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E34 (1989 - 1995)

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  #1  
Old 02-14-2011, 02:30 PM
MRF4665 MRF4665 is offline
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1989 535i stuttering at low rpm

Hi all,

I have an '89 535i with ~120k miles that is currently being used as my second car. A few months ago it started running rather rough and would sometimes be difficult to start. Believing that the issue was somewhere in my ignition, I replaced the cap and rotor (both were original) and all was great for about a month.

Recently, I have been having an intermittent stuttering issue at low rpm (under ~1500 rpm) when accelerating (It seems as though at least 1-2 cylinders misses). When I get above about 1500 rpm, the stuttering largely vanishes but has occurred a few times above ~4500 rpm under heavy acceleration. When cruising at highway speed there is no problem at all. The low rpm stuttering problem is more prevalent sometimes and rare at other times and is seemingly independent of engine temperature.

I've measured spark plug wires (original) and all are between 5500-6000 ohms and have no obvious visible degradation. I measured the coil and the primary winding was in spec but the secondary measured ~9200 ohms (spec is 6600 ohms max, per Bentley). Thinking this was at issue, I ordered a new Bosch OEM coil. Upon receipt, the new coil measured 10,400 ohms on the secondary making me believe that either the new coil was bad as well or my coil was just fine. I've since returned the out-of-spec coil for refund.

It's been suggested by a friend to replace my original spark plug wires. However, since they have no visible degradation and measure fine, I'm skeptical as to whether this will be of any benefit.

Spark plugs are relatively new (<5k miles) and are Bosch Platinum. Removed, inspected, and replaced all 6 last week and they appear relatively clean and properly gapped.

Any ideas on where to look next? Should I replace my spark plug wires 'just cause'?

All help is greatly appreciated!

Mark
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  #2  
Old 02-14-2011, 05:51 PM
JMI JMI is offline
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Quote:
Originally Posted by MRF4665 View Post

It's been suggested by a friend to replace my original spark plug wires. However, since they have no visible degradation and measure fine, I'm skeptical as to whether this will be of any benefit.

Spark plugs are relatively new (<5k miles) and are Bosch Platinum. Removed, inspected, and replaced all 6 last week and they appear relatively clean and properly gapped.

Any ideas on where to look next? Should I replace my spark plug wires 'just cause'?
They are due and this was my experience ;-)

Jim
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  #3  
Old 02-14-2011, 08:01 PM
MRF4665 MRF4665 is offline
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Appreciate the quick response Jim.

I've read a few other threads that indicated that new wires cleared up an idle problem. Thing is, my beloved 535i is idling like a champ with rarely even the slightest bobble. The misfire / stuttering that I experience is only on relatively heavy acceleration and low rpm (under ~1500). If I back off on the throttle position, the stuttering goes away and when above 1500 rpm I can mash the throttle and I have no issue at all. As mentioned above, I have had a few misfire instances when above ~4500 rpm and heavy acceleration but the problem is mostly isolated to acceleration at low rpm.

If my wires are the best bet, I'm willing to give it a shot. I just want to avoid the insidious rat hole of swapping out good parts if I can possibly avoid it.

Next question - are some wires better than others? I've seen the OEM Bosch at BMA for ~$105, and Karlyn-STI at Pelican for ~$135. Any other recommendations on wires / vendors?

Thanks again!

Mark
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  #4  
Old 02-15-2011, 07:33 AM
JMI JMI is offline
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Quote:
Originally Posted by MRF4665 View Post
Next question - are some wires better than others? I've seen the OEM Bosch at BMA for ~$105, and Karlyn-STI at Pelican for ~$135. Any other recommendations on wires / vendors?
I don't care much for throwing parts at a problem, either. But those wire are 20+ years old and it wouldn't hurt to change them. Any of the above would be a good choice. I do most of my purchases at BMA. Always a pleasure.
Would stay away from so called "High Performance" wire sets.

Jim
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  #5  
Old 02-15-2011, 08:03 AM
injunmort injunmort is offline
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are you using premium gasoline? have you changed the fuel filter recently. i would fill with premium and seafoam, drive it for awhile and see if there is any improvement. my wifes car does the same thing when she cheaps out on gas.
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  #6  
Old 02-15-2011, 09:22 AM
robertobaggio20 robertobaggio20 is offline
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Are you running with a piggyback chip? If you are, the wiring between the chip and your stock ecu needs to be looked at. Symptoms similar to those you report were traced to the pig's wiring in another car.

Another thing I'd like you to check. The spark plugs....see if they are tight in their holes, and see if there's any fluid in them holes. If you do spot fluids, confirm what it is...oil or water. Water causes the exact problems that you mention.

The same car i mentioned earlier had some cold start problems ....that's what came to mind as i read your post. The solution was to change the wires. There was no visible degradation to the old wires, but the insulation there had microfissures allowing moisture to get in and screw things up on a cold morning. While that maynot be the issue here, I would go with Jim in that it can't hurt to replace the ignition wires on your car....and i'm getting the distinct impression that your car is generally problem free, in which case you can spend this money with a clear conscience. Despite the impedance of the existing wires being normal when you measure, they may behave differently under load...and in any case, new wires generally always leads to a tad better performance in the engine so even if this doesn't correct the problem, you're getting a good deal.
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  #7  
Old 02-15-2011, 12:37 PM
injunmort injunmort is offline
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a visual inspection of wires should be good, but you can open the hood and run car in the dark and see if there are any sparks around the wires. these cars are very tempremental to fuel quality. premium gas only and bmw means it. plugs and wires are a good idea for a car of this age anyway but i lean more towards fuel quality, fuel filter first. fwiw. 525's you can run on regular and get away with it, not so w/535.
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  #8  
Old 02-15-2011, 01:45 PM
MRF4665 MRF4665 is offline
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I have been running exclusively on minimum 91 octane from the get-go. Fuel filter is about 6 years old (~20k miles). No 'piggyback' chip. Everything is box-stock, except for my Bilstein's and heavy duty thrust arm bushings.

Have run the car in the dark on three separate occasions to see if I could find any dancing corona balls and sadly witnessed no fireworks at all. Gonna go ahead and place an order for new wires with BMA in the next few days and will toss a few oil filters as well as the fuel filter in the box.

Will post my results after I bust out my wrenches.

In the meantime, if anybody has any further tips, I'm all ears.

Thanks again for the help gents!

Mark
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  #9  
Old 02-15-2011, 04:29 PM
JMI JMI is offline
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Originally Posted by MRF4665 View Post
I have been running exclusively on minimum 91 octane from the get-go.
I use 87 octane which is the recommended stuff for a stock engine. The compression ratio on the M30 engine does not warrant anything more.

Jim
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  #10  
Old 02-15-2011, 04:39 PM
MRF4665 MRF4665 is offline
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I should check myself here. I ran 87 octane for my first 4 tanks after purchasing my 535i w/~45,000 miles about 14 years ago. I was getting occasional detonation under load in 5th gear (especially on a hill) so I switched to 91 and my detonation woes disappeared. I'm tempted to try 87 again but fear I'll get detonation again. Perhaps my next tank....

Thanks for the tip.

Mark
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  #11  
Old 02-15-2011, 05:11 PM
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BMR_LVR BMR_LVR is offline
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You may very well get detonation again. Over 14 years, carbon deposits may have built up in the combusion chamber. If so, this will hold heat and tend to cause detonation with the lower octane fuels and thus causing knocking.

Steve
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It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

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  #12  
Old 02-15-2011, 09:11 PM
MRF4665 MRF4665 is offline
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This is my fear and precisely why I've been staying with higher octane fuel for so long. Believe me, with California's painful gas prices, if my 535i ran great with no detonation on lower octane fuel I would certainly be doing it.

Mark
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  #13  
Old 02-16-2011, 05:42 AM
injunmort injunmort is offline
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535 has m50, m30 is 525 entirely different animal. the fuel of 14 years ago resembled gasoline, it no longer does. want the car to run like ****, put in regular. bmw recommends min octane of 91 for m50. fwiw.
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  #14  
Old 02-16-2011, 06:11 AM
robertobaggio20 robertobaggio20 is offline
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Quote:
Originally Posted by injunmort View Post
535 has m50, m30 is 525 entirely different animal. the fuel of 14 years ago resembled gasoline, it no longer does. want the car to run like ****, put in regular. bmw recommends min octane of 91 for m50. fwiw.
Your post is very confusing, please edit or repost if you don't mind. Thanks injunmort.
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  #15  
Old 02-16-2011, 07:07 AM
injunmort injunmort is offline
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simply referring to engine designation of different models. m50 is 3.5l that is in a 535, m30 is the 2.5l that is in the 525, 91-96. a post was made that 87 octane is sufficient for m30 engine (which it is) but OP has a 535 which is equipped with the m50 engine and requires 91+ octane per bmw. as i stated before, the m50 will run like **** if you put regular gas in it (87 octane). as far as the quality of gas goes, 14 years ago there was no ethanol in the fuel, today there is plenty. ethanol is alchohol and will absorb water from the atmoshpere. if it sits long enough 10% of your fuel will become water. internal combustion engines of the gasoline type will not run on water. there are a host of many maladies that todays fuel concoctions will cause away from poor quality and poor running. i hope this clears up any confusion of my previous post.
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  #16  
Old 02-16-2011, 07:38 AM
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BMR_LVR BMR_LVR is offline
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Injunmort, you have it backwards regarding engines.

M50 - 2.5 liter - 525 - factory calls for premium gas
M30 - 3.5 liter - 535 - not sure what the factory calls for, but I think it is premium as well

I ran my first 92 525 with premium its entire life. I have run my 95 325 and current 92 525 with regular with no advers affects. The 92 525 does not have knock sensors per the Bentley. The 95 325 does and the knock sensors will slighty retard the timing if knock is detected.

Steve
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Quote:
Originally Posted by noego View Post
It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

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  #17  
Old 02-16-2011, 07:39 AM
MRF4665 MRF4665 is offline
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My M30 535i manual specifies 87 octane minimum but I have been running 91 for several years due to aforementioned detonation under heavy load.

Mark

Last edited by MRF4665; 02-16-2011 at 07:41 AM.
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  #18  
Old 02-16-2011, 07:47 AM
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BMR_LVR BMR_LVR is offline
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Yeah. I don't think that your 535 has knock sensors. Running premium in a car that only calls for 87 will not enhance performance or provide benefit and is usually not indicated. However, in your case, use of the premium is appropriate to prevent the detonation.

Steve
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Most problems are usually something simple !

Quote:
Originally Posted by noego View Post
It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

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  #19  
Old 02-16-2011, 08:04 AM
injunmort injunmort is offline
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my bad and appologies, my wifes 1990 535 m30 says on the fuel door "premium unleaded only" my 1990 525 m20 says, in the same location "unleaded fuel only" by personal experience and that of other local e34 drivers, if you dont put premium in the 535 it will run poorly. this happens whenever my wife puts regular in her 535. my w124 mb has the same requirements as well "premium unleaded only" when you put regular in it, it runs like ****. no power, hesitation and rough running.
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  #20  
Old 02-18-2011, 11:27 AM
MRF4665 MRF4665 is offline
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*****Update*****

Received my fancy new ignition wire set from BMA yesterday (thanks BMA!) and swapped them out late last night. Test drove my 535i last night and also drove to work today and sadly, my stuttering problem at low rpm while accelerating still exists.

Should I have concern with my coil that measures high on the secondary winding (measured ~9K ohm vs. spec 6K ohm)?

Any advice on what to check next or methods to diagnose further?

All help is greatly appreciated.

Mark
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  #21  
Old 02-18-2011, 01:00 PM
JMI JMI is offline
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Sorry to hear that, Mark.

Sometimes it just pays to bite the bullet and get a professional diagnosis. That is what I did when I was having "my" issue and the pulse generator on the plug set was bad. A good independent BMW shop can save your time and sanity.

Jim
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  #22  
Old 02-18-2011, 03:12 PM
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luckydog luckydog is offline
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Quote:
Originally Posted by MRF4665 View Post
running rather rough and would sometimes be difficult to start.
Mark
My hard starts were related to bad Fuel Pump. $100 On Ebay never looked back. Oh and when you are in the tank siphon out the pile of dirt under the mesh prefilter of the pump.

Last edited by luckydog; 02-18-2011 at 03:14 PM.
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  #23  
Old 02-18-2011, 03:18 PM
MRF4665 MRF4665 is offline
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Thanks Jim.

The last time my 535i was at an independent shop was for a new clutch that set me back >$1000. After the clutch job I immediately had a vibration in my drive line during acceleration that had been butter smooth prior to the new clutch. Took it back to the shop and they said that I had a bad drive shaft and that they could install a rebuilt shaft for another $1000. I declined and this experience left a bit of a bad taste with me. As such, I'm gonna grit it and try to figure this one out on my own until I can identify a good local shop.

Will try seafoam and a gallon of diesel in my next tank and see if that helps.

Mark
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  #24  
Old 02-18-2011, 03:24 PM
MRF4665 MRF4665 is offline
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Quote:
Originally Posted by luckydog View Post
My hard starts were related to bad Fuel Pump.
After swapping out the cap and rotor ~3 months ago my 535i has been starting and idling perfectly. My current issue is strictly misfiring under acceleration at low rpm. Will keep fuel pump in mind if I start to have other quirks or am unable to correct my stuttering by other means.
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  #25  
Old 02-18-2011, 04:48 PM
robertobaggio20 robertobaggio20 is offline
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Quote:
Originally Posted by MRF4665 View Post
After swapping out the cap and rotor ~3 months ago my 535i has been starting and idling perfectly. My current issue is strictly misfiring under acceleration at low rpm. Will keep fuel pump in mind if I start to have other quirks or am unable to correct my stuttering by other means.
1. Why did you swap out your old cap and rotor?

2. Do you still have the old stuff?

3. If you swapped it all out as a means of anticipatory replacement and not because they were damaged per se, then you can try swopping them back out to see if it helps.

4. Can't remember - have you cleaned our your idle control valve and the air hose that's fixed to it? Wd40 will suffice for this. If this doesn't help, it is possible that your idle control valve may need to be replace - be prepared for this possibility

4.5 HYour air filter and air hoses and intakes are ok right?

5. Have you cleaned out your throttle position sensor? Not sure if a manual car has one actually but yea probably does.

6. Don't feel poorly about the ignition wires. Your car needed a new set. You're staying ahead of the curve. It was a good move.

7. Have you cleaned out your fuel filter recently?

8. Why did it cost $1k to change the clutch on your car? The clutch itself should not cost more than $200...did you buy some dual mass thingamajig, even then it should be around the same price.

9. Do you still have driveline vibration? Your driveshaft is fine. Those idiots did not fix the bushings properly. Everyone...please note this. If something else goes wrong after a repair, and especially if that something else is physically close to that thing being repaired, the bloody workshop has screwed something up in the reassembly process. They are liable for the costs of repair, if not lawsuits and bad publicity should be threatened.

10. If you had installed a replacement driveshaft, you may have to do things like rebalancing the driveshaft.....**** that costs alot of money i assure you.



rgds,
Roberto
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