New E21 owner - Gas smell/leak from fuel distributor, where to start?

[JBT]

Hi everyone,

Just wanted to introduce myself as I just picked up a 1977 320i 4spd manual. I previously owned a 1987 VW mk2 GTI 8v, 1997 VW mk3 VR6, and my current family/daily 2009 E91 LCI. I've always wanted an older BMW to work on and finally found one with low mileage 109,00km.

Body/Exterior:
Is straight, some minor surface rust, no rot. Weather stripping all around is still in great shape, no leaking as far as I can see. Door seals new. Will pursue repaint and euro bumper conversion down the road.

Interior:
Blue vinyl, overall great shape other than a tear in the drivers seat and small crack on the dash. Carpet and headliner still looks brand new. Sunroof crank works, doesn't leak. Electronically everything works, original am/fm radio.

Steering/Suspension:
Plan is to replace with poly bushings, debating on bilstein shocks/sport springs or coils.
I think I have the steering rack with the damper. Appearance of the steering rack is quite a mess. Torn boots and what looks to be some thick grease coated on the rack. Any idea what this is about?

Engine/Fuel:
Some sweating around the valve cover and oil pan gasket.
Starts up with no hesitation. Previous owner said it sat for considerable time before he bought it. Previous owner had some work done with the fuel system and managed to get it running. There's to be some obvious gas sweating/leaking from the fuel distributor where it mounts on the air flow box. I'm assuming that's where the strong gas smell is coming from (enough to smell up the garage). No gas smell in the cabin or trunk, but will look into the fuel system at back end at some point.

Overall I'm super excited to work on this car. First on my list is to address the gas smell and fuel distributor leak and hope to get some guidance on where to start. Maybe FD Rebuild kit or remanned FD? Is there an O-ring between the FD and air flow box that can be replaced to remedy the leak?

Goal is to get this into a solid weekend cruiser to boot around with the wife and kids. Looks like a great community here and look forward to hear from you. Thanks in advance!

Justin

[320iAman]

"There's to be some obvious gas sweating/leaking from the fuel distributor where it mounts on the air flow box. I'm assuming that's where the strong gas smell is coming from (enough to smell up the garage). No gas smell in the cabin or trunk, but will look into the fuel system at back end at some point."

Check all the Banjo bolts that connect fuel lines to the Fuel Distributor and see if one or more is wet from fuel , could be copper sealing washers are not sealing, the O-Ring that is between the Fuel Distributor and the Air box does not seal up any fuel , its function is to cushion the Fuel Distributor from metal to metal contact with the Air Box. If the copper sealing washers are good-you may have an internal leak within the fuel distributor and yes they can be rebuilt-they have a thin flexible plate and several o-rings inside that keep the fuel contained-there are kits available. Check all the gasoline hoses as well connecting to the fuel distributor. No 1 priority is find and locate where the fuel smell is coming from and then repair it.

Randy

[OLD MAN]

I have injector lines that leak at the injectors - I think I need new lines as I have worked on fixing this a few times now.

My car starts right up but has a miss for about 5 seconds.

[jclausen]

All so the rubber fuel hose at the clamps can leak vapors when cold and then as things heat up the smell will go away because the hose becomes pliable

[cgifool]

I had good luck finding a pesky fuel smell with a cheap "combustible gas detector" I got off ebay for about $30. Turned out to be a cracked very small vent tube in the trunk.

[JBT]

Check all the Banjo bolts that connect fuel lines to the Fuel Distributor and see if one or more is wet from fuel , could be copper sealing washers are not sealing, the O-Ring that is between the Fuel Distributor and the Air box does not seal up any fuel , its function is to cushion the Fuel Distributor from metal to metal contact with the Air Box. If the copper sealing washers are good-you may have an internal leak within the fuel distributor and yes they can be rebuilt-they have a thin flexible plate and several o-rings inside that keep the fuel contained-there are kits available. Check all the gasoline hoses as well connecting to the fuel distributor. No 1 priority is find and locate where the fuel smell is coming from and then repair it.

Randy

Thanks for all the tips everyone. Appreciate it. Dealing with gas certainly concerns me which is why I want to address this asap.

I'll give the area a good clean, check/tighten the banjo bolts/washers and then observe any forming wet spots. Could I simply disconnect all the lines from the FD and replace all the copper washers? If so is there any pressure in the lines to consider?

here's some pics. Looks to be some wet spots and some sludge between the FD and air box.
IMG_20200530_194309.jpg
IMG_20200530_194318.jpg

[320iAman]

"Could I simply disconnect all the lines from the FD and replace all the copper washers? "

Yes, there a few lines that use specialized sealing washers, Realoem has a parts list with bmw numbers for all of these sealing washers. #'s 3,6, and 7.

https://www.realoem.com/bmw/enUS/sho...diagId=13_0110

Randy

[40320i]

Welcome fellow Calgarian,

I picked up my '82 320i in October. Snowed a week later and had to put it in the garage for the winter before I had a change to drive it much. 104,000km, zero body rust (lots of under cartage and hidden rust was found later) and spotless interior. I'm extremely new to mechanics work so I have no idea if I over paid or not ($3200 on Kijiji).

Finally got her out in April and started experiencing fuel issues. Took forever to start, so I replaced the external fuel pump, accumulator, hoses and fuel filter. This helped the problem for a bit but I'm guessing the fuel filter is plugged again because the new fuel pump is struggling and making a ton of noise. When I replaced the external system, I found a ton of rust, which is always a bad sign. I'm experiencing the fuel smell and fuel leaks if I completely fill my tanks. Pretty sure I'm going to drop the tanks and replace all the hoses and seals.

Other than that, I haven't experienced too many major issues. My blinkers wouldn't work but once I repaired the hazard light button they started working (I guess that entire system is tied together). Also, my wipers wont stop once they are turned on. I have no idea how to fix this problem but I don't drive her in the rain so it doesn't really bother me. My lack of experience caused me to replace the alternator before realizing that my issues were in the fuel system.

Feel free to shoot me a private message, maybe we can help each other out if we come across similar issues.

Chris

[cgifool]

My blinkers wouldn't work but once I repaired the hazard light button they started working (I guess that entire system is tied together).

Now there's an understatement!

ps. welcome to the obsession!

[JBT]

Welcome fellow Calgarian,

Feel free to shoot me a private message, maybe we can help each other out if we come across similar issues.

Chris

sounds good, nice to have a local to share tips with.

As for an update, seems the FD internals are likely the issue. First thing yesterday morning i did a thorough clean up of the FD, drove to work and then checked around lunch time to find a clean and dry FD. Soon as I got home there were wet spots, most notable were at the middle contact point between the 2 halves of the FD (failed diaphragm?) and around the flathead 3 screws/bolts that mount the FD on the airbox.

At this point I'm pretty set on getting a remanned FD to replace as soon as possible. I will also a get rebuild kit for this leaking FD with intent of having a spare.

[320iAman]

Sounds like the "sealing compound" on the diaphragm either top or bottom or both is spent, there may also be leaking around internal O-Rings that contribute to gas coming from the Fuel Distributor Halves, yours is non adjustable one, these can be rebuilt by shops or diy. FAQ's has E21 Fuel distributor rebuild on adjustable FD's,, non adjustable FD are actually easier.

DSCI0406.JPGDSCI0118.JPG 1st picture all new o rings in, Indian Head Shellac applied and ready too put the plate and halves together, 2nd picture whats inside, yours wont have small fuel adjustment screws below the plate. I'm running this rebuilt fuel distributor now and for some time.

Randy

[JBT]

Sounds like the "sealing compound" on the diaphragm either top or bottom or both is spent, there may also be leaking around internal O-Rings that contribute to gas coming from the Fuel Distributor Halves, yours is non adjustable one, these can be rebuilt by shops or diy. FAQ's has E21 Fuel distributor rebuild on adjustable FD's,, non adjustable FD are actually easier.

DSCI0406.JPGDSCI0118.JPG 1st picture all new o rings in, Indian Head Shellac applied and ready too put the plate and halves together, 2nd picture whats inside, yours wont have small fuel adjustment screws below the plate. I'm running this rebuilt fuel distributor now and for some time.

Randy

Thanks for the info, been reading up all the diy instructions last night, while most cover the steps when the FD is off, there's no mention of basic steps for prior removal like lines/banjo removal. Is it safe to remove lines and expect some gas spillage? Or is there any pressure in the lines to be concerned about? I have about 1/4 gas in the tank if that has any affect on anything.

Being a non-adjustable FD, would mine be more or less a disconnect of lines remove the FD, rebuild FD and reinstall? Maybe a silly question being "non adjustable", but is there any adjustment or calibration of others parts involved or do we expect the car to start right up when reinstalled? Couldn't find a clear mention of this.

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[320iAman]

Once the car has been sitting for hours the pressure in the lines is minimal, there is some gas that comes out of the lines yet it is not a lot a rag will do.

One less line-the Frequency Modulation Valve line.

No adjustment or calibration of the fuel distributor on non adjustable Fuel Distributors.

The only adjustment would be the Air/Fuel Adjustment once its installed and maybe not.

Your Fuel Distributor is a Bosch 0438100023

Here are two kits with new plates with all o-rings $79, $70

https://www.ebay.com/itm/0438100023-...ss!95821!US!-1

https://www.ebay.com/itm/Bosch-Fuel-...AAAOSwuk1Zvo4R


Here is a rebuilt Fuel Distributor by Python Injection -now out of business- I know this guy and he is good people--I bought a brand new Bosch ECU from him for $150--very very good price. His name is Randy. $190 + $12 shipping --1 Yr Warranty, This is buy , install, and drive----best price for rebuilt---only 1 available,, Randy here deals in MB parts yet gets deals where he finds them.. He'll work with you for shipping to Canada--contact him thru e-bay if you want to buy,install , and drive otherwise rebuild kits above--other sellers of rebuilt fuel distributors ~ $500 with 1 yr warranty, send yours in, exchange, ect.

s-l1600.jpgs-l1600a.jpg

https://www.ebay.com/itm/Re-Manufact...5.c10#viTabs_0

Randy

[dreiermann]

I rebuilt my fuel distributor, there is probably a thread somewhere here in the forum that talks about it. I found the info on a Porsche 928 site (it was the 928 Owner's Club, the article is by Richard Andrade). It is really not difficult to do if you just keep track of the parts and keep everything super-super clean (I worked over a stainless-steel tray the whole time to keep everything together and clean). Somewhere, maybe it is on the 928 site, is a list of the o-rings that you need to rebuild everything. I ordered them all from McMaster-Carr for something like $15. The first time I put it together I used Indian Head Shellac, but that did not work well - it ended up leaking and was very messy. Then I cleaned everything up again and re-assembled without the shellac - it has been working beautifully ever since (more than a year if I remember correctly). That may not have been the case though if there had been corrosion or pitting on the mating surfaces or elsewhere in the FD - if you open it up and see signs of corrosion, you may need a completely new part. With mine, the original problem was that one of the large o-rings in the middle was messed-up, and it may have been damaged during the original assembly due to some sharp edges in the FD body (those edges cut up the first o-ring that I installed there), which lead to subsequent failure.

[dreiermann]

I found the info that I copied about which o-rings to use, here it is:

Fuel Distributor O-Rings

There are 3 o-ring sizes. The material MUST BE VITON. If you use standard buna-N they will fail. They can be purchased in bulk from Mcmaster.com, or switlikbob has recommended
The O-ring Store where they can be purchased individually.

On the metering assembly (CS=cross section):
(2) 2mm CS - 15.5 ID x 19.5 OD
(4) 2mm CS - 7.5 ID x 11.5 OD

And the metering assembly bore in the FD housing:
(1) 3mm CS - 18 ID x 24 OD

I priced them out on the O-ring store.com and they came up to $15.84. Not bad...

For the pressure regulator:

Small o-ring for old style needle/crimp piston (shown on the left below):
Viton 2x4mm (cross section x ID)

Small o-ring for new style 1 piece piston (shown on the right below):
AS568A size #008 - 3/16" ID x 5/16" OD (~ 5x8mm) These are probably not for 1977s

Large o-ring to seal regulator body to fuel distributor housing:
Viton 2x7mm (cross section x ID)

- - - Updated - - -

[cgifool]

How often is it necessary to replace the metal diaphragm?

[dreiermann]

I can only say that in my case, the diaphragm was in perfect condition so I just put it back in. It seems to be extremely delicate though, like you could destroy it with a sneeze.

[JBT]

Once the car has been sitting for hours the pressure in the lines is minimal, there is some gas that comes out of the lines yet it is not a lot a rag will do.

One less line-the Frequency Modulation Valve line.

No adjustment or calibration of the fuel distributor on non adjustable Fuel Distributors.

The only adjustment would be the Air/Fuel Adjustment once its installed and maybe not.

Your Fuel Distributor is a Bosch 0438100023

Here are two kits with new plates with all o-rings $79, $70

https://www.ebay.com/itm/0438100023-...ss!95821!US!-1

https://www.ebay.com/itm/Bosch-Fuel-...AAAOSwuk1Zvo4R


Here is a rebuilt Fuel Distributor by Python Injection -now out of business- I know this guy and he is good people--I bought a brand new Bosch ECU from him for $150--very very good price. His name is Randy. $190 + $12 shipping --1 Yr Warranty, This is buy , install, and drive----best price for rebuilt---only 1 available,, Randy here deals in MB parts yet gets deals where he finds them.. He'll work with you for shipping to Canada--contact him thru e-bay if you want to buy,install , and drive otherwise rebuild kits above--other sellers of rebuilt fuel distributors ~ $500 with 1 yr warranty, send yours in, exchange, ect.

s-l1600.jpgs-l1600a.jpg

https://www.ebay.com/itm/Re-Manufact...5.c10#viTabs_0

Randy

Thanks Randy, appreciate all your detailed replies and info. I've actually been looking at all the options you mentioned (saved in my ebay watchlist as we speak) and debating which route to go. I actually msg'd about the Python FD to ask about whether the o-rings were viton, but response couldn't confirm it and I couldn't find much on Python either. For the price seems like a good buy and worth trying. In addition I will likely venture to one of the mentioned rebuild kits for my current FD to gain a spare.

I got some info from Colin at K-Jet in Australia. Said installing new FD's are not typically "plug and play" due to relationship between FD center piston and air flap not being the same between 2 units. And that install steps following a rebuild would include things like "bridge fuel pump relay" and watch for fuel to come out of injector line outlet ports, and adjust mixture screw (3mm allen key) to achieve correct mixture settings and other things. I found a youtube video which I think demonstrates this, but on a benz. These are things I'll want to read up some more to be comfortable with install.

Either way, I'm pretty set on going for the Python remanned FD and will see how it goes from there.

[320iAman]

Sure,,Python FD is a good value and I doubt Viton,, Viton is a plus yet many fuel distributors have buna ect from the factory and ran for a very long time, Viton is better and while its a part viton is the way to go and will last longer than buna.

Read FAQ's---there is described how to set your baseline up for the Air / Fuel Mixture by listening for the squeal of the fuel injectors spraying fuel , ect.---do this if it wont start up, then next.

What I'd do is buy, install , and start up and adjust the Air/Fuel mixture on the fly with the car running, by listening to the motor and revving it up and let the adjustment runs its course( 30 second- 1 min) you'll be good in the neighborhood. The set screw that adjusts the A/F mixture is on the platform the fuel distributor is secured too. ( long 3 mm Allen wrench is your tool)Clockwise adjustment enriches A/F mix, counterclockwise leans air/fuel mix. It generally takes a very small adjustment to hear the change in the motor idle and its stability--not back firing ect when revving.
Of course driving it around is necessary as well and if under load it starts back firing, low power, ect then adjust and drive around some more till its good in the neighborhood.

If the motor heats up very fast as seen on the temperature gauge--this is too lean--clockwise adjust to cool it down.

I adjust mine with the car running, even when lean or rich they will start up with a new install, been there, noticed it , and adjusted on the fly to stable idle ect with my new rebuild in faq's.......buy, install, and drive( adjust if necessary). if I were too quess I'd say new startup will be rich and needs to leaned- less loss of fuel pressure-new o-rings and new sealed plate, so adjust is too lean till stable idle and clean revving. I quess my quess is more than a quess...

How often is it necessary to replace the metal diaphragm?

Its not a time factor with the diaphragm when the plate becomes more than slightly dented in the area where the spring valve seats contact the diaphragm its time to change it out to a new one.

auf wiedersehen for now.

Randy

[JBT]

Sure,,Python FD is a good value and I doubt Viton,, Viton is a plus yet many fuel distributors have buna ect from the factory and ran for a very long time, Viton is better and while its a part viton is the way to go and will last longer than buna.

Read FAQ's---there is described how to set your baseline up for the Air / Fuel Mixture by listening for the squeal of the fuel injectors spraying fuel , ect.---do this if it wont start up, then next.

What I'd do is buy, install , and start up and adjust the Air/Fuel mixture on the fly with the car running, by listening to the motor and revving it up and let the adjustment runs its course( 30 second- 1 min) you'll be good in the neighborhood. The set screw that adjusts the A/F mixture is on the platform the fuel distributor is secured too. ( long 3 mm Allen wrench is your tool)Clockwise adjustment enriches A/F mix, counterclockwise leans air/fuel mix. It generally takes a very small adjustment to hear the change in the motor idle and its stability--not back firing ect when revving.
Of course driving it around is necessary as well and if under load it starts back firing, low power, ect then adjust and drive around some more till its good in the neighborhood.

If the motor heats up very fast as seen on the temperature gauge--this is too lean--clockwise adjust to cool it down.

I adjust mine with the car running, even when lean or rich they will start up with a new install, been there, noticed it , and adjusted on the fly to stable idle ect with my new rebuild in faq's.......buy, install, and drive( adjust if necessary). if I were too quess I'd say new startup will be rich and needs to leaned- less loss of fuel pressure-new o-rings and new sealed plate, so adjust is too lean till stable idle and clean revving. I quess my quess is more than a quess...

How often is it necessary to replace the metal diaphragm?

Its not a time factor with the diaphragm when the plate becomes more than slightly dented in the area where the spring valve seats contact the diaphragm its time to change it out to a new one.

auf wiedersehen for now.

Randy

Thanks again Randy. Appreciate your explanation. I pulled the trigger on the Python FD from Randy on ebay. Got a better price than listed which helps offset the shipping to Canada. I'm sure Covid will delay shipment. Will update once it arrives.

In the mean time, I'm reading up on suspension and steering. I see tears in control arm ball joint boots, tie rods boots and steering rack bellows. Being 1977 I believe I have the steering rack with the damper as per realoem. Seems to indicate 2 different part#s for the bellows and tie rods vs the non-damper rack.

[cgifool]

Thanks again Randy. Appreciate your explanation. I pulled the trigger on the Python FD from Randy on ebay. Got a better price than listed which helps offset the shipping to Canada. I'm sure Covid will delay shipment. Will update once it arrives.

In the mean time, I'm reading up on suspension and steering. I see tears in control arm ball joint boots, tie rods boots and steering rack bellows. Being 1977 I believe I have the steering rack with the damper as per realoem. Seems to indicate 2 different part#s for the bellows and tie rods vs the non-damper rack.

Yeah the right side boot is a different diameter along with the different sized rubber dohickey on the inner tie rod that it slides over.

[320iAman]

Thanks again Randy. Appreciate your explanation. I pulled the trigger on the Python FD from Randy on ebay. Got a better price than listed which helps offset the shipping to Canada. I'm sure Covid will delay shipment. Will update once it arrives.

Sure, His Name is Randy Steele and he did the same thing for me on the ECU purchase he told me what his bottom line was and adjusted the price downward some and I bought it. You can rebuild the Fuel Distributor you have on the car now at your leisure and have a backup .


Randy

[JBT]

After a month, finally got the FD in the mail. I also replaced the gas cap with a new oem cap. Install for the FD was straight forward as mentioned. Upon startup, the car turned over but immediately died. Tried few more times and tried to pump the throttle but hesitated and died. Finally managed to start the car while keeping a steady throttle around 2000rpm, kept it there for several minutes which I assume gave the car a chance to adjust and at last the car maintained a steady idle. Now came to the mixture adjustment with the 3mm allen. Took the car for a spin in the neighborhood and noticed the engine really struggling towards 3000rpm. Followed adjustments mentioned by Randy and the FAQs. Went for another spin and car is back to running smooth again at higher revs. Will monitor and gas leaks and smells. Thank you all who have contributed to this thread. Looking forward to the next fix.IMG_20200718_151930.jpg00000PORTRAIT_00000_BURST20200719214907411.jpg

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[dukedkt442]

Great thread, I can almost guarantee I'll be traveling down this road on mine as well!