One day last year, I decided I was going to buy myself a car. I’d grown tired of my Mercedes E240, which had been fine, if uninspiring [Ed note: even with its angry eyes?]. I spent the day driving a series of terrible Honda HR-Vs, and then something on Facebook Marketplace caught my eye. A 2007 BMW 320D for just $3900. Too good to be true; seldom anything past 2002 was selling for those prices, let alone a BMW in good condition. I had to check it out.
I bought the car the next day, having knocked a further $200 off the price. $3700 all in, and that’s Australian dollars, too. The seller claimed it was so cheap for the lack of working air conditioning, which bothered me not in the winter. I felt myself having secured a bargain, despite one red flag. It kinda looked like the guy that sold me the car was running a car flipping operation out of a house and without a license, by and large forbidden by state laws. But I wanted my cheap BMW, and it drove great, so I bought it. Who could say no to a 2.0-liter turbodiesel rear-wheel-drive sedan for that kind of money? Not I.
It was a day later that I first reckoned with its issues. A barely-perceptible RPM flicker at cruise. I Googled and Googled and Google led me astray. I spent the next few months changing transmission fluids and filters and seals until eventually I found that a dose of Lubeguard’s Instant Shudder Fixx solved the problem for less than $30.
Of course, that was after I’d been to hell and back. Using a third-party transmission fluid that was supposed to be compatible with ZF Lifeguard 6 led to hard shifts and transmission warning messages. Getting the right fluid in has largely solved the transmission problems, though it still jams in first or second sometimes under a heavy right foot, with the engine soaring to the rev limiter until it eventually grabs the next gear. I suspect that it’s down to some of the wrong fluid still being in the transmission. ZF recommends multiple fluid changes if the wrong fluid is used, as the transmission and torque converter tends to hold on to a few quarts even with the drain plug out. At the same time, I’m not exactly eager to spend another $250 on more OEM-spec fluid, nor go through the excruciating procedure to get the levels right.
So, transmission problems solved, the car drove great again, right? Well, no. The car started exhibiting an obvious RPM fluctuation at idle, of around 100 rpm. This didn’t seem like a transmission thing, and engine diagnostics suggested it wasn’t either. Hooked up to a laptop with a CAN bus tool, I could see the fuel pressure fluctuating all over the place, in rhythm with the RPM fluctuations. The car was also often hesitant when you pressed the accelerator pedal, often taking a second or so to respond with more power. Given the diesel engine lives and dies by fuel flow, these issues seemed likely to be related.
Genuinely can't figure out if this is a fuel rail pressure sensor issue, fuel delivery issue, or wiring issue.
I am exhausted, though. pic.twitter.com/HN33jcyXJU
— Lewin S. Day (@rainbowdefault) August 21, 2023
My first suspect was the fuel pressure sensor. A replacement was only around $150, so I ordered a third-party model as it shipped the soonest. It seemed I was cursed for not going OEM, though, as the new part seemed to present a different output voltage range to the existing sensor, and the car wouldn’t run properly with it installed. Sourcing what I thought was the right Bosch part number, I found I had the same problem. I simply couldn’t figure this out; it was like there were different versions of these near-identical sensors that had different output ranges. That, or something truly weird was going on, electronically speaking.
I found one other person who reported a similar issue with an N47 engine in a 520D. Instead of displaying the usual 0.5 volts with the fuel rail pressure at zero, his displayed 0.3 volts. So did mine! However, his problems were down to an empty fuel tank caused by bad fuel level sensors. When running normally, his sensor still displayed those voltages, and ran fine. I decided to temporarily rule out the fuel pressure sensor and kept hunting for an answer. In any case, if you know if BMW uses a weird 0.3V-zero diesel pressure sensor, unlike most others? I’d love to be told I’m not a crazy person.
I kept running diagnostics on the car and diving into forums to figure out what was going on. Eventually, a diagnostic procedure suggested the fuel quantity control valve might be at fault. This is a valve controls the quantity of fuel that flows from the low pressure pump to the high pressure pump. Controlling the quantity of fuel reduces load on the pump, according to diagnostics firm Auto Ditex. It also keeps fuel temperature lower, because less fuel is being needlessly pumped to high pressure and then sent back to the tank when not needed by the injectors.
The fuel quantity control valve being faulty made a lot of sense. My research told me that in cold temperatures, below 59F or so, the engine doesn’t use the quantity control valve, simply leaving it in the fully-open position. I’d noticed that the car would often drive much better when starting it on a cold morning, at least until it warmed up a bit.
Investigating further, I decided to unplug the valve and see what happened. This was no mean feat, with the valve buried at the back of the engine under the intake manifold. When I started the car with it disconnected, though, I was amazed. Sure, the car was in limp mode and running at reduced power. And yet—no RPM fluctuation to be seen! Surely, this had to be it.
I didn’t really fancy changing the part myself; it looked far too difficult to reach. I wanted to get the air conditioning fixed, anyway, so I took the car to a mechanic. I asked them to investigate the fluctuation and hesitation issue for me while they were in there.
After three long weeks, they finally rang me to say they’d gotten the air conditioning sorted. Someone had been in there before trying to fix it, they explained, and made a total mess of the wiring. They’d had to reprogram several modules and put everything back as it should have been stock, but they got it done. I wasn’t really surprised by this. Over time, I’d found a few grease pen marks on various components under the hood. I suspected the vehicle might have been repaired over time with bits and pieces, and not always in the best way.
Beyond the air conditioning, the mechanic told me they found an issue with the fuel rail, and swapped it out for one off another engine that was going to be junked. I was busy getting made redundant that week, and just wanted my car back, so I took this explanation as valid. I assumed it was an issue with a pressure relief valve or something, and moved on.
In the weeks that followed, it became obvious that the fuel delivery issue hadn’t been solved. The car was still hesitating, particularly when pulling away from a stop. I vacillated between selling the car off and forgetting about it, but I couldn’t. I needed to know what was going on.
I bought myself a proper Bosch fuel quantity control valve, or at least I thought it did. It appeared to me in every way to be the real deal, but the hologram sticker code didn’t check out on Bosch’s site and it didn’t come with replacement fasteners, either.
In any case, I had to know if it would fix things, and I set out to do the swap. Only, I faltered. Between cables from the ECU, coolant hoses, and the intake manifold, access to the valve was near impossible, even with the cowling panel removed from the engine bay. I tried for half an hour on a hot day, and threw my hands up in frustration. No way would my tools get on to the bolts and free the valve. It was hopeless. Besides, I’d just started a new job (hello, Autopians!) and didn’t have time to be messing around with my cars (ironically).
Months passed and I found myself still stuck in the same position. I’d bought this BMW 9 months ago, intending to replace my Mercedes. And yet, I still owned both, because I could never quite trust it! I need to sell one or the other, and yet I couldn’t bear to sell the BMW without knowing what was wrong with it. I had to change that valve and see what happened.
I bought myself a new Torx socket set and found my smallest socket wrench, and had another crack. Focused, calm, and determined, I freed the first bolt. I could hardly believe it when the second came free, easier than the first. Within an hour, I held the valve in my hands, all thanks to having the right tools for the job.
I couldn’t believe it. This impossible task, achieved! Sure, it’s not that crazy or difficult a job, but for me, this was a big win after some very trying days spent tangling with that transmission.
Inspecting the part showed little obvious problems, but I pressed on regardless. It’s entirely possible that after 100,000 miles, the valve is gunked up or worn, no matter how good the fuel filters are.
And yet, reassembly remained. The first bolt found its thread just fine, but the second, I fumbled. Lost in the bowels of the engine bay, and try as I might, I couldn’t find it for the life of me. An interstate BMW dealership had the bolt for $15, but wouldn’t ship it. A British eBay listing had one too, for just $5, but shipping would push that to $40. Such a pain. I just needed an M5x18 Torx fastener, did it have to be so hard?
I headed to a specialist fastener dealer, and they had something close. An M5x16 with a T25 head, albeit a button head instead of a socket head. “Great!” I said. “I’ll take five.” 2 millimeters shorter (~1/16th inch), but no big deal. There was plenty of thread to do the job. It was all good… until I realized when I got home that these were security Torx bits, with a little button in the middle. The Torx sockets I’d bought wouldn’t work with them.
In the end, I had to go and buy another set of Torx security sockets that finally let me get the thing slotted home. I’m pretty sure I stripped the security fastener as I tightened the valve into place, too, so it was all or nothing. This had to work or the car was pretty much doomed.
To my joy and relief, it did. The car suddenly had its verve back. The nice punch of torque from the turbodiesel was right there when I hit the pedal, no longer coming in late or not at all due to a lack of fuel. The gorgeous handling of the 3 Series never left the car, but now I had the engine back to match.
It’s still not perfect; the transmission is still hanging in gear often enough that I don’t feel confident to drive the car hard. I’d hoped maybe fixing the fuel delivery issue would solve the transmission tripping over itself entirely but it’s not quite so. I’m tempted to try another fluid change to get the last of the supposedly “wrong” fluid out, but I know I’ll be mad if that doesn’t fix it. The other half of me is tempted to sell it and use the proceeds to whack new tires on my Mercedes and fix some worn suspension components.
For now, I continue to flip-flop on the matter and pay for both cars to stay on the road. So, grand Autopians, which way do I go? The older 1998 E240, with its ho-hum V6 but roomier interior, or the turbodiesel 3 Series, with its enjoyable handling and lovely engine, let down by an auto that’s not all there? I can’t decide, but maybe you can help me.
Image credits: Lewin Day
Hey mate, I take it that the trans fluid you used was the Penrite BMV? I’ve had no issues with it in my G6E turbo with the ZF 6HP trans however I have heard others have similar issues to you but with other cars that aren’t Falcons……………………
That’s the one!
Honestly, I was skeptical when the mechanic said the issues were down to it being incompatible fluid. I suspected much of the problem was due to me getting the level wrong. At the same time… I dunno, I kinda came around after putting the proper ZF stuff in.
If I had time I’d do a few swaps back and forth and learn the truth.
Pretty good argument for buying used manual cars; typically you can tell immediately on a test drive if the trans is junk or not, whereas issues with an auto may be masked or its lifespan shortened by inadequate maintenance. I’ve bought several automatic cars in the past where it wasn’t until putting a few hundred miles on the car I realized the trans was doomed, due to not immediately being familiar with its shifting intricacies.
You’re absolutely right.
If this was manual, it would be really hard to give up this car. The 320D isn’t fast, but the torque is so good. You just don’t get to experience it as much with the auto.
Your picture reminds me of an Aussie version of John B from the Electrostep Album cover.
Ha! I get it. I am an eccentric frontman to my bones.
You’ve got a Mercedes that you love but you’re tired of, and a BMW that you love and you’re scared of. Clearly the only solution is to sell them both and buy a 25 to 30-year-old Jaguar.
god, you’re so right. or maybe a Peugeot?
I have in the past been a German diesel fan. In fact I own two right now. But the crazy engineering decisions they seem to go with by default have put me off my initial fascination. My previous tolerance and patience have been replaced with an entirely American contempt for needlessly difficult procedural complexity.
My new automative paramour is Mazda. Ahh.. now THERE is some engineering…
Fie on thee, proprietary tooling. I am cured of that addiction. Be gone.
on the one hand, I love finding forum posts on my issues. but when there’s a ton of them, and very few with resolutions? eeeeeeh
and that’s where I’m at with Beemer diesels
also Thomas’s reaction when I said I had an N47 under the hood was hilarious
I’m currently in love with Diesels, so that’s my vote. Keep the Bimmer.
I do really love the torque.
I didn’t discover Diesel until about five years ago and rue the time lost. Keep that sparkless ignition as long as you can.
Recently put just under 5 figures into a Ford 460 and find myself thinking, “should I have just started over with a 6BT Dodge?”
Ford also made their own (licensed) version of the ZF 6HP26, the 6R60/80 series of transmissions, used in a bunch of US trucks and SUVs, as well as a couple of Australian/SE Asian market SUVs (Territory, Ranger, Everest). So, one should be able to get Ford’s Mercon SP fluid at a Ford dealer parts counter for roughly half the price of the ZF LG6 fluid. Mercon SP is directly compatible with LG6.
Sonnax Zip kits work great on a valve body overhaul; combine with a set of fresh ZF solenoids, a seal kit (bridge seal and tubular seals between valve body and trans) and resetting the trans adaptations (which you should do, even with a basic fluid change), you should be able to resolve the transmission issues you’re experiencing unless it’s too far gone.
Iiiiinteresting. That Ford fluid could be a lifesaver.
I love it! Try every ‘similar or better, but slightly cheaper’ fluid possible, except for the correct one specified in the manual, wasting time and money and possible breaking stuff that then will cost even more to replace 🙂
There are dozens of posts in the VW GTI forums from people who tried different fluids for the VAQ active diff, just because the 1.5 liters of the VW-branded fluid is ‘expensive’. It was the same story with Citroen LHM back in the day.
The Ford ATF exactly meets the Shell spec of ZF Lifeguard6, so this is one of those rare cases where it’s identical in specification and performance (other than the color–LG6 is honey-ish color, and Mercon SP is red colored).
I’ve been tempted to reset the transmission adaptations but I don’t really have anywhere to do the crazy long drive cycle you’re supposed to do to train it. That’s kept me from hitting the button.
I’ve not had time, patience or enough road to do the proper adaptation kabuki with my Jaguar (X350 XJ8). However, gentle driving (keep things under 2000 rpm for a while) will eventually teach it well enough. If one doesn’t reset adapts, the old habits and behaviors will continue to affect operation, even with fresh fluids, etc. Change fluid again, then reset adapts and see if things behave better.
Sell both and get a Holden ute instead as any good australian should do!
Just kidding, keep both if money allows, so you will have something to drive when one of them is broken, although there is the risk of both being broken at the same time.
I had two dead cars at once back in 2016 and I had never felt such despair
Buy Cactus off Laurence. Problem solved.
Does the 320d have the same soot buildup problems as the 335ds we got here in the states? While I absolutely adored my 335d, I knew the intake clean up thing was in my future, so I moved it along.
I haven’t cleaned the intake, but the EGR valve did need serious cleaning
Modern BMWs are never fixed. They’re temporarily repaired.
Yeah, it feels like that. It coughed up coolant at one point. I’m not even diving into that.
Does every single writer on staff besides Torchinsky and Mark own an old BMW?
They are the only ones crazy enough to try.
You could rebuild the valve body of the transmission for under $1k. Sonnex makes a rebuild kit. Just stay away from eBay solenoids (you seem to have learned that lesson already). Spend the extra to get OE or at least brand name.
This is the wisdom to follow for a German car. They get pissy with non OEM/brand name parts
Not just German cars. I learned long ago that it’s worth several evenings on the forums figuring out if your particular beast will tolerate equivalents.
But, with the recent spotty quality of just about everything, real OEM seems the way to go unless it’s well under $100 & really easy to swap
(says the guy who has several ‘correct #, but-not-OEM’ O2 sensors floating around)
The only cheaping out I’ve done recently is a thermostat, and while it’s doing a great job now, I dread the day it goes, since it’s so sandwiched in on the block behind everything else that I had to weld together a tool to reach it. What a nightmare that was
As someone who has twice replaced weeping valve cover gaskets (and still has the weep) on an 02 Subaru, I feel at least a certain portion of your pain
I’m wondering if the Delco thermostat I bought from RockAuto was counterfeit. It bounced around 10-15 degrees F higher than the fine Motorrad that it replaced. During a recent water pump change the fluky Delco came off, the Motorrad went back on and the engine is back where it should be. Other Delco parts I’ve purchased from there have all been fine.
Did you test it after you pulled it?
I had a bad out-of-the-box Stant years back, thereby learning to test them before installation—and modern cars require a much larger investment of wrenching time than that 1980-something Mazda truck did.
It’s electrically actuated and integrated into the housing. Not sure how to test one.
This sounds so stressful and frustrating, but so utterly normal for those who own German cars. Life is short, and wouldn’t you rather something that runs most of the time, and if it doesn’t, you don’t have to journey to Mordor to forge a new part? Japanese cars make life better. American ones maybe don’t improve it that much, but at least they can be repaired.
Life is short. If it fits like a glove, dances to your every input—and you grin every time the rear steps out at a slight twitch of your right foot, then throw some money you can walk away from out there, and enjoy life. 🙂
I know it’ll likely end in sorrow, but getting there is damned fun so far.
My friend has a 90s Legend Coupe and I envy her often.
Stay away from Stellantis too if you value a long life.
Somebody’s been holding back the years
As a German diesel owner as well, I can feel every word of this article. I had to replace my entire transmission at about 109k, so it’s not inconcievable that you may be at the same point. Part of me was amazed to find the clutch slipping and not wanting to go into 3rd, but the other part of me remember that I drive a VW, and it suddenly made sense.
Simply Dread
(Owning an old BMW with all of their endless issues)٩( θ‿θ )۶
Nope, I refuse: I drive it harder. If it’s going to fail, it better be spectacular!
To go out in a blaze of glory, so to speak. ᕦ(ò_óˇ)ᕤ
Yep. I’ll be pissed if it’s just the plastic water pump coming apart: the other two major contenders are the oil pump nut backing off & the rearend ripping out :0
It must be a love/hate relationship I assume.
Not a bit. I put myself in a place where I could just let go the money I paid for it. I’m too old to run off with a secretary I don’t have, so I bought rather quick convertible that causes me to chortle gleefully (if often nervously) every time we hit the mountains. Some people take beach vacations: I treat my MRoadster like a red-headed step-mule that owes me money. Each to their own
honestly, this thing represents the E-type I’ll never be able to afford—something I’ve wanted for 50 years
I say “good on you!” Happy motoring!
That nervousness never goes, and any new noise is always a little heart attack. But I get it, I love my stupid wagon, and despite the pain nothing else feels quite right
I have a couple of friends with E-types, one a hardtop and one a convertible. They both seem to follow the old adage of not driving them farther than they care to walk home from. You are probably better of with your M and saving a bit of cash along the way.
Plus, if I ball the M up, it’ll be a shame—but I won’t be destroying a thing of beauty. That snarling beast my neighbor had is best left to memory while I enjoy sunrises on the Blue Ridge this century
My MB trans had to go at 109k last year. It was sad and expensive.
VANOS: Valuable Autopian Non-fixable Ordeal Stories
So good.
COTD
Wow, what an ordeal. My only advice is to stop buying crapped-out late-model expensive German cars. Or don’t. It makes for good stories.
I vote don’t stop. I love these cautionary tales
Yeah, that’s the thing hey. If I bought a Corolla and just did oil changes, we’d all be short of something to read!
I own lots of “interesting” vehicles so I understand the attraction, tradeoffs, and the stories that come with. But is it worth it for a 2 liter BMW diesel? Now for a Toureg Diesel or a V10 M5…
Stop buying expensive German cars made after 1990.