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Omega Help Area => Omega General Help => Topic started by: JamesV6CDX on 28 June 2010, 01:05:55

Title: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: JamesV6CDX on 28 June 2010, 01:05:55
I have fault code:

61   Fuel Tank Ventilation Valve Voltage Low

This is a current fault code - the only one.

The consumption is disgusting. I have a 56litre usable LPG tank, and it used the lot in 160 miles. (12mpg?)

The consumpt. on petrol is also down, though not as noticable as LPG.

Idle is too fast (idles at 850rpm with climate on or off) - and the exhuast smells very petrol like / rich at idle.

Any ideas? Lambda operations look normal, and so does the coolant temp sensor values.

 :y

Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: tunnie on 28 June 2010, 08:54:12
It's running up to temp ok?
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: 2woody on 28 June 2010, 09:25:40
by fel tank vent valve I think it means purge valve, the one located under the plenum top cover ( red connector )

make sure the plug isn't off and there's a supply (don't be surprised if its 5V) to one side of the valve
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: JamesV6CDX on 28 June 2010, 09:56:10
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It's running up to temp ok?

Perfectly - as confirmed by the dash gauge, the CTS reading, and the vaporisor reading  :y
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: Entwood on 28 June 2010, 10:28:31
Not wishing to tell someone as knowledgeable as yourself anything .. but if its bad on BOTH petrol and LPG I'd be looking for a vac leak/timing issue.

The fuels supplies are totally seperate, right up to the point of injection. So, IMHO, the "system" is injecting too much fuel.

This implies that both ECU's are doing the same ... can't see a purge valve failure causing an ECU to give excess fuel ??

High idle speed is also caused by vac leaks ..... .. ?? 

:(
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: JamesV6CDX on 28 June 2010, 11:51:45
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Not wishing to tell someone as knowledgeable as yourself anything .. but if its bad on BOTH petrol and LPG I'd be looking for a vac leak/timing issue.

The fuels supplies are totally seperate, right up to the point of injection. So, IMHO, the "system" is injecting too much fuel.

This implies that both ECU's are doing the same ... can't see a purge valve failure causing an ECU to give excess fuel ??

High idle speed is also caused by vac leaks ..... .. ?? 

:(

Hiya Nige,

Thanks mate - I have re-seated the whole inlet, checked connections/pipes, and there is no plausible place for a vacc leak...  I guess I can check again  :)

The valve timing is perfect, so no problems there. Live data looks OK. Is a strange one  :-/
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: Sixstring on 28 June 2010, 15:42:07
James.......
Havent you sorted it yet??


Not like you..........................LOL!!!


(thought a bit of encouragement might help)
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: Kevin Wood on 28 June 2010, 16:09:38
What rate of airflow does the MAF report at idle?

Has the throttle stop been set so that the throttles close completely?

Do you get normal "cycling" of both Lambda sensors during idle and cruising? (should be possible to see in live data or via the LPG ECU).

Are the fuel trim values plausible and roughly similar for the two banks?

Do the injector durations seen in the LPG ECU cycle in "blocks"? (i.e. same duration for all 3 cylinders of one bank, different duration for the other bank)

I would do all the above on petrol. Keep LPG out of the equation for now.

If nothing unusual in the above, remove the plenum and check the injector wiring, or even remove the LPG piggy-backs and test it back with the original petrol wiring on.

I'm wondering if you have an injector cross-wired between banks.

Kevin
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: JamesV6CDX on 28 June 2010, 16:14:04
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I'm wondering if you have an injector cross-wired between banks.

Kevin

Would that not cause me a missfire Kev? The performance is great.

I am certain the injector piggy backs are ok, as I checked, and double checked them  :-/

Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: Kevin Wood on 28 June 2010, 16:24:25
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Quote

I'm wondering if you have an injector cross-wired between banks.

Kevin

Would that not cause me a missfire Kev? The performance is great.

I am certain the injector piggy backs are ok, as I checked, and double checked them  :-/


Nope. If it's just squirting into the wrong pot, you'd never know, but the fuel trims will be all over the place. It's not impossible that the LPG system loom has a fault either.

I'm also concerned by the code you're getting. If the purge valve is plugged in then why is the code still present? Is it possible that this connector got swapped for something else?

Worth checking the colour code of the wire in the plug, and checking for connection back to the correct ECU pin?

Kevin

Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: Lazydocker on 28 June 2010, 19:08:54
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Quote
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I'm wondering if you have an injector cross-wired between banks.

Kevin

Would that not cause me a missfire Kev? The performance is great.

I am certain the injector piggy backs are ok, as I checked, and double checked them  :-/


Nope. If it's just squirting into the wrong pot, you'd never know, but the fuel trims will be all over the place. It's not impossible that the LPG system loom has a fault either.

I'm also concerned by the code you're getting. If the purge valve is plugged in then why is the code still present? Is it possible that this connector got swapped for something else?

Worth checking the colour code of the wire in the plug, and checking for connection back to the correct ECU pin?

Kevin


There speaks the man who has experienced it ;) ;)

I agree... It's not unheard of (but is uncommon) for the loom markers to be incorrectly placed ;)
Title: Re: 2.5 V6 AWFUL Fuel consumption, and a fault code
Post by: PhilRich on 28 June 2010, 22:33:59
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Quote
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I'm wondering if you have an injector cross-wired between banks.
Kevin

Would that not cause me a missfire Kev? The performance is great.

I am certain the injector piggy backs are ok, as I checked, and double checked them  :-/


Nope. If it's just squirting into the wrong pot, you'd never know, but the fuel trims will be all over the place. It's not impossible that the LPG system loom has a fault either.

I'm also concerned by the code you're getting. If the purge valve is plugged in then why is the code still present? Is it possible that this connector got swapped for something else?

Worth checking the colour code of the wire in the plug, and checking for connection back to the correct ECU pin?

Kevin


There speaks the man who has experienced it ;) ;)

I agree... It's not unheard of (but is uncommon) for the loom markers to be incorrectly placed ;)







It's also not unheard of (Now!! >:() for the loom wiring to have been incorrectly connected on an injector piggyback plug!!! >:( I have been tearing my hair out, trying to trace a fault on my new system for the past TWO MONTHS! only to find today that the lpg  piggyback plug on the loom for petrol injector No. 1  has the wiring transposed causing a 'no petrol injection' reading from that cylinder  >:(.  I sincerely hope you don't have this problem James, but IMHO you need to be aware that faulty loom wiring is a distinct possibility :'(