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Discussion Starter #1
Interesting thing has happened since I replaced my fuel filter.
When cold, the car (03' E39 M5, 127k) fires right off, and runs sweet.
After a spin, and before it cools, it acts like it is out of fuel.
Plenty of petrol on both sides of the tank.
It pulled a FP relay code, and relay was replaced. (Hats off to the Bavarian engineers for putting it behind the glove box).
Same problem.

OK, I might have tweeked the regulator when I tightened it, but there are no leaks.

I have read fuel pump threads, and this problem doesn't seem to fit, as when the car runs, it RUNS AWESOME.

Thanks for taking the time to read this.

Mahalo,
Tom
 

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It is the most common failure to have the pump fail when you see that code. It is a check through the relay then through the pump to ground. It has been the relay too, but most times it is the pump. Did this start right after you changed the filter?
You should definitely check your work and the reg. If the reg is leaking back to the tank then you will lose your fuel pressure. The difference between warm and cold starts is the DME runs the pump for a few seconds on the cold start. It does not do that on warm starts until after the car has been cranked.
 

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Discussion Starter #4
Sailor24,

Sorry for the delay in response.

Very much appreciate your help.
M5 Expert is a highly appropriate title for you.

I will get under her soon, and see if I damaged the regulator.
In thinking about it, the housing may have suffered slight damage, but no leaking from there.
It just was not a perfect removal. (Better than Primitive Pete, but not much.)
Don't sandbag your doctor, lawyer, or the guys trying to help you on the boards.

As for the pump, I guess you really can't be in this club until you have replaced certain parts, FP being a top 10.
The 540 has been a great training ground.

On behalf of everybody who has benefited from your time and efforts on this board, Thanks.

I'll post back on my success's or failures.

Regards,
Tom
 

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Discussion Starter #5
All,

I double checked my work, and all seems fine.

No leaks at the regulator.
I did a pressure test, and had 62psi at idle.
Close to 70 at 3k rpms.

New twist...P0171, and PO174

Already have new o2's all around.

I'll run the sh*t out of it this weekend, and report back.

regards,
t
 

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You need to get some kind of diagnostic system that can read BMW codes. INPA software is a very good software that I almost use it daily.
 

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Discussion Starter #7
Deaf,

Thanks for the reply.
I purchased an Innova 3040 reader, and will give it a go.
I checked out the INPA, and wished I had waited...Looks great.
Anyway, I'll run it through the paces and see what's up.

Also did the cluster MAF test, and can't seem to get the numbers past 100 or so.
I'll keep trying.
I think the tester has a graph system on it, so I hope that can shed some additional light.

Still haven't had the original problem repeat itself, though!

Last thing...
I love going through all this stuff, and then, to top it off, SEAT TWIST!!!

Maybe if I had stuffed $1000.00 in the tailpipes, this sh*t would go away...

It doesn't matter, this car is still BadAss.

Best,
Tom
 

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Deaf,

Thanks for the reply.
I purchased an Innova 3040 reader, and will give it a go.
I checked out the INPA, and wished I had waited...Looks great.
Anyway, I'll run it through the paces and see what's up.

Also did the cluster MAF test, and can't seem to get the numbers past 100 or so.
I'll keep trying.
I think the tester has a graph system on it, so I hope that can shed some additional light.

Still haven't had the original problem repeat itself, though!

Last thing...
I love going through all this stuff, and then, to top it off, SEAT TWIST!!!

Maybe if I had stuffed $1000.00 in the tailpipes, this sh*t would go away...

It doesn't matter, this car is still BadAss.

Best,
Tom
Did you make sure you went second test in test 4? You will want it to be in Liter per hour.
 

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Discussion Starter #9
Deaf

Yeah, went to L/ph
Getting WOT is easier said than done.

I Think I got 120 on one run.
I need to find a better testing area.
One place is wide open for traffic, but crawling with cops.

Also, my original problem reared its ugly head this afternoon.
Time for a new fuel pump.

I'll plug the reader in, and see what it says.

Thanks again for the input, Deaf.

Regards,
Tom
 

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i had the exact opposite of your problem until recently. the car wouldnt start when cold at the first turn of the key. when warm it would start fine. I replaced the pump and this resolved my issue.

Good luck!
 

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Thanks Dog.

I'm goin in!

T
Have you had any progress on this? I'm experiencing the same warm start problem as well. I changed my fuel filter two weeks ago.
 

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Have you had any progress on this? I'm experiencing the same warm start problem as well. I changed my fuel filter two weeks ago.
To reply to myself, I've fired up INPA and there are no codes stored in my ECU. The problem is still persisting. If the car is cold it immediately starts. If it's warm, I have to crank the engine a few times for it to start.

Based on a suggestion from rao, this is very likely related to my FPR (or things in that area) not holding pressure correctly. I'm unsure how to test this, or determine where the leak is though. Will I hear / see something when the fuel pump engages?
 

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Discussion Starter #14
chuffykow,

I am waiting for delivery of my fuel pump.
I got a great price from BMW of South Atlanta, but delivery is a bit slow.
I will post results asap.

DeafM5, I pulled 140's on my MAF this weekend.
Car runs great, once it warms up.
I get the hunting idle on start-up, but then it relaxes, and really comes alive.
Still having the probs with the warm start, though.
INPA software in my future.

Thanks again for the consideration.

Regards,
Tom
 

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Discussion Starter #15
Problem Solved!

Sailor24, et al,

Installed new FP today.

Warmed her up, shut her off...and she FIRED right up!

Got brave, took her a couple of miles, getting on the gas.
Stopped by the local store, did some business.
Got back in, and she FIRED RIGHT UP!

Made a bee line to the petrol station, and fueled her up.
Get back in, and (you know, SFRU), then I hit the street.
About a 1/4 mile down the road, I noticed NO CEL!!!

Man, am I f*ckin happy!

Now, about the MAF test...
Getting solid 140+ in WOF 2nd gear, to the top of the tach.
I don't know if it counts, but it hit 400+ in 1st, WOF.

So, my Beast has consumed 4-O2sensors, 2-MAF's, 1 Fuel Pump, and a Partridge in a pear tree.
This, in my first 15 months of ownership.
128xxx on the clock, and I feel right fortunate as to how inexpensive she is to maintain!

Thanks to all who chimed in, and gave words of wisdom.
I am grateful.

Mahalo to All,
Tom
 

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Discussion Starter #16
Last thing...

Oh, forgot to mention...

I replaced the other MAF, and idling problems have stopped.

The car runs bloody great!

Cheers,
T
 
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