Fuel pressure issues

[old_skool]

Guys,

I am experiencing fuel pressure issues with my S50B30 (3.0ltr M3)conversion. I have done a fuel pressure test and am getting near enough 3bar at the FPR however I think I am still suffering occasional fuel starvation at WOT. It's only occasional but it is sometimes there.


The reason I am convinced is that the fuel pump is sometimes a little noisy. So rather than simply replace it with another E30 item, I was considering a standalone unit and possibly an adjustable FPR.

Is there a setup anyone can recommend that will be quiet and reliable?



Thanks in advance

[wrobstar21]

random i know but do u own a 2002? im after a turbo but probably can't aford it!

[320Touring]

Dameon- I know that fuzzy runs an upragted pump in his cozzy touring

flows more fuel, and costs less than a standard BMW PUMP...

[e30_Turbo]

Walboro 255 is the one to get, awesome performance, used in everything from scoobies to supra's!

Toby & Ant run them and they fit with minor mods, £80 or so new.

I have a adjustable FPR which someone wanted but never paid for, it's got a gauge too if you're interested?

HTH, Mark.

[old_skool]

Walboro 255 is the one to get, awesome performance, used in everything from scoobies to supra's!

Toby & Ant run them and they fit with minor mods, £80 or so new.

I have a adjustable FPR which someone wanted but never paid for, it's got a gauge too if you're interested?

HTH, Mark.

Cool. do they fit inside the tank still or are they external fit?

[e30_Turbo]

Internal fit, straight swap for the stock unit, IIRC a wire or two needs lengthening but over all it's a simple one, well for someone like you it will be anyway

These are even cheaper http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0181628593

HTH, Mark.

[old_skool]

Cheers Mark, what type of FPR and gauge do you have available. Sounds like I'm going to need one then

[Toby_Unna]

Dameon

these go onto the standard E30 in-tank cradle (which might need some modding with a file...); dead easy to fit.

however it's worth mentioning that they aren't especially quiet - not excessively noisy either but mine's louder than the pump that came out.

[e30_Turbo]

Cheers Mark, what type of FPR and gauge do you have available. Sounds like I'm going to need one then

It's a chrome fpr with a gauge stuck out of one side, it was the original "brain" to sort fueling prior to MS but was never used and has sat awaiting some use ever since.

Toby's using one too I can't find any pics here at work, Toby do you have one? If not I'll sort one out tonight.

There's some adpaters with it o fit certain fuel rails or just stick it inline, which is how it was going to fit on the M20.

HTH, Mark.

[Toby_Unna]

yeah hang on a mo then


...not the best, but you get the idea.

[ste]

I'm having exactly the same problems Dameon, definite hesitation at WOT, and especially if applying WOT after a long corner, i.e. off a roundabout or similar. All these symptons are also amplified if the tank is below 2/3rds.

Just to clarify, if I fit an uprated pump in theory I shouldn't also need to add an adjustable FPR as the standard FPR should just maintain standard pressure to the fuel rail?

[ste]

This has got me thinking actually... I'm using an M50b25 fuel rail with my M52b28 injectors in it. This means I've got the M50b25 FPR on the fuel rail. Is this still the correct 3 bar that I need?

[ste]

...also (apologies for complete hijack Dameon!), I'm getting appaling MPG at the moment, I'm getting maximum 220miles from a tank - my Sport with the 2.7 used to get 330 or so.

Related?

[old_skool]

^ I have a feeling that E30 fuel pumps are not giving the high flow required. Maybe not surprising is it, after all they are <15 years old.

In theory the FPR dumps pressure in excess of 3 bar back to the fuel tank, right? Hence the maintained fuel pressure should be 3bar even at WOT, I know mine is around 2.5 - 3.0bar at idle to WOT, although under real load, who knows? I'm not sure that the FPR's would be fifferent from B25 to B28, maybe a higher flow rating? Have you checked realoem and compared part numbers Ste?

I've ordered one of those HRC fuel pumps so I'll try it with the standard S50 FPR and see what happens, then maybe look at fitting an adjustable unit. I may do a free flow experiment into a 1 litre container with both fuel pumps to compare the actual flow rate. Sort of a before and after test.

The car is going to Paul at Circuit Motors next Wednesday for a rolling road session so we'll see what's what then :fingerscrossed:

I may very well need to take you up on that FPR then Mark. Thanks for the pics and input Gents

[e30_Turbo]

Always glad to help, if you need it just shout and I'll stick it on a next day for you.

The only input I can give re fuel pumps is 99% of the americans swap them straight away and all the swedes/norweigians ( sp?) will tell you anything over 300bhp needs a betters pump.
Just hope you fix it
@ Toby, cheers dude, mines still minty mint and chromie for now.....

[ste]

I'm only supposed to be putting 218bhp out, which is why I've dismissed the fuel pump as not being an issue before now... I'm tempted to change it anyway as like Dameon says it's probably the original 16 year old pump in there and it is pretty noisey.

[e30_Turbo]

I'm only supposed to be putting 218bhp out, which is why I've dismissed the fuel pump as not being an issue before now... I'm tempted to change it anyway as like Dameon says it's probably the original 16 year old pump in there and it is pretty noisey.

Interesting, my pump ( original ) is very quiet and only noticeable when either the fuel level is really low or when the pump primes, something MS does prior to ignition starting.

I'm wondering what Deamon's "pump test" will show, should be interesting!

@ Deamon, would you be so kind as to give us some feedback on that pump, might get one myself for that money, seems silly not too.

Thanks, Mark.

[Colonel Sanders]

i have a walbro 255 too from ebay, bought the escort cosworth one and modifyd my cradle like to fit like tobys

[old_skool]

I'm only supposed to be putting 218bhp out, which is why I've dismissed the fuel pump as not being an issue before now... I'm tempted to change it anyway as like Dameon says it's probably the original 16 year old pump in there and it is pretty noisey.

Interesting, my pump ( original ) is very quiet and only noticeable when either the fuel level is really low or when the pump primes, something MS does prior to ignition starting.

I'm wondering what Deamon's "pump test" will show, should be interesting!

@ Deamon, would you be so kind as to give us some feedback on that pump, might get one myself for that money, seems silly not too.

Thanks, Mark.

Cheers all,

For that money it has got to be worth trying, even as a process of elimination.

Thanks again for the help. I'll do a comparison test with the old and new pumps. Probably do the free flow rate into a litre container then time it and convert into l/ph, static pressure and maintained (running) pressure and note the observations. Hopefully there should be some improvement.

My pump is quiet most of the time but has senior moments occasionally. I'm sure that 16 years of use have taken even a small amount of toll on it's operating efficiency.

Going back to OEM pumps, the S50B32 (evo engine) fuel pump can achieve a pressure of 5bar and has a much larger body and fuel intake in the pump itself. Obviously the larger diameter inlet is required to manage larger fuel flows however I'm sure the E30 OEM pump could manage 5bar static, it's the maintained (running) pressure we are interested in, especially when the throttle is nailed into the engine bay - WOT.

I read on the Ireland Engineering website www.bmw2002.com that they recommend an adjustable FPR to see good power increases on M50 and S50 engines. Take a look. Unfortunately the information there is brief. Makes no mention of uprating pumps.

I'll report back with my findings as soon as the new pump arrives

[Jon_Bmw]

Just to back up what toby said. Aftermarket high flow fuel pumps are proper noisy.

You WILL think it is broken the moment you turn it on I can guarentee! At a guess, 5-10 times louder than a standard pump

[old_skool]

^ Good job I have a Db meter then, I'll measure that too

[Assault]

I've got a walbro 255 in one of my cars and its noisey as hell. Luckily my exhaust covers up the whine a bit. It is touching the bottom of the tank which doesnt help
I rewired it with another relay to ensure it was getting a good power supply but the E30 wiring might be alright. I also suggest thinking about an adjustable FPR as the stock FPR may not be able to handle the pressure increase from the more powerful pump and therefore your fuel rail pressure may be too high. Something to watch for anyway.

[Nickk]

I would be carefull with tie wrapping the pump to the cradle as petrol does melt some plastics
and the residue aint good going through the fuel system !

[buster]

I'm having exactly the same problems Dameon, definite hesitation at WOT, and especially if applying WOT after a long corner, i.e. off a roundabout or similar. All these symptons are also amplified if the tank is below 2/3rds.

I have this problem with mine after a roundabout or very long (taken fast) right hand bend.I am assuming that the evo pump i am using is functioning correctly,but getting fuel starvation as all the fuel goes to the passenger side of the tank.Not a problem with the standard e30 engine as it doesn't consume as much fuel.The solution i think is to fit a swirl pot.
Small pump feeds that ( standard e30 one would be fine) then a high pressure pump goes from the swirl pot to the engine.

what do you think ?

[oze30]

I have what seems like a fuel cutout when doing WOT changes from 2nd to 3rd. It's like it cuts out for a split second, then gets fuel. Will a new fuel pump cure this? It does have a newer pump/tank. I'm getting about 250miles from my tank, but i'm hammering it every now and then. Best Milege i got was roughly 270 on a motorway run with 3 people plus luggage and some rubbing over the bumps (hitting the brakes in a way), not bad considering it was a constant 90 ish !

[Toby_Unna]

I would be carefull with tie wrapping the pump to the cradle as petrol does melt some plastics
and the residue aint good going through the fuel system !

they come as part of the kit with the pump, and i didn't notice anything amiss when i had the pump out after a year or so.

[Gwynleym10]

Random idea, but do e36 m3's use the same size diameter fuel pipes? - Do they have such sharp "corners" as e30 ones have?

Just a thought.


I found my new fuel pump louder than my old one, I just put a bit of dynamat on the underside of the cover and its back to "normal" noise level now.

[old_skool]

Ok,

I fitted the new ebay fuel pump this afternoon. I was impressed with the quality of it and size wise it is very similar to the E30 pump. The box comes with everything you need include the short length of fuel pipe and the acoustic rubers for the pump. Even the new pre filter that comes in the kit looks excellent quality. The only additional part required was a new O ring for the pump housing and a couple of stainless steel zip ties.

The only mod was to cut away most of the metal bottom of the fuel pump bracket and that was it. I unsoldered the old E30 wires and resoldered the new pump on. All in all it took me just over and hour from start to finish, including removing/refitting the rear seats and carpet. The acoustic boot that comes with the pump fits really well and looks great quality btw.

The car started first turn of the key and idled along fine, which was a surprise because it sounded like the pump wasn't running. To my surprise it was! After a 20 mile roadtest, I can report that the pinking has gone and the performance is.........'rejuvinated' to say the least. So I am quite rightly chuffed to bits with it. As long as you have a soldering iron, I would say this is a very simple and worthwhile modification to make. The pump is so quiet you can hardly hear it.

It would appear that my fuel problems weren't really pressure related, moreso fuel flow rate.

Tomorrow it's booked in for a dyno session so we'll see won't we!

[Jhonno]

im waiting with excitement in my pants Dameon..

Mine still is sat with no head on

[old_skool]

im waiting with excitement in my pants Dameon..

Mine still is sat with no head on

Lol!

I reckon it's going pretty well now but we shall see.

Whatever the result I shall post a scan of the dyno sheet, warts and all 'coz I don't really care - it feels fast enough, I just want to make sure it is running right and is fit and healthy. As long as it's getting 286 then I'll be happy. lol.

[Jhonno]

its gotta placebo, should have stuck with a superchip n k&n innit bruv.. Nevermind this proper malarky..

[old_skool]

its gotta placebo, should have stuck with a superchip n k&n innit bruv.. Nevermind this proper malarky..

The 'ebay resistor' was out of stock so I had to make do with fitting an M3 engine.

[beardymat]

would it be ok to fit this type of pump to run with an m20b25 just in the short term. i want to do a few jobs on my car whilst it is still mobile in preparation for an engine swap that will require this type of upgrade. im just trying to reduce the time it will take to do the swap as i will have to take time off work so the car can be completed swiftly as i cant have it hanging round my workshop.

[hass]

hi guys just bought this item
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... :IT&ih=015

is this a good 1

[buster]

matt,
I think it will be fine fitting it now as the regulator dumps the surplus fuel back to the tank.
It may even improve it.