Sudden Power Loss - Lumpy Idle

[Yangi19]

It is a Bosch VP44, a VEP "Verteilereinspritzpumpe" or distributor injection pump.

The reason cam wear can cause a sudden loss in power is a pair of followers on one cylinder being thrown out. On could have been out for a long time, in fact each cylinder could lose two and you would barely notice but if a pair of inlets come out they misfire, if a pair of exhausts come out they run like **** and soon lock up due to diesel being injected but not ejected!

Ahhhh.... I Now understand what you are saying Crasher.... sorry - I more used to Bike engines with Buckets and shims And until NOW didn't even realise that Cars still use Rocker Arms/Fingers........... that's a lot of mech parts to go wrong!!!

So yes, beginning to make much more sense if I understand correctly:

So I could have already been Running with 1 of the Cylinders only working 3 Valves??? (or even 2 only working 3 valves!) without knowing ... just disappointed with performance (although it is never a race car - just a cruiser!)

Which 'might' explain why the car always felt like it should have a little more ...Ommph than it did - but always got there cruising.

So if THE OTHER Valve stopped working on a SAME cylinder - would obviously cause major power loss? because Fuel not getting In / or Out as case maybe.

I kinda understand now

SO NEXT QUESTION is how difficult to take Cam Covers Off???

I guess, Undo Injector Rails from Injector AND Pump
Remove Injectors
Remove anything in way
Take Cover Off?

Thanks Crasher
Kind Regards
Yangi19

[Yangi19]

SO.. QUICK UPDATE after Fettling Today (and I think this car is now starting to taking the P*** out of me!..... despite the fact I have luved it and have spent almost as much as paid for it to keep it running in 3 years of ownership!!)

Today:

1) Looking over things - noticed a Plug/Sensor not plugged in underneath on Driver side at Front - Not sure what it does or connects to (maybe intercooler?) But I don't know. So got underneath and plugged in..... Made no difference!

2) Checked if fuel getting through Filter - undid Airscrew on filter - and all I managed was to drag air into system!! (school boy error!)

After many attempts to turn over - with aid of a Jumper Starter Pack attached - eventually got fuel back to engine and started after many attempts.

Still Running Lumpy and No/little throttle response
Noisy on N/S bank of cylinders
Little White smoke from both exhausts (I don't even know if exhaust if 2 into 1 into 2 system???)

3) Checked Fuel getting to each Injector by cracking off the Injector feeds.
All getting fuel....

4) Had already visually checked Hoses that I could see and all looked okay.

5) Decided to have a look at Turbo Inlet.
Found that Inlet Rubber Pipe from Air Filter/Maf was majorly split underneath the Jubilee Clip - only obvious when taking clip/pipe off

..... Thought WOW could be issue!

5) Checked Turbo from Inlet side. Vanes Okay, Spins, tiny bit of movement on centre bearing - but nothing like I seen on some other vehicles. Small amount of oil on intake side - but only small.

6) Started engine without Intake pipe connected.
Started.
Ran Higher Revs than normal
Still noisy from N/S bank of cylinders
BUT - NO WHITE SMOKE......

7) Bodge repaired Pipe Just for now with hot Glue Gun - just to see if issue.
As soon as started again - and straight away HIGH PITCH NOISE from front of engine!!!!
Started again, and Battery Light ON / NO Power steering!!!

8) Checked belt from what can see on Aircon Pump (I think- Near Side Bottom) and still on there???

So people
Why has it suddenly ****** the Alternator/Steering belt or system?
Why Noisy On N/S Bank (Crasher may be correct in his thoughts about fingers - and maybe Additional issue other than split pipe that I may have had for a while and not noticed?)
What do I do next?

Don't want to just throw money at a 16yr old car in hope cures it ......no matter how much I love it

Thanks always for the support of members - always helpful and knowledgeable.

[Crasher]

Take the bloody cam covers off!

[Hannu5]

As above, you need to get a look at the valve gear on that bank as priority.

I've got AKE in 2000yr Quattro but lower mileage.

It seems that cam/follower loadings are very close to practical limits on this design. Any compromise in oil will be punished severely it seems. As soon as a cam picks up the surface of its follower it's not going to last long.

I use ZDDP oil and keep the changes short on mine in attempt to avoid this problem. All reports of them appear to point to this.

With bright led torch you can see one cam lobe only when looking down oil filler hole, may tell you something.

You can feel injector pulse when running by holding the steel feed pipes in your hands, just about, but it is there from internal pressure.

Clutching at straws, but check the EGR valve isn't stuck open. Either by mechanical or held by a malfunction on vac circuit that operates it.

Exhaust is single out of turbo exit, then splits later. White/grey smoke is usually unburnt diesel.

[Crasher]

You do the right thing, add ZDDP because the EU said this is no good as our scientific department said this will damage the cat IF the engines burn oil so it had to go, saving the cat but screwing the engine, great idea..... Until the removal of protection such as ZDDP, everything was fine, the EU stick their foot in and all hell breaks lose. Students protest us old gits are poisoning their future whilst buying Chinnese phones and clothes at the same time as snorting N2O, hypocritical *******! nitrous oxide environmental damage - Google Search

[Amphitryon]

Exhaust is single out of turbo exit, then splits later.

That explains something. I had noticed that the car has two exhausts and each looks to have a cat in-line as you might expect if they were independent, but there is only one turbo. Any idea why they didn't split after the cat to save fitting two.

White/grey smoke is usually unburnt diesel.

So why would the diesel fail to ignite? I can only think of three reasons:

1. Too little compression.
2. Too cold - glow plug not working?
3. No air, possibly because neither intake valve is opening.

Are there others?

As the original loss of power hapenned at speed, no 2. seems unlikely. No. 3 would be consistent with Crasher's idea about ejected valve fingers. If both inlet valve fingers on the same cylinder were ejected wouldn't that leave the inlet valves not opening (always closed)? I am sure I have seen a video in wich the valve covers can be fitted (and therefore presumaby removed) wih the injectors still screwed into the head but with the pipes from the injector pump removed.

[Amphitryon]

5) Decided to have a look at Turbo Inlet.
Found that Inlet Rubber Pipe from Air Filter/Maf was majorly split underneath the Jubilee Clip - only obvious when taking clip/pipe off
...
BUT - NO WHITE SMOKE......

That seems a little strange. What is the MAF used for? What I would expect it to be used for is to limit the amount of fuel injected so it never exceeds the amount of fuel that can be burned with the amount of air entering the engine and therefore the engine doesn't produce clouds of soot when you suddently put your foot down but then surely, if it was disconnected, or the air was not routed through it, wouldn't the amount of air be calculated as zero and thus zero fuel injected? Thus, if the engine runs without it, It seems like it must be more complicated - anyone know more?

[KevTrem]

Before trying to find other problems drop your rocker covers off and have a spy in there, it may save you time looking for other issues.
All the sensors and fuel metering on your car is set for all the valves to open an everything to be functioning, if you have valves not functioning then your car will have unburnt fuel, whether that be intake or exhaust valves. If its exhaust side and you keep the engine running or keep trying to start it then there's a good chance its going to go bang. Or at the very least fill your oil pan with diesel as its forces it past the piston rings.

[Hannu5]

Diesel fail to ignite:- taking out too cold condition, so it wouldn't need the glow plugs as it was running up to temp. Then the obvious one is if valve sealing has been compromised, compression lowered it will not fire that cylinder. This could be if it's bent or destroyed a valve.

All of this needs you to confirm what the status of the cam and followers are like. You probably can't get anywhere without doing this.

The cams are driven from belt wheels without key, they are long taper as far as I know on this. Which means that jamming a loose rocker as it's ejected can alter the cam timing! Obvious valve contact potential. It can also make the cam jump belt teeth, the fuel pump is timed off the left bank cam set, so it can alter that too. All serious, but been seen on these with some regularity. You can see what we are getting at.

MAF, obviously measures airflow on the fly. Unplug it and during start sequence it's then recognised as failed. They ecu has very competent base map to use in this eventuality on most cars. It does most of the job like this as it has multiple report lines of revs, temp, throttle, road speed etc etc to assist it. Makes a very good job of running engine without MAF. MAF could be considered as just refinement in strategic terms to give final "icing on cake" resolution by adding or subtraction of gain factors to load site data programmed into ecu base map.

Tickover is monitored by flywheel pulses in more or less real time. If a pulse say for cylinder three arrives early or late, it'll pull or push injection quantity and timing to speed or slow that cylinder on next crank revolution. That's why modern motors haven that flat steady idle characteristic. So it'll try it's best to compensate for lumpy idle.

You've gotta get a look at those cams, think it's disconnect pipes, leave injectors, pull cover.

Also the belts to see what's going on there. You'd hope it's alright, but it's central to what is happening here and you can't avoid it to appraise problem you have.

[Yangi19]

Take the bloody cam covers off!

I hear you Crasher.... not simple at moment as need to move to car to mates garage next door when he has space in the week... so was doing some basic investigations that would leave to car at least 'drivable' at moment. (OR that WAS the plan!!)

Cheers