New Buzz from Fuel Pump on 72 450 - Page 2 - PeachParts Mercedes-Benz Forum

Gurunutkins · #16 04-24-2008, 12:45 AM

Hi Ron
the third bit is the pressure accumulator for the cis system. Dont need it for djet system. The blue regulator I bought from one of the boy racer shops on ebay for $19. I will look for one next time I go to ebay and send you the number. I actually mounted mine under the trunk next to thew pump as I didnt want to have the return fromk the first regulator mixing with the return from the engine regulator and trying to put everything down the return pipe. I wanted the first return as short as possible.
cheers
Barri

Gurunutkins · #17 04-24-2008, 12:54 AM

Hi ron
just had a look at ebay and there are lots similar to the one I have (shipping seems to have gone up a lot!) here is a number for the item (just stick it in the ebay search bar) 170212546563
cheers
barri

meltedpanda · #18 04-24-2008, 10:21 AM

perfect, thanks

Tomguy · #19 04-24-2008, 12:31 PM

Ron, my 4.5's pump always buzzed.
I am pretty sure you can hear it in at least 1 of my YouTube videos before the car starts. I have no speakers here so I can't verify for certain.

http://youtube.com/user/axia24

350SL4spd · #20 05-02-2008, 04:59 PM

Hey Gurunutkins,

Great post! I'm in the middle of a similar retrofit, as the old style pump/filter set-up is either no longer available or ridiculously over priced.

Can you post a picture of your final pump set-up? I'd really like to look at how it was plumbed.

Also, did you delete the Damper (round can thingie) AND the CIS Pressure Regulator?

Thanks!

PS: Are you adding a fuel pressure gauge anywhere in your set-up? If so, where? I was thinking about adding one, but undecided as to where to plumb it in...

Gurunutkins · #21 05-03-2008, 12:57 AM

Hi 350
I will try to take some pics this weekend. the system is back together but because of other changes with my megasquirt system I dont have the pressure regulator inline. I can show on the pictures how it all goes together though. It may only be sunday as i am wiring up my 450sl CIS with megasquirt and thats a priority for this weekend before my wife kills me!
I have to take some pics of converting my mercedes seats to jaguar seats as well so will do the whole lot one go!

Basically though I took the acumulator out of the system and the screw in pipe for the acumulator will actually fit into the NAPA gold fuel filter as it comes with an adapter to fit the threaded pipe (it comes in the box with the filter). its best to keep the swirl can in the system though. I plumbed the first pressure regulator (the blue one in the pics) immediately after the filter at the rear of the car under the trunk and then plumbed that into the fuel return from the engine regulator right at the junction with the tank using a y connector. I originally wanted to put the blue regulator in the engine compartment but the fluid flow dynamics only just worked out to have both regulators feeding into the return line in the engine compartment, the figures were much better to run the initial return line to join the original return line as close as possible to the tank. if the return line had been 3/8 (9.5mm) instead of 5/16 (8mm) there would not have been a problem with flow rates. should make more sense when you see the pictures

.
cheers
Barri

Gurunutkins · #22 05-03-2008, 10:41 AM

HI 350
I just re read your post, I think we may be talking a little at cross purposes, the can thing is just that, a swirl can to get good flow into the pump after the 90 degree turn in the pipe and you need that. the d jet damper and pressure regulator are at the back of the engine next to each other and you need to keep them. the big can thing at the top of the CIS fuel pump assembly is the CIS accumulator and you dont need it for Djet (sell it on ebay). I have put in some pics of mine that I had on the computer and labeled the bits. Ill take new pics of mine this weekend
cheers
barri

350SL4spd · #23 05-03-2008, 12:39 PM

Barri,

I was definitely referring to the swirl can (my FSM calls it a damper) and the accumulator (FSM calls it a pressure reg), so I'm picking up what you're laying down.

I'd still really like to see a pic of your set-up. I'm still a bit confused about the how you plumbed in the blue regulator that you used (inc. the return line business).

Thanks!

Gurunutkins · #24 05-03-2008, 09:31 PM

Hi 350
took some pictures but they may not be that helpfull as I am just changing systems on my cars again! also i would suggest you do things differently to mine as you have the CIS swirlcan (I didnt when i originally did mine) which has 3 inputs as opposed to 2 on the djet swirlcan.

Mine currently does not have the pressure regulator under the trunk as I have it in the enginebay now but will be relocating it back to under the trunk. as you can see I have the CIS pump connected to the more modern filter with the pipe with a banjo fitting at each end. the filter has a screw fitting on the other end so i got a scrap pipe and cut it to connect straight into the input on the blue pressure regulator (shown in the next picture) the output from the regulator I plumbed straight into the pipe to the engine using a brass 1/4inch id barbed fitting also in the picture. The return oin mine (the smaller spigot on the blue regulator I plumbed into the return from the engine right where it enters the tank. I would change this on yours now (which is what I am doing right now!) as you have the CIS swirlcan it has a 3rd small spigot that accepts excess pressure overflow from the accumulator and I would plumb the return from the pressure regulator straight into the return spigot on the swirlcan.

you dont need the accumulator at all so just remove that section from the pump holder assembly (its just 2 nuts as i remember).

I have scanned in a sketch of what i would do remember that the bit of pipe to the engine gets connected to the existing piping with the 1/4 inch id brass barb and good clamps. also the 50psi rubber pipe is good enough for the ring in the engine but the plumbing under the trunk where you reduce it to 60 or 70 psi with the blue regulator should all be with 180 psi rubber tubing.

Hope it will work for you, worked fine for me. if you drop me your address offline I can send you the short piece of pipe for the connection to the filter. I have tons of old pieces of fittings.
cheers
Barri

Gurunutkins · #25 05-03-2008, 09:34 PM

I should add that the picture with the pump is actually of a djet pump with a modern filter, the cis pump is in the next picture. I just shot pics of what I had in the garage
cheers
barri

Gurunutkins · #26 05-09-2008, 07:23 PM

HI 350
I had to refit the CIS pump with the pressure regulator. here are some pics of it. I always use the 180 psi piping as if the engine regulator fails then I want to make sure i can contain the pressure at each spot. although the regulator says 32psi it is set at 50psi, it just reads 32 psi because the engine regulator is only holding pressure at 32psi (should be 28 but I run 32). however if that faisl then the blue regulator at the back will dump pressure above 50psi back into the swirl can (plumbing back into the second spigot on the CIS swirlcan worked out really well). To set the pressure on the blue regulator just clamp the return line in the engine bay with a p[air of vise grips with rubber tubes over the jaws. If you want full size pictures just email me
cheers
Barri