Poor Cold Starting Solution

[nine-fiver]

Hi All,
Been a while since last posting, but have been watching from the wings.

Her 9-5 Linear wagon has given us huge issues in recent months. Poor cold starting issues have plagued us on a daily basis. But it seems we have it licked now.

A fresh 2011 DI has cured some of it, especially poor power in high temperatures. But not cold starting.

Crank angle sensor changed, with some effect but not reliable.
New plugs
Another fuel pump and filter
New vac lines
Cleaned throttle body and afm
Re-torqued the head (finally has stopped eating oil after all these years!)
Checked for air leaks many times
Rebuilt alternator and new battery, after being damaged for months attempting to start.

But it seems the main culprit was a slowly failing fuel pressure regulator. A quick job with a huge effect. Lots of fuel now just when it needs it and it starts first pop, without all that coughing and bucking.

Boost is back and lots of it, having none for months. Almost feels as quick as a new one. Amazing how compromised you get in close traffic with no power when you need it. Now it just needs a new driveshaft boot and front subframe bushes to stop the knocking.
But that can all wait for a bit...

The car is 14 and has done 207,000km, which down here isn't all that much. Looking forward to a time when I don't have to pop the bonnet unless I really want to...

[Audax]

But it seems the main culprit was a slowly failing fuel pressure regulator. A quick job with a huge effect. Lots of fuel now just when it needs it and it starts first pop, without all that coughing and bucking.

I very often wonder that once you get past 100k (miles) how many things like fuel injectors, FPR and fuel pump all end up slightly out of spec and how much of an effect it has. I've known a broken injector to kill engines before, no warning light at any point until the damage was done!

[nine-fiver]

Old car issues, for sure. And I'm fine with that.
It's got to the point though that almost everything has been replaced in some form or other now. What else is there left?
So her motoring future is actually looking quite solid. Maintenance is 'replace-enance'. Maybe that's just how it has to be to keep things on the road. You can't expect things to last forever like they used to. (Maybe they never did if I remember accurately).
The engine is super clean inside, being over serviced all these years under my paranoid watch. The turbo is still near perfect, which amazes me, with no end-float, no smoke, which is the main reason I think the car has still got a solid future. Cam cover off saw no sludge and an oil pump seal change saw the pump innards like new. So lots of engine confidence at this point.
Happy to clean the injectors and replace the o-rings in due course, but that's to be expected now. So yes, a new approach and a new mindset for the old girl to keep things running smoothly.
I want another 100K from it and at least another 4 years, but it will be a challenge no doubt.

[Audax]

So her motoring future is actually looking quite solid. Maintenance is 'replace-enance'. Maybe that's just how it has to be to keep things on the road. You can't expect things to last forever like they used to. (Maybe they never did if I remember accurately).

You might get an unlucky turbo failure but even a new one isn't that much money in the grand scheme of car ownership, there's the holy trinity of petrol 9-5 failures which are the usual, crank sensor, DI cassette and fuel pump. Other than that there are a few bits that might cause problems every so often (fuel pressure regulator, throttle body, air mass meter, lambda sensors) but none of those by themselves are expensive and are either cheap or worth a go second hand.

[nine-fiver]

Might have been a bit premature with the good news. It coughed on startup from cold this morning, after sitting about overnight. Didn't fire up on all cylinders and took a fair bit to run on all four. Surely it cant be another DI...?
Thought I had its measure....apparently not.

[Audax]

Might have been a bit premature with the good news. It coughed on startup from cold this morning, after sitting about overnight. Didn't fire up on all cylinders and took a fair bit to run on all four. Surely it cant be another DI...?

Interesting, I had a similar fault last week where I jumped in the car, started it (but didn't let it prime properly as I was in a hurry) and ran for a couple of seconds then went "pop" and died. I then tried turning it over and it just wouldn't fire, it'd nearly fire but then die. After trying to start it a few times it caught and has been fine ever since. I also had another failure a couple of months back when it was properly cold when I drove a mile down the road to pick up a colleague and as he got into the car it just died. I'd put this down to a faulty fuel pump (hence asking about replacement units the other day).

One other possibility for my case and yours is a faulty one way valve on the fuel line but I don't know if one is fitted or where it is.

[nine-fiver]

Audax, thinking along the same lines now myself. There is a ball bearing style return valve on the pump side outlet. I assume this is to maintain pressure in the system when everything is off? I pressed it to check, big mistake, petrol sprayed all over the place. But there was a heap of pressure, so it looks to be doing its job.
I read about this issue while digging away as one does trawling the forums. How do you know that it is leaking? And then the painful thing will be changing it if it is. The fuel line isn't friendly for this issue.
I am not entirely sure of the pump in this car now, so that is still a suspect. It isn't brand new.
The weird thing is that after fixing something, it starts perfectly for a day. Then reverts to type two days later. Now it is starting a little bit poorly on hot restart, just catching and running, with revs really low around 400rpm, just. Is this fuel-starve? Dunno.

[Audax]

Head gasket?

[nine-fiver]

Just this morning, right when I really needed to leave early for crucial work related stuff, it flatly refused to even catch. Cough, bang, nuthin'. Cranking away, nuthin'. Slammed the door, swore loudly, and stormed inside to cool off. Came out 5 mins later, cranked it belligerently, and it Just caught. Revved up and hey...back to normal. What IS this? Runs great once running, lots of power, no smoke, good traction, fabulous. Just not first thing in the morning!
Argh.
If it is a head gasket, I'm done and dusted.

[Audax]

I only say that as mine has done a similar thing and takes ever so slightly longer to crank the past few days. It also flashed a "low coolant warning" at me today but the level has only dropped by a few hundred ml over a thousand miles and I did have the water pump replaced and I know that it has a very slight leak here and there. I hope mine isn't a head gasket but it really needs some attention as it's getting into a bit of a state.

[nine-fiver]

Coolant levels are not stable. But I think it is possibly the radiator weeping at the tank seams. Having said that, there is black dust floating in the coolant in the bottle. So it isn't looking flash, is it...
But it runs well once it runs. Should do a pressure test I guess...

[Neil of Stevenage]

Coolant levels are not stable. But I think it is possibly the radiator weeping at the tank seams. Having said that, there is black dust floating in the coolant in the bottle. So it isn't looking flash, is it...
But it runs well once it runs. Should do a pressure test I guess...

Use a block tester.

[nine-fiver]

What's a block tester? Is it a chemical test?
The car went back to the workshop Friday. Expecting bad news Monday, after they poke around...

[Audax]

What's a block tester? Is it a chemical test?

It's a chemical test that checks for the presence of hydrocarbons in the coolant, if they are there then somehow exhaust gases are mixing with coolant.

[nine-fiver]

Thanks. Will get the boys to do one. I can't see it being the root cause but with this car, who knows? It's worth doing, nonetheless.