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[danzigfan]

Hi guys, my Omega developed a strange starting problem. It starts ok when cold, it starts ok when hot.
But if I turn off the engine and wait for 30 mins to maybe 2 hours, it just cranks to infinity.
But if I turn the key off and crank it again, it always starts without any problem on second try. Like nothing has happened.
Any ideas, before it lets me down?
Thanks in advance, Stan

[Nick W]

Crank sensor?
Fuel pressure regulator?
Failing fuel pump?
Vacuum pipe leak?


You are feeding it genuine GM air?

[danzigfan]

Oh yes...only the best air for her..
Oh and as I remember, it seemed strange to me, that no fuel came out of both fuel lines that go under plenum, when I disconnected them when doing cambelt job.
Pressure in fuel lines droping after a while?

[Nick W]

Oh yes...only the best air for her..
Oh and as I remember, it seemed strange to me, that no fuel came out of both fuel lines that go under plenum, when I disconnected them when doing cambelt job.
Pressure in fuel lines droping after a while?

There's your starting point: acquire a fuel pressure gauge and take readings

[danzigfan]

Well the Omega is booked on wednesday at the mechanic, it took a bit longer to start today in the morning even from cold now.
I checked for the codes and got 12 and 31, which is normal...am I missing something here?

[Doctor Gollum]

Fuel pressure isn't measured electronically, ergo no specific codes

It will be either a failing fuel pressure regulator or the pump starting to get weak.

If the first start is slow but the rest no issue then the regulator is failing... Proven by firing straight away if you cycle the ignition twice before cranking (as you might on a cold diesel), but if it repeatedly poor to start or stutters at higher rpm then the pump is on its way.

[danzigfan]

That seems logical, thanks. A I don't have pressure gauge I might as well buy a new pressure regulator.
Does anyone have part number for it?
I assume it's plenum off job, am I right?
Thanks in advance

[Doctor Gollum]

https://www.ebay.co.uk/itm/164364988451

Should give you enough info to get doing

Yes plenum off, but just to one side rather than completely removed...

[danzigfan]

Thanks

[danzigfan]

I replaced fuel pressure regulator and it still does the same thing. It seems it's loosing fuel pressure somewhere as there is no fuel loss, when I unscrew 17 and 19 mm fuel lines that go under plenum

[Doctor Gollum]

Pump it is then.

[danzigfan]

Ok, then pump will get replaced...thanks

[dave the builder]

I had a split in the pipe between the pump and tank outlet
sometimes the split would open and petrol just pumped back into the tank .
there are a couple of different pumps ,so removing the old one to get the part number and examine pipe etc might be wise 

[danzigfan]

I already had the pump out, when working on it, because there was old fuel in tank, I should have taken a number of it then. I'll check all the rubber lines tomorrow, It's not that difficult.
Thanks

[danzigfan]

Well I've found rubber outlet line on the top of the pump spinning almost freely, which could allow fuel to escape back from the pressured fuel lines.
I took omega for a drive after retightening the rubber hose and now I'll wait for an hour to see if it starts. Will report