Fuel additive caused rough running & white smoke

[TDi_B5]

I did a diesel purge yesterday, I'm sure that will be an unfamiliar term to many people, see here for an explanation http://forums.tdiclub.com/showthread.php?t=87948

Anyway, instead of using liqui molys 'diesel purge', I used their 'super diesel additive' and the car did not react well to it. It ran very lumpy and there was very little power and clouds of white smoke. We stopped and hooked up all the fuel lines and it ran just the same, plumes of white smoke which I assume is unburnt fuel and it barely drove. I've since found out that the stuff I used is not intended to be used neat, it needs to go into a 3/4 full tank of full, so it must be pretty concentrated stuff.

I ran some clean diesel straight into the pump with a small inline filter and it is still running terribly, white smoke, chugging and really lumpy, like its getting too much or too little fuel.

Has anyone got any ideas what has happened? Has the timing been thrown out due to running this stuff through neat? Click here for a description of the stuff http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/e_5120.html

I wanted to clean the injectors as she's approaching 190k, the liqui moly stuff is very big in the states and europe. I removed the injectors today and had them checked and although they could be better, they are okay, which makes me wonder has the pump been damaged??

Suggestions, ideas would be greatly appreciated. Car is a 1997 Passat TDI AFN 110. No silly comments please, I'm kicking myself enough already :mad:

[martin1810]

Your description sounds like the injection timing is out. VW can check this with computer and I think vag-com can. Has the belt jumped a tooth or has the belt drive sprocket moved. (This has been known to happen).

[macquatic]

Can't see the timing being out because of an additive.
I'd be tempted to replace the fuel filter and run the car for a while and see if it settles down. If the pump's damaged - it's damaged, so running it won't do much further harm.

[TDi_B5]

I just can't understand why the timing could be out, just went out to see if I could move it and it shudders something chronic at idle, really rough. The timing was finally sorted out by the garage that did the cambelt a few weeks back so it was spot on and running great before the additive. And the fuel filter is about 2 weeks old. I will try and get it onto vagcom, although my version never seems to work, if anyone is in/near Swindon and can help that would be absolutely fantastic.

[snapdragon]

It does sound like the injection pump is knackered. No dirt got into the pipe did it? ie none fell in or got poked in when connecting the tubing.

[TDi_B5]

I can't see how any dirt got in, it was only disconnected for a minute and we were very careful not to contaminate anything. What are the symptoms of pump failure? It starts okay and is supplying each injector well, the aa man slackened each union and got a good spray of diesel from each injector.

[zollaf]

could just be that the pump and injector pipes are still full of this cleaner,and thats what the engine is trying to run on. i would just try and run it for a while to see if it clears. i cant see how it could damage the pump that quickly.

[TDi_B5]

We had it running on fresh diesel from a jerry can (through a small diesel filter) for several minutes and it didn't run any differently. I thought the same too, that just letting it run would clear any traces of additive and the running would get back to normal, but it still pumps out puffs of white smoke and judders like mad.

[zollaf]

it may take a while running it to totally clear the lines and purge all this stuff out. the pump and lines do hold a fair amount of fuel. i would just keep it running for a bit longer. how did you test the injectors? if it did any damage to the pump, i would have thought it would wear the cam ring out, and then the pump would not pump.

[TDi_B5]

Ok, I may try running it longer this morning. The injectors were tested by a local diesel specialist, he put each of them onto a machine and tested their output.

[zollaf]

ok, so the injectors work properly. you could try loosening the connections on them and cranking it over. this will pump out this cleaning fluid quicker. then run it on diesel and see what happens. worse case is the pump, but make sure its just on diesel before condeming it.

[TDi_B5]

Ran the car again this evening for around 45 mins to an hour, it reached operating temp in this time. No difference, still pumps out a steady stream of white smoke, runs lumpy and rough. I gave a few revs and it just poured even more smoke out than before, clouds of it. Topped the tank up with 20 litres of diesel from a jerry can in the garage just to dilute the cleaner and existing fuel.

Does this point to a pump problem...? I don't see what else it could possibly be? Does anyone have any suggestions on which way to proceed? I'm assuming a pump replacement/recondition will be enormously expensive and time consuming?

[martin1810]

Injection timing.

[zollaf]

i really cant see it being the pump. does the white smoke stink of diesel? presuming it does, this indicates fuel not being burnt on combustion, which could be timing as suggested by martin. either that or low compression somewhere. maybe a slightly bent valve from your previous timing problem?possibly a headgasket ? im just thinking that the cleaner has done something somewhere else. maybe get the timing checked and if thats ok get a compression check.
just checked autodata, and white smoke can be down to the timing solonoid or fuel quantity adjuster. now both live inside the pump???maybe one of these has been killed .

[TDi_B5]

Thanks Zollaf, the white smoke does stink of diesel. The car was running spot on before this, it did a 1500 mile road trip to germany last week without a glitch. I can't understand how this cleaner could have triggered a timing fault? Not that I'm disputing you.

The car was re-timed by the vw specialist that did the cambelt about three weeks ago and it was spot on. If there was a bent/damaged valve for example (and this would have been damaged since the cambelt change 10 months ago) how could running this cleaner through it make it worse?

I suppose the only way forward is to check the timing using vagcom and maybe a compression test? If anyone can help with that in Swindon, Wiltshire, please, please let me know.

[zollaf]

what im thinking is, that the cleaner may have upset the timing solonoid within the pump. the static timing may still be spot on. i think a session with vag com may give some clues. it certainly does sound like a timing issue.

[TDi_B5]

Right its time to revive this post as the car has been off the road for many weeks now. I called a mobile mecanic to see the car and as soon as I started the car he said it was running on three cyclinders. After some tinkering and discussion we concluded that there was very little compression on cyclinder number 2 by doing a compression test.

I had the car trailered away to his garage and the first thing he checked was the lifters. Three of them were duff and were replaced, but still no joy. He then removed the head to reveal two bent valves within the cyclinder with no compression. He said they were completely bent not just a little bit.

Now, it began to run on three cyclinders by running the diesel treatment neat through the engine. Prior to this the timming was incorectly set by a VW specialist and so potentially a couple of valves could have already been damaged. The timing was set correctly a few weeks before we used the diesel treatment.

The car was running spot on until I used the diesel treatment, even when the timing was out, it ran absolutely fine. The mecanic has suggested replacing these bent valves but he is not 100% sure that it will rectify the issue. Therefore I am reluctant to shell out this money and be left with a car that still isn't fixed but a bill for the work so far.

We discussed the idea that the incorrect timing may have damaged a valve(s) and running the treatment through may have just pushed it over the edge and caused a complete lack of compression. I'm completely stumped and don't know what to do, does anyone have any ideas? Why have I got two bent valves, was it caused by the incorrect timing, would the car have ran like this and if not could they have been bent by adding this treatment??

Thought and suggestions would be much appreciated, I hope it makes sense.

[martin1810]

My money is on a foreign object getting into the cylinder. Bit of turbo, broken glowplug etc. Wrong timing doesn't usually bend two valves in one cylinder only.

[TDi_B5]

Can anyone tell me why only 2 out of the 8 valves are bent? Is this significant? If it was a foreign object, surely the mecanic would have come across when removing the head?