Technical fuel pressure regulator mounting

[Lecook]

Hi guys I thought id make a new thread up incase this the answer is ever needed again... so here goes

basically ive bought a cheap ebay special adjustable fuel pressure regulator, it only has mounting holes in the right hand side rather then the back or all 3 sides

My question is... does it need mounting upright or would it still do its job if I were to mount it say.. on its side or upside down as such... plan is to mount it In the old battery tray on the left hand side of the bay... I dont have a upper strut barace so mounting it to that isnt an option

Cheers in advance guys

lee

 

[LewisCinquecento91]

Hi lee, sorry I can't help with your question but your post grabbed my attention because my cinquecento is pouring fuel out of the tank causing me to believe there may be a pressure issue. What does this fuel pressure regulator do (apart from the obvious) and where is it?

Thanks!


'98 Broom Cinq Sporting

 

[fingers99]

On the cinqs it's in the throttle body. Really, really, can't see it being a factor in your case (or worthwhile in Lee's, come to think of it).

All it does is sets the rate at which fuel is delivered to the engine (and on the SPI cars that's done by returning the excess to the tank. Can't account for your symptoms, though.

 

[LewisCinquecento91]

Ok thank you!


'98 Broom Cinq Sporting

 

[LewisCinquecento91]

All it does is sets the rate at which fuel is delivered to the engine (and on the SPI cars that's done by returning the excess to the tank. Can't account for your symptoms, though.

The petrol in my tank seems to rise though, causing it to flow right out of the cap at a constant pace for a few minutes (on a full tank) and then just every now and then all other times. So on second thoughts could the regulator be a consideration? Thanks, sorry to change topic!!


'98 Broom Cinq Sporting

 

[fingers99]

Can't see it. If it was pushing that much fuel back into the tank the engine would protest.

There is a vent tube which runs from the tank to near the top of the main filler neck. I suppose there's a chance that this has been malfitted (I've an idea that there's a valve in it, too). Worth a look, but I think the filler cap is the more likely culprit.

 

[fingers99]

Can't see it. If it was pushing that much fuel back into the tank the engine would protest.

There is a vent tube which runs from the tank to near the top of the main filler neck. I suppose there's a chance that this has been malfitted (I've an idea that there's a valve in it, too). Worth a look, but I think the filler cap is the more likely culprit.

 

[LewisCinquecento91]

Yeah I can see two small pipes facing the floor behind the wheel arch near the filler neck. One of them is the overflow from where the fuel cap is, but I don't know what the other one is...but The top of it is wet and when I tap it, drips of petrol come out I've ordered a new cAp for now... Start with the cheapest solution first eh?!


'98 Broom Cinq Sporting

 

[cartledge_uk]

In answer to the op's question. It depends on the type of the regulator most of the newer types can be mounted any which way. If your unsure, then give it a a quick test.

 

[blu73]

mmmmm, please explain how angle could effect a FPR - i don't mean to be argumentative and i could be wrong but having had a few apart i cannot see how angle would stop them working properly. My rising rate FPR on the seiT is not at all upright, nearer to completely upside down actually.

 

[fingers99]

Would be odd, pressure reacting to gravity like that............

But assuming 8v and SPI, not a turbo or a second injector in sight, how are you going to by pass the first one, Lee?

I've run a 1242 8v with an absurdly expensive ported head, ported inlet mani, decent exhaust and 40mm TB. The stock FPR coped just fine.

 

[blu73]

Would be odd, pressure reacting to gravity like that............

well that was my thinking exactly - i hold my hands up and stand to be corrected but can't see it making any sense

 

[cartledge_uk]

Some of the old fpr are gravity fed. And like carbs need to be kept at the correct angle.

The op hasn't stated what he has. Therefore it could be some cheap Chinese bit of crap that uses 1960's technology.

 

[cartledge_uk]

mmmmm, please explain how angle could effect a FPR - i don't mean to be argumentative and i could be wrong but having had a few apart i cannot see how angle would stop them working properly. My rising rate FPR on the seiT is not at all upright, nearer to completely upside down actually.

So, in the one you had apart I presume it had a spring loaded check valve?

Not all of them used too.

As implied in my post above its almost impossbible to get a modern one that has issues with orientation. But if one has a ball check valve, it won't work.

I guess my posting on your thread trying to be helpful upset you in some way, so I apologise and will go back to skulking or another forum.

 

[blu73]

no idea why you think you have got my back up, we are just discussing, which is what the forum is for . I've had several apart but yes they all are rising rate ones with spring inside a chamber with a diaphragm and a vacuum line to them which clearly changes the pressure inside the chamber and thus changes how far the needle moves and the pressures that are getting through etc. My previous post was just to say i know they work at whatever angle cause mine is at a jaunty angle.

I appreciate they are not all like that and there is other types but i just wander how angle can effect one no matter what style it is - and i don't know how other types work cause i never taken them apart. I'm not having a go or anything like that, i'm just genuinely interested how the angle could make a reg not work properly. For example, i have never removed and looked inside the standard regulator fitted to an spi throttle body - i'm sure inside it must work differently to my rising rate reg but i still don't see how angle would effect how its working.

So was hoping you would be able to tell me/us what kind of reg is effected by angle and why it is effected by angle just cause such a comment i find interesting and think warrants explanation.

 

[Lecook]

Yes its a cheap Chinese ebay jobby... it was a genuine question... its more of a gauge for me to adjust the 1.4 16v in the cinq... after having the engine apart and some head work done there is evidence of cylinders 1 and 2 running lean... plan is to purley try and keep 3.5 bar in the rail...

I havent used a fpr before.. and like many are trying new things... thought It may be nice to put a tread up so people in future with the same question may find the answer without looking as much of a tool as I have... ill try it... I dont know the inner workings of them and didnt want to damage it in any way shape or form.... roll on the comments of cheap Chinese ****e fpr... again... if it cures the problem im hopeing it will then ill uprate to a decent quality one...

Cheers for the input as always...

lee

 

[fingers99]

What pump are you running?

There are small adjustable FPRs which fit in the place of the original ones.

Pressure may not be the issue -- and 3.5 bar is more than the test pressure of the injectors. Remember, fuel pumps are sold on the basis of delivery rate (gallons or litres/hour).

 

[Lecook]

Running a mk2b 1.4 fuel pump however theres evidence of det. In cylinders 1 and 2 which iirc are the 2 furthest away from the feed side of the 16v rail the idea of the aftermarket fpr is to hold the pressure in the rail if im correct??

Cheers

lee

 

[fingers99]

Well, allegedly. Whether that's the issue or not is a different kettle of custard.

Possible test is by using the valve fitting in the end of the rail to take a pressure gauge.

A couple of cures seem to be to bore out the fuel rail (suggesting that flow, rather than pressure, is the problem -- fairly common, this, in MR2 circles) or to take the flow to the middle of the rail (effectively shortening the distance it has to go. (Again, this is flow, rather than pressure).

Odd though, if there's det but no sign of the knock sensor being activated. Or..............

 

[blu73]

Well i would say don't trust the gauge on the cheap fpr - i got good quality inline gauges on the seiT and they tell a very different story to the gauge on the ebay special fpr.

Other thing to remember is that they control pressure in front of them - i seen endless people stick them on the wrong side and be confused nothing works properly anymore. It controls upstream. And example would be an spi setup, fuel goes in, across the injector and then into the reg on the return as it controls the pressure in front of it and returns whatever is left down the return. So you want to be sticking this fpr on the fuel line coming out of the rail not the fuel supply.