Trouble starting - pointers appreciated

[leftfootleashed]

My V40 decided last night not to start, and I need the car tomorrow

I'll describe the symptoms and what I've tried as briefly as I can, and if anyone has any suggestions, they'd be gratefully received.

The engine turns over fine on the starter (sounded a bit sluggish, so I charged the battery for a few hours and it sounded better and has cranked it for quite a while).

It sounds as if it's about to catch but doesn't quite.

I've checked:
Spark (the two plugs without the coils, because I can't connect my ignition tester to the ones with them, but that indicates there's a spark from both coils)
Plugs (the two without the coils, visually - bit sooty but nothing major)
Fuel pump fuse - good
Continuity from fuse to plug on fuel pump unit - good
Voltage on fuel pump when cranking - matches battery voltage... ~9V expected for cranking or too low? (Battery could be charged but internal resistance is increased, so not quite capable of starting?)
Fault codes via OBD2 reader - no codes showing

Since there appears to be a spark as far as I can tell, and the starter appears to be OK, I'm beginning to suspect it's the fuel pump. (Possible related: fuel gauge stopped working at the beginning of the year. I checked the electrical connections then, and again now, all good. Since they're part of the same unit, could it be related?). With the fuel pump unplugged, there's no noticeable difference when cranking.

I would put a bit of petrol into the air intake to determine if it's fuel related, but a) I don't have any at the moment, short of siphoning, and b) I can't see an obvious way of squirting it in.

Other thoughts: injectors? crank position sensor? Seems to be a common problem, but no fault code.

(Battery background:
The car was used last week for a trip to the Hebrides so did 700 miles. It's sat since Saturday when I moved it from one side of the drive to the other to make room for a mate's van. Started fine then.

It's occasionally been slow to start over the last few months. I know the battery is coming to the end of its life and was planning to replace before next winter. Slow starting was inconsistent however (e.g. starts on the turn first thing, then needs turning over a few times after stopping for a break).)

Cheers!

[cheshired5]

You could squirt a tiny bit of petrol into the air intake, Easy Start style.

[leftfootleashed]

Where abouts exactly would you squirt it? I couldn't see any obviously way of getting it into the manifold.

Take an injector(s)/plug(s) out?

[Clan]

Originally Posted by leftfootleashed

My V40 decided last night not to start, and I need the car tomorrow

I'll describe the symptoms and what I've tried as briefly as I can, and if anyone has any suggestions, they'd be gratefully received.

The engine turns over fine on the starter (sounded a bit sluggish, so I charged the battery for a few hours and it sounded better and has cranked it for quite a while).

It sounds as if it's about to catch but doesn't quite.

I've checked:
Spark (the two plugs without the coils, because I can't connect my ignition tester to the ones with them, but that indicates there's a spark from both coils)
Plugs (the two without the coils, visually - bit sooty but nothing major)
Fuel pump fuse - good
Continuity from fuse to plug on fuel pump unit - good
Voltage on fuel pump when cranking - matches battery voltage... ~9V expected for cranking or too low? (Battery could be charged but internal resistance is increased, so not quite capable of starting?)
Fault codes via OBD2 reader - no codes showing

Since there appears to be a spark as far as I can tell, and the starter appears to be OK, I'm beginning to suspect it's the fuel pump. (Possible related: fuel gauge stopped working at the beginning of the year. I checked the electrical connections then, and again now, all good. Since they're part of the same unit, could it be related?). With the fuel pump unplugged, there's no noticeable difference when cranking.

I would put a bit of petrol into the air intake to determine if it's fuel related, but a) I don't have any at the moment, short of siphoning, and b) I can't see an obvious way of squirting it in.

Other thoughts: injectors? crank position sensor? Seems to be a common problem, but no fault code.

(Battery background:
The car was used last week for a trip to the Hebrides so did 700 miles. It's sat since Saturday when I moved it from one side of the drive to the other to make room for a mate's van. Started fine then.

It's occasionally been slow to start over the last few months. I know the battery is coming to the end of its life and was planning to replace before next winter. Slow starting was inconsistent however (e.g. starts on the turn first thing, then needs turning over a few times after stopping for a break).)

Cheers!

an ageing battery can turn an engine over ok but have no reserve to power the ignition , borrow a good battery ..

[canis]

One way would be to take the large "concertina" hose off the air filter and hold it upright as best you can, and tip a cup of petrol in. Make sure the air sensor won't get drowned by keeping it upright, as dowsing that in petrol can't be healthy. It should get it to fire at least a little.

Alternatively, you could put a bit in each cylinder through the spark plug holes. Be frugal though, as unburnt fuel is very bad for catalytic converters.

Perhaps a more elegant solution (not tried it, but worth a shot) would be to trace the vaccuum hose from the airbox. It's a tiny narrow hose at the back of the airbox. It runs to the throttle housing, there are several vaccuum hoses there, take your pick. Pull one off and attach a small hose to it, fashion something to feed petrol in that way.

I shouldn't need to warn you about the explosive nature of petrol, but please be careful.

[leftfootleashed]

I haven't ruled the battery out (partly because I'd love it if it was such an easy fix!) but I'd be a bit surprised given how easily it turns the engine over. I topped the electrolyte up first thing (I didn't think you could get non-maintenance-free batteries anymore) and put the charger on to give it a bit of a boost.

Meanwhile, I pulled the CPS to check that. Seems fine visually. Plug on firewall isn't corroded. Bit of a long shot but I've eliminated it now.

Next step will be to try and get it to fire. I still haven't got any petrol (annoyingly, my jerry can is full of diesel I use as solvent) but I have got a can of carb cleaner spray. I think first thing will be just to take the big hose off the the air filter and spray some in there, Easy Start style. Then depending on results spray a little into each cylinder through the plug holes. I reckon carb cleaner should be suitably combustible and carries less risk of soaking something in fuel.

Don't worry, I have a mate who destroyed a project car with a fuel mishap, so I'm well aware of what can go wrong.

[leftfootleashed]

Well I've got it running. I tried it having topped the battery up and charged it for a couple of hours, but no joy - though I later realised the fuel pump was still unplugged from yesterday (whoops).

I tried carb cleaner first in the intake and then in the spark plug holes and I could hear it firing on that. Then I realised the fuel pump was unplugged and plugged it back in - now starts fine.

I listened to the fuel pump with the cover off and the engine running. Wiggling the connector I could get it to make two different running tones, and if I pushed it far enough, to starve the engine a little bit. I took it out and cleaned the contacts with contact cleaner, and bend them in to try and make it a tighter connection. I can still hear a change if I wiggle it when running.

I hoped the fuel gauge might come back, indicating a definite electrical problem with the fuel pump/sender.

I think there's two possibilities:
a) the battery is getting on a bit and needed topping up and charging, and the fuel pump business is just a red herring;
b) the battery's fine and there's a dodgy connection somewhere in the fuel pump unit which I fixed by messing with it, possibly temporarily.

Might be a good idea to replace the fuel pump just to be safe. Should fix the fuel gauge too.

Thanks for all the help.

[pierremcalpine]

Does it start if you put the pedal to the floor when turning key? If so, pull your idle control valce out and soak it with brake cleaner to clean insides. Easy to try. Fixed my starting issues immediately.

[leftfootleashed]

Interesting you should say that.When I sprayed carb cleaner into the air intake as fuel, I realised I needed to open the throttle right up to pull that through, but not til I'd moved on to spraying it into the cylinders. I tried it anyway, and that might have been when it started, but I'm not sure.