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7 Series - E38 (1995 - 2001)

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  #1  
Old 07-19-2014, 01:01 PM
JasonSC540ia JasonSC540ia is offline
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Location: Alamogetto NM
 
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Mein Auto: 1999 740i
Misfire and hesitation

99 740i with 114,000m

Car has run great with no issues since I owned it from 74,000m. One month ago I retired and sat around for 2 weeks(car sitting for 2 weeks). I decided to drive to California, visit my parents and take an A&P certification course in Riverside. Keep in mind the car has ran great with no SES light ever and most preventive maintenance complied with. The day before I drove to California I drove to Lowes and noticed the car hesitating and missing when leaving stop signs or signals. Nothing crazy, car still moved fine, just a slit hesitation(no SES light and no codes). I cleaned the MAF and added a bottle of Techtron that afternoon with no change. The next day I drove to Cali and car was down on power a little with some hesitation from time to time(still no codes). No change in MPG. I still got 25 doing 85mph all the way.

In Cali I was driving from Beaumont to Riverside every morning about 7am (70m round trip). Car started running rough at first in the mornings. After a few days I got a code. #8 mis-fire. I changed the plugs with new NGK's and swapped coils 7 & 8. Misfire was worse and I got multi mis-fire. I put the Bosch plugs back in and it ran like it did before with slit hesitation. The next day I got #7 misfire. No brainier, I went to NAPA got a coil and replaced. The next day the car ran great. The following day I got #8 & multi misfire. Drove the car back to NM after 2 weeks with slit hesitation and no codes. Same MPG as before.

Back in NM I tripped #2 & multi misfire. Doing some research I found people have spent thousands trying to fix the same problem changing everything from all 8 coils, 8 injectors, computer...ect. Seems they had clogged cats. I ordered a fuel filter, needed it anyway (no change) and some "cats" from FrozenBoost.com. Got the cats changed this morning and that was NOT it. Still getting multi mis-fires. The other day when I changed the fuel filter I did a vacuum leak check with no results (no change in idle while spraying MAF cleaner around every mating surface/connection). I Changed plugs again back to the factory NGK BMW plugs I still had in my garage (not new plugs) no change.

Looking at my engine software (not BMW software) it seems bank 1 & 2 are a bit off more than the norm. From fuel trim to pre & post cat o2 readings. Every time Iv pulled the plugs they look normal. All other readings look normal. MAF temp, coolant temp, engine vacuum ect. I did notice ignition advance going to 45.5 degrees at times when I rev'd it. Don't know if that's normal. Idle between 9-10 degrees.

Anyone have any suggestions?

So far iv spent $70 on a coil, $60 on a fuel filter, $100 on the cats and $86 to have them welded in.

Last edited by JasonSC540ia; 07-19-2014 at 01:06 PM.
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  #2  
Old 07-19-2014, 01:03 PM
JasonSC540ia JasonSC540ia is offline
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Mein Auto: 1999 740i
Forgot to mention; when car is cold misfire is worse and car shakes. After warmed up it idles fine with slit hesitation and if I stomp the gas it will mis-fire and through a code.
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  #3  
Old 07-19-2014, 02:52 PM
JHains JHains is offline
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Location: Woking, UK
 
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Mein Auto: 1998 740i
Have you thought about it being the cam or crankshaft sensors...I had a problem recently with poor running...not pulling away smoothly, lasted for just over a week before the engine just cutout mid journey one day...like the fuel had been cutoff.

I got an independant diagnostics guy round to take a look at the car and it turned out that there were no error codes. Surfed the web for descriptions of similar symptoms and ended up thinking it was the camshaft position sensor...I replaced it and the car started up first crank never had the problem since.
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  #4  
Old 07-19-2014, 03:08 PM
JasonSC540ia JasonSC540ia is offline
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Thanks for the reply JHains.

I have thought about those but figured I would get a code for cam sensor. I wanted to get opinions before throwing more money at it. Was your car acting the same like mine or just poor running in general? mines going on about 3 weeks meow.

I'm getting codes for both banks so I don't see both cam position sensors failing at the same time. Stranger things have happened though. I was thinking crank position sensor since theirs only one and it effects both banks.

EDIT: I don't think its crank sensor. Car has always fired right up. I just ordered the rear manifold cover (crankcase vent). I tested for leaks all around it and found non but I dont have anyway of checking it for internal leaks. Kinda makes since if the car was fine then sat for 2 weeks and it started doing this. I did replace it about 1.5 years ago with a cheap aftermarket one and its had kind of whistle ever since. I ordered a BMW OEM one this time. I should get it Tuesday.

Last edited by JasonSC540ia; 07-19-2014 at 04:24 PM.
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  #5  
Old 07-21-2014, 03:54 PM
JHains JHains is offline
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Location: Woking, UK
 
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Mein Auto: 1998 740i
My symptoms were that the car fired up fine initially and then intermittently it would not run smoothly on a journey...this steadily deteriorated over the period of about a week and on the day it cut out all together it had a bit of a strange start where it turned over more than usual..ran fine for a while then cut out all together. I agree I don't think its a crankshaft sensor, it was the camshaft sensor that went on mine. The rear manifold cover is a good call and sounds like it needs sorting anyway...normally if this isn't sealing properly the rough idle is also accompanied by some white smoke from the exhaust. Hope it sorts your problem...
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  #6  
Old 07-21-2014, 05:31 PM
setconstr setconstr is online now
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Mein Auto: 2001 740i sport 2006 m6
I agree that when my camshaft sensor went the car threw all types of codes which could of cost me lots if I had followed by repairing each item . Once I replaced both camshaft sensors it ran fine also when my MAF went it threw all different codes and ran bad then good for a bit then bad again . One thing I've read is not to us aftermarket in either case........
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  #7  
Old 07-22-2014, 08:57 PM
JasonSC540ia JasonSC540ia is offline
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Was hoping to get the rear cover today but no dice. I just cleaned things up today and replaced the the bigger hoses that I didn't replace last year. Now all hoses are new. They sure did need it. Very brittle and cracked. Inside the manifold looked fine. No pools of oil. Just a normal light coding on everything. Weird thing happened when I disconnected the fuel line though. A lot of air came out of the line. I'm thinking it still had some air trapped in the system from changing the fuel filter the other day.

Did both of you guys get codes at all for the sensors? The only codes I was getting was multiple mis-fires, and a hard mis-fire hit for 8, 7, 2, and 3, that's it. No cam sensor codes.

Everything is looking normal though. No smoking gun. I ever took the vacuum tester to all the hoses just to make sure everything was good downstream. If this doesn't fix it, without codes Ill just have to through parts at it, starting with the cam sensors. I'll see if I can find some ohm specs on them and ohm them out.

Thanks for the help guys. I'll keep you posted.



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  #8  
Old 07-22-2014, 11:38 PM
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FABOCH FABOCH is offline
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Quote:
Originally Posted by JasonSC540ia View Post
99 740i with 114,000m

Car has run great with no issues since I owned it from 74,000m. One month ago I retired and sat around for 2 weeks(car sitting for 2 weeks). I decided to drive to California, visit my parents and take an A&P certification course in Riverside. Keep in mind the car has ran great with no SES light ever and most preventive maintenance complied with. The day before I drove to California I drove to Lowes and noticed the car hesitating and missing when leaving stop signs or signals. Nothing crazy, car still moved fine, just a slit hesitation(no SES light and no codes). I cleaned the MAF and added a bottle of Techtron that afternoon with no change. The next day I drove to Cali and car was down on power a little with some hesitation from time to time(still no codes). No change in MPG. I still got 25 doing 85mph all the way.

In Cali I was driving from Beaumont to Riverside every morning about 7am (70m round trip). Car started running rough at first in the mornings. After a few days I got a code. #8 mis-fire. I changed the plugs with new NGK's and swapped coils 7 & 8. Misfire was worse and I got multi mis-fire. I put the Bosch plugs back in and it ran like it did before with slit hesitation. The next day I got #7 misfire. No brainier, I went to NAPA got a coil and replaced. The next day the car ran great. The following day I got #8 & multi misfire. Drove the car back to NM after 2 weeks with slit hesitation and no codes. Same MPG as before.

Back in NM I tripped #2 & multi misfire. Doing some research I found people have spent thousands trying to fix the same problem changing everything from all 8 coils, 8 injectors, computer...ect. Seems they had clogged cats. I ordered a fuel filter, needed it anyway (no change) and some "cats" from FrozenBoost.com. Got the cats changed this morning and that was NOT it. Still getting multi mis-fires. The other day when I changed the fuel filter I did a vacuum leak check with no results (no change in idle while spraying MAF cleaner around every mating surface/connection). I Changed plugs again back to the factory NGK BMW plugs I still had in my garage (not new plugs) no change.

Looking at my engine software (not BMW software) it seems bank 1 & 2 are a bit off more than the norm. From fuel trim to pre & post cat o2 readings. Every time Iv pulled the plugs they look normal. All other readings look normal. MAF temp, coolant temp, engine vacuum ect. I did notice ignition advance going to 45.5 degrees at times when I rev'd it. Don't know if that's normal. Idle between 9-10 degrees.

Anyone have any suggestions?

So far iv spent $70 on a coil, $60 on a fuel filter, $100 on the cats and $86 to have them welded in.
ouch, after a few coil changes I would of replaced the MAF....you went the $$$route
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  #9  
Old 07-22-2014, 11:45 PM
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FABOCH FABOCH is offline
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Well Now that u have the manifold off Your gonna fix a lot of issues....You might of had a vacuum leak? 1 of your Spark plugs might of loosened up? 1 or 2 of the coil Bremi packs could of been shorted? Make sure the entire AIR intake system is SEALED. I once had a hesitation due to a Sleeve and Clamp (BEFORE) the Air box was not on right...Air was escaping before the air box..Hence the hesitation!!! Good Luck....
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  #10  
Old 07-23-2014, 06:44 PM
JasonSC540ia JasonSC540ia is offline
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I'm not calling it fixed just yet. Ill know more when I drive to El Paso on Friday.

Got everything back together and she fired right up after the fuel pressure built up. No mis-fires at all, and that's when it would do it the worst. Also got rid of that annoying whistle at idle. Took her out for a test and nailed the gas a few times and she just go's. No hesitation or flashing SES light.

God let that be it.

Ill re post after I get back from El Paso on Friday. Its about 200 miles round trip.
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  #11  
Old 08-09-2014, 04:05 PM
JasonSC540ia JasonSC540ia is offline
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Fixed!

Its fixed! my baby is back better than before.

Even though, replacing the rear manifold cover OSV and replacing all vacuum lines helped, it didn't fix my problem. Incidentally I sucked on the cheap OSV and the BMW one, as any good mechanic would, and the new BMW one was easier to suck closed. The spring tension on the cheap made in china one is to tight. It wasn't closing when it should of. After that I ordered a new Bosch MAF from Amazon for $150. Again, car ran better but didn't fix it. 8 new NGK plugs, car ran better but didn't fix it. Got hard misfire hits on 2. Swapped with #1 and code hits on 1. I changed the coil with a spare and code goes away but car still hesitates and misses without throwing any codes. Went out on a limb and ordered 8 new Bremi coils with boots from Amazon for $300. That's $37.50 a coil, not a bad deal. Problem solved! It seems I had multiple coils on there way out but not bad enough to trip a code.

With all the other stuff I changed, the car runs awesome. The engine runs so smooth. Seems it needed the other things as well.

Makes me wonder though. I had hard hits for a short to ground on 1 coil. Does anyone think it was possible for that coil to short out the other coils in the surrounding area? I mean, if the coil is shorted to ground all the coils energy is being transferred to the ground where the other coils are grounded to.....right?

Anyway, its fixed and runs like a beast.
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  #12  
Old 08-09-2014, 04:36 PM
JasonSC540ia JasonSC540ia is offline
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Forgot to mention. After changing the OSV my oil leak, which was very very minor, has stopped. I would have a few drops of oil on the pan in the garage but the dip stick never came off the full mark. The pan has been clean for 2 weeks now.
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  #13  
Old 09-02-2014, 06:31 AM
injuhneer injuhneer is offline
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I have been chasing a similar problem on my car except that it runs fine cold and hesistates when warmed up.

On a related note; I am looking at fuel filters and 1998 shows a different filter depending on where I look (rockauto, ebay, autozone, etc). Was the filter with fpr used on all E38?
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  #14  
Old 09-06-2014, 07:44 AM
JasonSC540ia JasonSC540ia is offline
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I believe they started the return-less system with the FPR on the filter in 99 with the Vanos engines.

I'm not 100% sure on that.
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  #15  
Old 09-06-2014, 01:22 PM
tomloans tomloans is offline
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Yeah I have a slight rough idle too currently cold or hot. Goes away when air is on. It's probably a coil too.

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