Turbo Fuel Vapour Piping Malarky

[MGTurbo469]

Hello again everyone, hope we had a nice Christmas/New Year :beer:

Slow progress being made on Turbo No. 469 - assorted problems really but still going at least.

Whilst investigating the piping in the engine bay for splits/cracks etc., I notice that there is 1 pipe redundantly hanging there!

The pipe in question is split away from the main input (i guess) pipe into the vapour seperator, near the bulkhead. It looks like a permanent split and not a home-made jobbie, but can find no reference as to what it may be and where it should go....

Any suggestions / questions gratefully received.

Happy new year everyone.
Cheers
Alex

[MG1600S]

Any chance of a picture?

[MGTurbo469]

Unfortunately I now have no digital camera, since my 6 year old cousin thought it would be hilarious to stand on it and throw it around the place. Game over for that camera!

Sorry the description is so terrible on the 1st post....
If you are looking at the fuel vapour seperator from the front grill (it is on the right hand side near the washer reservoir), the pipe that comes out of the top of it is fine and returns to the metal piping on the bulkhead, the pipe into the side of the FVS is OK, but at the base of this pipe it splits into 2, and this branch off it is the redundant one.... it branches off near the air filter bin, and the redundant pipe is in the direction of the carb/plenum chamber assembly.

- Oh how joyous I think she's burning oil now also, magical :banghead: :horror:

Any thoughts on this pipe would put my mind at rest but she seems to be running well enough besides my recurring turbo problem.

Thanks again.
Alex

[MGJohn]

There are THREE tubes on the FUEL VAPOUR SEPARATOR. I have not had a look at my car - too cold but, from memory, fuel comes from the fuel pump into one side of the fuel vapour separator. Fuel comes out of the tube ON TOP OF THE SEPARATOR to supply fuel to the carburetteur. The remaining tube on the side of the separator goes to the FUEL PRESSURE REGULATOR where any surplus fuel above certain pressures is returned to the fuel tank via the return tube.

That is for an unmodified car with original equipment. I'll try and get photo tomorrow but I believe I already have a good one but that is on my son Martin's PC, not mine.

As for your 'redundant' tube, really need a comprehensive description of it or, much better still, a picture to be able to suggest what's what. There is a tube which runs from the side of the carb which is the carb vent valve. On some cars, at first glance that appears to go nowhere .... :)

[MGJohn]

2nd thoughts:

As for your 'redundant' tube, really need a comprehensive description of it or, much better still, a picture to be able to suggest what's what. A pure unseen blind guess is that it's the one which should go to the Fuel Pressure regulator. There is also a tube which runs from the side of the carb which is the carb vent valve. On some cars, at first glance that appears to go nowhere ....

[MGTurbo469]

Sorry for delay, my access to the internet is getting a bit thin on the ground nowadays!

After much fiddling and scratching of the head, it was found to be the pipe that comes from the actuator and should go towards fuel pressure regulator/carb in a T-piece sort of vibe....

This has now been done, but the car seems now to have real problems getting above 3,500rpm - possible fueling problem from some filth getting stuck in the pressure regulator or piping? Could also be leaking boost from one of the gaskets....

Its time to get it to a garage!!

Any further suggestions (short of scrapping please) would be magic.

Thanks again everyone.
Alex

[G Force]

Hi, Its pretty hard to follow what has been the problem in this post, but if I understand correctly the pipe that was adrift is actually the boost signal pipe from the plenumn chamber to the wastegate actuator & fuel pressure regulator. And before you reconnected the pipes the car seemed to have no problems.

Now the pipes are connected the engine won't rev much above 3500rpm is this right?

If this is the case I think under normal driving conditions the car was loosing boost pressure through the open pipe and was just running almost like a n/a engine, but now the pipes are connected you have unmasked another problem.

The problem could be the float chamber vent valve stuck open, you can check this by removing the pipe at the float chamber end (the pipe that disappears under the servo) and with the ignition on try to blow down it. It should be sealed, if it is not check if the valve has a 12v feed and good earth if it has then the valve needs renewing. You can temperally fix the prob by blanking off the pipe, but you may have trouble restarting a hot engine.


Regards Gary :)

[MGTurbo469]

Hi Gary,
Thanks for the reply - much appreciated.

Think you have hit the nail on the head there, it had some problems before hand but that was the spring in the plenum chamber - you could compress it just by looking at it almost. That had been replaced and I then noticed that this pipe was melted/ripped/half-missing - the one from the actuator to the fuel pressure regulator/carb via a T-piece (metal) piping on the bulkhead.

Since then the turbo spins in a much more controlled manner and doesn't go to a trillion RPM, but now of course this problem - one thing after another at the moment!

It has been extremely difficult to start when hot, and twice it has been nigh on impossible, so maybe the previous owner has already blanked off the float chamber vent valve - I will have to pay particular attention to this over the weekend and get my thinking cap on :idea:

Thanks again.
Alex

[MGTurbo469]

Well... On the weekend had some police issues as I got "abusive" with a traffic warden, when she put a £30 ticket on my windscreen outside my own house (it IS a main road BUT I do have residents parking permit!).... also the fact that the bonnet was clearly up and I had bits of carb all laid out should have given me at least some cause for feeling a bit cheated.... they are the rules though and I am scuppered as far as that is concerned.... psychopathic rage anyone?! :mad:

Anyway, after all that fuss I got round to actually looking at the carb vent valve. It appears to be functioning to some extent - it is much much harder to blow down it with the ignition on, though I am sure that it is letting SOME air through... is this cause for concern?

Hurrah! My new brakes are now on and working correctly, they are still not wonderful though - at least now I don't have to anticipate 30 seconds in advance when someone might cross the road.

Progress at least :D

Thanks again
Alex

[tony]

The vent valve should have 12v at it with ignition on and not be able to blow thro it.
When there’s no power there you should be able to blow thro it.

"It is much much harder to blow down it with the ignition on, though I am sure that it is letting SOME air through... is this cause for concern?"

So yes its time to change it for a new one as it is not working properly

[MGTurbo469]

OK thanks thought so but wasn't sure if there was some tolerance.
Cheers everyone.
Alex

[Blair G]

but if I understand correctly the pipe that was adrift is actually the boost signal pipe from the plenumn chamber to the wastegate actuator & fuel pressure regulator.

I done away with this, the rubber hose from the wastegate go's to the FPR and nowhere else. No T-piece (exept for the boost pressure gauge)

Works a treat, on my car anyway.

[G Force]

I done away with this, the rubber hose from the wastegate go's to the FPR and nowhere else. No T-piece (exept for the boost pressure gauge)

Works a treat, on my car anyway.

I would have thought your maestro is slightly modified though?

On a standard set up this will give unregulated boost, the only protection will be the plenumn chamber dump valve.

The fueling and ignition settings should be modified if boost pressure is lifted in this way to prevent damage to the engine.

Cheers Gary :)

[Blair G]

I would have thought your maestro is slightly modified though?

Just a tad :laugh:
http://img.photobox.co.uk/1686341705a8720bd7de9fd78eb995106332d37226df619f09 a30f11.jpg
http://img.photobox.co.uk/44508675100506c278b5f5d63049926f2ce4947f4726f41b77 12a5b0.jpg

[G Force]

Hi there, Blair G, Had a look at your website some underbonnet shots would be nice ;) Any chance (Both cars) :)

Hmm Duffus Dip :violin:

Cheers Gary :)

[Blair G]

Hi there, Blair G, Had a look at your website some underbonnet shots would be nice ;) Any chance (Both cars) :)

Hmm Duffus Dip :violin:

Cheers Gary :)

Hi Gary, the red one (in pics above) is a NASP T16 recently had a top end rebuild with high lift cams ect. At a guess its running 160-170bhp with unichip which may be removed as the engine is running far too hot. Its certainly quicker that a standard turbo at the minute.

The white car (MG 2) is an EFI which I put a Monty turbo engine in. It got HG failure running 16psi boost, its now fixed and running 15 PSI with ease. I will take some under bonnet pics in the next few days but there not nice and shiny like Gareths or Victors as they are constantly being worked on ;)

Blair

(sorry for going off topic on this thread)

[Maria]

Is that 2nd pic pink inside, or is it just a trick of the camera? If it is pink, is it one of the ex-Darryl Davi(e?)s MGOC series cars?

[Blair G]

Is that 2nd pic pink inside, or is it just a trick of the camera? If it is pink, is it one of the ex-Darryl Davi(e?)s MGOC series cars?

Both cars were built by us from road going versions. The reason it appears as pink is because this one runs a straight through unsilenced exhaust which runs through the spare wheel well (you can see the entry hole in the pic). There was a leak in the pipe which caused carbon build up in the spare wheel area (which is normally covered by a board).

We removed the exhaust to clean off all the carbon deposits, that white thing in the foreground is a heater to dry the car off and the glare from it makes it look pink.

Blair

[MGTurbo469]

Hallo again everyone.... your car looks like the set up MAY BE slightly different to mine!

Surprisingly enough the MGR dealers in the area tell me the float chamber vent valve is NLA; anyone have any ideas where I could get one / is it worth trying to repair mine? Seems to have good voltage/earth and closes to some extent. Appreciate any help/info again.

Car making not bad progress - new discs/pads on the weekend has made such a difference, and the N/S CV joint is next up which should complete everything less the engine (sounds disheartening now I've said that :banghead: )

Splendid stuff.
Cheers again
Alex

[G Force]

Hi, you could try make the valve function again with some WD40 It can't hurt, also try comparing the engine performance with the valve pipe blanked off then you will know to what extent the faulty valve is having on your running problem. It may be that you have further problems beyond the valve or it could prove that it is only the valve you need to focus on repairing.


Cheers Gary :)