Turning over more when warm?

[Sagwala]

As the title says have noticed today that it turns over noticeably more before firing but only when warm. This morning, second or two and she was away. But this afternoon a bit more effort.

Isn't driving or performing any differently. All still good.

Is it just me, is there a knack to starting these, ie foot to floor or not, I am used to a glow plug symbol with diesels but haven't noticed one on the dash, is that normal.

Have also read a post about fuel pressure reg, is that something I may need to check?
Little bit of advice would be welcome.

[jonsowman]

The HDis do have glow plugs but it really doesn't need them to start, this is very unlikely to be your problem. There is a glow plug light on the dash, you may see it flicker briefly on very cold winter mornings. Certainly not in this weather!

The CTS (coolant temperature sensor) would be my first bet - this is often the cause of weird temperature related problems.

[PeterN]

If you find it gets progressively more difficult to start when hot it will likely be the filter in the pressure regulator on the pump. I changed a pump on the C5 for this problem and it turned out to be the regulator.

Peter

[Sagwala]

Thanks Peter, That's what's a search on the forum seems to be pointing toward.
Is the filter easily removable and therefore cleanable, any piccies ??
Cheers,

[Welly]

Did I read you right when you suggested you floor the accelerator while starting? this is definitely not required and will mess up the starting.

I wouldn't even think about this being a problem unless it's taking noticeably long (or a few separate attempts) to fire. The fact that it starts readily first time in the morning is proving there are no fuel leaks anyway.

It wouldn't hurt to slosh-in a bottle of Forte injector cleaner and check the condition of the air filter, maybe replace the fuel filter etc.

[steve_earwig]

It's an HDi, flooring it won't make any difference as the throttle isn't actually connected to anything mechanical, it'll start how it starts and then there's a good chance you'll be revving it before the oil pressure builds up...

[Welly]

I was just thinking the ECU will be looking for certain values while cranking and if the throttle is pressed it could delay starting?

[Sagwala]

Is the filter on the F Press Reg something that can individually cleaned?

[PeterN]

I have not had success with cleaning these filters as they are made of very hard metal and the holes are microscopic but some regulators come with out a filter, on the strength of that I removed mine and its fine now. The easiest thing to do is just grind the end off, you will see what I mean when you remove it, but make sure you get all the swarf out.

The regulator is easy enough to remove, its held on the pump by two torx or allen screws and a plug, you will see the filter on the end. I got a secondhand one off ebay but unfortunately that was clogged too.

Peter

[Sagwala]

Thankyou Peter, I will take a look.

Just trying to logically understand the mechanics, how does a potential blocked filter have more of an effect when warm starting than cold

Cheers.

[PeterN]

I can't answer that I'm afraid or I wouldn't have changed the pump as I did only so subsequently find it was the filter. I can only surmise that because of the tiny holes in the filter a partial restriction becomes a greater one when whatever is that's blocking it increases in temperature, mine was blocked with shards of metal, probably from the lift pump Which I have since changed, I tried pulling them out but not only were they very tight in there but they were to small to get hold of effectively. It could also be that because the viscosity of the fuel is reduced when hot the pump doesn't produce so much pressure, which is what I thought was causing the original problem.

It wasn't until I had another fault that required a regulator and fitted the one from the pump I had removed and found that it then wouldn't start when hot. One of the several regulators I had didn't have a filter at all so I removed it from the one that wouldn't start when hot and it did.! So my fault finding was purely trial and error.

I can't guarantee that's what the problem is but that regulator/filter seems to be responsible for a whole raft of problems.

Peter

[Sagwala]

Cheers Pete, your time in responding is very much appreciated.

Am gonna have a go tomorrow anyway, will report back

Trev.