VR6 won't start

[Neil VR6 0]

I took it all the way to Silverstone and back yesterday, a round trip of about 230 miles and it performed flawlessly. Then I get in it this morning and it won't start. :censored: It turns over very strongly so it's definitely not the battery or starter. It's an early coilpack VR for the record although it's had a new distributor arm wotsit quite recently.

 

It's always turned over quite a lot before it actually catches but I've never had it not start before.

 

Any ideas before I call out search and rescue and have it towed to a garage? :help:

[Kevin Bacon 5]

Yeah I noticed how long yours took to start when we met up and Blue water.

 

Is it like that from cold?

 

Do you have VAG-COM?

 

If you turn the ignition on, do you hear the fuel pump prime?

 

 

 

I'm warming towards a crank sensor fault at the moment. The ECU won't activate the injectors until it sees a strong crank sensor pulse, and thusly, won't start the engine.

 

There are a number of things to check, just depends how you feel about car wiring and fault finding? I hate it personally.....

 

OK, try pulling relays 109 (ECU) and 167 first (Fuel pump). Prize the lids off both and look for burning on the contact pads. 167 has a lot of load going through it and gets hot in operation. I've got numerous spares of these relays, so let me know if you need one or both.

 

Both relays can be bypassed for testing purposes by making up a small length of wire with male spades at each end. For the fuel pump relay, the spades go across the two very fat pins.

 

Actually, for the ECU, the easiest test to seeing if it's getting power is to pull the Motronic plug and stick a meter across ground and pin 23. Should be getting 12V.

Also, the pins directly under it (green and red wires) are your crank sensor wires. Put a meter across the green wire to ground, should be 5V.

 

And lastly, this will sound weird but I had the same problem recently. Engine cranks super fast (indicating a good battery) but no firing! Oddly enough, putting the battery on charge for a few hours cured it. Motronic is VERY fussy with power supply and it needs a lot of juice to start properly. I was seeing a 1v difference at the ECU compared to the battery.

 

As I say, just depends how keen you are to do these checks or get the AA man to do it :D

[Neil VR6 0]

Thanks very much for the thorough reply Kev.

 

The trouble is that we move house in 2 weeks and the last thing I've got time for is diagnosing and curing car problems :(

 

It's always started like that from cold or hot - makes no odds.

 

I don't hear the fuel pump prime either but having said that I never have done and I've listened for it before.

 

I don't have VAGCOM but I think I'll try the relay job as that's easy to diagnose and easy to rectify - thanks for the spares offer :)

 

If it's more involved than that I'll tow it to the local garage I think - it's only a mile down the road

[Jim Bowen 1]

run out of petrol?

 

:lol: had to ask

[Kevin Bacon 5]

Ah OK, maybe OBD1 is like OBD2 in that it won't trigger the fuel pump relay until it sees a crank signal. It's a saftey mechanism for when you crash. The loss of crank signal (engine stalled) turns everything off......fuel pump, injectors and coils.

 

I'm sure when mine was OBD1 I could hear the pump whir for 5 seconds when turning the ign on, then it went silent?

 

Anyway, as an experiment try charging the battery overnight as that will point to a voltage drop issue......which won't be too pleasant to trace.

 

I reckon it's either your crank sensor or fuel pump though..... as a hunch :D

[Neil VR6 0]

run out of petrol?

 

:lol: had to ask

 

No I bl00dy didn't run out of petrol you cheeky get :lol:

 

I thought fuel pump instantly - purely a hunch too. I've got an A4 file full of receipts from when the car was new and it's still on the original fuel pump AFAIK so 15 years and 125,000m aint bad if it's that!

[Neil VR6 0]

Recovery man turned up: Car too low

 

Recovery man #2 turns up, :censored: ing car starts. Then my darling fiance

[Kevin Bacon 5]

Defo a dying crank sensor or fuel pump!

 

Neither are cheap unfortunately.

[Neil VR6 0]

Defo a dying crank sensor or fuel pump!

 

Neither are cheap unfortunately.

 

No surprise there then :brickwall: :sad:

 

I'll just keep driving it and hope for the best for the moment!

[mattkh 0]

Hi

You should hear the fuel pump priming .

My money is on the ignition switch.

[Critical_Mass 10]

Hi

You should hear the fuel pump priming .

My money is on the ignition switch.

 

There's been alot of ignition switch issues lately., maybe the warmer weather ??

[Neil VR6 0]

It finally died on Saturday for good :(

 

Getting towed today to a local garage

[Jim 2]

Replaced the fuel pump relay yet mate? Might be a cheaper fix than a whole new fuel pump and i've seen the exact same behaviour on a VR with an old / dying fuel pump relay. Car wouldn't start after lots of cranking - removed the relay, cleaned contacts and put it back and it started and ran fine.

[Kevin Bacon 5]

Mr Biege went through this with his Missus's Golf and I think a replacement crank sensor cured it.

 

The pump relay (167) is worth a punt though. It has a lot of load running through it as it's the main safety relay (cuts fuel pump, injector and MAF sensor power when the crank signal is lost, i.e. when crashing and stalling!).

 

Ignition switch should be OK if it's been replaced with a VW one in recent years. New GSF ones are worse than a 10 year old factory one!!

[CorradoVR6-Turbo 0]

im having this with mine,but it always starts,but when hot crancks for around 5sec then starts,only when hot,ive got a spare crank sensor i think i will fit to find out...

[Kevin Bacon 5]

It's also worth checking all engine earths and the power supply wires from the alternator > starter solenoid > battery. Not forgetting the big earth strap on the gearbox.

I was seeing a 2V voltage drop at the ECU because of this and it caused no end of grief. It will also mean power to the cam's hall sensor will be very low during cranking, which if Motronic starts in sequential mode, will also cause very long crank times....

[Neil VR6 0]

Thanks again all. It got trailered to the local garage last night. They tried it this morning and lo and behold it fired first time! :brickwall:

 

They're going to run VAGCOM on it and replace those relays which a couple of you mentioned for a start. I might get them to replace the CPS as well as they're not hugely expensive.

 

I'll check the earths when I get the car home. Unfortunately I'm very time-poor at the moment as I moved house last Monday!

 

Thanks again :salute:

[Neil VR6 0]

All sorted now - the diagnostics showed a faulty Hall sensor as a lot of you suspected :) She's running sweet now

[AB 0]

where is this sensor located, is it the one up by the coil pack?? thanks

[Neil VR6 0]

I think it plugs in underneath the dizzy and is mounted lower down.

[Toad 0]

There's 2 hall senders Bood,

 

The crank sensor mounted below the oil cooler, and the cam position sensor, which is in the dizzy (I think, could be wrong though) or in the endplate next to the coil pack on later cars

[Neil VR6 0]

OK not funny. Car won't start again. Same as before - engine turns fine but won't start.

 

There's a crate of beer and a big hug for anyone who wants to come round and fix it.

[Critical_Mass 10]

im going to say the good ol' ignition switch.

[Neil VR6 0]

Will it still turn over even if the ignition switch is broken?

 

There is a slight pause between twisting the key and the engine turning though. If you turn the engine over for quite a while there is sometimes a painful buzzing sound too. Would these be symptoms of a dodgy ignition switch?

[Critical_Mass 10]

Yes the engine will still turn over. When mine was on its way out it also developed a pause. Though im not sure about the buzzing, can you tell where its coming from?