Rough start, white smoke, rattling...

[Kraftwerk]

I bought a '94 960 D24TIC2 a year and a half ago with dead engine. Rebuilt it ground-up, and made less than 15k miles since.

It ran like a dream, started warm or cold with no cranking, never smoked, just like it was supposed to, until about a month ago.

Then, strange things start happening: First, there was some rattle under the hood, which I supposed to be loose alternator belt, but it didn't go away after tightening it.
Somewhere around that time, it would still start at first crank in the morning (naturally, I always wait for the glow plugs light to go out, then crank it) but it would sound like it's working some 200-ish rpm below normal idle. Tacho is broken, so I can't be sure. Also, the whole car would shake as the engine would work really rough untill normal working temperature is reached. Then, problems usually stop, except for that rattling noise (tak-tak-tak-tak...goes faster/louder as I rev the engine up, and vice versa). If I'd start driving immediately after firing it up, it would jerk forward every couple of meters, on low revs. As if clutch would slip and then grasp tightly...I was told that might be due to injectors.
Also, it smoked like a wildfire.
I went to my mechanic, he said that VE pump "moved" somehow, and therefore ignition was off...I left the car overnight there, and in the morning he unscrewed it a bit, I started the engine and he tilted the pump left-right until smoking and shaking completely stopped. Then he tightened screws and I drove off. Everything worked like a charm again for some 7-10 days (except the rattling was still there) but then it all started coming back.
Now it takes longer to warm up, it shakes really roughly while cold, smokes EVEN MORE (if possible...makes smoke granade look like a joke) untill warm (then there is no more visible smoke, as if everything is fine) sounds a bit different all the time, I think I feel slight lack of power, but when I floor it, it does quite a nice burnout, no torque loss there.

Worth mentioning is that at one moment it lacked 2 liters of oil out of the blue...I filled it up straight away, and it hasn't used a drop of oil since.
It doesn't lose water and there is no oil in water expansion container, no blue smoke as well, so I would rule out piston rings, blown head gasket or cracked head. I guess worth mentioning is that it never overheated, actually, the temperature never went up more than half the scale (which is normal working temperature).


So...my lucky guess would be something related to Bosch VE pump or injectors...but I have no specific clue.

Anyone?

Thanks a lot in advance and sorry for such a long post.

[ngoma]

Was the IP rebuilt from from the ground up also? What is its history?

Can you identify where the rattle is coming from?

What is the ambient temperature in your area?

How long does it take for the car to reach operating temp.?

What kind of cold start mechanism does your car have? The ones I am familiar with (USA) have a thermostatic actuator as part of the cooling system that advances timing and opens the throttle more, when the engine is cold, to aid starting.

[Kraftwerk]

IP and Injectors were taken to a specialist Bosch VE-pump shop and thoroughly examined while the rest of the engine was being rebuild, and the shop owner (working with those a lifetime) found them all to be in great shape.
He did the timing matching when the pump went back on the assembled engine, and everything really worked fine untill recently, as I said, for over 15.000 miles it always started, never smoked, etc.

Rattling...no, not really. I've tried, and it sounded like something in front part of the engine compartment, that's the most specific I managed to get. Sometimes it seems to me that the exhaust gasket is leaquing, but it's also just 15k miles from brand new, so I don't see a way that could happen. Whatsoever, it is related to some moving part since it fluctuates in sync with the engine's revolutions.

Ambient temperature...it's rainy these days and mostly around 20'C, but most of the time in the last few months it's been 30-something, even over 40' Celsius.
Last winter had some really harsh moments of even -20'C, but all that time everything was fine...took longer to warm up than nowdays, obviously, but never smoked or shaked as it does now.

I didn't really measure precisely...I guess if I just turned it on and left it idling, it would reach it in some 10 minutes or so, whereas when I leave it idle for a minute or two and take off, it reaches it in about a kilometer or so. Never goes beyond.

This is European TIC engine, but I believe it is the same thing, it has "slow" glow-plugs and thermostatic acutator, though I'm not sure about advanced timing and opened throttle...might have been earlier, but now everything is messed up when it's cold, it acts like timing is far off retarded and throttle too closed...

[michaelovitch]

The injection pump must be adjusted properly and not by hand or hear....
that's what you MUST to do before thinking about the rest.

you must have 155 bars popping injectors.

The tak tak is coming from your vacuum pump shaft maybe.


what do you mean by "it lacked 2 liters of oil out of the blue" ?

[Kraftwerk]

Vacuum pump? Didn't think of that at all, but now it suddenly makes sense.
I will try changing the pump, I think it might be due anyways.

Well, I guess the pump is off to the shop again...


Thing with the oil...I mean: one day it had maximum level of oil, as it always does, next morning it lacked two liters.
I poured two liters and it didn't burn any oil since.

[Kraftwerk]

Ok, here is the thing now:

I have had it set up once again and everything was fine for a day. Started right up without any shaking or smoke, but second day it was already shaking and smoking for about five seconds, then went to normal again.
Third day, a bit more smoke...
Today it lasted for about 20 seconds, then went to normal. I guess it just builds up and I can expect ever worse state tomorrow...
Anyway, yesterday I found out that the hard line going from the pump to the first cylinder is probably cracked at the place where intercooler hose is crossing it on it's way to the intake manifold...kind of hard to spot, found it out by chance, after I opened the hood with the engine still running after a bit "harder" driving...fuel was spraying quite a bit from the place.
I got new set of those fuel lines and am about to change it...
I was just thinking, is it possible that that is the cause of all the mess? Losing fuel like that could cause engine to misbehave as it is, in my opinion.
Even, it would be possible that fuel spraying and not going into cylinder in quantity it should is the cause of rattling I mentioned before?

Anyway, I will change the line and have it set up again and see how it goes.

Any helpfull thoughts would be appreciated...

Regards.

[MoeTell]

What type of chilly begin procedure does your car have? The ones I am acquainted with (USA) have a thermostatic actuator as aspect of the air conditioning that developments moment and reveals the accelerator more, when the motor is chilly, to aid beginning.
cars rent surfers paradise

[Kraftwerk]

Yes, it has a thermostatic acutator.

However, I have since solved the issue.

It turned out that it was caused by multiple things going wrong in the same time, and, together with me insisting on driving it almost daily it lead to a complete destruction of the top part of the engine.
An expensive lesson, especially considering that I rebuilt the engine ground-up a little over a year ago and put less than 20k kilometers on it.
Though I didn't pay enough attention to the head, as it turned out a couple of weeks ago.

To my understanding, this is what happened:
Engine was constantly "running" out of phase because cones on the belt-sprocket on the front of the cam was pretty much done. Furthermore, main crankshaft pulley's central wheel was ruined, along with the sprocket (probably wasn't tightened enough at some pont) so it had some play...enough to ruin the cam's sprocket enough to let it completely slip out of phase, as if the belt broke.
The end-result was pistons catching up with the valves and destroying them.
So I took the head apart, expecting broken pistons or con-rods, but ot was all fine.
Though...cam broke in half, all 12 valves were scrap, along with valve-guides and adjustment plates (as my head doesn't have hyrdaulic lifters).
Basically, every removable part in the head was replaced with new (except for cam-bearings, of course, and the cam alone, which I had to source used), head was machined and placed back on the engine with new Victor Reinz metal head-gasket, new intake and exhaust gaskets, cam "semmerings" (o-rings?) and cam sprockets.
Also, new cam-pulley assembly, new VE pump O-rings and setting it up correctly, injectoors check (they turned out to be just fine, but I plan to replace them some time soon as a mean of precaution).
I also took the opportunity to flush oil and coolant, clean the radiator and engine bay in general.

This lesson in D24TIC maintenence did cost me arount 650$, (converted to $), but I'd like to consider it a well spent money, since it is now running smoother then ever with significantly more power.