Xoutpost.com

Xoutpost.com (https://xoutpost.com/forums.php)
-   X5 (E70) Forum (https://xoutpost.com/bmw-sav-forums/x5-e70-forum/)
-   -   Several Misfire 4.8i (https://xoutpost.com/bmw-sav-forums/x5-e70-forum/110729-several-misfire-4-8i.html)

Hjaltivignis 08-26-2019 09:37 AM

Several Misfire 4.8i
 
Hello all.

Got an X5 4.8i and when I start it cold, I get misfire on several cylinders 4,5 and 8, if I drive about 400-500meters turn ignition off and on again, than the problem is gone and the engine acts normally.

New spark plugs and injector in cyl. 8. Swapped the coils and the error does not follow the coil so the coils seem to be ok. Is there any known malfunction that you know that could be causing it?

SlickGT1 08-26-2019 09:40 AM

How cold is it when you start up. There is a known intermediate lever issue that can cause exactly this.

ard 08-26-2019 11:44 AM

Valve cover oil leaks letting oil settle into the spark plug wells.... Goes away after burning off.

Just a wag....

Hjaltivignis 09-25-2019 05:54 AM

Quote:

Originally Posted by SlickGT1 (Post 1167857)
How cold is it when you start up. There is a known intermediate lever issue that can cause exactly this.

It doesn´t matter how cold it is, 3°c or 15°c, always the same. The eccentric shaft and everything related to that have been changed.

Baby Unicorn Taco 09-25-2019 06:06 AM

Definitely check for oil in the spark plug wells as stated earlier. Also, you replaced one spark plug but if they all haven’t been replaced recently that could be your issue as well. You might have plugs that are in bad shape and don’t like the low rpms causing the multiple misfires that disappear at higher rpms. I had this issue on my 4.8i and 8 new plugs solved the issue.


Sent from my iPhone using Xoutpost.com

Hjaltivignis 09-25-2019 06:09 AM

Quote:

Originally Posted by Baby Unicorn Taco (Post 1169215)
Definitely check for oil in the spark plug wells as stated earlier. Also, you replaced one spark plug but if they all haven’t been replaced recently that could be your issue as well. You might have plugs that are in bad shape and don’t like the low rpms causing the multiple misfires that disappear at higher rpms. I had this issue on my 4.8i and 8 new plugs solved the issue.


Sent from my iPhone using Xoutpost.com

Less than a year since they were all changed, did check for oil on cyl 5-8 and no oil visible and spark plugs looked perfect.

Baby Unicorn Taco 09-25-2019 09:11 PM

I would check for vacuum leaks.


Sent from my iPhone using Xoutpost.com

Orthotist 09-25-2019 10:40 PM

Vacuum leaks
 
I second the possible vacuum leaks. Use the carburetor cleaner spray test method to help rule in or out.

ard 09-26-2019 04:25 PM

Quote:

Originally Posted by Hjaltivignis (Post 1167856)
Hello all.

Got an X5 4.8i and when I start it cold, I get misfire on several cylinders 4,5 and 8, if I drive about 400-500meters turn ignition off and on again, than the problem is gone and the engine acts normally.

New spark plugs and injector in cyl. 8. Swapped the coils and the error does not follow the coil so the coils seem to be ok. Is there any known malfunction that you know that could be causing it?




Sounds like you have and issue with rich/lean... it can throw random misfire codes, but not linked to any one cylinder (the reason for this has to do wth how the DME detests misfires, CU calibrations, etc) The DME will declare a cylinder, but these are not NECESSARILY linked to one cylinder. (note: another give-away is a code of 'misfires- multiple cylinders'...this means the DME is seeing a lot of jiggle in the crankshaft accel and cannot decide which cylinder(s) to blame.)


Is this a cold start issue only?
Does disconnecting the MAF change this at all?
How old are your pre-cat O2 sensors?
What are your short and liong term fuel trims?
When you run a VANOS function test, results?

Baby Unicorn Taco 09-26-2019 09:20 PM

So I looked back at my pictures from the misfire issue I had last year. I was driving back from vacation trip to Disney. 6 hour trip. Probably 3 hours in. Began to run rough. Ran fine for three hours of highway driving but when I got to lower rpms on a side road it began to run rough. I scanned it on the spot and got codes for “combustion misfires several cylinders, misfire on 4, 5, & 8, and a catalytic converter conversion” code. Was all solved by new spark plugs. I was able to get home at highway speeds and slower acceleration on slower roads. Sound like your status? This was 20,000 miles ago.


Sent from my iPhone using Xoutpost.com


All times are GMT -4. The time now is 10:04 AM.

vBulletin, Copyright 2019, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.6.0
© 2017 Xoutpost.com. All rights reserved.