Volkswagen Mark IV Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Hello fellow VW lovers,

Last week I was on my way to work when I started to notice that my car's clutch all of a sudden appeared to be slipping. As I went along it began to get worse and started to produce a knocking noise, it then began to run really rough as if it was being starved of fuel. I managed to get to work and popped the bonnet to be greeted with the unmissable smell of a diesel leak. After examination I found that the short feed pipe to the tandem pump had a pin hole in it and was leaking fuel everywhere.

I tried to carry out a temporary repair on the fuel hose, just to get me home, but ended up breaking down completly about 10 miles into my journey home and had to get the car recovered at 4 in the morning.

The next day I sourced a replacement hose and changed it. After turning the engine over for a short while it caught and fired up. There was loads of white smoke, a knocking noise and the engine was running really rough (missfiring as if there was air in the fuel.)

I put it on a VAG and it reported a missfire on cylinder 2. Knowing that this problem began from when I found the fuel leak I thought that maybe the starvation of fuel may have damaged cylinder 2 pd injector and so I took the rocker cover off and removed the injector and sent it away to be tested. I also tested the injector wirring harness for continuity and resistance, both were fine. The place where i sent the injector found that it was "massively" out of parameters and over hauled it for me.

Whilst the rocker cover was off I checked the CAM lobes for wear and damage but it appeared to be fine with no flat spots.

When i got the injector back i refitted it with new stretch bolts and fired it up but the same syptoms were present- loads of white smoke with unmistakeable diesel smell, a knocking noise, rough running as if there was air in the fuel system and no pwer to the point where it is undriveable and you cant even pull away. I put the VAG back on and the misfire on cylinder 2 code was no longer there (so at least that had been cleared up.)

I next checked my engine timing and this was all fine with the CAM lock pin inserted the crank locking tools marks all lined up perfect.

Whilst pulling the intake pipes off I have noticed a fair amount of oil both around the turbo and inside the pipes. Could a faulty turbo cause these symptoms that I have. Also I was wondering if the fuel leak could have affected the tandem pump and if this could cause these symptoms. It is as if the timing is retarded. Could the DMF cause these issues if it has failed, the initial fuel leak was directlty above the bell housing.

I haven't taken the sump down yet and checked for any bent rods as I don't think that the cause is from the bottom end.

The engine was only partially rebuilt about 50,000 miles ago due to the DMF failing which resulted in the crank snapping. It had new crank, DMF, rings, water pump, oil pump, hydraulic tappets, glow plugs then and has run perfect until last week.

Please could someone give me some advice as to where to try next as short of replacing everything one part at a time I don't really know where to try next.

Thank you for any help or advice in advance
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #3 ·
Could other injectors also be out of spec?

I did consider that but the VAG is not showing a misfire on any other cylinder. The company that over hauled my number 2 injector did say they were surprised that it needed ohauling because they said "very rarely have the PD injectors fail".
 

·
VR6 GT35 4mo
Joined
·
11,745 Posts
The short hose from the tandem - was it the feed or return? Knocking, white smoke and diesel smell sounds characteristically like injector timing. Assuming the lash hasn't changed, I'd be considering the other injectors. Assuming no other codes?
 

·
Registered
Joined
·
11,301 Posts
if the clutch is slipping ( could be the DMF is the problem by the way not the clutch) it can cause an imbalance on the crankshaft thus the ecu retards or advances the timing to get it to fire right ... i would split the gearbox from the engine and use some brakecleaner to check if that isn't the problem... plus by doing so you can see if there is something wrong with the dmf/pressure plate/clutch/clutch slave cylinder...

but I would be inspecting the dmf and friction material.
 
1 - 5 of 5 Posts
Top