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Trouble Starting Car with the issue still undiagnosed

Trouble Starting Car with the issue still undiagnosed

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PatKing00

Original Poster:

22 posts

2 months

Tuesday 8th August
quotequote all
Hello everyone, this is my first post on PistonHeads which my father suggested to me as a reliable site of enthusiasts one of which he is!

Here is my dilemma and if anyone can help point me in some sort of direction as to the potential issue I would be greatly appreciative!

I have an Audi A4 S-Line 1.9 TDI (2005). I have sent thousands on this car as I'm a fixer not a scrapper. The problem appears to be a simple one, the car intermittently doesn't start first time and can crank for up to 20 seconds before firing up.

It isn't just on a cold start, it can happen if I leave the car for half an hour after driving it for a while. The issue is totally random.

It is regularly serviced but when the head gasket went 2 years ago I had that done along with the cylinder head, cambelt & pullies, water pump, thermostat and turbo. The glow plugs and battery are also new. NOTE: ever since the head gasket and other work was done the car hasn't fired up as smoothly as it did before but pretty much straight away.

I have taken it to my local garage who did diagnostics and could only find one of the glow plugs was dead so this was replaced and is working fine. The mechanic seemed at a loss as to what it could be so I took it to Audi to diagnose assuming they would have gadgets main dealers can only have (expensive mistake, £350 to tell me they don't know and that I should just start changing parts of the engine until the issue is found, which is so uneconomical)

Both garages ran diagnostics but could not find a fault and I have also run my own ODB just to check but nothing shows up. Audi did find that 1 of the blanking plugs by the camshaft was missing and one was loose but thye didn't seem to think this was the route of the problem just something which needs doing. Here is a link to the "AUDI CAM" video where you will be able to see what I am talking about (FYI they wanted £1k to do the work suggested in the video):

https://www.youtube.com/watch?v=xjXh4ZembfU

There are no fluid leaks and once the car is running it runs okay, the engine might might miss a beat when idling every 20 seconds or so. I have used easystart on it once and that helped start the engine so not sure if that rules anything out.

I think that covers everything. So if you have any advise on what the best next step is please get back to me. Any suggestions as to what it might be, surely there can't be many more things under the bonnet to replace!

Thanks in advance

Kind Regards Patrick








DuraAce

2,241 posts

82 months

Tuesday 8th August
quotequote all
Lift pump?

Video didn't work for me.

NDA

13,145 posts

147 months

Tuesday 8th August
quotequote all
Fuel pump?

Could be any number of things, but I'd be checking that first.

PatKing00

Original Poster:

22 posts

2 months

Tuesday 8th August
quotequote all
Thanks for the swift replies. The video should be working now (if was set to private not public).

Surely one of the garages would have picked that up!

PatKing00

Original Poster:

22 posts

2 months

Tuesday 8th August
quotequote all
The lights buzzer and internal light work as they should when the door is opened. I will try the next few journeys and leave a gap between turning the keys and ignition. Would that point towards the fuel filter then?

I will also check the lift pump. Is there a certain way to test that?

Thanks so much for the help
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cuprabob

4,568 posts

136 months

Tuesday 8th August
quotequote all
You're probably leaving a gap anyway while you're waiting for the glow plug light to go out
Just try a little and see if it helps to allow the pump to prime and get the fuel pressure up.

Another possibility the the Engine Coolant Temp sensor. That doesn't always show a fault but can cause dodgy starting.

stevieturbo

12,647 posts

169 months

Tuesday 8th August
quotequote all
Crank and cam triggers.....good chance when they put it back together after the head gasket, they did not align everything correctly

I think VCDS can give indications as to whether cam timing is correct or not and may also help check the triggers.

Generic OBD wont do squat.

PatKing00

Original Poster:

22 posts

2 months

Thursday 10th August
quotequote all
Hi, I meant to say that the garages have both run VCDS tests and nothing has shown up (I ran an ODB check), hence I am dubious about the camshaft/timing (hoping and praying it's more simple)

I will clear out the mass sensor & throttle and check the fuel pressure.

Does anyone know where abouts the fuel pressure check valve is situated on this model of Audi (1.9 TDI 2005 B7), that way I would know if the lift pump or fuel pump are at fault right? Then I'll change the filter either way and hopefully on eof these will be the issue.

I will report back in a few days.

Thanks for all the help and knowledge so far.

Kind Regards Patrick

PatKing00

Original Poster:

22 posts

2 months

Wednesday 16th August
quotequote all
So after testing the fuel pump resistance it is kicking out a reading of 10:

According to this video it should be between 1 and 3:

https://www.youtube.com/watch?v=qV78c3TjzQA

So I just wanted to clarify that the issue is definitely the fuel pump if this reading is at 10? I'd imaging that it can only be the fuel pump but might this reading be showing up because of the lift pump and through to the fuel pump or is this simply not possible?

When taking up the fuel pump cover it was clear to see that Audi had not tested this as it was full of dust and the cover had to be prised open. Charlatans!

Anyway I am just looking for any further issues which it might be before forking out for a new fuel pump

Kind Regards Patrick


cptsideways

12,305 posts

174 months

Wednesday 16th August
quotequote all
Open the door & turn the ignition on, can you hear the fuel in the tank priming for a few seconds on each turn of the key? My bet is you can't hear it or only sometimes. Should do it every time.

99% its the lift pump in the tank & fit a new fuel filter while at it.

PatKing00

Original Poster:

22 posts

2 months

Wednesday 16th August
quotequote all
Hi, I have just tested it and it makes a noise every time (I did it at least 30 times) Does that mean that the lift pump is okay but the fuel pump will need replacing then?

Kind Regards Patrick

E-bmw

2,842 posts

74 months

Wednesday 16th August
quotequote all
Does the pump stop again after starting when you turn it on?

If so, then it is "getting up to pressure correctly" so should be OK, if it were to run & run then it isn't delivering enough fuel to pressurise the fuel system correctly.

As yours is not a Passat, do you know the pump is the same?

If not the test may be irrelevant, is his a petrol or diesel? He doesn't say unless I missed it.

PatKing00

Original Poster:

22 posts

2 months

Wednesday 16th August
quotequote all
Hi, I believe that model of passat and my audi A4 essentially have the same fuel pump systems and engines.

I have run into a slight issue with testing further as the car now simply not start after a little spray of easystart (only the 3rd time the car has had some)

Here is a video to illustrate:

https://www.youtube.com/watch?v=D5VCGut6rIc&fe...

I think i'm going to go ahead and change the fuel pump and filter however now it won't start and there will be easystart in the engine is there anything I need to do before or after installing the fuel pump and filter so the car starts? Or if the issue is the fuel pump will it simply work as it should and flush the easystart through? I'm thinking the engine might need to be primed or something.

I am determine to sort this car out!

Thanks for all your help so far

Kind Regards Patrick

E-bmw

2,842 posts

74 months

Wednesday 16th August
quotequote all
Your battery is flatter than a flat thing!

GreenV8S

24,745 posts

206 months

Wednesday 16th August
quotequote all
PatKing00 said:
I am determine to sort this car out!
If it isn't immediately and blindingly obvious to you that the car has a flat battery, you might be better off finding somebody to sort it for you.

PatKing00

Original Poster:

22 posts

2 months

Wednesday 16th August
quotequote all
I have tested the battery on a voltmeter and it is just under 12v. A flat battery was my first thought.

PatKing00

Original Poster:

22 posts

2 months

Wednesday 16th August
quotequote all
I'll give it a charge as you're probably right and it'll need a bit more charge to get it going.

E-bmw

2,842 posts

74 months

Wednesday 16th August
quotequote all
Give it a full 24 hour charge rather than a quick top up.

StoatInACoat

1,060 posts

107 months

Thursday 17th August
quotequote all
I had a similar fault and as others have said, mine was the lift pump and showed no errors on the dash but it did cause funny driving characteristics as well though when it got REALLY knackered. I rolled the dice and replaced it which fixed the problem but the proper way to do it would have been to test fuel pressure which would have been expensive as I don't have the kit to do it myself.. If you're lucky you'll have separate fuel regulator on the rail which might be playing up but if you're unlucky it'll be part of the pump itself and the whole lot will need changing.

tight fart

779 posts

195 months

Friday 18th August
quotequote all
When it won't start on the key have you tried to bump start it?