass and friction of internal parts, important at high speeds. But how does the ECU 'tune'?  I'm not sure if these CR engines have knock sensors, but that feedback could be used to modify the defaultinjector calibration for minimum knock?

 

I took the Yeti on a spirited 30 mile fast drive to complete the dpf regenerating cycle and burn off any unburned fuel left over from the fault. When I got back, I wiped the inside of the tail pipe with tissue and there was zero carbon deposit.

 

I don't know if you've looked at Bosch piezo injectors?  I'm glad I don't have them!  These are more complex and their calibration data also includes a (high) voltage parameter.  Their advantage over the simpler solenoid type like mine is they can turn the nozzle jet on and off 5-10 times faster. This allows the injector, to pre- squirt, normal squirt and post squirt fuel for each firing cycle up to the maximumum engine rpm. You get better efficiency, lower emissions and less diesel knock.

Edited 12 June, 20223 yr by voxmagna

Whilst it's good to keep the grey matter turning and essential (for me) to keep on top of understanding these developments to avoid having my money spent by a garage who won't have kept on top playing parts bingo, the complexity of my current engine let alone those that follow, hybrids etc, is way too far removed from the simplicity I enjoyed when I first switched to diesel power with a 98 90hp Alhambra followed by a 2001 110hp Octavia.

 

That simplicity meant such reliability in the first 20 years that I learned absolutely zero about diesel engines , boy  have I had to play catch up going from EU3 to EU4 and EU5, yes the CR is a smooth engine compared to the PD but the MK1 Octavia was smoother and gave equal if not better fuel economy.