Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: danzigfan on 24 March 2022, 09:13:28

Title: Starting problem 3.0 v6
Post by: danzigfan on 24 March 2022, 09:13:28: 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
Title: Re: Starting problem 3.0 v6
Post by: Nick W on 24 March 2022, 09:20:10: Crank sensor?
Fuel pressure regulator?
Failing fuel pump?
Vacuum pipe leak?

You are feeding it genuine GM air? :P
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 24 March 2022, 09:33:26: Oh yes...only the best air for her.. ;D ;D
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?
Title: Re: Starting problem 3.0 v6
Post by: Nick W on 24 March 2022, 10:10:18: Quote from: danzigfan on 24 March 2022, 09:33:26
Oh yes...only the best air for her.. ;D ;D
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 :y
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 27 March 2022, 08:09:37: 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?
Title: Re: Starting problem 3.0 v6
Post by: Doctor Gollum on 27 March 2022, 10:37:59: 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.
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 27 March 2022, 10:47:00: 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
Title: Re: Starting problem 3.0 v6
Post by: Doctor Gollum on 31 March 2022, 16:53:39: 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...
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 31 March 2022, 17:40:58: Thanks :y
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 06 April 2022, 18:47:37: 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
Title: Re: Starting problem 3.0 v6
Post by: Doctor Gollum on 06 April 2022, 18:55:36: Pump it is then.
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 06 April 2022, 18:58:07: Ok, then pump will get replaced...thanks
Title: Re: Starting problem 3.0 v6
Post by: dave the builder on 06 April 2022, 19:00:00: 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 :-\
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 06 April 2022, 19:05:03: 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
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 07 April 2022, 13:47:07: 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
Title: Re: Starting problem 3.0 v6
Post by: dave the builder on 07 April 2022, 17:49:53: that would do it
fuel is too lazy to travel all the way to the rail if there's a hole nearer :P
my in tank rubber fuel hose had started to deteriorate .
it's NLS and shaped (so not easy to replace with standard hose)
i replaced with a PROTEC CONVOLUTED NYLON IN-TANK FUEL HOSE clicky (https://www.protecfuelpumps.com/fuel-hose-and-connector/)
14503 Convoluted In-Tank Fuel Hose, 280mm Length, 8mm & 9.5mm ID
Available from Deamon-tweeks
https://www.ebay.co.uk/itm/311899165989 (https://www.ebay.co.uk/itm/311899165989)
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 07 April 2022, 18:05:04: Nice to know it can be replaced because I found cracks on both bigger hoses inside the tank
Title: Re: Starting problem 3.0 v6
Post by: dave the builder on 07 April 2022, 18:23:06: Quote from: danzigfan on 07 April 2022, 18:05:04
Nice to know it can be replaced because I found cracks on both bigger hoses inside the tank
If that's the case it might be wise to replace the delivery one (from the pump out) sooner rather than later ;)
sudden power loss can put you in a dangerous situation :-X
Title: Re: Starting problem 3.0 v6
Post by: danzigfan on 07 April 2022, 18:32:16: It's on to do list, thwnks.
Well car starts fine now, from first try