Not Starting Too Well After M.o.t

[burundi]

HI, wonder if anyone can suggest what might be causing this problem?

 

Before M.O.T the Sharan (1.9tdi 90bhp Manual) was running ok but not great, little sluggish at times although hard to notice as it was a gradual deterioration. Started perfectly everytime though, ho hassles, even if the locks were frozen solid, once i'd got into it the bus would start first time every time.

 

After M.O.T, the next day after the bus has been left overnight, it is a very lumpy start, catches first time but is lumpy for about 5 or 6 seconds and then it catches and is fine. I notice performance seems better though and I'm suddenly getting better MPG to and from work???

 

The starting issue seems to be getting worse however, this morning It didn't catch first time, second time it started but was very lumpy and the oil pressure light was flashing on and off whilst it was turning over. Once it had caught it was fine again.

 

When I stopped at work I turned it off, left it for about 15 seconds and then tried to start it again and it started perfectly.

 

I have spoken to a mate who says the only thing they would have done to it on the M.O.T is to rev it quite hard for the emissions test. I normally have no need to take it 3k rpm, I expect the tester will have nearly red lined it for a bit to get it warm before taking the emissions readings.

 

any help appreciated.

TIA

Burundi.

[mumof4]

when i watched my car going through its mot, the car is started to get the engine to a certain temp for the emissions test, and yes he did rev it after that bit to see how high it would go, mine went up to 4200 revs ,.it is only for a couple of seconds though as he noted down my idle rev and the highest rev. otherwise they do nothing detrimental to your car at all.as the guy who did my car explained everything as he went along..(coz i asked) .As your oil pressure light flashed, i would check your oil.The oil pressure sender is less than a tenner as i changed mine.

 

when did it last have an oil change??

[burundi]

Cheers, the oil was last changed around november'ish and I checked it at the beginning of the month and it has barely used a drop. I think the oil light may be a red herring though, because it works fine when the engine is warmed up i'm wondering if it might be a glowplug problem? Edited March 28, 2007 by burundi

[Andrew T]

My experience of Glow plug problems is that even if just one fails, the car is an absolute B*st*rd to start.

[burundi]

Some new info now. managed to get a mechanic friend to look at it last night, he checked all the glowplugs, checked the feed to the glowplugs, checked the temp sensor was connected ok.

 

We couldn't test properly as the engine was warm so it wasn't igniting the glowplugs anyway, tested it this morning witha cold engine and the glowplugs were being ignited (sent a 12v charge) for at least 6 or 7 seconds, this indicates the temp sensor is ok, the feed to the glowplugs is ok and he is getting a good read from the actual glowplugs so we're not sure what the issue is as it doesn't seem to be related to the plugs.

 

Next step is to check for air being sucked in somewhere he says.

 

Any other ideas?

[mumof4]

turbo?maf?

[burundi]

Not sure, I would expect performance issues in general if either of those were going knackered but the performance seems quite good (for what it is). I am not ruling anything out yet though :)

[burundi]

To update further on this it looks like it is the engine temperature sensor that has failed.

 

We disconnected it and tried to start the engine and it was still rough but it started better so the ECU was compensating and this improved things somewhat.

 

We then tried a 10Kohm variable resistor on the connector (instead of the connector being plugged into the temp sensor) and we set the resistance to approx 4.5Kohm, this is the same sort of resistance that the temp sensor should be giving when the engine is cold, the engine then started very well, almost normally.

 

So time to get myself down to the dealers and pick up a new temp sensor and hopefully the bus will be back to normal \o/.

[burundi]

ok, to recap, TDI was suddenly starting badly, this went to very badly and then to running badly as well as starting badly and then to not running very well at all & not revving. Plumes of white smoke were coming out of the back when trying to start and when it was ticking over lumpily.

 

We firstly sent the fuel pump away to Fuel injection Services Ltd in Burscough in Lancashire. They found an issue with the stop solenoid which was apparently leaking, this may have been sucking air in and causing the starting problems.

 

My mechanic put the pump back on but it still wouldn't start or run properly. So we sent the entire vehicle to Burscough and they found the main crank timing out by 1 tooth so they reset the timing, reset the fuel pump timing and tuned it all up. They said they think the fuel pump was the original cause of the starting problems, we are not sure how the main timing belt got out by a tooth or why it was ok for so long after the belt was last changed and suddenly started going, perhaps the ECU was trying to hard to compensate for the pump timing or perhaps it was just coincdental and it was the pump timing that badly needed resetting and not the main crank timing.

 

Anyhow, the bus now starts perfectly and runs sweet as a nut \o/ I would recommend FIS Ltd, quick turnaround!

 

Hope this helps someone.

 

Cheers

Burundi

[Brookydave]

Sounds suspiciously like mine.

I got it off a diesel fitter in Longridge as a scrapper because it kept doing what yours is doing.

If it does it again check the timing pulley on the crankshaft. It is a type fault on one of the tdi engines - well documented on tdiclub. Took me a week to nail the problem. New crank pulley =

[burundi]

Thanks Dave, wish I had spoken to you earlier, my problem did re-occur again just 5 days later, I took it back to FIS in Burscough and they checked the bottom pulley that's connected to the crankshaft and sure enough the crank had worn away the keyway on the pulley (my bus has 180,000 miles on it so not an unexpected failure really).

 

They replaced the pulley and reset the timing again and it has been fine for the last three weeks.

 

My mate initially couldn't understand why the timing had gone out when his timing marks where still perfectly matched up, this explains it.

 

Apparently this is a common issue on higher mileage diesels of this type.

[johnswlondon]

if the battery is disconnected for any reason ,the engine will not respond properly for 5 to 10 mles until the ecu has relearned the engine characteristics(see handbook)