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7 Series - E65 / E66 (2002 - 2008)
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  #1  
Old 01-31-2013, 01:05 PM
mws mws is offline
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Mein Auto: 760Li, F250 V10, Ex 7.3L
760Li long cranking and drivability issues solved--mostly

2003 760Li, 135,000 miles

I put drop-in flat K&N filters in with the stock amount of red oil on them. After not too long, I started getting really long cranking and also, some driveability issues It turned out to be two things happening at once:

1] hunting idle, and sometimes dying when just going into closed-loop mode, until the car is really warm.
2] Dying while driving, coming up to a stop sign when not fully warm.
3] light, occasional bumping feeling when driving at 1500-2000 rpm, feels like you are close to running out of gas, but still have some.

Cleaned the oil completely off the K&N filters and for now, driving on them with just the clean, dry cotton (yes I know, I know). Also cleaned the MAF sensors with sensor cleaner. Did not see any mention of a special tool needed for a 5-point Torx Plus Security bit, that information would have been nice for removal of the MAFs.

http://www.google.com/search?client=...UTF-8&oe=UTF-8

so that was a nasty surprise. I simply cut a big slice in each small bolt-head and used a flat-blade, since my car was apart and I needed it that day. No one and I mean NO ONE had or had heard of those tools.

that solved the serious drivability issues: No more dying at stop lights, much less hunting when cold. Still a bit of bumping at cruise, though.

Now, according to the posts, the long cranking seemed always related to the HPFP on the 760Li, but solved for most V-8 owners with a new fuel filter with fuel pressure regulator. That did not fix it for me. But the new fuel pump did. I was cranking for like 8-10 seconds before starts when it had been awhile, but it would start instantly when I had just stopped the engine. Obviously, the system was draining off pressure slowly while the car sat. Now it starts like it should.

I know the TIS mentions the special tool, and a lot of people suggest using a screwdriver and hammer, but I would not suggest screwing the tightening ring for the fuel pump back on unless you have a special tool, something like this

http://compare.ebay.com/like/1907324...Types&var=sbar

I made one from a 4" pipe PVC coupler. Cut notches in it. Took me about 5 minutes.

The hammer and screwdriver trick gets it off, but does not tighten it enough for me. I still had a leak from the seal when the gas tank was full.

So, thanks to everyone for the posts I read where you "clean your MAFs", "don't use K&Ns" and also, "replace the pump and filter". I appreciate it.

I still have a bit of the bumping like I said, and some minor hunting when not fully warm, but no engine dying. I might clean the MAFs one more time.

Past that, I might still be looking at HPFP issues, in my near future.
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  #2  
Old 02-02-2013, 07:31 PM
mws mws is offline
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I spoke too soon. A few days after this, and some long delays between starts and the time to start the motor is still long, it's just better than it was before. Something is still up. Not sure what.

Also, was searching around the web on how to test a MAF with a multimeter and ran into this claim from K&N that they get MAF sensors sent to them on occasion and could never find any proof of their oil on the MAF. K&N says there was always some other reason for it's failure. In fact, since I joined the BMW forum, it is the first time I have heard of MAFs getting out of whack using their filters


http://www.knfilters.com/MAF/MAFTestresults.htm

and

http://www.knfilters.com/MAF/massair.htm
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  #3  
Old 02-03-2013, 04:23 AM
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csmeance csmeance is offline
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The MAF could be the source of the problem if it's not giving the car a correct reading. Another member had the problem on his 745 and he disconnected the MAF completely. The car ran STUPID rich but all the drivability and sluggishness was gone. In all honesty, I would buy 2 new MAF sensors and put them in. They should help a LOT, and if not you can return them!

FYI, K&N has been known to mess up sensors because of the oil in their kits! The problem is not the filter nor the oil itself, but the amount of oil that is put on the filters! When people recharge the filters they use WAY to much oil and that can coat components over time.

IMO the best filter design I've seen is on the OEM Honda Filtech filters, they are a 2 stage filter with oil on the bottom half and then paper on the top half. This allow any oil vapor to be caught and allows for superior filtration. The only downside is that they need to be REPLACED every 30K.

Also, one thing you might want to look at is going to an independent mechanic and have them check the FUEL PRESSURE after the HPFP, after the in tank pump and at the filter as well. It could be possible that there is an obstruction of some sort.

Ethanol in the fuel now allows parts to corrode and have build-up accumulate on them! I've gone through 4 fuel sensors because they stop reading properly! I wouldn't be surprised if the same stuff doing that was clogging the lines or doing other sorts of damage.

I've been using Redline SI-1 fuel cleaner RELIGIOUSLY for the last 15K miles (every 5K a full bottle and mini maintenance doses in between) and I've noticed that my car is running a LOT better and as well gives better gas mileage!

One last note, I see that it has 135K miles on it. The spark plugs are supposed to be changed at 100K along with the intake manifold gasket. If the plugs have 135K then I wouldn't be surprised if it was the problem! However if they are new, an improper job reinstalling the intake manifold can cause a LOT of problems on the 760 as well!
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  #4  
Old 02-03-2013, 08:03 AM
mws mws is offline
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thanks for the reply

K&N expressly states in one of those links I posted that they ran 1000cfm thru a heavily oiled filter and that no oil came off. They also state that many MAFs have been sent in and they could tie the failure to something electronic, but not something oil-related.

Now, that said, it's K&N who is doing the testing, but they do have hundreds of thousands or millions of filters on the road and only hundreds who suspect oil is causing the issue, and to date, no one can comprehensively prove K&N filter oil caused the breakdown.

The only way to know is to buy a brand new set of MAFs, drive with them on K&N filters, watch them fail in an untimely fashion. buy another set, run on stock filters and see them last 100K miles.

any takers?

They also point out some OEMs use oil on their filters as well.

I know I cleaned my MAFs and they seemed to do better, but... they could have needed a cleaning anyways. I still have all the issues I had before, just less amplified.

The manifold has been removed recenently and the gasket was not replaced, and neither were the plugs. I thought the manifold gasket looked like it could survive the trip. I was thinking of doing the AGA tube and decided the job was too big for the time I had. The issues did not surface until a thousands miles later, though.

But thanks for the tip on the plugs. I will look at the BMW service sheet I got from the dealer for plugs. If they are not changed, I'll look into it sometime soon--WITH a manifold gasket
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  #5  
Old 02-20-2013, 09:20 PM
mws mws is offline
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I know I'm just talking to myself here, but for any of you 760 owners reading this, my HPFPs have been filling up the Tank Vent tubing and giving me Tank Vent valve errors. When I remove the quick-release tube on each throttle body I would find some gas there. That is from the HPFP failing. Nothing else can fill these with liquid gasoline. Then if you relase the quick-releases at the Tank Vent valves in your engine bay, they pour with gas. Again, this is and can only be: a HPFP failure.

My car will start, but now, pours gas from the tailpipe. It's being sucked into the intake manifold from these tubes, and is like flooding the motor. It'll get fixed soon. Hope this helps you 760 owners, since we are all pretty much "due" at this point.

Oh, and CS, once I figured out how to use DIS to measure manifold pressure, I am pretty sure the vacuum at idle and all thru the rev-range is fine. I'm pulling around 17-18 " Hg (converted from bar). No vacuum leak large enough to cause an issue. I don't remember specifics. But I have changed dozens of UIM to LIM gaskets on other cars. I remember being very impressd with this gasket and thinking the UIM/Plenum could just go right back on, and it appears to have. Not that a vacuum leak like that would be fun to fix....

Last edited by mws; 02-20-2013 at 09:26 PM.
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  #6  
Old 02-21-2013, 03:59 AM
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Rick in Yuma Rick in Yuma is online now
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Mein Auto: 05' 760li,94' H1,08'Smart
MWS... I have been watching your posts. I have 85k on my 05'. Only put K&N's in at 80k so far no issues. However have not re oiled them yet. I have run them in all my other vehicles with out a problem. including my 97' 540. because of your issue I will keep a close eye on the MAF sensors. None of the other issues you mention have come up yet. Thanks for keeping us up to date. Rick
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  #7  
Old 02-21-2013, 04:17 AM
bmwoem1 bmwoem1 is offline
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Why do think HPFP failure has anything to do with liquid fuel getting to your tank vent valves? If the HPFP failed, why would it fill the intake manifold with fuel?
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  #8  
Old 02-21-2013, 06:46 AM
Davidf Davidf is offline
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Quote:
Originally Posted by bmwoem1 View Post
Why do think HPFP failure has anything to do with liquid fuel getting to your tank vent valves? If the HPFP failed, why would it fill the intake manifold with fuel?
The tank vent lines have a direct connection to the HPFP and fill with fuel if the pump seals are failing. The fuel collects at the vent valve when it is closed. When the DME decides the vent valves need to open to purge the carbon canister, the build up of fuel is released into the intake manifold causing a flooding or super rich fuel mixture. Drivability issues is the result.

Quote:
Originally Posted by mws View Post
2003 760Li, 135,000 miles


Now, according to the posts, the long cranking seemed always related to the HPFP on the 760Li, but solved for most V-8 owners with a new fuel filter with fuel pressure regulator. That did not fix it for me. But the new fuel pump did. I was cranking for like 8-10 seconds before starts when it had been awhile, but it would start instantly when I had just stopped the engine. Obviously, the system was draining off pressure slowly while the car sat. Now it starts like it should.

I know the TIS mentions the special tool, and a lot of people suggest using a screwdriver and hammer, but I would not suggest screwing the tightening ring for the fuel pump back on unless you have a special tool, something like this

http://compare.ebay.com/like/1907324...Types&var=sbar

I made one from a 4" pipe PVC coupler. Cut notches in it. Took me about 5 minutes.

The hammer and screwdriver trick gets it off, but does not tighten it enough for me. I still had a leak from the seal when the gas tank was full.



Past that, I might still be looking at HPFP issues, in my near future.
Your description leads me to believe that you replaced the in-tank fuel pump only. The in-tank feed or pre-pump is similiar to the V8 equipped cars other than being of higher capacity/slightly higher pressure. The HPFP's are mounted on either side of the engine and driven mechanically from a 3-pointed lobe on the exhaust camshafts.
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  #9  
Old 02-21-2013, 07:07 AM
mws mws is offline
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I took my K&Ns out, then put them back in

Quote:
Originally Posted by Rick in Yuma View Post
MWS... I have been watching your posts. I have 85k on my 05'. Only put K&N's in at 80k so far no issues. However have not re oiled them yet. I have run them in all my other vehicles with out a problem. including my 97' 540. because of your issue I will keep a close eye on the MAF sensors. None of the other issues you mention have come up yet. Thanks for keeping us up to date. Rick
after taking the time to look it up and reading these links and watching the movies, I'm convinced the techs at small shops and BMW have been perpetrating a "guess" that K&N filters are killing MAFs

http://www.knfilters.com/MAF/MAFTestresults.htm

there's several videos here. watch them. Especially watch the one where they submerge the MAF entirely in K&N oil and it still functions.

http://www.knfilters.com/MAF/MAFTestresults.htm

that said, I am just figuring out you can use DIS to measure the manifold pressure differential (MAP) sensor and try to determine if there's a restriction at WOT while driving. The problem is: DIS is insanely slow to refresh and very low-resolution. The results are not that accurate. My pal and I made some videos of the PC's screen and it was a bit dicey to try to make a decision based upon the super slow output of the Virtual machine and DIS.

I'm talking with Bimmersoftware.com to try to get his software to work on the N73 engine so it can log data nicely. Compare MAP to throttle position and RPM and go up past 6000 rpm for several runs. Then try stock filters. If the stocks show some restriction, then the K&Ns help. If not, don't bother.
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  #10  
Old 02-21-2013, 07:17 AM
mws mws is offline
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turns out I was wrong....

Quote:
Originally Posted by Davidf View Post
The tank vent lines have a direct connection to the HPFP and fill with fuel if the pump seals are failing. The fuel collects at the vent valve when it is closed. When the DME decides the vent valves need to open to purge the carbon canister, the build up of fuel is released into the intake manifold causing a flooding or super rich fuel mixture. Drivability issues is the result.



Your description leads me to believe that you replaced the in-tank fuel pump only. The in-tank feed or pre-pump is similiar to the V8 equipped cars other than being of higher capacity/slightly higher pressure. The HPFP's are mounted on either side of the engine and driven mechanically from a 3-pointed lobe on the exhaust camshafts.
good thinking: after this occurred, it turned out I had a lucky few goes at starting the car, and wrote this post premauturely. Meantime, long cranking came right back. Since there were other people who had posted miracle cures, like replacing the vent valves, I started reading and continuing my story on their posts. I am sure their problems came back, but I've had no response yet.

Also, after that, I started to get PM'd buy a guy on the forum who clued me in. I started opening the quick releases at the Tank Vent valves, and saw I had liquid gasoline flowing out.

I did try a few purges of gas from these quick releases in the morning to see if I could drive well on my commute. It worked half the time, the other half, did not help a bit. It was totally chance.

Now, the car has so much gas in the lines, and the HPFPs appear to be filling the lines up even faster, I cannot drive it.

Time to fix.
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  #11  
Old 02-21-2013, 07:30 AM
Davidf Davidf is offline
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Ok. I failed to notice that it was you who posted the message above from long ago. I did know you relized what the true cause was in your other posts. Be careful on any creative fixes as you dont want to cause a situation that can lead to an engine bay fire. Seems from one of your other posts that you might try diverting the leaking fuel directly to the tank so it cannot be ingested by the engine or foul the tank vent valves. Given the costs of the pumps, I would be tempted to try anything that worked and was cheaper. But, eventually, you will have to replace the pumps. Do one at a time if you have to in order to let the bank account recover. Good luck and be careful.
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  #12  
Old 02-21-2013, 08:30 AM
mws mws is offline
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thanks for the concern for my safety...

Quote:
Originally Posted by Davidf View Post
Ok. I failed to notice that it was you who posted the message above from long ago. I did know you relized what the true cause was in your other posts. Be careful on any creative fixes as you dont want to cause a situation that can lead to an engine bay fire. Seems from one of your other posts that you might try diverting the leaking fuel directly to the tank so it cannot be ingested by the engine or foul the tank vent valves. Given the costs of the pumps, I would be tempted to try anything that worked and was cheaper. But, eventually, you will have to replace the pumps. Do one at a time if you have to in order to let the bank account recover. Good luck and be careful.
your solution is a novel one. Had briefly thought of that. But no... my solution is arriving in about 10 minutes, actually, and once I get a chance to look it over, I'll have two courses of action. Both will be absolutely stock. And the impact to pocket book will be minimal. Thanks for "that" concern as well.

I just want to look things over before I post what I'm up to, Might need some help here and there.
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  #13  
Old 02-24-2013, 07:40 PM
mws mws is offline
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Here is my possible fix:

http://www.bimmerfest.com/forums/sho...384&highlight=
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  #14  
Old 02-26-2013, 02:18 PM
mws mws is offline
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This is going to seem anticlimactic, but the actual "long starting times after a few hours or more" has been temporarily fixed: my battery was low, apparently, and did not notice it till I was farting around with DIS and suddenly the warning came up on the car. Checked it and for sure, it needed a good charge.

The non-BMW AGM replacement is only about 9-12 months old, and I am sure I registered it, so not sure what's up. But the car starts in about 2-3 seconds even when it's 32*F outside, and been 24 hours. I've checked this every day since Friday so I know it's consistent.

Still codes, still has gas in the Tank Vent valves. Just reporting the starting is not bad now.

I guess the reason it cranked faster after it's been running was the alternator had recently goosed it. Alt has 135K on it. Good thing I have a parts car now ;-P
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  #15  
Old 03-01-2013, 02:15 PM
mws mws is offline
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Bahhhh, I hate bad science. But I have to report, my battery died pretty quickly in a week of not being driven, so the charged battery from several days ago was not helping the crank times. Even the night before it completely died, the battery was getting low, and still the car cranked over pretty quickly. I just forgot to charge it after that and it was dead in the morning. The only thing I can say about my dying HPFPs is, they are not predictable--as far as whether the long cranking is always directly related to them dying. Just documenting this in case it helps someone else.

It's charged back enough for me to move the car in and out the barn while I work on the parts car.

And my driver car still has gas in the vent tubes and drives like crap because of the HPFPs.
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