Fuel accumulator?

[Andrewcarelock]

Hey guys, I’ve had a couple 320i’s over the last few years and have always used these forums to help in my repairs. Finally made an account to ask for some guidance. I’ve been having a warm start issue on my 83 320i that has recentlybecome a cold start issue as well. I’ve read every forum post on warm start, vacuum, and cold start issues that I could find and just completed testing the accumulator after going through the complete vacuum system including gas lines. I’ve seen two different guides on the accumulator test- one says that if there is any leakage at all from the accumulator (when jumping the fuel pump) then the diaphragm inside is bad, another says that a little bit of leaking at the start of the test is normal. When I tested, I found that at the very start that the accumulator leaked out maybe 3-5 ml of gas and then had a fairly consistent drip once every 15 seconds or so. It was such a slow drip that it was hard to tell wether or not if it was just residual from the beginning of the test or if it was continuing to “leak”. Either way, does this sound to you guys like a bad accumulator or would your bet be on something else? The symptoms of my problem is that the car would run when cold for about 2-3 minutes and then the idle would start dipping and then raising again like it was trying to save itself, eventually the idle would dip so bad that it would just die unless I feathered the throttle. In the last week it has started to just die when trying to idle cold also.. I recently (2 months ago) took the car to a reputable mechanic who set my fuel, timing, and reset my valves. He told me about the problem and said he thought it was the o2 sensor, which I have also tried replacing with no change in issues. Sorry for the long post, just trying to fill everyone in on all the details as best as possible.
Thanks in advance to anyone who might have an idea to help!

[epmedia]

Hi Andrew and welcome to the forums.

...I found that at the very start that the accumulator leaked out maybe 3-5 ml of gas and then had a fairly consistent drip once every 15 seconds or so...

The 'one drip every 15 seconds' is not enough to cause performance issues after the engine gets started. It will however cause loss of 'rest pressure', which is 1) a start-up problem when the fuel is hot and 2) maybe too many drips after sitting overnight (because may need to re-prime the fuel system, which takes a several seconds). If that drip is because of leaky accumulator internals, the accumulator should be replaced. * it is normal to loose all rest pressure after some time, not normal for the fuel supply lines to drain back to the gas tank.

The 3-5 ml is concern if it does that every repeated test. Do several tests (1-2 hours between the tests), keep the flex-hose disconnected/plugged between the tests so it cannot put fuel to the accumulator's flex-hose connection. If that 3-5 ml continues as you describe, the accumulator should be replaced.

Hope I explained all that ok.

ps: did you also replace a 3 pieces of fuel hose on the suction side of the external fuel pump (at the metal "Y" connection)? Any leak on the suction side of either fuel pump will cause air bubbles in the fuel system.

Have you replaced the fuel filter while troubleshooting?

Here's a picture of basic components inside the fuel accumulator.
* the 'spring chamber' will get fuel inside because of the flex-hose connected to it, and from leaky accumulator internals.
accumulator.gif

[Andrewcarelock]

Thank you for the super detailed reply epmedia! Very good explanation.
I have done the test multiple times now and have found that the initial little stream is present with every test regardless of the interval of time between tests. I believe I will need a new accumulator after reading your advice and finding the results that I have in the tests.
As for the 3 hoses, I believe they have all been replaced, but I have not done it myself. The current hoses installed are not braided cloth like what I read they would be if they were the originals. I have inspected them and they look and feel quite new. However I do have one braided cloth hose under the rear seat beneath the cover that exposes the top of the gas tank. The hose is about 2-3 inches long. I haven’t read anything about this specific hose and am unsure if it would cause any air to get in the system. All others in the vicinity look good though.
I haven’t replaced the fuel filter either. That probably should’ve been my first try as it’s so cheap, but I’m waiting to order parts untill I can get a list of possible causes so I can just buy everything at once and not have to pay shipping multiple times 👍🏼

[okieflats]

However I do have one braided cloth hose under the rear seat beneath the cover that exposes the top of the gas tank. The hose is about 2-3 inches long. I haven’t read anything about this specific hose and am unsure if it would cause any air to get in the system.

that would be the vent hose and would not cause air to get to the fuel pump. There is both a very short and a long one, they are 1/2 inch or 12mm braided hose that lead to the trunk for vent.
Camera Shots 588.jpgCamera Shots 586.jpgCamera Shots 585.jpg

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you see that white plastic Y-fitting? It connects the long vent hose from the left tank, to the very short vent hose for the right tank, then the third leg of the "Y" fitting goes to the trunk vent.

[okieflats]

Where is the best place to buy an accumulator? I think I should get one too. Rock Auto doesn't have a lot of this stuff. They are good for buying windshield wiper blades and oil filters.

[Andrewcarelock]

Okay cool so it looks like I should be good to go as far as hoses go as the only braided cloth in the series is the short one on my car! Looks like I’ll be ordering a fuel filter, accumulator and some orings for the fuel distributor. Fingers crossed it’s not something else. I’ll update The post whenever I can get the parts and install them

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Where is the best place to buy an accumulator? I think I should get one too. Rock Auto doesn't have a lot of this stuff. They are good for buying windshield wiper blades and oil filters.

Okieflats - I’m about to order my accumulator from “Fcp euro”. They seem to have it for the cheapest price.. here is the part number if you would like to try and find it anywhere else for cheaper. 0438170007 let me know if you do!
Other than that I use “pelican parts” for all of my 320i goodies.

[okieflats]

This is from a 1983 model like yours. You would have two tanks just like this. The braided lines are vent only. You have one short one and one long one. Don't need to change them I'd suppose. You also have that large diameter hose shown in the picture connecting the two tanks.

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Did you remove the in-tank pump to see what it looks like?

[320iAman]

16121118899.jpg FCP euro good choice-lifetime warranty

Randy

[Andrewcarelock]

Got the parts quick from fcpeuro, I just took forever to order them.
Anyway, I just got the accumulator and fuel filter both installed and unfortunately neither part was the cause of the issue. Now the car doesn’t need to warm up to die. Basically, if I don’t have my foot on the throttle at least a little, the engine will just stall out.
I adjusted the mixture screw one turn out to see what it would do and found that it’ll stay running for a while but it’s idle is erratic jumping up to 1500rpm and then dropping nearly stalling out, but then saving itself again by jumping up to 1500 etc... untill it dies about 2 minutes later. this is exactly the same as the original issue just now it falls on its face right away with the mixture screw in its original position. (Again unless I’m at least feathering the throttle)

I think I’m down to checking the fuel pumps. I’ve had fuel pumps go bad before, and both times the car just died and seized to start. So it just hasn’t been the first suspect in my mind.
Any thoughts?

[cgifool]

I'm wondering if your engine is too lean when cold. Have you checked your cold and hot control pressures?

Also have you done a comprehensive search for vacuum leaks?

[Andrewcarelock]

It could possibly, but I wasn’t having any cold start issues before. My main issue is when the car warms up. I haven’t checked for hot and cold control pressures, I’m not quite sure how to to test for them. Before replacing fuel filter and accumulator I’d only have the issue after the car warmed up for about a minute or so. Since replacement, it’s doing having the same symptoms with the addition of not wanting to start cold. I have tested for vacuum leaks quite a bit, I’ve gone through two full cans of starting fluid and couldn’t find anything. Also I have gone completely through every hose, boot, and seal in the vacuum system by removing, cleaning and inspecting for pinholes and can’t find anything visually.

[epmedia]

Related to the suction side of the external fuel pump and air bubbles; there's also a piece of rubber hose/grommet on the in-tank pump that can go bad. I've never tried this, but you may be able to look for air bubbles in the fuel by installing a short piece of clear hose between the external pump and the metal "Y" fitting (~3 inches long).

Maybe you can rig something for checking fuel 'system' and fuel 'rest' pressures. I've used a 'gutted' fuel pump check-valve at the fuel inlet at the fuel distributor. Either that, or find a k-jet pressure test kit.

For testing only.
attach a gauge to the hose. This screws in where the banjo bolt at the fuel dist inlet fits.
click to enlarge
fuelsystester.jpg

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Also, there's originally tiny cone filters under the injector line banjo bolts, on the fuel distributor. They are very finicky about debris.

You mentioned about to get a new o-ring for the pressure regulator on the fuel dist? How's that coming along?

* also see if there's a mesh filter stuffed into the suction side of the external pump. Also maybe the pick-up screen on the in-tank pump is dirty.

[Andrewcarelock]

So I am still having the same issue, I tried out the clear hose idea to check for bubbles and there wasn’t any. Also made sure that the cone filters under the injector banjo bolts where clean. The in tank mesh screen is clean as well and the pump is for sure operating. I’m completely stumped on this. Does anyone know if converting to efi from the e30 is an easy thing to do? My car is an 83 and from what I’ve read on the forums I’d have to swap heads... if that’s the case, is converting to a carb a viable/ easy swap? I’m just so sick of this non stop problem and would do anything for some reliability out of my car.

[epmedia]

So I am still having the same issue, I tried out the clear hose idea to check for bubbles and there wasn’t any. Also made sure that the cone filters under the injector banjo bolts where clean. The in tank mesh screen is clean as well and the pump is for sure operating. I’m completely stumped on this. Does anyone know if converting to efi from the e30 is an easy thing to do? My car is an 83 and from what I’ve read on the forums I’d have to swap heads... if that’s the case, is converting to a carb a viable/ easy swap? I’m just so sick of this non stop problem and would do anything for some reliability out of my car.

It's easiest to just find the existing problem, whether it be the K-Jet or something else.
Can you re-state existing symptoms please.

Also, we should determine if the engine is getting too much fuel, or not. Remove the key from the ignition -- after failed start, or after engine dies - does the tail pipe smell like gasoline?

Edit: the gasoline smell test at the tailpipe may not work if a catalytic converter is installed. May have to inspect spark plugs instead...