940 LPT 2.3 problems starting in damp

[haymitch]

Yes, I heard the pumps running after you flick the starter (you can also hear them priming when you turn the ignition on).

I've also taken the petrol cap off with the engine running and I've heard what I assume is the faint noise of the intank noise running (suggested by this guide: https://www.volvoclub.org.uk/faq/Hot...enceGuide.html).

I've also removed the hose to the FPR before and immediately after the engine has been running (no presence of fuel or smell of fuel). I haven't checked the FPR hose on a hot engine 10 minutes after the engine has been turned off though (like the guide above suggests). What doesn't seem right in the video?

[Laird Scooby]

Originally Posted by haymitch

Yes, I heard the pumps running after you flick the starter (you can also hear them priming when you turn the ignition on).

I've also taken the petrol cap off with the engine running and I've heard what I assume is the faint noise of the intank noise running (suggested by this guide: https://www.volvoclub.org.uk/faq/Hot...enceGuide.html).

I've also removed the hose to the FPR before and immediately after the engine has been running (no presence of fuel or smell of fuel). I haven't checked the FPR hose on a hot engine 10 minutes after the engine has been turned off though (like the guide above suggests). What doesn't seem right in the video?

Did you also remove the small bore hose to the FPR with the engine running? When you do, you should hear a slight change in engine note and looking for any fuel coming out of the stub the hose fits on.

Not sure what isn't right at the moment, can't put my finger on it, need to jump start my brain cell.

[haymitch]

No, I haven't tried that will give that a go with the engine running

Funny you should say that you can't put your finger on it. I've had the same feeling with the car - something hasn't felt quite right since around September last year. I've had a few more ideas of things that might be relevant. I'm slightly grasping at straws but hopefully something might be useful:

I think I might have introduced some vacuum leaks when cleaning the IAC which might complicate things. I'm going to check the hoses are attached properly. They've been attached without hoses clamps (!) since I replaced them because the the clamps sent with them didn't fit (and then I forgot to replace the clamps whilst concentrating on other things). The hoses have a very tight fit even without clamps though - very hard to get on or off.

I'm also wondering about a vacuum leak at the PCV system because I had this cleaned out about 3 days before my 'original problem' with cold starting last year. just looked at my bill for this dated october last year and I was advised that the 'PCV pipes were very hard.' I think there is a hissing noise in the engine bay, but I'm not used to checking for these things so I'm not sure it's a vacuum leak.

The bad idle started about 7 months before the car began not-starting making me wonder whether this is a cumulative problem involving different components getting old over time. Whenever something is replaced it seems to cover up the problem a while before it returns. For example, the previous owner replaced the spark plugs with aftermarket versions and the car wouldn't start up - tried to find the problem for two weeks. Once he put the OEM plugs back on then the car started up (and worked fine for me for one and a half years).

Finally, I took a picture inside the throttle body whilst it was still attached to the car. It could do with a clean but doesn't look too dirty to my untrained eye (it's high up my list of things to try):

https://imgur.com/a/Hbop3V1

[Laird Scooby]

Originally Posted by haymitch

No, I haven't tried that will give that a go with the engine running

Funny you should say that you can't put your finger on it. I've had the same feeling with the car - something hasn't felt quite right since around September last year. I've had a few more ideas of things that might be relevant. I'm slightly grasping at straws but hopefully something might be useful:

I think I might have introduced some vacuum leaks when cleaning the IAC which might complicate things. I'm going to check the hoses are attached properly. They've been attached without hoses clamps (!) since I replaced them because the the clamps sent with them didn't fit (and then I forgot to replace the clamps whilst concentrating on other things). The hoses have a very tight fit even without clamps though - very hard to get on or off.

I'm also wondering about a vacuum leak at the PCV system because I had this cleaned out about 3 days before my 'original problem' with cold starting last year. just looked at my bill for this dated october last year and I was advised that the 'PCV pipes were very hard.' I think there is a hissing noise in the engine bay, but I'm not used to checking for these things so I'm not sure it's a vacuum leak.

The bad idle started about 7 months before the car began not-starting making me wonder whether this is a cumulative problem involving different components getting old over time. Whenever something is replaced it seems to cover up the problem a while before it returns. For example, the previous owner replaced the spark plugs with aftermarket versions and the car wouldn't start up - tried to find the problem for two weeks. Once he put the OEM plugs back on then the car started up (and worked fine for me for one and a half years).

Finally, I took a picture inside the throttle body whilst it was still attached to the car. It could do with a clean but doesn't look too dirty to my untrained eye (it's high up my list of things to try):

https://imgur.com/a/Hbop3V1

The throttle body doesn't look too bad to be honest but always worth a clean. Likewise the PCV system, checking for potential vacuum leaks as well as the sound is almost as if there's a vacuum leak somewhere, just not quite right on starting and sounds like something isn't quite right but can't put my finger on it. Definitely worth cleaning the PCV system again, if it hadn't been done for a long time before you did it, there's a very high chance it needed doing again a couple of months after you first did it.
You might even find a split, disconnected or perished vac hose while you do it!

[haymitch]

Checked the hose going into the FPR with the engine running and there was no fuel coming out of the stub, so it looks like the FPR is okay. I must admit, I didn't notice any change in the engine note when doing it though.

There was a strong smell of fuel in general when I started up the car though.

[Laird Scooby]

Originally Posted by haymitch

Checked the hose going into the FPR with the engine running and there was no fuel coming out of the stub, so it looks like the FPR is okay. I must admit, I didn't notice any change in the engine note when doing it though.

There was a strong smell of fuel in general when I started up the car though.

That answered what would have been my next question. The anecdotal evidence of no engine note change adds to the theory of leaking injectors.
It's the other theory that fits with the symptoms.

[haymitch]

Interesting...is there another test I could do to confirm whether the fuel injectors are leaking? Would fixing them involve changing the o rings? The smell of fuel was outside rather than inside the car if that helps.

[Laird Scooby]

Originally Posted by haymitch

Interesting...is there another test I could do to confirm whether the fuel injectors are leaking? Would fixing them involve changing the o rings? The smell of fuel was outside rather than inside the car if that helps.

It could if you wanted it to. You could try a seriously heavy duty dose of injector cleaner but that may not shift the dirt that's causing them to leak.

http://www.emeraldm3d.com/emerald-se...ditioning.html

Not far from you, they do an injector cleaning/refurbishment service for £18 per injector (£72 all in) including new "O" rings.

[haymitch]

Hmm...okay, sounds like I need to think about that a bit. If I wanted to chance the injector cleaner route, would any brand of injector cleaner do or are there any that are particularly good?

[Laird Scooby]

Originally Posted by haymitch

Hmm...okay, sounds like I need to think about that a bit. If I wanted to chance the injector cleaner route, would any brand of injector cleaner do or are there any that are particularly good?

Good question, all the ones you can buy in the shops are much of a muchness. I did have some exceptional results with Carlube ATF-U in both my beasts, only need about an egg-cup full per tank for normal cleaning (50ml) but for heavy duty cleaning i'd say twice this amount - 100ml in a full tank.

I've mentioned this to a few other people who have also tried it with excellent results, has to be worth a go i reckon!