Wont start. Fuel pump/relay

T

Tmmo

New Member
Hi there folks. My a2 came to a sudden stop the other week. Battery and all sounded strong but the engine just wouldn’t start back up again. Mechanic diagnosed a bad fuel pump. Replaced that but it still won’t start up. Was reading about the fuel pump relay at times being the secret culprit. Any advice on what to do is greatly appreciated. Having a garage go through a stream of unnecessary fixes over the next month would be great to avoid ; )

Ps..there is a small wire that is plugged in to the front of the engine. If one looks down from above , it’s a bit more to the right side of the block under the spark plugs a bit. Small Wire into a thin flat end. I ask because this seemed loose when I initially looked at the engine but I couldn’t find out what exactly it was.

Many thanks!
 
Oil Pressure switch? From the way you've worded the above that is a small sensor towards the right hand end of the engine front side as you look at it with the bonnet removed.

circled in the first image in this thread :

 
A2 would not start this morning. Called the RAC out. Man just thumped the Fuel Pump with a Rubber Hammer. Is this a common fault ? Does it mean a New Pump is needed ? Can I fit one myself ?

Steve U
 
I had the same problem. Engine cut out twice at traffic lights and would not start. Changed the fuel filter, some of the hoses on the pump annd filter as well as the camshaft position sensor as apparently this can cause this. Been OK since.

Was it the fuel pump under the back seat?

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Tmmo said:
Hi there folks. My a2 came to a sudden stop the other week. Battery and all sounded strong but the engine just wouldn’t start back up again. Mechanic diagnosed a bad fuel pump. Replaced that but it still won’t start up. Was reading about the fuel pump relay at times being the secret culprit. Any advice on what to do is greatly appreciated. Having a garage go through a stream of unnecessary fixes over the next month would be great to avoid ; )

Ps..there is a small wire that is plugged in to the front of the engine. If one looks down from above , it’s a bit more to the right side of the block under the spark plugs a bit. Small Wire into a thin flat end. I ask because this seemed loose when I initially looked at the engine but I couldn’t find out what exactly it was.

Many thanks!
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Hi, my A2 suffered from the same fault… broke down and would’t restart. AA thought faulty fuel pump and towed the car to an AA approved repairer. They said fuel pump was fine more likely to be the relay but couldn’t find a replacement part and wouldn’t fit a second hand part. Had the car brought to my local garage who started the car straight away. They ran it for a week in the hope it would break down but it didn’t. They suspected the fuel relay had become excessively hot (as the car broke down in temperatures of 27 degrees Celsius. Only relay I could find for that particular year and model was a second hand part from Spain and it cost me £180!
Car’s running fine still. I hope that helps you.
 
Having this issue this morning with 75 1.4 TDI. Been driving and running OK, cut a long sytory short was meant to get MOT done yesterday, MOT station had issue with ramp so couldnt complete. anyway aborted MOT and got car home parked up , went to restart and cranks but wont start. Checked earthing as have had issues in past, buit when this was issue never had any crank so have dismissed this. Next Battery, Its probably 9mths old so new, Checked v 13.3 so assumed strong indicator also green , nothing on a diagnostic scan that wasnt there before.... door locks... so at a loss? engine just wouldn’t start. Called AA , great guy, arrive quickly! Diagnosed and confirmed bad fuel pump. AA checked by firing Easy Start spray into the air intake and it did fire up , and run for a second or so, > fuel related issue .... we tried both keys, confirmed power to fuel pump under rear seat, said relay was then good as wouldnt get power there also . tried a few thumps to awaken the fuel pump and he then confirmed it was the fuel pump. Now reading this thread just want to get other opinions if this is likely issue before blindly replacing pump. or are there any other likely culprits, easy to check first? Is changing the in tank fuel pump simple enough to do if I can locate one? I dont want to scrap, but quotes ive got in last hour for just aftermarket new pump fitted wouldnt be worthwhile and I need to get MOT done this weekend. Car is currently not in a good place on my drive , blocking all the family cars so not very popular at moment :) cant even move it as my drive is on an incline and yellow lines on the road outside. the wardens will be round quicker than I can blink
 
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Certainly sounds fuel related. If it's been parked outside and idle then mice might have nibbled a fuel line. This would let air in the system and it won't start. Easy and free to check the fuel lines for rodent damage.
 
The reason I would steer away from an in tank fuel pump problem is that all my tdi90's don't have one. I think they share the same tandem pump with the 75. Could be a leak in the tandem pump seal.

Whilst a scan is always a good start, TDI fuel issues (normally air in) rarely throw a code.
 
TAABVW said:
The reason I would steer away from an in tank fuel pump problem is that all my tdi90's don't have one. I think they share the same tandem pump with the 75. Could be a leak in the tandem pump seal.

Whilst a scan is always a good start, TDI fuel issues (normally air in) rarely throw a code.
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In which case, a scan with no DTCs would, (probably), confirm that, and should there be a DTC, that would help too.
Not sure about electric pumps in diesels, but only BAD, AUA and BBY have fuel pump relays, which could be a clue.
Mac.
 
tnpali01 said:
Reading this thread Im now not sure if the diagnosis from the AA is correct about the in tank pump? https://www.a2oc.net/community/inde...the-fuel-pump-electrical-or-mechanical.30523/ . Is there an intank pump?
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I've encountered this with the AA once - they confused the 1.4tdi with the 1.9tdi in lots of VAG vehicles which I think does have an in-tank pump?

Unless a very early 1.4tdi it is just the mechanical fuel / vacuum pump on the end of the engine that pulls the fuel up, and if this fails, the fuel level backs off as air is drawn in and it takes progressively longer cranking to get it to fire if at all.
 
Robin_Cox said:
I've encountered this with the AA once - they confused the 1.4tdi with the 1.9tdi in lots of VAG vehicles which I think does have an in-tank pump?

Unless a very early 1.4tdi it is just the mechanical fuel / vacuum pump on the end of the engine that pulls the fuel up, and if this fails, the fuel level backs off as air is drawn in and it takes progressively longer cranking to get it to fire if at all.
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Is there a simple, (ish), way to do a check, (not a fix), without spending to much money, Robin?
Mac.
 
PlasticMac said:
Is there a simple, (ish), way to do a check, (not a fix), without spending to much money, Robin?
Mac.
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I've forgotten who it was who had some really useful advice - a similar discussion has come up here recently in another thread involving a piece of clear tubing and looking for bubbles. Also some discussion of non-return valves and so on.
@audifan perhaps ?
 
Recent thread shows could be ock fuel.sender in tank. Remove it and clean it all.put, really easy, apparently! Black globs of snot everywhere on it and inside the unit.
 
CrispyEdd said:
Recent thread shows could be ock fuel.sender in tank. Remove it and clean it all.put, really easy, apparently! Black globs of snot everywhere on it and inside the unit.
Click to expand...
Ed's comment is especially relavant, if the fuel level is low. The level sender sits in a "swill pot" a reservoir around the fuel draw off, that maintains a reserve of fuel when cornering with a low tank. That reservoir is topped up via a filter, which, if blocked, won't allow fuel in. If the fuel level is higher, no problem.
So, if low, put some fuel in. If not, I'd ignore my rambling.
Mac.
 
Thanks all for all the replies , I have had one crazy day with the car and goings on around my house , On top of not being able to move the A2 , a bus decided to break down across my driveway, so when I returned in my other A2 with new fuel and filter I had no parking. nearest off street parking to me is over 1/2 mile a way. Dont want to bore you but Im in a residents parking zone but dont get option of parking as I have a driveway. Crazy politics of Watford ! Anyway the bus has just been sorted 9hrs without access! . I am going to start looking at this with a fresh and less frustrated pair of eyes in the morning. First stop the level sender . - The fuel level in the car was just between 1/2 and 1/4 nearer 1/2 but where i parked on my driveway is on an incline so dependingon where it picks up maybe it is this. I have spent most of the afternoon evening pushing the TDI up the driveway, its now on the level and still not starting,
 
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