Hi guys,

 

This is my first post on here so before anything - Hi!

 

I've been having a bit of an issue with my 53 plate Fabia 1.9 Tdi.  I've done some research online (mostly on this site) but have so far only managed to find possible fixes to the individual problems and not the two symptoms together (as they appear to be related).

 

The car starts perfectly from cold and drives fine.  If however I stop the car once warm and try to start it again the engine turns over for 5 or 6 seconds until eventually firing up.  Once it has done this I often find the car will lose power when driving.  What revs I am doing doesn't seem to make much difference here.  If I dip the clutch and reengage the problem goes away and will not reoccur again on that drive.

 

This started happening about a month ago and  after doing some research I concluded that the battery was most likely at fault.  A new battery was fitted which seemed to cure the problem - until now.  The car has also recently had a new alternator and the load wire has been replaced (turned out it didn't need the alternator after all!).

 

The car has done just shy of 120,000 miles, has been serviced regularly.  The coolant temperature sensor has been replaced within the last year due to an unrelated fault (although it was an aftermarket part fitted).

 

I'm really puzzled here so any help would be very much appreciated!

 

Thanks in advance! 

 

Sam

I used to own a 2.0tdi Audi A3 (PD engine) and there were loads of people with this problem. I would go and look at audisport.net and read some threads.

boost sensor maybe http://www.ebay.co.uk/itm/MAP-Sensor-Manifold-Air-Pressure-Sensor-Turbo-Boost-Pressure-AUDI-SKODA-/360690648881?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Model%3AFabia&hash=item53fad68731 mine lost power and sometimes come back this cured me

Thanks for the replies guys!

 

I've had a look at Audi Sport and there are many possible causes but the most likely seems to be the coolant temperature sensor.  I would have investigated this sooner if it hadn't been replaced so recently but it is possible that the sensor I fitted is faulty.  The odd thing though is that none of the other people in various threads seem to have both of these problems - the big one on Audi Sport seems to be the hot starting issue.  Maybe if I sort that the power loss will sort itself out at the same time.

 

I've also had a look into the boost sensor however I'm not sure that this is the cause of my problem but thanks for the suggestion anyway!  It's not something that I had considered and it's good to rule that out!    Most people with that particular fault seem to have the car go into limp mode hence the loss of power but mine does not - it just loses power for a few seconds then seems to be fine.

Have you checked that you don't have a partially blocked fuel like/fuel pump or injectors as I also read these were potential resolutions for the hot start issue. I did have this problem with my Audi, but I sold my half to my x-missus who had no idea as I drove everywhere

any light on on the dash?

Nope.

No lights on the dash and my 15 quid code reader's not showing up any faults. I'll investigate the fuel lines. the fuel filter has been replaced fairly regularly since I've owned the car although the the one from the previous owner was seriously gunked up! I had read that this could be a potential cause but it was replaced fairly recently. I'll read up on the injectors and see if I can work out how to check them myself!

Hi guys,

 

Sorry for the delay in getting an update to you all! 

 

I've replaced the Coolant temperature sensor and coolant.  The hot start problem is possibly slightly better but t's hard to say.  I have also had the engine lose power since fitting it. 

 

I have checked the fuel lines for obvious signs of deterioration but haven't found anything.  I've had a bit of a look about but am not entirely sure how to test the injectors so I'm not fully able to rule these out.

 

The car's still not throwing up any fault codes.

 

Further research has indicated that the crank speed sensor could also be a likely cause.  I think I'll go ahead and replace this next and fingers crossed it'll sort things out once and for all! 

 

 

Cheers

Sam

I would try a cam position sensor first, I have replaced many more cam position sensors than crank sensors, i would also get vcds plugged in and get the codes read before spending any money on parts.

The power loss could possibly be the injector wiring loom breaking down, quite common and easily enough fixed but really without a good play around with vcds on the car it could literally be anything and just swapping bits till it works is an expensive way to do it mate..

also there was a workaround with the starting map for some of the pd motors where the starter was getting a bit tired and not spinning the engine quite fast enough to hit the required start rpms when hot.

Thanks for the reply.

 

Would the VCDS not just come back with no codes seeing as the code reader I have isn't throwing any up.  I'm assuming that it could be useful for running diagnostics but I've read a lot of threads where people have been having similar problems and the garage have had no luck with the VCDS and have just started replacing the likely culprits.  Because of this I am reluctant to pay the garage another £60 unless I'm sure it will throw up a code.

 

Also, I'm wondering if the two faults are related.  I have two reasons to suspect this.  Firstly that when the battery was replaced both problems went away (although I'm struggling to find an explanation for this temporary fix other than the starter motor as you mentioned however this doesn't explain the power loss).  Second is that both problems will happen together (i.e. the car struggles to start.  Once started the car will temporarily lose power whilst driving). If the car starts first time (even when hot) the car will not lose power. 

 

It's maybe worth noting that if the car struggles to start but when it does is left idling then the revs will occasionally drop as if it's about to stall then the engine will catch itself again and go back to idle.

 

It would be interesting to hear your thoughts on this.  I am going to try and scan for codes this morning with the engine hot as I read another thread saying that because the faulty sensor (assuming the same could apply to a wiring loom) fixes itself as the engine cools the car may forget about it when cold.  I was under the assumption that the code would be stored but hey, it's worth a try! 

A quick update. I drove into work this morning and read the codes when I got there. Nothing came up so I cleared the code history, started the car and wehey! Fault code 19463. I'm at work just now so haven't checked the table that came with the reader but a quick google suggests that it is the cam sensor so I'll give that a go and update!

It is not just about stored codes tho mate, vcds will alloy you to see the live data and that can pinpoint where a fault lies, ie it will display the engine rpms when starting which will show if it is going fast enough and it will show all the sensor data. sounds like a cam sensor fault but check that you have the correct voltage at the connection to it too.

Thanks - I'll check the voltage when I install the new sensor. 

 

I've had a look online and found a pretty useful video showing how to test the voltage if anyone else is interested:  http://www.youtube.com/watch?v=yeqzE_eNlio

 

I've ordered all the parts for now so should hopefully have an update by the end of the week!

Hey, did you get anywhere with this? I'm currently seeing the same problem

I'd imagine the cam sensor has sorted this. Usually take longer to start with a dodgy cam sensor and I'd imagine it's trying to cut the power as the ecu won't be getting a clear signal for tdc.

Cam sensor fault is also thrown up when timing out defo check mechnical timing too.

The cam sensor will always show anyway if you have starting trouble because the adjuster would go out of range.

 

The coolant temp sensor is the very well known problem for this.  The other 2 things that are well known for causing the problem you're having is the fuel temp sensor and the tandem pump seals on the side of the head.  Both easily fixed.  The fuel temp sensor is easily tested by unplugging it.

I had a suspicion the starting from hot issue was the coolant temperature sensor so had ordered it already. After fitting the new coolant temperature sensor today and resetting the ECU ( disconnecting the battery for 40 mins) it appears to have cured all the issues being experienced.

The same problem reoccurred tonight, its not cured after all. Anyone have any more ideas?

Did you try unplugging the fuel temp sensor?

A stater thats a bit old will also not help, im sure a pd needs to get to 250rpm before it will inject fuel, i did a golf once with same fault as yours was a tired starter

I had the car scanned using vagcom and a list of faults initially came up.

 

Address 01: Engine

 

19463 - Camshaft Position Sensor (G40)
            P3007 - 35-10 - No Signal - Intermittent

 

Address 08: Auto HVAC

 

65535 - Internal Control Module Memory Error
            00-00 - -
01596 - Motor for Outside/Recirculated Air Flap (V154)
            30-10 - Open or Short to Plus - Intermittent

 

Address 09: Cent. Elect.

 

01117 - Generator Terminal DF Load Signal
            27-00 - Implausible Signal
01598 - Drive Battery Voltage
            07-00 - Signal too Low

 

Once cleared none of the faults re-occurred on the second scan.

 

After doing some research I inspected the alternator Load Signal Cable  and discovered my car was subject to the common failure of it being snapped at the plug.

 

I have now repaired the load signal cable and am now getting much better starting as the battery is now charging correctly.

 

Although the cutting out issue has remained, I have inspected and tested the relays on the car today using a multimeter and they all appear to be working ( although I was not able to test them by applying 12v to activate them).

 

Any further ideas ?

 

I have yet to check the fuel temperature sensor could this be a cause and is it likely to cause the car to cut out ?

The 109 relay is a common faulty part on all vag stuff.  And it'll never show a fault when it's bust either.  They're intermittent as well so really hard to test.  Better off just replacing them.

Hi guys,

 

Really sorry it's taken so long to get back with an update as due to Christmas and a load of wet weather I've only just got round to having a go today!

 

Installing the new camshaft position sensor was a doddle - except the replacements lead was too short so I've had to stick the old one back in for now!  Now I know how it's done installing the new one should only be a 15 minute job.

 

Still a bit baffled mind as after the car through up the fault code it's been faultless.  Hasn't skipped a beat in almost a month!  This is strange considering it was doing it every time the car started from hot before.  I'm still planning on replacing the sensor anyway just as a precaution.

 

It's interesting to hear about the 109 relay.  After a bit of research it appears that this could cause the engine to cut out intermittently.  If the problem reoccurs after the cam sensor has been replaced I'll look into this. 

 

I'm not sure about the Fuel Temperature Sensor - it's not a part I had looked into when troubleshooting although if testing it is as simple as disconnecting it then that could be worth a shout if the problem reoccurs.  Out of curiosity - if the sensor was unplugged what would I expect to happen?

 

Cheers,

 

Sam