528i No Start - Throwing ideas around

[jmc1590]

Hi all,
So this morning I head out for work, and bang! Problems. Turn the key, starts, idles for 3 sec, then dies. I'm thinking "That's odd." Try again, same result. 3rd try, add a touch of throttle, it revs to 1k, then dies. Then just starter without starting.

Car, '97 528i, ran fine 10 hours earlier when I drove home. We did get hit with about 6" of snow / freezing rain last night. (Lots of ASC activation in the snow / slush.) No real time was spent troubleshooting, as I needed to get to work.

The symptoms remind me of a "no fuel" situation. Fuel gauge shows better than 1/2 tank, which corresponds to the last time I fueled up. The battery is now a bit low, from the attempts to start. I'll have my charger, booster pack & tools on hand when I try again.

Any "I've been there" ideas to look at from the masses?

Thanks!

[Ed CT]

My first thought, too, is fuel pump not delivering.
Also might try to disconnect the MAF and start it - on the thought that the MAF suddenly failed catastrophically.
And on a flier diagnosis, Did you run thru any snow banks that may have clogged up the air intake ports? (or did it snow after you parked?)

[DennisG01]

The fuel pump is actually very easy to diagnose - whether it's by listening for the pump to run when the key is first turned, jumping the solenoid in the trunk, or checking for pressure while attempting to start. It could certainly be something else, but a GOOD battery and checking the fuel supply is a good place to start.

FYI, the battery shouldn't be low from those few times that you attempted to start it.

[jmc1590]

Ed - Good idea on the MAF, I'll give that a try. And I considered the air inlets - tried to start with the filter cartridge removed. Same result.

Dennis - It possible I'm a bit stubborn and ran the starter a bit longer that I should have those last "few" times. lol. But I agree, I'll see if the booster pack makes a difference. I'm trying to recall, with memories mixed between the E28, the E36, the 944 and this E39, is there a schrader valve on the fuel rail for pressure tests? I think so, but can't remember.

[jmc1590]

Update - MAF disconnected, still no start. Checking the Schrader valve at the end of the fuel rail shows no fluid. (Gauge missing since move!)

I'm now following the fuel pump / relay tests that are commonly available. Jumper the two large (2.5mm) wires Red/Vio & Wht/Blk in the fuel pump relay socket. Listen for the pump. Or check for pressure again at the fuel rail.

Worth mentioning, a small amount of fuel is coming thru. When I tried to start it today, I got the same 2-3 second run at first, followed by only cranking when attempting to start again. Is this something that extended cold (<20 degree) weather can induce?

[mattmar1]

the small amount of fuel coming thru indicates fuel is your problem, whether its the pump or filter. you should be seeing 50 psi at the rail with the key put to pos 2. is the fuel pump original to the car? mileage?

[Ed CT]

Sounds fuel related. It's not totally unheard of to get some bad fuel with water in it, or condensation in the fuel system that freezes. But you may want to rule out the fuel pump first.

Can you hear the fuel pump ramp up when the key is turned to position 2, or if you jumped the relay?

[jmc1590]

Initial tests say the pump. I was unable to hear anything when jumping the relay. (No start while jumped either. )

I suspect the pump is original. I haven't changed it since I've had the car. (Purchased at 220k. Now with 340k on the clock! )

Perhaps it's time...

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[mattmar1]

one other test...measure the B+ applied to the pump either with the jumper installed or at the moment the key is turned to pos 2. no 12vdc, something else is wrong. 12 vdc, no pump sounds, bad pump. either way, i do recommend replacing the pump at that mileage. 340k is well above average for a fuel pump to live.

[DennisG01]

In addition to checking to see if the power is making it to the pump, also double check that you have power at the solenoid. It doesn't save that much time to first check for voltage at the solenoid... just a little bit. Or just go right to the pump and then if there's no power there, backtrack to the solenoid.

My pump lost power because one of the connections on the pump (inside the tank - on the actual pump) had fallen off. Just a side note.

Pretty straight forward and easy replacement, though. FYI, you don't need the special tool to remove the locking ring - just a big screwdriver or a cold chisel and a hammer. "Pound" the locking ring open. I found it best to do a couple bumps on one side, then switch to the other - and back and forth like that.

You'll know if someone has been into the pump (or sender) once you look at the sound deadoning material under the seat. If the perforations in the material have not been cut, it has never been touched.

[jmc1590]

Thanks for the info guys. I've done a pump / sender replacement on an e53. I suspect it'll be similar.

Dennis, when you say solenoid, do you mean relay?

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[DennisG01]

\
Dennis, when you say solenoid, do you mean relay?

Yes, relay. Sometimes those terms get used interchangeably, but even though we've been using the "relay" term, I still had a brain fart and used solenoid - apparently just to confuse things

[jmc1590]

Assuming that the fuel pump has lived a long, healthy live prior to this, I've been looking at replacements. Can really justify the $400 for an oem pump. Have others had luck with any of the replacement pumps available? In particular, TRE pumps? The price is more than acceptable, but I can't find any good info on their pumps.

Thanks!

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[geargrinder]

Basically there's a few categories of pumps out there once you go beyond "factory drop-in"... Using an aftermarket should be fine as long as it supports enough flow but doesn't flow so much that it overwhelms the factory fuel pressure regulator and return line system.

• OE German pumps - bosch/pierburg etc. although its the Bosch ones that get used in track car / project car builds most often
• Branded aftermarket pump designs (which sometimes are in turn Bosch copies...) - Walbro, Aeromotive, Deatschwerks, AEM, others...
• Cheaper Chinese generic versions of either of the above (even though the aftermarket ones might be made in China anyway... if its true-brand it will be likely a higher QC part than the knock offs). These can either be just oddball-off-brand or non-branded, or, worse for sure, counterfeit branded. Lots of fake Bosch and Walbro pumps on eBay.

I've used a few different pumps although not in my E39. Had excellent luck with a Deatschwerks after buying a Walbro that pooped out. Whether my Walbro was a counterfeit or just Walbro QC isn't what it used to be (some think thats the case) I dunno. But that's the watchout - not buying the cheap knockoff pumps.

Any of the brands I mentioned above should be good as long as they are legit (tip: don't buy fuel pumps from sketchy eBay / alibaba / whatever sellers). I dunno 'bout TRE, they look kinda cheap, but maybe they buy from some of the same factories as the good brands, maybe they buy from the crappier knockoff factories, who knows. They all generally copy some version of Bosch / Pierburg form factor - most are dimensionally nearly identical.

If diameter is different than the factory basket you can 'sleeve' it with neoprene sleeves that some of the pump makers sell, or make up your own mods to deal with it. Certain OEM cars came with the pump in a plastic sleeve in fact so with my Deatschwerks I got junky Audi A6 pump, pulled the sleeve off it, made a few mods to it, and slipped it on my pump. The other issue to deal with is pump outlet location vs your pump basket - center vs offset. Sometimes that doesnt matter too much or at all, sometimes it does.

Philly98540i is running an AEM or Aeromotive I think. Check with him about fitment with E39 cuz like I say, I've done this job adapting aftermarkets to the OEM basket on other cars but not on this platform yet...

[jmc1590]

-- Update --
Went ahead and picked up the TRE Performance OEM replacement pump. (TRE-438) With a current sale price of $21.99 + shipping, I figured it was worth a shot. Placed the order Thursday, pump was delivered Saturday. Physically, it looks like a dead ringer for the orginal pump. Length, diameter, pickup location, and electrical connectors were a match. Installation was a breeze, thanks to quite a few YouTube videos on the subject.

After replacing the pump, it did take longer than expected for the engine to fire, which I'm thinking was due to there being zero fuel in the lines at that time. It did finally struggle to start, and began to hold idle. At this point, my 528 is back on the road!

Thanks to all that provided insights!