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I had just had both cylinders 5 and 6 throw misfire codes. I was pulling up to a stop sign and suddenly the car began to run rough. It appears that both misfires occurred at the same time. I had this problem on my 2010 E91 wagon and it would come and go. I replaced all plugs, coils and injectors and it has never come back. I think it may not be coil or injector related since it happened to two cylinders at once. I wonder what would be common to cylinders 5 and 6 that I should start to look at. I know I need to dig deeper but any feedback to get me going is appreciated.
98 328i Vert
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Remove the coils and look down to the sparkplugs for any water or oil. Then remove the sparkplugs to see if they're good.
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Also, starting with the worst cause, a head gasket crack between cylinders 5 and 6 could be something that causes problems to both cylinders.
But first things first.. Like Eric wrote, visual inspection of the spark plugs..
Then I'd do a compression test on all 6 cylinders. If compression is all good, then swap coils around to see if the problems moves to the other cylinders or not.
Could also be a problem in the wiring (DME to coils) or in the DME it self. Good luck!
1997 E36 BMW 323i (European) 275k km (171k miles), with following small mods:
- Chip tuned DME (190HP/257Nm); 328i dual pipe exhaust (plug&play); Meyle HD control arms, Bilstein B4 shocks
- Fan delete mod: Stock 92C thermostat, 80/88C temp. switch, 80/20% water/coolant; INPA says temps 100% OK
- Throttle body coolant hose delete mod; Comprehensive ASC Delete option list; Solved: -30 additive adaptation values
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I don't want to promise this is the head gasket...Originally Posted by sharadn
... but it's the head gasket.
It's driveable, but rough, right? This is exactly how my car went. Check your compression. If you do it wrong and leave the other plugs in, you'll get about 50-60 psi in 5 and 6. If you do it right and pull all the plugs, you'll get no compression in 5 and 6. At that point, case closed.
Not only did this exact thing happen to me, I can't think of anything else that would cause adjacent cylinders to fail at exactly the same time.
The only thing common to 5 and 6 is the head gasket between them.
If it's anything like mine, this means your head will still be straight and you won't be mixing oil and water. You should still send the head out to have the valve guides replaced (which should come in the HG kit) and have it checked. It could also be a good time to do a set of cams, since it would basically be free installation at that point.
I'd start looking for a set of cam locking tools and start reading up on how to do this.
You can do this. It's very straight forward, but you need to be detailed and organized. Take lots of pictures, use Ziploc bags and a Sharpie to label everything you take off (or have a BIG table for everything to stay organized). Make sure you read the Bentley manual and as many online DIYs as you can find (starting with Pelican).
One tiny bit of advice I wish I'd known when I did my car, but did learn in time to use on my Escalade last week - the auto parts stores sell some gasket remover with a little applicator brush as part of the nozzle. The bottle is about the size of a can of easy cheese, and has a similar nozzle you push sideways to use (but with a brush). Not only does it take off gasket residue, it is fantastic at removing carbon buildup from the tops of your pistons.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
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Has it been raining a lot there? Water could have splashed in if your drain is clogged
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cylinders 1-5 all show good compression around 165-170 Cylinder 6 zilch. no compression at all.
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You can do a leak-down test to see where the leak is (be sure to also do cylinder 5, because a leak down tests shows more than just the compression test). On the top (valves or head gasket) or below (piston rings).
If it's the piston rings, then you might be able to revive them. No guarantees but you could be lucky.
Check this video:
Here's another one: https://www.youtube.com/watch?v=kqgrNxDZeIQ
Last edited by ed323i; 09-01-2018 at 07:36 PM.
1997 E36 BMW 323i (European) 275k km (171k miles), with following small mods:
- Chip tuned DME (190HP/257Nm); 328i dual pipe exhaust (plug&play); Meyle HD control arms, Bilstein B4 shocks
- Fan delete mod: Stock 92C thermostat, 80/88C temp. switch, 80/20% water/coolant; INPA says temps 100% OK
- Throttle body coolant hose delete mod; Comprehensive ASC Delete option list; Solved: -30 additive adaptation values
Member
This is what I did today:
I just did a leak down test on cylinder 6. At TDC both on the compression and exhaust strokes I get the same thing. Air out of the oil fill and the throttle body. I did it with both all other spark plugs in and with them out. With them out I was getting air out of cylinder 3 as well. I then did the test to the rest of the cylinders with the plugs in. All in all the rest of the motor looks pretty healthy as there was very little leakage on any cylinder except 6. Lot of leakage out of the oil fill. when I capped the oil fill it came out the throttle body. I am not sure what this means. Either the rings are carboned up and stuck in the lands or maybe I broke a ring. Also I am wondering why it is coming out of the throttle body. Bad intake valve also? It would seem kind of unusual to have both problems at once, especially considering that everything else in the motor looks good. Nothing into the cooling system and nothing out of cylinder 5 when testing cyl 6. Cracked head maybe.... I am used to working on MG 4 bangers and these bimmer straight sixes are new to me at this level. I filled cylinder 6 with techron and will leave it overnight. Please share any further thoughts. I don't really want to jump into a head removal if I can avoid it but if I can't.....
Last edited by sharadn; 09-02-2018 at 04:44 PM.
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I wouldn't worry about 3. You're getting air into the intake. With plugs out, that air is just routing through the open valve on 3 and out the plug hole.
You could pull the valve cover and see what you can see / do the leakdown again and see if it is coming through a cracked head or out the bottom.
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I will do that. What is odd is the fact that when I cover the oil fill it comes out the throttle body. Bad intake valve? cracked head? not sure a how blown head gasket would do this.
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So when you do a leakdown test after you confirm that it's leaking, squirt a small amount of oil into the cylinder to see if the leak stops. That small amount of oil temporarily seals the piston rings and you can confirm whether the air is leaving via the vales or the rings.
If it's seems to be the rings because the leak stopped, you can try that youtube video posted earlier to attempt to free up a stuck ring. Also realize a ring can be damaged.
As to your earlier question why you hear air coming out the intake, this is because if air is leaving vis the piston rings, it then travels into the crankcase and can then leave either out the oil filler or travel further through the crankcase vent (oil separator) which leads to the intake.
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Thank for the suggestion. I will try it and see what happens with the oil.
Member
The leak down test is much better with the oil (Lucas oil stabilizer) So it is looking like a ring problem, but still getting zero on compression test. I don't want to do this with much oil in there and bend a rod
Last edited by sharadn; 09-03-2018 at 04:36 PM.
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Maybe I missed that you were getting zero on #6 compression. So the head has to come off, it's most likely cracked.
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I'd start looking for a set of cam locking tools and start reading up on how to do this:
What else do I need besides these:
https://www.bavauto.com/bmw-camshaft-tool-b8800040
https://www.bavauto.com/bmw-camshaft-tool-b8800018
I don't think that I need this set but please confirm and let me know what I can do with this but not with the others:
https://www.bavauto.com/bmw-camshaft-tool-b8800027
Also I guess I need a thin wall torx to remove the head bolts.
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I woudn't speed that much money. I don't think that vanos "blank" is needed? Maybe someone else can comment, but I don't think it's needed. Personally I made the vanos tools out of spare parts and bought a rectangle of aluminum to make the cam block, there are dimensions for it in the Haynes repair book but should also be here on the forum. But this deal on ebay sounds more reasonable. Try to think of whatever other maintenance things you want to do while in there, for instance Vanos seals, there is a guide at the Besian systems website. The only bad part in that guide is where they show you to cut out the old seals with an Xacto knife, you have to do this very carefully to not cut into any metal. Alternatively you could use a special seal pick (not the cheap pointed pick). Also I did the seals one time with seals from Besian and now I did it with seals from ebay, the besian seals did not last long but I don't know why and I cannot comment on how long the ebay seals will last either so I cannot really make a recommendation.
https://www.ebay.com/itm/For-BMW-Tim...s/263554324150
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Be sure to read other threads where people overheated and had to have the head machined. There are options and if you do take the head to a machine shop make sure they are very familiar with BMW heads.
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Mine was six or seven years ago at this point, so it's all a bit fuzzy.
I used the stuff in the first link (some of them, at least. I used a nail for the timing chain tensioner). I don't remember using the second tool, though I have a friend who is the BMW CCA quartermaster for his local club who helped me and might have brought this (or had a trick up his sleeve and just did it). But I don't remember using it to get the sprocket set properly.
Number three... I've got no idea. Anyone else use this recently / regularly (poor bastards) who does know?
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
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Looks like that big block of alum is for double vanos people, so the ebay kit looks like the way to go.
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I pulled the valve cover and plugged the CCV hose that goes into the valve cover and repeated the leak down test. It is definitely going into the sump. I can actually hear the oil bubbling from the air pressure. It seems the air might be coming in below the level of the oil in the sump. If the problem was rings then it should not make the oil bubble because the rings are above the oil level. If it was a ring problem, would the pressure be enough to disturb the oil? It would not seem so to me. Would it do it if the head was cracked between an oil passage and the combustion chamber? Or does it have something to do with air escaping via the CCV?
Last edited by sharadn; 09-08-2018 at 10:22 AM.
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Dont cheap out on tools. I bought a cheap eBay fan clutch wrench and spanner once and after the first use it deformed and wont fit so now its totally junk. Also it slipped and stripped the bolt on my water pump a bit.
OP you need the cam locking blocks, vanos sprocket, and head bolt socket. Either Get quality ones that will last and not Fuck up your car when they break, or just rent them from someone on here.
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The bubbling is through the CCV. It is definitely leaking through the rings into the sump. I will try some ACDelco upper head cleaner to see if that frees up the rings. It seems that the head itself is good.
Member
It could still be valves - the CCV pulls vacuum off the intake manifold. I'd open the throttle body and make sure it's still doing the same thing. If not, it could be traveling back though the oil separator and down the dipstick tube - which could cause your bubbling.
Member
It only bubbles if I block the ccv tube that goes into the valve cover. If I don't block it the air just comes out that tube.I will try that with the throttle body. I am wondering if I need to remove the intake manifold to really diagnose this. I don't really want to as it is a PIA but I also don't want to pull the head unless I know that it is necessary.
Last edited by sharadn; 09-08-2018 at 01:08 PM.
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I pulled the throttle body and it is definitely coming out the intake manifold. Are there any other tests I could do before jumping and pulling the head? Could it be a broken spring on the intake valve?
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