Mk5 ngine developed fault, erratic revving/idleing

[didicoy]

Advice needed. My 1995 mk5 banana 2.5 turbo Di has been a really reliable engine. It's been stood for many months. Until last week, when started normally. Left to run for five minutes. I noticed it was revving a little higher than usual. Hour or so later started engine and red (engine block) warning/attention light came on and stayed on. Engine had not power. Very slow and sluggish to rev, slowly building up revs but seemed flat and powerless. I drove it up the road and it would eventually build up speed but on pulling up. The red engine block light stayed on. Having checked in engine bay. I found nothing. Later I turned key and red engine light went out at same time as alternator light did. Throttle seemed to return to normal noise and engine response. Just like it had resumed to full power. However. It appears to be revving a little sporadic when idling. Ben revving high. I've run it for 5 miles and it appears to drive normally, turbo working etc. Just before I reached my destination. I felt the power reducing and the symptoms returned. Only crawling with limited response from engine. again I let it stand for half hour and tried engine again. It did start a little sluggish,light went out but the throttle did eventually respond . Parked it up over night and when tying to start engine next day. It Completely felt powerless again. Engine would slowly rev up, (again red engineblock warning light on) but obviously quieter and not responsive on the throttle. Having stopped and started it several times on the key. It fired up quite normal again. Raved up fine, red light went off and had all the power back through the turbo. I drove it a further 5 miles, ran fine. Possibly a little trembly on the eves at if speep I'll revs, a tiny bit juddery? I Stopped to get fuel. Engine revving sporadic during idle. Like it's revving it's self a little. If red engine block service light is on, no power, revs low and quiet, slow to build up revs. If red engine light off, sounds back to normal. Revs up responsive. Turbo sounds healthy. But it has a erratic idle rev. P and down like it's searching for fuel or air? I also think it's getting hot under the bonnet, more than I would expect, almost like its over revving while Im driving it or stationary. Can anybody one please point me in a direction of diagnosis? Your time and advice greatly appreciated.

[didicoy]

Does anyone have any ideas? I know it's a bit of a ramble. But It's parked up outside on a comunial drive. I really need to make a start on diagnostic. However wild a guess your opinion is appreciated? Fuel pump? Air leak? Electrical contact problem? Please do offer your thoughts. Cheers

[vanfox]

Patience. There are well versed members who will be along shortly. It may help if you say where you are, there may be someone with the test gear in the next street.
May help to rename your topic, "Mk5 Turbo engine has fault, please help".

[CamperVanBeethoven]

Well I am no expert but ... for a diesel engine to run, there are three vital factors:
- Fuel
- Air
- Injection volume/timing

1. Fuel. When was the filter last replaced? From what you say you don't run it a lot. The filter attempts to separate out water (which condenses in the tank) and other crap. Could be the fuel filter.

2. Air. This includes the turbo, of course, since it compresses incoming air. Air filter OK? EGR, if not blanked off, clean?

3. Injection volume/timing. It is possible for the pump to go bad, or the timing belt for the valves to slip.

Now, those are all so vague as to maybe not help you, but those are the things I can think of... I am no expert either, but if I help by bumping the thread perhaps someone more expert has some better ideas ... You have I guess an EPIC pump (as you have a turbo on a later van) so the erratic idle may well be the system trying to compensate for one or more of these faults.

[didicoy]

Thank you. Air filter clean and replaced about two years ago. The vehicle was last run any distance in summer 2015. Only run 40 miles in 2016 until the other day. Same diesel in tank since summer 2015. I've not touched the fuel filter, I guess it's just a case of remove and replace this filter, no other way of servicing it or emptying it of any water contamination? Timing belt slip? Would this make the sluggish symptoms coincide with the red engine bloke light coming on and the same red light going off when engine regains full reponce and power (although) revving a little erratic on tick-over?
The vehicle is now parked up in Nottinghamshire and many miles away from me. I need to be more prepared for when I go to retrieve the vehicle. Thank you very much for your imput. It's given me some direction to start with.

[CamperVanBeethoven]

I was hoping someone more knowledgeable might chip in But if all else seems good then yes I'd suspect the fuel. It does go bad (algae grow in it and water condenses in the tank) if left long enough ...!

To be honest timing belt slip is unlikely given what you describe. It sounds like fuel blockage somewhere is most likely if the fuel has been standing that long.

[MinorMatt]

My 1st guess would be timing belt right on the limit of timing tolerance

[CamperVanBeethoven]

Ok so if Minormatt reckons it could be the timing I'd check/get that checked

[weseeyou]

erratic idle is frequently the result of a vacuum leak. if you can do a smoke test on the vacuum system it would be useful to eliminate it from the issues you have.
I'm constructing a simple smoke machine myself to test my petrol injection car out of an old paint tin a portable air compressor and a tubeless valve and a bit of pipe . Plenty of guides on youtube.

The issues you are having with your ignition warning light makes me wonder if you have a fault with your Alternator rectifier or regulator ? You can get plugin replacements on ebay very cheaply . Might be worth sticking a multimeter on the alternator and monitoring the output when it plays up.
Other than that I'd be looking at the fuel delivery, filter and pressure etc

[didicoy]

Thank you. I will set to and make a smoke machine. Having checked out YouTube they look straight forward and I've plenty of bits knocking about to make something that will work. I really appreciate all of your views and ideas. There's no substitute for lifelong experience. Every vehicle I've owned I end up learning something new about them. This is the 4th mk5 Transit I've owned in 29years but my first Turbo.

Is there a visual way to see if the timing belt has slipped or is that done via calibration after locating TDC.
Would a plug-in diagnostic code reader indicate if timing was out or timing belt had slipped?

[CamperVanBeethoven]

A diagnostic code reader might help ... but the hard part would be finding one It's not OBD-II or anything else common. Some members do have them.

viewtopic.php?f=4&t=173783&p=1476952&hilit=laser+2000#p1476952

[ricc]

dont beleive all you read on the internet about fuel going off.

ive got 4 old tractors, 1000 litre bulk red diesel tank is now nearly empty, i cant remember when it was last filled... got to be over 5 years ago.
i cant comment on new diesel with a bio componant , the bio diesel fraction is alledged to grow algae that will glog filters.

same with petrol, were told it goes off in weeks rather than years... ive never had a problem with over wintered mowers starting in the spring on last autumns petrol. last year i cleared a widows garage and found a gallon can of petrol that her husband had bought , we reckoned it had to be 3 years old maybe 5, my ride on mower used it with no problem

[Jim Archer]

Intake air leaks seldom affect a mechanical diesel - well unless large amounts of foreign matter are getting through. Amount of fuel governs a diesel not air until you have airflow measurement, EPICs are simple alpha/N systems using throttle position relative to Rpm.

As Matt suggests, first thing is a new correctly timed cambelt, then the throttle pedal wants looking at or replacing.

Jim

[MinorMatt]

The symptoms don't match the pedal in this situation...

My educated guess is cambelt timing, or the advance cam in the pump is intermittantly sticky (which means a new pump)

[MinorMatt]

Oh yes, if your not local... if you send me your ECU I can read the codes on it, if there has been lots of pissing about and codes generated then it may mean nothing, but I can clear it and then you can send it back again once the fault has occured again?