Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: The Cambelt Kid on 15 September 2008, 20:59:39
-
Hi guys,
Ive had a look for this one on the forum but cant find an exact match, so i hope someone can help me pick up my pieces and fix my motor.
The problem is running on petrol.
recently i noticed while starting that there was a slight pause in the middle of cranking, nothing much, just a brief pause and then it started. It's done this once or twice over the past few weeks. I drove the car to london on friday night and then back again, although i gave i a right old ragging while on some country roads and then even more on the M25, alfter that i took it easy.
Today i cranked her for the first time since friday and she not starting at all. Not even a cough! :(
Me thougn it was low on fuel so put 5L's in and still she wont start.
Does anyone thing the pause while cranking aver the past few weeks has got anything to do with my non-starting problem?
Any help would be great as i am really stuck now. :'(
Cheer
-
My guess would be crank sensor ... have you tried the pedal trick as yours is 2.6 ???
Brake pedal to the floor, accelerator to the floor, switch ignition ON but do NOT start engine ... if no codes EML light flashes continuosly .. if it flashes in bursts, count the EML flashes .. they are in groups of 4 .. and 10 flashes means 0
let us know what you get ... :)
-
crikey (or should i say crankey) i never knew that!
I do have a cheapo code reader and there are no codes but ill go and try this little trick. Back in a jiffy.
-
Flashes 4 times and then goes out. Nothing sfter that.
I am gob smacked, i never knew i could do that!
-
mmm don't understand that .... unless the code is 1111 ... and my listing dosn't include such a code .. :(
Confused now ..... :-/ :-/ :-/ :-/
-
Me too, i tried many time and it flashes four times and then goes out.
When i returned on friday night it only had 14 miles in the tank, i now remember driving it to B+Q on sunday morning and it then 5-7 miles or so left in the tank. I had no problems then, i just couldn't be bothered in putting any juice in.
If the tank was bone dry, would 5L's be enough to get the pots firing?
I just put 5L's in and now the pooter says 7 miles.
-
Continual flashing indicates no codes stored.....I assum the ECU light does not flash when trying to start the car.
Any of the LPG wiring look iffy i.e. around the fuel pump relay etc?
-
I have tried removing the power wires for the LPG. the injector wires still remain though, that would mean a strip down.
Which is the pump relay? Just having a look in haynes...
-
One of the top ones (purple?) in the relay box.
I would be bunging another 5 litres in as a starter to help it re-prime to.
-
Thanks Mark! I'll give the relay a prod and then try another 5L's in the morning. 10L's to get the piston party started? WOW
Thanks for your help chaps, i'll report back ASAP.
-
The replays are rick solid. No bad connections there. I found two purple ones, are they the same and can i swap them over?
Surely with the fuel rail being pressurised, i should have heard a fart at least?
how can i test if the fuel pump is running?
-
Just tried again and cranked for 10 seconds or so. The EML goes out eventually.
I'm betting on lack of fuel now, even though ive just put 5L's in the tank. I am a arse for not filling her up on time... :'(
LPG regulator is up the spout and i have a new one being delivered weds. If the LPG was working i would have started her on LPG, warmed her up and drove the station.
-
Right, dropped another 5L's in this morning, o should be about 12L's al least in the tank and still no start :'(
The only thing that can stop the injectors for sqirting is if the LPG ecu has been disconnected, which it shouldn't be.
I will ahve another look this afternoon.
Cheers
-
Can you hear the fuel pump starting when you get someone to crank the engine? If not, check fuse & relay and also suspect crank sensor, I'd say. ECU will only energise the fuel pump when it detects cranking.
If pump is running, have you got fuel pressure? Loosen the flow union from the fuel pump to rail and see if fuel escapes under pressure.
Have you tried cranking it with foot on floor for a few seconds? Just thinking if an injector has leaked and flooded it?
If there's no fuel pressure, it could be that it has sucked air due to the low fuel level but needs considerably more in the tank to prime the pump.
Try taking off the flow line to the rail and extending it with some fuel hose into a can, then crank the engine so the pump can prime with no restriction to flow (i.e. it's not pumping against the FPR so may prime easier). Make sure you get a solid stream of fuel here, then reconnect.
Then disconnect the return line from the rail, extend the union on the rail with a length of fuel hose into a can and check you have plenty of flow here.
Indicentally, if you want to run the fuel pump without cranking the engine, take a short length of cable with a spade connector on each end and short the two wider pins on the fuel pump relay base. Be very wary of generating a spark with fuel vapour around, of course.
I assume the LPG wiring doesn't break into the fuel pump circuit? Mine certainly doesn't. Fuel pump runs as usual on LPG.
I'd be surprised if it were the injector signals because unless there's a major problem with the LPG ECU you would only lose one injector as they're individually switched. Would be worth checking the supply to the LPG ECU, although even still, I'd expect it to loop through the injector signals if its' supply failed. Mine certainly does.
Kevin
-
Thanks Kev, thanking you for your reply.
Right I’ll have spades at the ready this afternoon. Yes you are right about the fail safe LPG ECU injector wiring to and from the petrol injectors. If the unit looses power the petrol injectors remain connected, so I am pretty certain that this isn't the problem. I even removed the LPG ECU a while back and then the car wouldn’t start, so this enforces this theory.
I find it hard to imagine that priming the pump takes so much fuel, but I have never needed to prime one and have never completely ran out of fuel. So I will try again with more juice tonight.
What really puzzles me is that if the fuel pump/fuse or relay is up the duffer, surely the car would cough and fart a little and try to start, but this isn't the case, it just keeps cranking over.
-
When did it last run on petrol?
Is it very free turning over on the starter motor?
Could be crank sensor
-
Very free, no problems.
Last ran on petrol sunday on a 5 mile run to B&Q, nice and easy drive.
Correct me if i'm wrong, i though cam sensor flags EML?
Regards
-
Cam sensor or crank sensor? Crank sensor didn't light the EML on my car but did cause a code (0335 IIRC).
Symptoms were not starting when hot, which isn't a million miles from your symptioms.
Cam sensor shouldn't stop it starting but again should raise a code.
Kevin
-
Very free, no problems.
Last ran on petrol sunday on a 5 mile run to B&Q, nice and easy drive.
Correct me if i'm wrong, i though cam sensor flags EML?
Regards
Turns over easier with dodgy crank sensor than without, I have had a similar problem but mine cleared itself after a little while - it would not fire on petrol, previously done a hard long run on LPG and the injectors got clogged.
-
you could check whether you are getting fuel pressure at the pressure relief value at the back of the plenum (a bit below it). looks like a schrader value. press it - release the pressure if any - crank and then try again - if you get petrol emerging then you probably have fuel pressure and its something else
-
Hi guys, you'd never guess what??
Finally cracked this one this evening. As per your advice Kev, I disconnected the fuel pipes dropped them into a pint of Guinness (well an empty Guinness glass!). I then shorted out the two larger connectors on the pump relay for a fraction of a nanosecond and I hey presto – half a pint of fuel! I then reconnected the fuel pipes back onto the fuel rail and then shorted the relay out again and I heard a swirling and whoosing coming from the fuel rail, similar to a central heating boiler with water rushing around the pipes.
So now I put the relay back then cranked her over and after about 2 or so seconds I heard a small fart then purrrrrrrrrrrrr, the cat was purring! Even quieter this time, no more lifter rattle. Maybe the hard ragging in London blasted the gunk from the gunked up lifter?
I find it hard to believe that cranking the car alone wasn’t enough to get fuel into the injectors?
Anyway the moral of the story is not to panic and start eyeing up a crank sensor, burnt out plugs etc... I’ve been with Omegas for nearly three years now and not had any major issues! (touch wood) Nearly all of my problems have been very simple and reasonably easy repairs!
Next job – new LPG evaporator and flexi LPG pipe to install this week. Should be arriving tomorrow.
Once again chaps, thanks for you kind help – who do I make the cheque out to?
-
Really pleased to hear its fixed :y :y :y
Now can I ask a favour ?? ( nowt to do with the cheque but if you insist ..... ) give it a week or so, at least 20 odd starts, then do the pedal check thing again ??
I'm really intrigued at your 4 flashes then nothing .. on mine I either get continuous flashing (no codes) or, when I had a problem, 4 groups of flashes, a pause, 4 more groups to give me the 2 error codes.
I'm wondering if your 4 odd ones will vanish now the car is fixed ... :)
-
Glad to hear it's working. I guess the fuel pump was struggling to prime. When connected to the rail it's pumping against a closed pressure regulator and if it's sucked air it may struggle to make the 3 BAR required to open it and bleed the air out of the system.
Kevin
-
Hi,
Would seem i spoke to soon. Problem returned to haunt me this afternoon in Morrisons carpark. :-[
I rectified it by shorting the relay out again and then starting her up. One thing that springs to mind i that i may not have primed the pump up correctly the first time round. I did as Kev advised and took the fuel pipes off and ran the pump but i only pumped out 1/2 pint of fuel and not any more into a fuel can. Maybe this wasnt enough?
The 4 flashes still stand, which i assume = zero errors.
Cheers
-
Once it has run I would have thought any air would bleed out very quickly. Fuel is constantly being circulated between the tank and the rail via the flow and return pipes so it's not really important how much fuel you bled from it, just that the pump was clearly able to make normal fuel pressure after that.
I wonder if your fuel pump or the relay is a little dodgy? Problem on the V6 is the ECU is not configured to prime the fuel pump (most EFI cars run the pump for a few seconds each time the key is turned to II). So, if pressure doesn't build up during cranking (when the volts are low anyway!) it doesn't start.
I guess a clogged fuel filter or pickup strainer in the tank might also cause fuel pressure to build slowly but would also give fuel starvation during running, IMHO.
You should have got a trouble code if you started it with the pump relay bypassed (ECU monitors the coil circuit of the relay).
Kevin
-
Kev,
I didn’t have an error code...? and no EML lit.
I’m thinking the fuel pickup may be clogged. If what you say is correct about the pump not operating until the engine is cranked and the pump unable to build the pressure up quick enough, because of a clogged pickup and low voltage due to cranking. That coupled with me forever running the tank very low sounds very feasible.
As you say other EFI cars run the pump for a few seconds before starting, so I am surprised to hear the V6 doesn’t.
I may have to limp my way to work tomorrow by shorting the relay again for a few seconds if needed. I will make plans to open up the tank this weekend.
Cheers
Marc
-
How does it run when it's working? Does it pull ok? Just thinking it would suffer from fuel starvation under load if there was a serious problem with fuel delivery.
I know how it is on LPG. you can put off filling up with petrol for too long. The problem is, you can run it low enough for the pump to suck air without noticing, and because the engine stays running on gas, the pump will run dry.
Kevin
-
IKWYM - I know what you mean about putting off fueling up with petrol :-[ very shameful
No issues while running, none at all.
Just popped outside and the car and it will not start, just cranking over. I then shorted the relay out and cranked the car at the same time and cough cough it fired up. I then opened up the shorted wire over the relay and stays running ok.
By pre-pumping the fuel it seems to fix my problem. :y
When i open the tank over the weekend i expect to see some dirt around the pickup, well hopefully.