MyE28.com

Hi All
I have a 524 td. It is the kind of car where as my saying goes, "If you have this car, you need to also have the boyfriend to go along with it". So far my "boyfriend" has been my Dad which is really really great. But Dad and I are running into some problems - he's the one who goes about collecting various old diesels, and this one has been in the shop for a while. I took it to the shop to get new glow plugs because it wouldn't start - but there seemed to be an additional problem that went right behind that - they (at the shop) said it needed a new turbo ($1600 from BMW, YIKES) and a new primer pump ($1000 from Germany, DOUBLE YIKES!!!!) The best we can tell on the manuals, the "primer pump" is also called "auxiliary fuel pump" and this is attached to a fuel filter. It is a manual pump that we are thinking also is operated electrically??? Because of course there are wires and such that plug into it. At the shop, It was thought that the pump was leaking fuel and therefore making air bubbles in the line and this is why the thing wouldn't start. They walloped on it quite a few times to get it going, but then it didn't start the next time it sat for a while. We were really stoked the first day we worked on this, because we thought we had the thousand-dollar problem fixed using a 67 cent O-ring from the hardware store, but unfortunately it wasn't the entire problem. Because it still failed to start. Also, unfortunately we did quite a bit of public gloating before discovering that there was still a problem. So now my Dad is out there with his little electrical meter testing out various things and getting various relays from the junk yard, looking for where some obscure electrical problem might be. But I am wondering if it is possible to by-pass the entire thing using a more readily available part(s) from O'Reillys???? It just bolts on to the body and then there are tubes that take the gas where it needs to go. Pardon me as my understanding is pretty simplistic. But it looks kind of like a heart! And like it could be taken off and replaced, by a replacement heart??? The thing says "Purolator" on it, how German can that be? And the filter is a Mann. Both of those names sound rather domestic to me, could this already be an after-market thing that somebody stuck on, or what is going on??? Many thanks in advance!

That pump only runs for a few seconds when you first turn the key. It is used to prime the fuel lines. Once the engine is running the IP has a pump built into it which draws fuel from the tank. Sounds like you have an air leak, the in-tank pump is on the fritz, or the in-tank pump's relay is acting up. People have rigged generic fuel pumps to till this role and some have even used the in-tank pump from a gasoline E28.

Search the archives here, your problems shouldn't be too expensive to fix.

Replace your fuel lines and hose clamps coming in and out of the in-tank pump - those could likely be rotted and leading to air leaks.

If you need a turbo and an injection pump, your existing units can be rebuilt for MUCH less money, probably $400 and $600 respectively.

Run a "one way valve" between the fuel filter and IP. This will fix the hard starting. I worked a lot on BMW diesels and 90% off them we put a one way valve in so that the fuel doesn't run back.

We used these:

All right! Thanks, everybody THANK YOU THANK YOU!!!!! I was feeling pretty hopeless the other day. I LOOOVEE this car & really would like to drive and care for it but as you guessed I'm on a pretty thin budget. I didn't want to have to replace it with some crappy old Mazda. I am reallllly hoping that we can get this resolved. It is so nice to have a forum like this - many thanks I did not expect this much activity so soon, and what sounds like really well-considered advice. I'll get back to ya on the results (but it might be a while, as my Dad is retired and likes to take his time with things like this)

Hello everyone. Update & clarification: The car will run after it gets started; four times after the guys at the shop discovered the leak around what they call the "primer pump", it started up. First time successful start: The guys at the shop mashed on the primer pump manually and sprayed a bunch of starting fluid in the air intake and that got it running enough to drive the car home about 1 mile. Second time successfully started: We had replaced the O ring at the bottom of the fuel filter, thinking the source of the leak was there. Bled the fuel lines and it started just fine. Did not drive it anywhere. Third time it started: same evening, we drove ourselves out to dinner (drove about 2 miles) in celebration of the O-ring miracle. Fourth time: it started okay after we sat and ate and drank beer for a couple of hours during "O-ring celebratory dinner", and it drove the 2 miles back home.
Ok: is this logic correct: I am thinking that the in-tank pump must be functioning okay if it drove us to dinner and back.

Fifth time attempting starting: TROUBLE. Wouldn't start. this was after it had sat all night.
What we've done so far: Dad thinks that the thing called the "primer pump" at the shop isn't a pump at all but instead a heater. We discovered some leaks in the line around this part which we fixed with another o ring, tightening some bolts and putting form-a-gasket on some of the washers and grinding a couple of things flat that weren't quite flat. We can see through the tube connecting this part to the engine, whether or not it has a bubble in it. It seems to develop bubbles upon attempting to start the engine. After we put the form-a-gasket and such, the bubbles stopped happening in that fuel line. (this was way more complicated than I'm making it sound here, the result of today's effort is that I have diesel fuel in my mouth, my left eye and all over my hands and hair). Still the thing won't start. Dad has also found several other things possibly wrong such as another O ring at the filter, and perhaps some relays gone bad. He found some relays at the U-pull it which he was putting on and off.
Hmmmm. Don't exactly know what to do from here.

Oh - we briefly inspected the lines and such running from the gas tank, which Dad says are in the trunk and we could see them and they look really nice and new and neat. So we didn't worry too much about these but rather were focused more upon that heater or primer pump or whatever-it-is up front. I'll take a picture of it tomorrow when it's light outside.

Air can get into the system in several places. The pump is a common design, and should be familiar to a diesel specialist. I think you and your father need to find a mechanic familiar with Bosch diesel pumps, as it sounds like you are contemplating some pretty hack work that will come back to bite you in the near future, if you get it to run at all. Doesn't sound like he is familiar enough with these engines yet to be successful at this time.

If you replace a section of fuel hose with clear tubing before the filter, and after the filter, you should be able to determine where air is entering the system. The fuel heater screws into the fuel filter housing and has wires attached to it. The water sensor screws into the bottom of the fuel filter. My recommendation would be to replace ALL the fuel hoses and anything with seals on the filter housing. The manual primer pumps can be replaced and do leak fuel, which means they will also suck air. Check your in tank pump for operation. Actually pull it and test it, don't guess. How are your glow plugs? Operational? All of them?

Please refer to this diagram for reference:

http://www.realoem.com/bmw/showparts.do ... g=13&fg=10

Like I mentioned before, put that one way valve in the fuel line between the filter and injection pump!!

If the prime pump leaks ( and they always do), air gets into the system and creeps up to the injection pump overnight and with air in the injection pump it doesn't start.

Thanks again guys! Yes Kyle the picture you show is exactly what it looks like! Also yes, the glow plugs were all replaced just before this whole thing with the primer pump started happening. I knew it was the glow plugs at that time rather than a fuel line bubble because I limped the car along for a few days using two hot water bottles and a blanket on the engine for 30 minutes. The fuel line problem happened only a couple days after the car came home from the shop for the glow plug work, and I knew it was something different because the blanket and hot water bottles failed to help. Additionally we tested each glow plug w/ the electrical meter and they were all getting voltage. Ok on the one way valve sounds like a great idea. Any further info on the type or brand? or is such a thing readily found off the shelf? THANKS!!!!!! S

I don't know the right diameter but something like this wil work:
http://www.ebay.com/itm/One-way-Check-v ... 67&vxp=mtr

Thank you Jelmer. Now I am noticing that the tank appears to be rusty on the inside. I don't mean just a little rust but a whole LOT of rust. I'm in western Oregon, so EVERYTHING rusts even shoelaces. Also, in Oregon, they pump your gas for you, and so I did not notice the rust because I don't usually look in there. And, the in-tank pump appears to be non-functional.

Lift up your trunk carpeting and remove the circular cover that is screwed into the trunk floor. This will let you get to the in-tank pump and remove it for testing. The one-way check valve that Jelmer suggested is a great idea and should definitely be used. i wouldn't worry about the rust in the tank right now, deal with that later. For now you need to eliminate all air leaks in your fuel loop. A bunch of new fuel line, hose clamps, and o rings will accomplish this. Look for anywhere diesel is leaking out.

I have witnessed far to many mechanics taking advantage of women and the autochallenged man. I would verify that these glow plugs are actually new and functioning. Replacing those little suckers is a painfull and time consuming process (at least the first time). I wouldn't worry about the tank pump for now, I have a euro 524td and it had no booster/lift pump at all when it shipped from the factory. I would say bypass the leaky fuel conditioning unit (purolator thingy), install a cheap inline fuel filter and check valve for now, along with new hoses and clamps around and your engine will start reliably once again. Assuming you have functioning glow plugs. If you still have issues after you've eliminated all leaks from the tank to the Injection Pump(the thing the gas pedal operates) you can further diagnose the situation by extending the fuel return line(smaller of the two lines) from the tank and running it into a clear plastic container with some diesel in it. submerge the open end, start the engine, and watch for air bubbles. There will be some present initially, as the piece of hose you have added is full of air, as is part of the return line once you disconnect it. So be patient, if you still have consistent bubbles after say 5 min. You probably need to look at rebuilding or just resealing you Injection Pump. good luck

Sorry to rehash this old post. How can I restore prime if my lift pump is bad? How would you do it in a Euro?

I have the check valve coming. I do have a new-ish 528e in tank pump. I can't remember if it's compatible.

Ps here's some eye candy

Can I install a hand primer like this one? Would it have to go before the bleed screw?

http://www.ebay.com/itm/Add-on-Hand-Pri ... 1813055924

Tell me if I'm crazy. Here's a pic of my spare filter housing. It has an extra out flow that's capped off can I connect a Bosch hand primer here? Or in place of the bleed screw? Just to get prime back. It only loses prime after sitting for 6 months+

Hi everybody: sorry to resurrect this old post but my 524 td now is running and sounding GREAT. I am hopeful of helping someone else save some time or trouble. I found a new friend who could make sense of everything, and so very thankful of that!! I had the rusty gas tank pulled, cleaned and lined. Then I had the car towed to a specialty shop and they said it needed a new injection pump and would cost $3100. My friend was horrified at this said lots of very colorful language, towed it home and started in on it - found that the existing pump was absolutely FINE, was simply completely clogged! Had to take it apart, first problem was the fuel cutoff solenoid, worked fine but clogged / stuck, so it would not let any fuel through. and then on to the injection pump. On the IP, there is a thing looks like a piston on the very top - CLOTTED with black goo. There's a little metal pin a bit further down - absolutely frozen with clogged goop, had to be manually moved back and forth a bunch. Car started for the first time after this was done - VIctory!! Because it would not even cough before that. But it could only idle, could not make any power, faltering etc. Next day, failed to start, again took apart that pin, and it was again frozen with goop, let the IP sit marinating in parts-cleanser for a week, then when started again ran diesel purge thru it. Did this 3 x. Exciting, you could see the Injection pump becoming stronger, and stronger as the diesel purge continued to run thru it. There was a very obvious air leak which turned out to be an "induction leak" I think was the word - A loose nut on the Turbo and some loose connections on the line carrying the air. And, Wow! The car became even stronger after these were tightened. Turbo was not spinning and was frozen, just needed to be forced to turn and then it turned by itself. Now, ha ha! so much victory!! But still it is hard to start once it sits overnight, and I just ordered that one way valve to place between the IP and the filter. Thank you so much for that suggestion.
The car had sat for about 4 whole years!! Changed the oil, next will change the transmission fluid and look into why the brakes feel squishy. But so stoked its running and very happy to learn so much about it!!

Hello everybody: Here is an update on this little car: There remains a persistent starting problem in which it will not start if it sits for about 7 hours or more. Otherwise, when the car finally does start after the lines being bled, it runs fantastically and is very different than how I remember it when I drove it years ago. Lots of pep, running really well.
Here's what's been done I'll try to be brief:

Gas tank: took to get cleaned out and lined at Mac's radiator.
Removed and cleaned the fuel cutoff solenoid. It was caked w sludge & was stuck.
Took apart the main piston on top of the IP, removed black sludge / also got the little pin unstuck (black sludge again)
That's when it started for the first time but was running very weak couldn't even make it up the hill on my drive way without manually pumping the primer pump.

Ran lubro moly diesel purge through it 2 x. First time running this through, the engine wanted to quit and needed manual pumping to stay "lit"
Second time diesel purge: Running on its own. Replaced the filter after all this.

Installed one way valve between IP and the filter housing: this seemed to correct the problem but only temporarily. We had clear hoses connected here & there to try to see air bubbles.
We think the manual primer pump was starting to give out gradually over this time, because we had some intermittent problems running or starting - and by-passing this seemed to help the car run / start better. One day it had a spectacular failure and let all sorts of air in and stopped the engine while it was running. It was discovered that a little plunger inside that had failed, and we removed that, sealed over the primer pump with some epoxy and converted it into just a simple filter housing. I think the heater will still work but we have not yet tried that because the weather hasn't gotten cold yet. The car seems to have been built without a booster or in-tank pump, because the thing in the tank appears only to be part of the fuel gauge. The car ran great after this (sealing over the primer pump) was done.
Tightened up the fuel cutoff solenoid nut (it was loose)
It seemed there was some leakage around one of the injectors, and we replaced that one small fuel line there.

Of course along the way we flushed out the tranny fluid changed that filter, changed the oil, did the brake fluid and all that etcetera.

What we have not done yet: replace all the fuel lines coming from the gas tank / replace the fuel lines up there near all the injectors.
Question is: when we have had a clear line to replace the black fuel line (so as we can see air bubbles) : it is apparent that there is no or very little air in that line next to the IP. Appears full of fuel. It seems to me like the air is getting in the IP in front of the one-way-valve, right? If I jiggle the clear line (which has fuel in it) some air bubbles up as if it's coming from the IP. What do you all think should be next?

And, A BIG THANK YOU, everyone for all your very very helpful suggestions!!!

S