Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: stuvaux on 06 March 2014, 15:12:05
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Hi all
Over the past few weeks, my Omega (2.5 V6, LPG converted) has been a bit slow on starting. It then got worse a few days ago. I read codes, came up with 19, so replaced the crank sensor.
However, the problem is still there. I did forget to replace the vac pipe on the fuel pressure regulator, so thought that might be the problem. I replaced that, but still no joy. I am thinking it must be a fueling problem as the car runs fine on LPG (once I can get it started and switched over!)
Any ideas would be very much appreciated!
Thanks
Stu
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Forgot to mention, checked codes again and the 19 has now cleared
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Do you mean the cranking is slow? Or it's normal but takes ages to fire?
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Do you mean the cranking is slow? Or it's normal but takes ages to fire?
Sorry should have made that clearer! Turns over fine but taking ages to fire. It is definitely attempting to start. It will start sometimes, run for a few mins and then go lumpy and cut out. Runs fine on LPG
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Checked vacuum connections etc. Is there anything obvious I may be missing?
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I'm hoping the new crank sensor isn't faulty....surely if it was though it wouldn't run on LPG normally, and the fault code 19 would still come up?
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Code 19 sometimes does not show up, was the crank sensor an origanal gm part or copy(pattern)
if not gm thats your problem they are crap always by gen gm.
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Code 19 sometimes does not show up, was the crank sensor an origanal gm part or copy(pattern)
if not gm thats your problem they are crap always by gen gm.
It is a genuine GM one yes. But surely the poor running and stalling would still happen when running on LPG (which it doesn't)
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Code 19 sometimes does not show up, was the crank sensor an origanal gm part or copy(pattern)
if not gm thats your problem they are crap always by gen gm.
It is a genuine GM one yes. But surely the poor running and stalling would still happen when running on LPG (which it doesn't)
When was the last time the fuel filter (petrol) was changed ???
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Code 19 sometimes does not show up, was the crank sensor an origanal gm part or copy(pattern)
if not gm thats your problem they are crap always by gen gm.
It is a genuine GM one yes. But surely the poor running and stalling would still happen when running on LPG (which it doesn't)
When was the last time the fuel filter (petrol) was changed ???
Now that is a good question - not recently :-\
I was thinking that may be a possible culprit
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Any fuel in it?
Sounds like a stupid question, but estates are prone to fuel starvation if left on a slope with less than a quarter tank.
If in doubt, put AT LEAST 2 gallons into it and report back :y
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Any fuel in it?
Sounds like a stupid question, but estates are prone to fuel starvation if left on a slope with less than a quarter tank.
If in doubt, put AT LEAST 2 gallons into it and report back :y
That is something else I had been thinking too. It should have some in there, the gauge is reading just under the 20 mark and the range is saying 87 miles! Still possible though. Will have to try it tomorrow
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Not unknown for new GM crank sensors to be faulty ;)
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Not unknown for new GM crank sensors to be faulty ;)
Surely it wouldn't run well on LPG if crank sensor was faulty....or am I wrong in thinking this?
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Not unknown for new GM crank sensors to be faulty ;)
Surely it wouldn't run well on LPG if crank sensor was faulty....or am I wrong in thinking this?
Electrically the only difference between petrol and lpg is which injectors are working, so unlikely to be crank sensor, hence my fuel suggestion :y
Generally lpg is much more sensitive to weak or failing sensors than petrol, so I doubt it's a sensor issue :-\
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Not unknown for new GM crank sensors to be faulty ;)
Surely it wouldn't run well on LPG if crank sensor was faulty....or am I wrong in thinking this?
Electrically the only difference between petrol and lpg is which injectors are working, so unlikely to be crank sensor, hence my fuel suggestion :y
Generally lpg is much more sensitive to weak or failing sensors than petrol, so I doubt it's a sensor issue :-\
Thanks, that is what I was thinking. Going to get some fresh petrol to try that. Also ordered a fuel filter which should be here by next Tuesday. Luckily I have my Bedford CF2 to keep me mobile in the meantime! :y
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Quick update. Fresh fuel didn't make any difference :(
Next step fuel filter, as soon as it gets here
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Ive not driven a cf2 in a few years ....
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Quick update. Fresh fuel didn't make any difference :(
Next step fuel filter, as soon as it gets here
How much fuel did you add?
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Ive not driven a cf2 in a few years ....
Still as great as ever....better than any modern van :y. I have owned it for 14 years, only recently got it back on the road. I now use it almost daily as part of my business 8)
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Quick update. Fresh fuel didn't make any difference :(
Next step fuel filter, as soon as it gets here
How much fuel did you add?
10 litres.....it did start initially but then same problem happened after a minute or so of ticking over
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If you look under the car at the tank you'll see a round patch on the right hand side towards the middle...
Give this a thump with your fist as someone cranks the car... fuel pumps can stick when they're on the way out :y
To add, try and get the car as level as possible, any slope, especially to the left, and the fuel is away from the pickup.
If it starts when level, you need more fuel in it, when they run dry they take alot more than you think to get going :o
If it doesn't start, the whack the tank as above whilst cranking. If it fires and runs then budget for a new pump...
It will likely be one of those two things :y
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If you look under the car at the tank you'll see a round patch on the right hand side towards the middle...
Give this a thump with your fist as someone cranks the car... fuel pumps can stick when they're on the way out :y
To add, try and get the car as level as possible, any slope, especially to the left, and the fuel is away from the pickup.
If it starts when level, you need more fuel in it, when they run dry they take alot more than you think to get going :o
If it doesn't start, the whack the tank as above whilst cranking. If it fires and runs then budget for a new pump...
It will likely be one of those two things :y
Great tip, will give that a try thanks :y
It is parked on level ground so I'm thinking there must be enough fuel in there now. I won't be back to the car until Tuesday now, but will definitely give that pump a whack when I get chance ;)
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Update - changed fuel filter. Car ran for a few minutes, then went really choppy and cut out. I then noticed that the fuel tank had "sucked in" on itself! When I opened the fuel cap loads of air came out (this also happened last week but I assumed it may have been that I had left a vac pipe off....). the tank then returned to normal.
Is it possible that there is a small hole in the pipes above the fuel pump? I have had a look at them - there is some surface rust but no obvious holes. I'm thinking it must be drawing air in somewhere.
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Update - changed fuel filter. Car ran for a few minutes, then went really choppy and cut out. I then noticed that the fuel tank had "sucked in" on itself! When I opened the fuel cap loads of air came out (this also happened last week but I assumed it may have been that I had left a vac pipe off....). the tank then returned to normal.
Is it possible that there is a small hole in the pipes above the fuel pump? I have had a look at them - there is some surface rust but no obvious holes. I'm thinking it must be drawing air in somewhere.
That can't happen ... :) if the tank "sucks in" as you call it, when you open the cap then air will ENTER the tank to relieve the vacuum .. which is IMHO the cause of your problem !! If a vacuum builds up in the tank then no fuel will leave it... so suggestion #1 ... try running the engine with the fuel cap OFF if it works ok that proves the problem, you then need to find out why the fuel vent system is not working as it should, it is a sealed system to prevent pollution , but the system will replace used fuel with air via the vent pipe .. which yours does not appear to be doing
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Might be water in the fuel tank occasionally sloshing into the pump intake. I always wondered in the fuel filter would trap it as it lies horizontally and water would collect in the bottom. Could be faulty MAF Test for that is to unplug it and see if the fault disappears. But that would still misbehave on LPG.
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Update - changed fuel filter. Car ran for a few minutes, then went really choppy and cut out. I then noticed that the fuel tank had "sucked in" on itself! When I opened the fuel cap loads of air came out (this also happened last week but I assumed it may have been that I had left a vac pipe off....). the tank then returned to normal.
Is it possible that there is a small hole in the pipes above the fuel pump? I have had a look at them - there is some surface rust but no obvious holes. I'm thinking it must be drawing air in somewhere.
That can't happen ... :) if the tank "sucks in" as you call it, when you open the cap then air will ENTER the tank to relieve the vacuum .. which is IMHO the cause of your problem !! If a vacuum builds up in the tank then no fuel will leave it... so suggestion #1 ... try running the engine with the fuel cap OFF if it works ok that proves the problem, you then need to find out why the fuel vent system is not working as it should, it is a sealed system to prevent pollution , but the system will replace used fuel with air via the vent pipe .. which yours does not appear to be doing
Thanks for the explanation.
Right, car runs with fuel cap off. So where would I start in trying to find out why the fuel vent system is not working?
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Has it been pranged recently causing the vent pipe to become pinched? Only real way to check is to drop the tank :-\
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Has it been pranged recently causing the vent pipe to become pinched? Only real way to check is to drop the tank :-\
No prang recently and no work done anywhere near there either.....its really odd!
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Not certain if this thread helps.... I know you haven't got a warning light on, but it does, to some extent, describe the vent system, I have a strong feeling you have a blockage somewhere ... perhaps in the purge valve or the carbon canister ??
http://oldsite.omegaowners.com//forum/YaBB.pl?num=1180455423
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Not certain if this thread helps.... I know you haven't got a warning light on, but it does, to some extent, describe the vent system, I have a strong feeling you have a blockage somewhere ... perhaps in the purge valve or the carbon canister ??
http://oldsite.omegaowners.com//forum/YaBB.pl?num=1180455423
Thanks, I will have a look at that (and the not so helpful Haynes).
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Purge valve raises a code :y
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Purge valve raises a code :y
Thanks :y
Still no codes, but they don't always show up.....!
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Purge valve raises a code :y
I believe it only raises a code if it doesn't work electrically ... ie open circuit ?? so if it is physically blocked it might be "electrically" good but not actually passing any air/fumes/vapours ??
Clutching at straws .. but Haynes says nowt about the vent system and its ability to replace burned fuel with air .. it only mentions evaporative fuel being purged .... :(
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Worth looking at the plumbing under the car... the cannister is in the drivers front wheelarch, possible that the vent pipe has been crushed under the car :-\
Just had another thought...
The purge valve on mine died after a breather clean, resulting in a faint smell of petrol in the car...
If the breather pipes are connected the wrong way round, could the increased vacuum be enough to draw air out of the tank?
2.5 and 3.0 small breather pipes are the same diameter, on the 2.6/3.2 they're a different size. So possible to connect the breather box small pipe and the purge valve pipes the wrong way on earlier cars :-\
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Purge valve raises a code :y
I believe it only raises a code if it doesn't work electrically ... ie open circuit ?? so if it is physically blocked it might be "electrically" good but not actually passing any air/fumes/vapours ??
Clutching at straws .. but Haynes says nowt about the vent system and its ability to replace burned fuel with air .. it only mentions evaporative fuel being purged .... :(
Typical Haynes :-\
Thanks, I will investigate all possibilities mentioned as soon as I can (busy working most of tomorrow so likely the weekend now)
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Worth looking at the plumbing under the car... the cannister is in the drivers front wheelarch, possible that the vent pipe has been crushed under the car :-\
Just had another thought...
The purge valve on mine died after a breather clean, resulting in a faint smell of petrol in the car...
If the breather pipes are connected the wrong way round, could the increased vacuum be enough to draw air out of the tank?
2.5 and 3.0 small breather pipes are the same diameter, on the 2.6/3.2 they're a different size. So possible to connect the breather box small pipe and the purge valve pipes the wrong way on earlier cars :-\
Thanks, looks like I will have a busy weekend :y
I haven't done anything to the breathers recently so (maybe) ruling that out....
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first place to start will be at the tank, there should be a vent tube in or near the fuel tank filling pipe and runs to the front wheel arch, check the entire pipe run for pipe being trapped and blocked work methodicly and you should find the problem, as to the breather tubes, its a poss.
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Checked the canister and pipes in wheel arch today. The only pipe that seemed a bit blocked was the short one (about 6 inches long, just exiting in the wheel arch). It may have become a bit blocked with mud as I have no wheel arch liner fitted....
So I cleared this and refitted. The car still struggled a bit starting but then started ticking over fine. Tried driving it and it lost power and cut out again after a street or 2. It did start again though after a couple of attempts. So it is improved but not quite there yet. Tomorrow I will try checking the pipe running from fuel tank to wheel arch.
I have noticed that the filler opening doesn't seem fully seated now, so maybe that pipe is being restricted. Does anyone know what secures the filler opening to the body?
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All vent pipes from tank to wheel arch canister are clear. Problem is still there, but mainly difficult starting. Once running it doesn't just cut out like it did.
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All vent pipes from tank to wheel arch canister are clear. Problem is still there, but mainly difficult starting. Once running it doesn't just cut out like it did.
Is it any better with the filler cap removed ?? If it is, then there is still a vent problem somewhere .. if that makes no difference then it is something else ....
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All vent pipes from tank to wheel arch canister are clear. Problem is still there, but mainly difficult starting. Once running it doesn't just cut out like it did.
Is it any better with the filler cap removed ?? If it is, then there is still a vent problem somewhere .. if that makes no difference then it is something else ....
It now seems to be the same with or without the filler cap fitted. Not sure what to try next now :-\
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All vent pipes from tank to wheel arch canister are clear. Problem is still there, but mainly difficult starting. Once running it doesn't just cut out like it did.
Is it any better with the filler cap removed ?? If it is, then there is still a vent problem somewhere .. if that makes no difference then it is something else ....
It now seems to be the same with or without the filler cap fitted. Not sure what to try next now :-\
There is always the possibility that when the tank was evacuated and "sucked in" as you called it, that the internal pickup either moved or was damaged, likewise, possibility of damage to the fuel pump ?? If you have the facilities I would try disconnecting the fuel line at the tank and seeing if fuel flows/pumps at a decent rate .. obviously this needs to be done with great care to avoid fuel spillage/fire risk .... :-\ :-\ :-\
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All vent pipes from tank to wheel arch canister are clear. Problem is still there, but mainly difficult starting. Once running it doesn't just cut out like it did.
Is it any better with the filler cap removed ?? If it is, then there is still a vent problem somewhere .. if that makes no difference then it is something else ....
It now seems to be the same with or without the filler cap fitted. Not sure what to try next now :-\
There is always the possibility that when the tank was evacuated and "sucked in" as you called it, that the internal pickup either moved or was damaged, likewise, possibility of damage to the fuel pump ?? If you have the facilities I would try disconnecting the fuel line at the tank and seeing if fuel flows/pumps at a decent rate .. obviously this needs to be done with great care to avoid fuel spillage/fire risk .... :-\ :-\ :-\
Thanks for the advice, will try and do that as soon as I get chance. Thankfully it is still usable when running on LPG
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Depending on the type/location of lpg tank, liberating the petrol pump could be fun :-\
Might be easier to test at the manifold end :y
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Depending on the type/location of lpg tank, liberating the petrol pump could be fun :-\
Might be easier to test at the manifold end :y
Luckily the LPG tank is in the spare wheel well, so I can still get to the pump via the cover plate in the boot floor (Estate)
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Small mercies :y
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Small mercies :y
Yes indeed! :y
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Flow rate seems okay.
The problem does seem to have improved slightly. Starting is most difficult from cold, not too bad from hot. It does also seem to tick over okay now too. When driving there is definite hesitation, some times worse than others. I drove it for 7 mikes on petrol to see if it may clear, but hesitation continued.
I am not sure what to try next. Still no codes coming up... :-\
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I am still wondering if it may be the MAF...can anyone confirm if it would run fine on LPG even if the MAF was faulty?
Thanks
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Flow rate seems okay.
The problem does seem to have improved slightly. Starting is most difficult from cold, not too bad from hot. It does also seem to tick over okay now too. When driving there is definite hesitation, some times worse than others. I drove it for 7 mikes on petrol to see if it may clear, but hesitation continued.
I am not sure what to try next. Still no codes coming up... :-\
Have you checked the coil pack :y
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Flow rate seems okay.
The problem does seem to have improved slightly. Starting is most difficult from cold, not too bad from hot. It does also seem to tick over okay now too. When driving there is definite hesitation, some times worse than others. I drove it for 7 mikes on petrol to see if it may clear, but hesitation continued.
I am not sure what to try next. Still no codes coming up... :-\
Have you checked the coil pack :y
Coil pack was replaced 6 months ago. Also, the car runs fine on LPG
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New update!
Codes 73 and 74 are now coming up, which are Mass Air Flow Sensor Voltage Low & Mass Air Flow Sensor Voltage High.
So does this mean the MAF is definitely faulty? I thought the running on LPG would have also been affected :-\
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That does sound like the Maf sensor is on its way out :-\ does unplugging it make any difference?
Maf might not affect lpg running as the system possibly has its own pressure/flow sensor :-\
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That does sound like the Maf sensor is on its way out :-\ does unplugging it make any difference?
Maf might not affect lpg running as the system possibly has its own pressure/flow sensor :-\
Unplugging it does make it run a little better. Also, it seems to run fine on petrol once warm. I have ordered a used (genuine) MAF sensor now, just have to wait for it to get here, probably early next week now
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Replacement MAF fitted....car is still the same :(. Once warm, it ticks over quite normally, but has a lot of hesitation when driven.
The codes (73 & 74) are still there, so is there anything else this points to?
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All pipes/connectors around MAF area look to be fine. Not sure what next to try now :-\
Any advice gratefully received :y
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Still having the same problem. Sometimes car will not start at all though this is rare (only happened twice). I really am unsure what to look at next. The MAF codes are still there, but I was wondering what other faults this may point to? No other codes are coming up
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Hi all,
Just posting this as the problem is now cured!
The problem was the fuel pipes underneath the metal cover, the ones that go to the pump. It is normally the top of the cover that corrodes. On mine, the pipes both had splits in them (almost right at the top, underneath cover). Simple fix by carefully cutting off the damaged bit of pipe :y
Hope this may help someone who gets similar symptoms
Stu