As I'm sure many of you are aware I'm working on my car at the moment but have a question I though warranted a seperate thread....its all to do with fuel regulation, and I know there are a few peeps on here who are up on that kind of thing


Cinq's and Sei's (non-mpi) have a fuel line to the fuel rail, a return line, and a charcoal cannister line? Correct? Same as 1.2 puntos and bravo's.

I'm using a mk1 punto rail that has a return line I've capped. The regulator is at the end.

I have capped the return, as the MPI Sei has a fuel supply and a charcoal cannister line. NO return! Thats what I think anyway.

Obvoiusly capping the return renders the regulator on the punto rail usless, so;

A) How was my old setup regulated lack of mpi manuals etc doesn't help

B) How can I ensure the new one is regulated correctly? Other that installing a fuel return line and bodging it to the tank! That doesn't sound fun


Cheers for any thought or help


Kristian

kritip said:

As I'm sure many of you are aware I'm working on my car at the moment but have a question I though warranted a seperate thread....its all to do with fuel regulation, and I know there are a few peeps on here who are up on that kind of thing


Cinq's and Sei's (non-mpi) have a fuel line to the fuel rail, a return line, and a charcoal cannister line? Correct? Same as 1.2 puntos and bravo's.

I'm using a mk1 punto rail that has a return line I've capped. The regulator is at the end.

I have capped the return, as the MPI Sei has a fuel supply and a charcoal cannister line. NO return! Thats what I think anyway.

Obvoiusly capping the return renders the regulator on the punto rail usless, so;

A) How was my old setup regulated lack of mpi manuals etc doesn't help

B) How can I ensure the new one is regulated correctly? Other that installing a fuel return line and bodging it to the tank! That doesn't sound fun


Cheers for any thought or help


Kristian

Click to expand...

The regulators in the tank, its part of the pump If you pull it you can see a small regulator and a in housing return, problem solved.

It makes you wonder if you need to cap the return, because if your pump is less than 3 bar the regulator on the rail will never let fuel past Mind you I'm not the one who is gonna risk it.

Thats great then!!! I'm not sure what the pressure is set at thought now Hopefuly enough


I thought that may have been how it was regulated, but couldn'y find any facts and didn't want to risk full pressure at the rail.

TBH though, why is it regulated? Surely the injectors will only inject when they are triggered, and a higher pressure all the time would be benificial? Or is it a case of too much is not a good thing?

Also, aftermarket and manf regulators, wy do they return, and are not inline and resistive? I have loads of technical books from my local library but they don't address these issues

If I do need more pressure, I don't look forward to adjusting it

I need to buy some high pressure hose tomorrow to get the intake and fuel to fit, but at least worrying about regulators is no more.

I can ditch the regulator vacuum hose and tubing or the regulator then That'll look neater

The other option could have been to remove the regulator and link the return pipe up too a gauge :chin:

Cheers for your help dave, yor proving a great source of inspiration and knowledge

Cheers,

Kristian

Also, aftermarket and manf regulators, wy do they return, and are not inline and resistive? I have loads of technical books from my local library but they don't address these issues

Click to expand...

you want to regulate pressure, not flow rate. If you restrict the flow, you'll over stress the pump. so a regulator simply bleeds off excess pressure from the supply line back to the tank

fyi, modern cars use a variable speed pump - no need for a pressure reg, the ECU adjusts the pump as it needs it.

So obvious when its spelt out to you. Can't believe I didn't realise that lol :spin:

Cheers arc!


Kristian

i didnt understand how they worked at first, and then it clicked and i want "oooo yeah, duh!"