Anybody know what this is? '86 325es

[VIDA]

Stole this from a tech article on this site, but i have a small fuel leak from a line leaving my fuel pump. my car has this same style pump, as opposed to the later styles. anybody know what the fuel pressure regulator-looking thing is underneath the pump in the picture? i have one on my car that i'd like to replace while i'm taking hoses off, but i can't find documentation on it anywhere. thanks

dana

[Jeron]

http://www.realoem.com/bmw/showparts.do?model=1554&mospid=47321&btnr=16_0172&hg=16&fg=15

[VIDA]

thanks jeron,

after extensive googling, i found out it's also called the fuel pressure damper...in case anybody out there with an early-model e30 twin fuel pump setup needs to know.

[Buckeye325is]

From your description and the name given it on RealOEM, I believe your referring to the Absorber, are you not? I had thought that it was some sort of a pressure regulator. So what exactly is an Absorber and what does it do???
And, what is a Damping unit, I thought this was the filter? all be it a strange looking one.
I just spent 3-4 hours tonight taking it off, fabricating in a 90-degree union and installing a fuel filter after the pump and before the Absorber, whatever that is.

So where is the fuel filter and what are the purposes of those 2 things and what trouble did I just cause by removing the Damping unit???

I would appreciate and enlightened replies that might clear away my confusion.

[Schneller]

The fuel pressure damper drowns out uneven fuel pressure fluctuations (pulses) of the fuel pump resulting in a more steady fuel pressure at the injector rail & hence a smoother idle. If the fuel filter on an e30 isn't located above the external fuel pump pictured in this thread, then it is located in the engine bay along the left (driver's) frame rail/Strut tower roughly below the air intake elbow.

Schneller

Mike Morris
Schneller BMW Performance
26 Middle Rd.
Newbury, MA 01951
978.465.2002

[Buckeye325is]

I appreciate the info. I don't understand why BMW uses 2 different names to refer to components that do the same thing(DAMPING UNIT and ABSORBER). The only difference appears to be size and placement but they perform the same task from what I gather.
Oh, and yes, the filter was where you said it would be on the left front fender.

One last question, Is it going to cause any problems now that I have removed the HOSE DAMPING UNIT from the line? Ok, lets make that 2 questions?
Is there any aftermarket, less expensive fuel pump that can be substituted? The one on my son's 325 is making a whining noise that is getting annoying, or should I just leave it be?

Thanks,

Greg

[Schneller]

Buckeye,

You can remove the dampener & the car will run well enough.

Two companies make replacement pumps for your car:

Bosch & Pierburg.... BMW list price $274

We offer the Bosch pump at $192.

There is also a 2nd "in tank" transfer fuel pump which, if the external pump is whining, may not be operating. Hence the external pump strains to both transfer fuel from the tank & pressurize the fuel rail. The transfer fuel pump is often times damaged by improper lifting of the car. Check the underside of the tank at the RR ahead of the passenger rear wheel. If it's crushed (from a jack or lift pad) then the transfer pump that sits against the bottom of the tank there is probably damaged as well. It is also common that these transfer pumps as they age simply fail to deliver the required volume of fuel.
Pull up the rear seat, remove the access cover & listen or "feel" to hear the pump run. If it's silent it's probably dead (provided it has power & ground).

The Transfer pump is also available from Bosch, list is $250.50, we offer it at $189.

Let us know if we can be of further help.

Schneller

[Buckeye325is]

Mike,

The tank is undamaged, but I'm still going to check the transfer pump tomorrow. This is the second line pump on the car, the first was making the same noise but worse. I just thought that this one was probably going bad as well, but it makes sense that it would be problems with the transfer pump as you mentioned.

Now a new question, I finally finished the timing belt and water pump ect. on my daughter's 325e, I wanted to do this before trying to start it for the first time after buying it. I bought it this summer, after she saw from the road, sitting forlornly out in a field. It had been there for at least 1-2 years. (Actually, I did try to start it when I hauled it home, just to make sure it didn't sound out of time, ect. It coughed and tried to run on about 2 cylinders then I shut her down.
Tonight, I tried to start her....nothing. I tested the electrical system and found there was no power at the coil with the key on. Replaced the coil with a donor, still nothing. So I disconnected the wire going to 15 on the coil and jumpered that from the hot terminal on the firewall. Shazam, she runs; at least as long as I hold the wire to the terminal.

I know, a long story but I wanted to eliminate the chance of some one telling me to check the transfer pump .

So, do I just assume it's the ignition switch and attack it, or should I try to trace out the wire first or is there something else that could cause me to have no juice at the coil ???

If it is the ignition switch, can I clean it, or fix it some how; or do I just replace it.

Thanks

I appreciate all the help I can get.

Greg

[Schneller]

If she's got no power at terminal 15 at the coil, more than likely it is the ignition switch which you'd just replace. Check for continuity from the fat green wire at the switch, back to terminal 15 at the coil. If you have continuity then the wiring is OK. Next check the fat red wire at the switch for power. It should have power all the time, if not there's a problem from there back to battery positive. When you click the ignition switch over (provided the switch is good) you should have power at the fat green wire, and if your wiring is OK, power at the coil as well.

Solve this issue first before moving on to the fuel pumps.

Relative to the fuel pumps, make also sure that the pressure line from the external pump to the engine isn't crushed, as that will also cause a pump to strain.

Finally, if you don't have one already, get yourself a Bentley Repair manual for the e30 3 Series. It's gonna be your Bible for this car.

Good Luck!

Schneller