Fuel Leak And Lumpy Smoky Start

September 27, 2010

My 60,000 mi 2003 D4D has just come back from a DMF & clutch replacement, timing (& serpentine & alternator) belt replacement & air filter replacement with a non Toyota garage.

The engine is now "lumpy" at start up & occassionaly smokes way more than before the service for the first couple of mins running - even with a luke warm engine. It runs sweetly at anything other than low revs. It recentley had a period of leaking diesel from somewhere above the right hand rear side of the sump - leaving a visible stain on the pavement and smelling heavily of diesel at start up but not thereafter, amazingly but not very reassuringly, this seems to have cured itself after several days leaking.

Its other long term niggle has been a squealing belt that since new has never been completley eradicated by Toyota servicing, I hoped that the belt replacements would have solved this but it has actually become more pronounced.

I have been back to the garage who are pretty dismissive of the faults although the fuel leak had not manifested itself until after this return visit. I would appreciate any help with ideas of why it may be smoking and running poorly at start up , also how there could be a sporadic fuel leak. Are these problems likely to be related to the recent engine out & belt replacements? Any ideas about squealing belts would also be very welcome. With a little more background knowledge I hope to be able to get my garage to resolve my problems.

Thanks & regards.

September 27, 2010

People tend to forget that if there's a leak in a fuel pipe on the low pressure side air can get drawn into the system even when fuel doesn't leak out. One of the most common symtoms of this on a diesel engine is lumpy poor starting or no starting at all and possibly smoke at low rpm. I suggest you have the fuel lines and their connectors checked out - if left unrepaired the engine could well stop altogether. It's possible a fuel line has been damaged or incorrectly reconnected during recent work.

Squealing belts are due to either faulty belts or their pulleys are faulty. Possibly even a faulty alternator. Don't be tempted to use any so-called anti-squeal sprays - they only hide the problem not cure it.:)

September 27, 2010

Don't forget the weather is turning colder but if your certain it is worse than before and it is OK when hot then should home in on the fuel system. Before you start it in a morning just pump that black plunger on top of the filter. It should be stiff after the first or second pump. If not it is drawing air or the fuel is running back. It could be associated with the fuel leak and certainly that needs to be investigated. It shouldn't be too hard to find especially for the garage if you are not mechanically minded.

Those belts are more of a nuisance than a problem. When it is idling just pour some warm water over them and see if it goes quiet for a few moments. If it does you might be better to forget about it as you could spend quite a lot6 of time trying to sort it. I have found that "Gates" belts are amongst the best probably along with Toyota ones but it will cost you another wedge of money to revisit those now. Better to sort the fuel issue.

September 29, 2010

Thanks James & Anchorman, your advice is greatly appreciated.

I actually supplied a Gates alternator & a/c belt but the garage provided the other belt - probably an aftermarket belt. The squealing noise was always there from new (i.e. with Toyota belts) and Toyota servicing occasionaly quietened it down but never eradicated it. I had hoped that it might have ceased with new belts and pulley. Is this fairly common on D4D 2.0 engines - I have never heard it on any others as they drive past ?

Prior to the recent work, the engine only ever smoked for a short period if I accelerated flat out to give it a clear out. It now smokes occassionaly on start up from cold or even if the engine is luke warm, the real clue is the lumpy running at low revs that was not there before.

I just tried the plunger on the fuel filter and it took around 3 to 4 pumps before becoming very firm. Is there any particular place that the low pressure system is liable to be damaged following engine out. Looking from beneath, the leak seems to come from above the right hand side of the sump but it is such a tight squeeze in the engine bay that its hard to see more than that. I would dearly love to find a loose connection & avoid a return trip to the garage but steel myself to having to go back again !

Following your advice Anchorman, I fitted a Valeo DMF and have found the car to be transformed. It pulls smoothly (apart from the lumpy fuelling !) from low revs and does not vibrate at higher revs. I had not realised just how uncomfortable it had become to drive with the worn origional DMF. I looked at the old DMF and whilst the spring loaded parts were locked solid, the friction surface appeared perfect. Why is it not possible to strip down and replace the springs of old DM flywheels or at least factory recondition them ?

Regards, Sean

September 29, 2010

The belts do creak often on RAVs. I guess it relies on every pulley being perfectly aligned or the edges of those "Poly - V" belts will grumble out loud depending on how far out and how close together they are. You can hear them creak even when the engine rocks back after switching it off only becoming silent when the engine is completely motionless. TBH, if you have all new belts I wouldn't worry too much about that unless you have a lot of time and patience on your hands - you've seen how much room there is to play down there!

Now with regard to the fuel issue. If you pump the plunger and it goes stiff does it cure the lumpy idle when cold? If not, look at the fast idle switch on the dash and see if a small adjustment make things better = there is a reason for it being there.

As far as the DMF goes, making it serviceable wouldn't really help. It is how much digging you have to do to get at it. The radial springs are very well enclosed within the flywheel mainly to contain them as the loading is extremely high under certain conditions and you don't want them popping out. It should be good for another good tour of duty now - that is the main thing!