Automatic Transmission issue?

[whiskychaser]

I'm not a great believer in the theory that the crap in the gearbox holds it together either :-) I can see how the mpg would be affected if you have a vacuum leak. What is the theory on the knocky noise though - bad combustion? Great result John!

[Tiger]

I suspect detonation for the knocky noises.

[e34.535i.sport]

Hi fellas - Yeah I'm pretty chuffed to be honest, massive improvement and car feels great again! The knocking noise however was there again this morning :S only very slight though in comparison, MUCH MUCH less than before... It's a puzzler. The only thing I can think of is rather embarrassing and I didn't really want to bring it into the equation but I did fill the car up with Petrol on the 2nd August (My wife's Bday!!) :O ... I know, what a muppet. I didn't run it of course and emptied the tank and refilled with Diesel before running it, at which point it ran perfect on first turn of the key. Thinking about it now though the timing is about right, yet it only happens when cold and is PERFECT after that. Detonation would be a problem with petrol in the tank though I'm assuming due to lower combustion temp??? I did flush diesel through using the fuel pump without starting the car before running it so I thought it would be all sorted? What do you think??! Could the residue from the fuel tank be enough to cause issues? Or could it have affected the fuel pump enough to cause issues on cold start??? Sorry for the questions - Just typing as ideas enter my mind!!!!! Yet why would the problem now be significantly reduced?!

Glad you questioned this Whisky - I hope I've not buggered something up and had the two problems on the go at once!!

[whiskychaser]

You will probably have read that you can damage the high pressure fuel pump with petrol. In which case you get swarf floating round the system. But you flushed your system and your problem goes away when it is warm. Is it possible it isnt actually a knock but a misfire? Maybe an injector leaking to the air or the exhaust leaking near the manifold? The noise might disappear as the metal expands with heat to seal a gap.

[Tiger]

Old diesel cars can run with like a gallon of unleaded fuel with a full tank of diesel.... like 20 gallons worth of diesel. No problem. Old timers use this technique to clean out the system.

What I would do is change the fuel filter first... maybe it is kinda clogged but unlikely... but if the fuel flow rate is affected... then that can cause the problem.

How long has it bince since that incident? Have you run the tank down or refill since then?

Check the vacuum hoses again... turbo and elsewhere. Unless you have access to a evap smoke machine... in which you hook up to your vacuum system and it will show all the leaks you have.

[e34.535i.sport]

I'm really glad you guys are with me on this, it's wrecking head!! Lots to think about there, and I ordered a fuel filter last night thinking the same thing!! It's strange because there's a massive improvement in both noise and running, but the issues that I've found still are:
1. Same noise only on initial running in the morning, just less pronounced.
2. I found today that it still is reluctant to go at times, then will spring to life (i.e as though the handbrake is released.
3. More power than before, but less than I think should be there now.

I didn't think the petrol would be an issue as it didn't get into the engine or injectors... And it's been about a month! However it did go through the fuel pump/s so Whisky, I fear you may be onto something. This may explain all three issues (made worse by turbo vacuum leak before???) - I'm pretty sure the noise is coming from the passenger side, which I think I read is the position of one of the fuel pumps?? It could have been damaged due to lack of lube when pumping the petrol out and it makes the noise when dry in the morning??? Seems to make sense. Would also explain power loss and hesitation if it wasn't operating properley. However I'll try the fuel filter first, might just be lucky you never know!!!

I'll also check out all vacuum hoses this weekend, thanks Tiger... I know there's one that leads to the EGR that needs checking, and others I probably dont even know of!

I really appreciate your thoughts guys, you've been really helpful throughout and helped me keep my sanity!!

P.S - Whisky - What is this swarf I hear about??? The only one I know is the one I use after messing with the car!!! :P

[whiskychaser]

I thought you did metalwork at school John?:-) Swarf is metal shavings. They reckon the diesel lubricates the high pressure pump and petrol takes away the lube so it runs metal on metal. It is supposed to be that bad you can see it in the tank! I agree with Tiger that you used to be able to put a bit of petrol in the tank for winter running but with these modern diesels you cant. That said, how much petrol can you have put through? A pint? I doubt that is going to kill the pump. If its not a leaky gasket I reckon a duff injector. In which case the engine will be a bit lumpy and vibrate more. IMHO if there was any real damage, it wouldnt just go away when warm would it?

[Tiger]

Bad EGR will cause knocking and lack of power. So follow the procedure and see if the EGR is bad. They are something that has to be replaced regularly.

[shogun]

a bit off topic, but I found zf repair manuals here, for the 4hp22 it is $20
ZF 4 HP-22 Repair Manual, repair manual, Cars Repair Manuals

anybody bought there, looks like it is a site from Russia?

[e34.535i.sport]

Haha, I honestly don't think I've heard that before! Then again I probably didn't listen hard enough!!! :P
Whisky, I put 10 gallons of petrol in it :O ... Unbelievable I know!! It had about a gallon of diesel in there too. It's still hurts thinking about it. I never ran it, got towed home slowly, disconnected feed pipe to filter - turned key to position 2 and primed fuel pump... Out came the petrol. Took a little while so pump damage is possible and it did make a high pitched whine when the tank was totally empty. Then I put a few litres of diesel in and flushed it through the pipes the same way to get rid of the petrol. Could I have done anything better??? When I started it up after this it ran perfectly! I don't remember having any issues at all after this but the pump may have been damaged through lack of lube yes? And when I run it in the morning it's possibly sticking or noisy, then once a bit of diesel goes through and re-lubes it it goes quiet again? Seems feasible? I also researched symptoms for a couple of hours last night and the pump under the passenger seat is a common failure and can be noisy when on it's way out. Some said that it would be sluggish at low revs/speeds then suddenly spring to life, much like what I'm experiencing. Yet I have no trouble starting? I have my fuel filter now though so will try that before work tomorrow just incase I get lucky. I certainly hope it's not injector or high pressure pump on the rail, and I doubt any petrol got anywhere near these (at least I hope not!).

I know what you mean though about it disappearing when warm, but the noise goes literally within a minute I'd say, way before the car hits temp... Still makes me think pump. I just feel as though the car isn't responding as well as it should still also, but my brain is mashed with it at the moment. It is driving smoothly though in general and gear changes are fine. I might need you to come and test drive it to see if it's in my head!!

I'll also check the EGR thanks Tiger, I've read a lot about these and encountered it when removing the swirl-flaps shortly after I got the car. DO you mean the EGR unit or a sensor that is regular maintenance?

Off to do more research now... Been at it for hours and hours, cant see to relax knowing there's a problem even though it's not a major one.

Hey Shogun, not seen those before but I'm hoping I won't need anything like that now, or ever!!! :P I was pretty scared when I thought the box was on the way out!!!!