Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[tidla]

some motors position the vent in a stupid place (wheel arch )that can block with dirt. (not sure on the mig set up)

[JamesV6CDX]

some motors position the vent in a stupid place (wheel arch )that can block with dirt. (not sure on the mig set up)

Can anyone confirm, please?

[Andy H]

some motors position the vent in a stupid place (wheel arch )that can block with dirt. (not sure on the mig set up)

Can anyone confirm, please?

I haven't actually seen it but...

When the engine is off the fuel tank vents through a charcoal canister hidden above the wheelarch liner in the front drivers side wheel arch. The charcoal absorbs petrol fumes to prevent them escaping to atmosphere.

When the engine is running the charcoal cannister purge valve opens and manifold vacuum pulls air through the charcoal to purge it of fuel fumes.

If the fuel tank became pressurised then that could a give a route for petrol straight into the inlet manifold.

[JamesV6CDX]

some motors position the vent in a stupid place (wheel arch )that can block with dirt. (not sure on the mig set up)

Can anyone confirm, please?

I haven't actually seen it but...

When the engine is off the fuel tank vents through a charcoal canister hidden above the wheelarch liner in the front drivers side wheel arch. The charcoal absorbs petrol fumes to prevent them escaping to atmosphere.

When the engine is running the charcoal cannister purge valve opens and manifold vacuum pulls air through the charcoal to purge it of fuel fumes.

If the fuel tank became pressurised then that could a give a route for petrol straight into the inlet manifold.

Many thanks for this, still doesn't explain why the excess pressure is in the system in the first place, though?  :-/

[Andy H]

some motors position the vent in a stupid place (wheel arch )that can block with dirt. (not sure on the mig set up)

Can anyone confirm, please?

I haven't actually seen it but...

When the engine is off the fuel tank vents through a charcoal canister hidden above the wheelarch liner in the front drivers side wheel arch. The charcoal absorbs petrol fumes to prevent them escaping to atmosphere.

When the engine is running the charcoal cannister purge valve opens and manifold vacuum pulls air through the charcoal to purge it of fuel fumes.

If the fuel tank became pressurised then that could a give a route for petrol straight into the inlet manifold.

Many thanks for this, still doesn't explain why the excess pressure is in the system in the first place, though?  :-/

I thought you were going to reserve judgement on that until you had checked :
- blocked cats
- blocked silencers
- crossed over plug leads
- crossed over lambda sensors

I still think that your fuel tank got very hot

[JamesV6CDX]

Leads - checked
Plugs - checked (black)
Lambda connections - checked

You may be right. I will run it up with new leads and dis, and we'll see where the land lies then.

New cats and new cat back exhaust is on order

[tidla]

vapours are drawn into the plenium as stated, but to suck fuel out and return to the tank require atmospheric vent.

[JamesV6CDX]

vapours are drawn into the plenium as stated, but to suck fuel out and return to the tank require atmospheric vent.

And where does this vent, any ideas?

[tidla]

Our flight arrived on schedule in Inverness at 14:25 yesterday afternoon, to collect a facelift Elite that was described as "mechanically perfect".


I'd taken a chance, and bought the thing unseen.. so I'm not grumbling... however, that description wasn't quite correct.

I'm not looking to moan, and have no intention of looking of recourse - I'm just after some opinions on fixing the damn thing.

First issue - drivers seat was right back, and wouldn't adjust. After spending an hour with various implements removing coins from the seat runners, I fixed that.  Ahh - ready to drive back at last!

First thing I noticed, was a misfire at idle. I now realised why the guy bu99ered off so quickly  knowing I had 650 miles to do in it.

Popped a lead off each side, tiny trace of oil but no contamination, they looked OK. Didn't have tools to investigate any further. I filled up with petrol and decided to do a few miles down the road to get a better picture.

At cruising speed - seemed OK! Just appeared to be missing at idle, and under load. I then decided nothing for it - will run the gauntlet for home. This turned out to be a bad idea 

I managed just shy of 400 miles - got from Inverness, down onto the M6.

I noticed during this time that the baffles must have let go in the exhaust - awful noise.
As I joined the M6, I noticed the fuel gauge appeared to have gone quite low, quite quickly. It went to red, and started flashing before I knew what had happend. Hmm.

Stopped at a garage. Revved the engine while outside the car - and it stank of petrol. Especailly at the rear. Had a look and couldn't really see any leaks.

It was misfiring - properly, at this time. Guessed it was unburnt fuel. Decided to take it to service area 17 miles down the M6, get some coffee and arrange recovery.

I put £40 of petrol in, and set off on the 17 mile run. As I took the petrol cap off to re-fill, there seemed to be a LOT of vapour type stuff coming out of the filler neck.

Drove on to next services - again, she seemed to cruise OK.

Bearing in mind I put in £40 - which took it to half a tank, it USED THE LOT, over 17 miles. Gauge flashing again, at the next stop 

 - now even if it's mis firing - this is like 2 miles per gallon - surely all that petrol couldn't have gone in the engine, over this time 

When I stopped again, I looked underneith, and the 2-4-6 side cat was glowing, absolutely red hot!!!

Is this pointing to a blockage - or is it unburnt fuel?

My thinking is, I will need -

Plugs
Lead check
DIS Pack
Good pair of cats
Eternalcar catback exhaust

Probably knackered the lambdas too.


Otherwise - the car's very nice 

Fixing the misfire I'm sure won't be a problem, but, I am thrown by the fact that SO MUCH fuel disappeared over 17 miles, with no trace of an external leak.

Opinions welcome, please 

cats giving up and being blown out of the back exhaust due to working so hard?

[JamesV6CDX]

Maybe - but still I can't link this to the cause of the fuel excess pressure?

[hoody]

Do the V6's have a coolant temp.sensor that signals the ECU?had a few rover 820/vitesse's that ate the things but when they went wrong they gave a misfire and acquired a thirst like a v12.

[pscocoa]

I have vents in the rear off side wheel arch on my Elite

[Kevin Wood]

Sounds like massive overfuelling to me, so try with the MAF disconnected.

Does it misbehave from cold or just when hot?

If just when hot, try unplugging the Lambdas.

Failing that, high fuel pressure? FPR / blocked fuel return line.

Maybe a stuck open injector (all plugs will be black after a cold start or period of idling. Check for a very wet one).

Only vent from fuel tank is into breather box so that can be disconnected from the purge valve to eliminate it.

Check the oil for fuel contamination too.

Kevin

[JamesV6CDX]

Sounds like massive overfuelling to me, so try with the MAF disconnected.

Will do!

Does it misbehave from cold or just when hot?

I've never driven it from stone cold. When I picked it up, the engine was warm, and a slight misfire.

It was only when I had been cruising at semi-naughty motoway speeds for an hour or two, that the massive fuel consumption started.

If just when hot, try unplugging the Lambdas.

Again - will do!

Failing that, high fuel pressure? FPR / blocked fuel return line.

Again, this was my school of thought. However, if the return line was blocked somehow, would I have stilll seen all the vapour from the neck of the tank?

Maybe a stuck open injector (all plugs will be black after a cold start or period of idling. Check for a very wet one).

No 4 seemed quite wet. Couldn't tell if this was a result of petrol, or water ingress in the plug recess, though....

Only vent from fuel tank is into breather box so that can be disconnected from the purge valve to eliminate it.

Check the oil for fuel contamination too.

Kev - many thanks. I will check these things later and report back

[Marks DTM Calib]

Remove the fuel pump insepction plate in the boot and check for damage and/or excessive corrosion around the plate on top of the tank.