Running on three cylinders

I've tried searching and was surprised to find very little on this problem.

My 2000 115 PD Golf GT TDI is running on 3 cylinders.

I drove about 300 miles on the motorway and then the car developed a misfire. I pulled into the services and checked what I could and then decided that as it was after midnight and I was about 75 miles from my destination I should try to carry on. I found that if I held it at 75mph it was ok so long as I didn't need to accelerate. I got to my hotel and then the next day found a VW specialist who kindly spent about 2.5 hours looking at it.

• First they connected it to diagnostics and found that the problem was at cylinder #1.
• Removed the valve cover and tried making better contact from the loom to injector #1. No change.
• Next swapped injector #1 with injector #2 to see if the fault jumped across. No change.
• Next they checked voltages/resistances on the injector loom etc. and were not able to find a fault (I replaced the loom within the last 2 years when diagnosing a shudder fault which turned out to be the DMF)
• They had the computer connected for some time and as far as I could see were going through various screens.

Time was getting on and they needed to get back on to cars that were booked in. He said the next step would be to do a compression test and if that was fine then to check more wiring.

I put it out of my mind for the weekend and then had the car recovered home with the AA last night. There is a lot of smoke and unburnt fuel coming out of the exhaust and the sump has got diesel mixed in so I can't really afford to drive the car anywhere.

I'm going to try to get hold of a compression tester but have a feeling it will be a dead end.

Has anyone had a similar problem and if so can you suggest where I should look next?

it sounds like they checked everything that needed to be checked.
Have the compression checked , it does not hurt.
The fact that is cylinder #1 makes me think it may still be a harness issue.
Clean the plug in the injector from oil , in my car a piece of plastic locking clip fell in there preventing the connector from seating all the way in.
It's a possibility since the harness has been changed.

BTW, don't drive the car around , the oil is getting fuel dilution

Thanks for the reply.

I'll see if I can find somewhere to do a compression test. I know my local VW specialist didn't used to have a tester and would just borrow one from an engineering place across the road if need be but they have since moved.

I've still got the injector loom I removed from the car last time and a complete set of spare injectors that I got when diagnosing my shudder problem as well. I'll try swapping the loom over and see if it makes a difference. If not I'll swap all the injectors as well.

edit: yes thanks I've been warned about the diesel diluting the oil so will not be driving it which makes a compression test difficult unless I can get someone to come out or borrow a suitable tool.

let us know what happens

I swapped out the injector loom - no change
next I swapped out all 4 injectors - no change

Injector 4 actually came apart, the part the spring is round came away from the injector and the spring came off. I got my hopes up at this point!

I'm away for the whole of October so will put it in to the local VW specialist when I return because I can do without the car until the end of the month. When it goes in I'll ask that he does a compression test first.

Is there anything else I can try in the mean time?

Absolutely- compression test. Symptom of low compression when you can get it to fire at high RPM, but normal RPM you get a mis-fire.
Run into this issue all the time with old IDI diesels.
Have you been running 100% diesel, or "something else"?

I dont have the tool for a diesel compression test and I think they're expensive compared to the petrol version? I dont really want to drive the car so next time I take it somewhere will be to leave it with the specialist. Just hope I haven't already done damage by driving it on 3 cylinders!

I've only ever put diesel in it...

Do you run stealth EGR throttle body? Weird question but humor me please with a negative answer...or positive if it is so.

You have very low compression in that cylinder. Probably a broken ring, melted piston or damaged valve.

kiwibru said:

Do you run stealth EGR throttle body? Weird question but humor me please with a negative answer...or positive if it is so.

Click to expand...

No not running that, the car is completely standard.

hustler900 said:

You have very low compression in that cylinder. Probably a broken ring, melted piston or damaged valve.

Click to expand...

A friend is going to see if he can borrow me a compression tester so hopefully I'll be able to find out shortly. Failing that I might even put it to the garage near my house for a compression test, it is only a mile down the road so I think I could get it there.

Does anyone know how much labour there is involved in doing a compression test?

Heater plugs are at the front of the engine so I would think < 30 mins but have never done a test on a diesel before?

ok I've sourced a compression tester so can do this tonight. I'll follow the guide here - http://forums.tdiclub.com/showthread.php?t=284978

Can anyone tell me if the glow plugs are the same size on the PD as the non PD? The non PD requires a 10mm long reach socket for removal, I'll need to buy one on my way home so wanted to check they are the same?

Just make sure it is a DIESEL compression tester -Not a gas compression tester!

It is a diesel tester and the glow plug does indeed require a 10mm long reach. Unfortunately the smallest adapter with the compression tester is M12 and is not small enough for my engine.

I'm hoping to source another adapter today. Can someone describe how to make it safe to run a compression test on the 115 PD?

Here are the steps from the other thread

Procedure (per Drivbiwire):
TDI uses the *glow plug holes* to test compression.

-Get engine to operating temp
-DISCONECT THE HARNESS GOING TO THE INJECTION PUMP AND THE FUEL SHUT-OFF SELENOID failure to do this WILL cause the pressure gage to explode!!!!!! (note: you will need to clear the codes when your done)
-remove all four glow plugs
-Hook up a battery charger to keep a uniform charge between cylinders
-Crank until the compression gage stops climbing

I cant see any harness going to my injection pump or anything that looks like a fuel shut off solenoid. Can anyone describe where it is on this engine and what I need to disconnect? Pictures would be a bonus!

I've had some luck on my lunch break, a local engineering place has leant me their compression tester with a suitable adapter. If someone can help with the question above I'm good to go!

blued said:

I'm hoping to source another adapter today. Can someone describe how to make it safe to run a compression test on the 115 PD?

Here are the steps from the other thread

Procedure (per Drivbiwire):
TDI uses the *glow plug holes* to test compression.

-Get engine to operating temp
-DISCONECT THE HARNESS GOING TO THE INJECTION PUMP AND THE FUEL SHUT-OFF SELENOID failure to do this WILL cause the pressure gage to explode!!!!!! (note: you will need to clear the codes when your done)
-remove all four glow plugs
-Hook up a battery charger to keep a uniform charge between cylinders
-Crank until the compression gage stops climbing

I cant see any harness going to my injection pump or anything that looks like a fuel shut off solenoid. Can anyone describe where it is on this engine and what I need to disconnect? Pictures would be a bonus!

Click to expand...

Your first step is different. Your injectors are electrically actuated- so to keep them from injecting fuel you pull the fuel injector electrical plug


The rest of the steps are the same.

Thanks, I didnt get this post in time but thats what I did!

When I did the test it jumped up to about 200 PSI on cylinders 2-4 but didnt hold. I couldnt get a socket on to the adapter to get it in tight to the glow plug hole so this might be why - it was just in hand tight. Cylinder 1 didnt cause the gauge to move at all so it looks like I have no compression there. A little engine oil in the cylinder did nothing.

So... next step head off. Is this straight forward and are there any problems I'm likely to run into? Any special tools needed?

When you had the valve cover off, did you check the condition of the valve springs? Only time this happened to me on a car in 52 years of driving is on a 1972 Fiat 124S. A valve spring broke on one cylinder.

No I didnt check, how would I go about doing that?

I did press down on the hydraulic lifters to make sure they weren't stuck.

Took the head off today and one of the valves has a v-shaped chunk out of it.

I'm going to stick it down to the recon place that gave me the compression tester and have them check it out and replace the valve.