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View Full Version : '95 525i FINALLY stranded me (fuel delivery problem)



billb
11-19-2010, 06:59 AM
Hi gang, been a long time since I posted, have had a long run of good luck with the 525, but age is catching up to it!

Very long fault analysis follows:
Vehicle: '95 525i automatic, 169k miles

So Wednesday (11/17), I had a job interview 40 miles away. Got in car at 8am, arrived at interview just before 9, no issues on the drive.
Left the interview at 12:40, drove 35 miles back, stopped to fill up with gas (17+ gallons), then drove on home, no issues on the drive.
Had lunch at home, prepped to go for a short run on a local trail. Drove to the trail at 3pm, no issues on the drive.
35 minutes later, drove to the grocery and "adult beverage" store on the way home. Went in, came out 5 minutes later, and the car initially fired (but stumbled a bit), ran long enough for me to put it in reverse and move 8 feet, then died. Repeated crankings would yield what sounded like 1-2 cylinders trying to fire, then nothing.

My first thought was "crap bad gas from the fill-up". But it was just running perfectly at shutoff. It sounded like lack of fuel to me. Checked fuse 23, good. Opened up the E-box, pulled and re-seated fuel pump relay. Loosened fuel supply hose and cycled ignition (to try to get fuel spray). Nothing.

Called my wife to come pick me up (was only 2.5 miles from home). Got home, had dinner, then we called AAA for a flatbed to bring it home. I drove back to the car in my wife's Taurus X, arrived before AAA, and walked to the Advance Auto store in the same complex. Bought a can of contact cleaner as a last-minute thought to clean off the CPS. AAA driver was onsite when I got back to the car, so I told him I wanted to try one last thing. I sprayed off the crank position sensor, and wouldn't you know the car fired right up.

I thanked him for coming out, and told him I was going to drive it home. He said he'd follow me, and he did until I turned off very close to my house. Got it home, and cycled it off and on a few times, each time it started without fail. I noticed the fuel pump was not running at a constant rpm; it seemed to rise and fall in speed, almost sounding like it was binding.

Shut it down, pulled the fuel pump relay and checked operation with a 9V battery and voltmeter; all was well for multiple cyclings. Put it all back together.

Thursday morning (11/18), I had a 10-mile run to do (I'm in week 3 of an 18-week marathon training plan), so at 9am I drove to the run trail, no issues on the drive.
Finished the run, got back to the car, fired it right up and drove to a local running/triathlon store to pick up a few items, no issues on the drive. Was in there for maybe 30 minutes, then had to leave to go pick up my son at preschool.
Of course, this is when the no-start happens again. Same scenario as the night before; cranks and fires, runs 10 seconds, then chokes off. I already had the fuel sender cover off, so I gave a sharp tap to the top of the sender with a wrench, and the car fired right up on the next cranking.
Drove to preschool, picked up my son. Back out to the car, and it started right up, no issues on the 2-mile drive home.
Later in the evening, had to take my other son to basketball practice. Fired right up, no issues driving to or from practice.

I just pulled the trigger on a new Bosch pump from BMA. I figured it's cheap insurance (under $200) and merits replacing at this age anyway. Fuel filter was last changed at 155k miles. I'll post back when the pump's in to let you know if the problem recurs.

By the way, planning to install BMA's Meyle brake kit this weekend (the $225 special for front/rear rotors, pads and sensors). That's a pretty good deal for brakes! Got 50k out of the last brake job (and 51k out of the one before that).

Tiger
11-19-2010, 09:12 AM
I am thinking CPS also... when was the last time that was changed?

billb
11-19-2010, 01:27 PM
It's totally dead in the water now. My wife drove it over to church, started right up from home. After her meeting, it would not refire. I went by on my way home today, and it won't go. Jumpered the fuel pump relay, and it won't go. No pump noises. Banged on the fuel tank (top and bottom) and heard the pump make an attempt to run a bit, then quit. Gave enough fuel to fire up, run 5 seconds, and quit. I wiped off the CPS again as well, but the fact that the fuel pump didn't run, then did briefly when the tank was banged, is enough of a diagnosis for me that the pump is toast.

Tiger
11-19-2010, 02:46 PM
Yep... looks like it is the pump.

billb
11-20-2010, 09:28 PM
New fuel pump solved the problem. Was going to order from BMA, but it would not arrive here until after Thanksgiving. Did some checking, and Advance Auto Parts could get it-list was $250, but they had a "order $150, save 20%" deal going, so I called my local store, they said they could get the pump overnight from Tennessee to NC no charge, and I could use the 20% off. So, at 10am today, I had a new Bosch pump in hand.

Went to the gym for a swim, then dropped the kids back off at home. Got in my 1929 Ford Model A, loaded my necessary tools, and drove the 2 miles to where "Ginger" was stranded (at our Church). It took all of 45 minutes to replace, and that included modifying the wire ends since the new pump has spade terminals (and opposite polarity!) and the old was ring terminals. Hooked it all back up, tightened up the hose clamps, reconnected the battery, crossed my fingers, and turned the switch. It turned over maybe 8 times, then fired off just pretty as you'd please. No hiccups, and a quiet, consistent buzz from the pump.

Postmortem on the pump: the screen on the bottom was torn, allowing gunk to be sucked into the pump. Probably would've run forever if that screen was still in place. Maybe some sort of preventive maintenance going forward, if that screen can be purchased separately!

Drove the Model A home, then Marshall (4 yo son) and I walked back up to pick up Ginger and drive her home. No problems whatsoever.

Made me feel so good, I brought her home and gave her a bath!

Next up; power steering hoses, belts, brakes, and a nice waxing for winter.

Dave M
11-21-2010, 09:22 AM
Glad to hear it worked out. I chased hesitation/difficult starting issues for quite a while that ended up being a bad pump. I was able get a pump from someone on the board for $75 and its been great ever since. Most of of, I learned that pumps don't always just die, they can screw with you a while first ;)\

Dave

billb
11-21-2010, 07:31 PM
Glad to hear it worked out. I chased hesitation/difficult starting issues for quite a while that ended up being a bad pump. I was able get a pump from someone on the board for $75 and its been great ever since. Most of of, I learned that pumps don't always just die, they can screw with you a while first ;)\

DaveAgreed 100% Dave. I'm already noticing improved acceleration and idle smoothness, running smoothness, and it "smells" like it used to when it's running (I know that one's hard to explain, but we all recognize how our car smells when it's running, and it smells right again). We'll see what mileage looks like on the next few tanks, but I'll bet it'll be better.

I bench-tested the old pump today with a 9V battery...it'll run in reverse, but won't turn a lick forward. Toast.

Tiger
11-21-2010, 08:44 PM
How many miles per gallon can you get out of the Model A? I heard it gets 20 MPG.

billb
11-23-2010, 06:33 AM
How many miles per gallon can you get out of the Model A? I heard it gets 20 MPG.Tiger-
I suppose on a good flat road and easy throttle inputs, 20 would be about right. 200 cu.in., 40hp@2200rpm stock, 4.5:1 CR, updraft Zenith carburetor, hardened valve seats. It's a (fairly) aerodynamic design for the day, but you start getting some pretty good energy waste with the engine driven non-viscous fan at higher rpm. Could probably go to electric design there and eke out a little more economy. 3.78:1 rear end ratio, but only a 3-speed and 1:1 top gear.

Here's a handy Model A link:
http://macsautoparts.com/article.asp?ai=215&camid=

Russell
11-23-2010, 03:35 PM
Agreed 100% Dave. I'm already noticing improved acceleration and idle smoothness, running smoothness, and it "smells" like it used to when it's running (I know that one's hard to explain, but we all recognize how our car smells when it's running, and it smells right again). We'll see what mileage looks like on the next few tanks, but I'll bet it'll be better.

I bench-tested the old pump today with a 9V battery...it'll run in reverse, but won't turn a lick forward. Toast.

I put a new fuel pump on mine this year at about 185,000 miles. it was singing fairly loud and my mechanic had beeen warning me of impending doom for about two years. No change in performance. I still have the old pump and it may have run forever as well.

However I do have a fear of being stranded. it happend once with a water pump failure. That reminds me. Should I replace my water pump soon as it has 80,000 mile on it? it Never stops.

Grantus
11-23-2010, 04:08 PM
I replaced mine as a precautionary measure when I got my car, for one with a bronze impeller.

billb
11-30-2010, 09:29 PM
One week(+) later, and still running smooth as silk. I'm eager to see what mileage looks like from here on out. I'm glad it happened when/where it did; a little earlier in the day and I'd have been stranded enroute to or from an interview!!