D5252T camshaft and crankshaft sensors.

[mangobob]

Hi,I’m looking at replacing the camshaft and crankshaft sensors.Anyone done this job and know the location of them?
Appreciate any info on this,thanks.

[Martin Cox]

Now I'm no expert on the D5252T engine and my experience is confined to having owned a car, a 1998 V70 Tdi, with this engine for 17 years and repairing the aftermath of a cambelt failure.

This meant I had to remove the cylinder head and I'm pretty certain I never found a camshaft position sensor. I don't know about the crankshaft position sensor since I didn't have to dig in that deeply.

I'd have thought that the camshaft position is probably derived from the injection pump.

Might I ask why you think the sensor(s) need to be replaced?

Please bear in mind there are others on this forum with far greater knowledge and experience of the D5252T than me and I could be completely wrong.

It might also be worth trawling the VW/Audi forums because the D5252T was sourced from Audi, The Audi AEL engine is its closest relative and transplanting the D5252T engine into VW transporters is quite a popular modification.

Martin
1998 V70 Tdi SE auto 225,000 miles

[mangobob]

Hi Martin,thanks for your reply,I had been checking for info but didn’t see it.
Anyway,reason for asking is I am having starting issues.first start up of the day and the engine struggles to fire up.It is very lumpy,even if I put my foot on the pedal to Keep it going.A lot of blue smoke belches out but once up and running runs fine.I had a cam belt tensioner failure prior to this issue.This was sorted out and luckily the engine seems ok.It started up on the second turn.The same time the new cam belt/watepump kit was fitted I also had new camshaft seals fitted as I couldn’t stand the oil leaks any longer.I had the fuel pump timing done properly.I also replaced glow plugs,maf,map,boost valve,filters air and fuel.
Vacuum test found a leak on the valve connected to air intake hose.(not sure what this does,I can find no info on it).Ive covered most issues here but was trying to find out if maybe there was a camshaft position sensor as these cause timing problems.I know there is a crankshaft shaft sensor but I’m guessing this is ok as engine RPM’s are still showing.Engine starts ok once warmed up.
The power and mpg’s are ok too.
I was thinking if there was a crankshaft position sensor it may have been disturbed when the seals were changed.Before the camshaft tensioner failure the engine would start on first turn of key.Someone suggested it maybe a thermostat as it is mainly a cold start problem but the thing is the gauge in the car works?
Any other suggestions?
Thanks
Rob

[dingov70]

Evening there Rob , I have a 2.5 tdi ( D5252t ) & as far as I can remember there is no cam sensor as the cam is not keyed to the pulley . If my aged brane is working ( & I doubt it ) you will find the crank sensor to the rear of the block near to the bellhousing .

Rubbish starting first thing , blue smoke & gutless performance is a clear indication of incorrect dynamic pump timing . You set everything using dial test indicator & then once the engine is working , you get the engine temp to 80C or hotter you use Vida/ Dice set up to adjust the timing to the required setting .

These engines are VERY sensitive to timing issues , slightly retarded & they generate blue smoke at tick over for fun

My first port of call would be to find a member with Vida near by to see how far out the injection timing is when running , even though it was done , it is not impossible that the timing is no longer accurate

[Martin Cox]

Rob,

Reading your post with the symptoms descriptions, my first thought was the same as dingov70; these are classic symptoms of the pump timing being out. However reading further you say that the pump timing was done.

As dingov70 says these engines are very sensitive to pump timing errors and even a small error will make a difference. I too would suggest getting the pump timing checked again as a first step.

Martin

[mangobob]

I’ve taken my car to have the codes read,both garages were unable to get into the ECU using Snapon equipment even though power was showing at their sockets.I seem to have an issue with the ECU ?.Without rectifying this problem I will be unable to sort out the pump timing.Engine lost power mid week,that turned out to be the MAF.I’d only just replaced this with a Hitachi part.Anyway i thought this might be causing the starting problem and have replaced it.No such luck.I have replaced the glow plugs but I need to check I have power going to them.Chap at the garage said it maybe the glow plug relay.I have found this in the right hand side fuse box and I’ve listened to this on start up but cannot here it clicking.Maybe I can replace it with a new one using a process of elimination?
Is this possible?.I know it’s said the glow plugs only operate at low temps but according to articles I’ve read they are crucial to cold starting of the Diesel engine.Cold starting is my issue because once it’s warm it starts first turn with no hesitation.
Not sure why I can’t read the ECU as In the past Snapon units have read codes,perhaps the socket has a fault?,or is there a small fuse within the ECU?
Thanks again
Rob

[Martin Cox]

As I understand it, the early V70s weren't fully OBD compliant. That's certainly the case with my 1998 Tdi which needs VOL-FCR to set the pump timing. However I believe later 1998 V70s may well be compliant but I'm not sure.

With regard to the glow plugs I can confirm from experience that they have precious little effect on starting unless it is seriously cold; well into minus figures.

My car has never had any bother starting in this country but it wasn't until I had to remove the cylinder head to sort out a bent valve after a cambelt failure that I discovered all 5 glow plugs were open circuit and had probably been like it for years. The only time it had failed to start first turn was when it got down to -11 Celcius on one occasion.

Martin

[brickman]

Sounds like a timing problem, how was the cam timing done? Once that's solid then you need to do fuel pump timing and then dynamically set it.
You say you changed maf? Must have a 1999/2000 car with a hot wire type as the older flapper box ones are long long long out of production, if you find a supply please share, i could do with one.
Maf might still be the problem, recently went through 4x maf sensor until i got one that worked (2 were genuine bosch, but reman instead of new) on another car. Went mad taking loom apart looking for breaks that weren't thre as was the maf all along.
Older msa 15.7 cars don't really work with obd despite the plug looking like one, so you'll never get any useful codes without the right machine.
15.8 cars you might get some codes but again not all of the..

[mangobob]

After a bit of digging,I’ve found the reason for my cold start problem.
On top of the fuel filter there is a non return valve.This is held in place with a plate using two 7mm bolts.The garage it last went into worked on my car and this plate had been taken off and put back on the wrong way round.I’m guessing they took the valve off for some reason?.Problem was they failed to re-seat the valve on the O-ring.This was allowing air into the fuel system causing poor running/power loss.The non return valve also turned out to be faulty as on testing you could blow through the valve on the non return side.This was allowing fuel to drain back to the tank over night and leaving air in the filter.
Perished fuel lines replaced and new valve/filter fitted and it’s sorted.
One bit of advice,when fitting the new valve you may need to use the old O-ring(mine was in good shape)
Carefully remove the O-ring from the old valve and fit to the filter housing and then gently squeeze on your new valve using some diesel for lubrication.
Make sure it’s seated down the refit the plate.This only goes on one way.
Hope this is of some help.
If you having issues with starting check your non-return valve.

[Martin Cox]

Thanks for the update. This sort of information is always helpful, Glad you got it sorted.

Martin

1998 V70 Tdi SE Auto 226,000 miles