200FT Hard cold start. Pulls like a train when warm.

[TonyS9]

So you have checked alot of stuff and I can see the semblance of diagnostic procedure, probably limited by equipment, however I don't think you have determined the basics of fuel, fire or air (which one).

Brainstorming;

So if the ECU is reading the correct temp is should be directing lots of fuel to the engine, so it 'should' not be a fuel problem, however perhaps there still is a pressure problem at cold. I'd like to measure rail pressure, incase is an unusual temperature sensitive failure. FPRs are a common fault, also you need feed and flow from the in tank pump (assuming 2 pumps), when the main pump will show dead end fine, live rail pressure will direct you in the right direction.

Air is decided by the idle valve mainly, is it operating well? Pull it out and look at it when you turn the ignition on (keep plugged in). Is the throttle closed switch working?

Does opening the throttle help the starting?

Sparks, is the rev counter needle flickering during this non-starting, after TDC pickup (takes maybe 1-2s)? have you a set of spark checker lights just to eliminate? Ignition amp can have temp sensitive problems (usually hot running problems).
The rev counter trick is a great initial diagnostic checker on the ignition system. It uses back emf from the coil, so checks for ECU, Crank sensor, ignition amp and coil. Spark check lights are the final check.

[AndyV7o]

I didnt note any fuel filter replacement (if it has one)
Also, if it is head gasket, you dont always get water in the oil, this is one of those common misconceptions, the gasket can go inbetween cylinders leaking compression, it can go from cylinder(s) to water jacket, cylinder(s) to oil galleries, oil-water galleries, or any combination thereof... Have you checked to see if coolant appears grimey, and for any excess pressure build-up?
Also check for any air leaks in the induction system, an engine can run lean when hot but wont bite readily when cold. Fractured gaskets, seals, split pipes including anything linked but not direct such as servo vacuum feed. I dont know if you have easy access to inlet manifol etc, but a possible test which can work is when cold and not firing, get someone to attempt starting whilst spraying easy-start all around manifold flanges, pipes, anything induction realated which may leak, if you spray a spot where a leak is present, itll draw in the evilstart and suddenly fire-up (doesnt always work mind)

[Laird Scooby]

Originally Posted by AndyV7o

I didnt note any fuel filter replacement (if it has one)
Also, if it is head gasket, you dont always get water in the oil, this is one of those common misconceptions, the gasket can go inbetween cylinders leaking compression, it can go from cylinder(s) to water jacket, cylinder(s) to oil galleries, oil-water galleries, or any combination thereof... Have you checked to see if coolant appears grimey, and for any excess pressure build-up?
Also check for any air leaks in the induction system, an engine can run lean when hot but wont bite readily when cold. Fractured gaskets, seals, split pipes including anything linked but not direct such as servo vacuum feed. I dont know if you have easy access to inlet manifol etc, but a possible test which can work is when cold and not firing, get someone to attempt starting whilst spraying easy-start all around manifold flanges, pipes, anything induction realated which may leak, if you spray a spot where a leak is present, itll draw in the evilstart and suddenly fire-up (doesnt always work mind)

Some valid points there but if it runs well once hot, it's doubtful it's the fuel filter - especially as the filter will "relax" overnight and any potential blockages will drop off the element allowing more flow for the cold start.
Along similar lines it could be the fuel tank breather is blocked so the pump can't pump anything but again, this would cause other problems once hot as well.

Likewise with the vacuum leaks - the arbitrary enrichment for cold starting will overcome most leaks which will then show up as an irregular idle once hot - also as whistling under boost.

The head gasket is a possibility but again, if it runs well once hot, less likely to be that either. A compression check will show it up though, if done correctly.

[AndyV7o]

Indeed, but Ive learned never to take these things as a given! Its surpring at times what manifests, and its in baffling times like this that the weirdest things come to light...
Fuel filter dependent upon type could also be harbouring water for example. Just posing questions as to things not mentioned.

[Laird Scooby]

Very true - the meths should sort the water in the fuel filter if so though.

Also as you rightly say, sometimes you get a weird set of symptoms which can be a real curved ball but something i've learned while trying to help on "remote diagnostics" is you go for the very obvious, simple stuff first and work through a procedure getting to the more difficult and bizarre as you go.

Granted in some cases it takes a little longer but by and large gets there in the end. Also one thing that is common to all faults, when the fault is eventually found, all the evidence was there to start with. A lot depends on how well the OP of any fault diagnosis thread has reported all the symptoms, whether seemingly relevant or not.

For example, i knew of one where the OP (this was on another forum) kept getting a flat battery. He was asked if the charge warning light came on with the ignition before starting - yes. He never volunteered the information until much later that the light failed to go out once started!

[AndyV7o]

Yeah exactly.

[Rversteeg]

In the past I had a HG failure on my 2 ltr 360. It was easily diagnosed when starting cold and not picking up on all cylinders. Before it ran on all four again, I took out the spark plugs to find one of them wet from coolant.

[960kg]

Just read most things and some good points to check on by others but you don`t mention Fuel Pressure?

You need at least 45psi to start from cold and it has to hold no lower than around 29psi for 20 minutes in the fuel rail.

To me it seems that you are on the verge of the pressure needed to cold start as when warm ok

I would replace the Fuel Pump also the warning of a poor FPR is a difficult hot start and not a cold start and you have the opposite.

Just found the post about the fuel pressure at the pump you really should be doing it at the fuel rail?

I had the `91 model of 2.0 Wentworth very nice machine but suffered from piston slap cos of the short skirts your model may have the longer skirted ones?
I had a new engine from Taunton Volvo only £2000 fitted in 2003

Good Luck

[Laird Scooby]

Originally Posted by Danders

Last night I did some more checks - I dead-ended my main pump into a pressure gauge - it holds 9bar so I'm happy with the delivery pressure and the non-return valve.

Originally Posted by 960kg

Just read most things and some good points to check on by others but you don`t mention Fuel Pressure?

You need at least 45psi to start from cold and it has to hold no lower than around 29psi for 20 minutes in the fuel rail.

To me it seems that you are on the verge of the pressure needed to cold start as when warm ok

I would replace the Fuel Pump also the warning of a poor FPR is a difficult hot start and not a cold start and you have the opposite.

Just spotted your bit about noticing the fuel pressure being ok but he's also checked the FPR as well.

It has to be something very simple (either contaminated fuel or something equally daft) or something incredibly complicated. My line of thought is it's most likely something simple.

Just had another thought - Andy, have you checked the carbon brush inside the dizzy cap? Also what are the plug gaps set to?

[Dirty Rooster]

What about that temperature sensor in the block under the inlet manifold?
If it's telling the ECU the engine is WARM when really its COLD ...