Random misfires on startup

Discuss problems you have had or are having with your Z4
Post Reply
JohnMRZ4
Newbie
Newbie
Posts: 8
Joined: Fri Oct 28, 2016 10:43 pm

Random misfires on startup

Post by JohnMRZ4 » Mon Jul 09, 2018 4:56 pm

Hi all, hoping you can help me diagnose a problem.
I started my z4 and it was running very roughly, I got P0300 and a warning light. The engine was physically shaking, so I took a look for anything obvious and found a hole in one of the hoses that runs from the air filter where the hose has perished over time. Looking from the front of the car to the rear, it's the hose that does goes left into the engine from the air filter housing. I decided not to drive it incase there's damage caused to the engine but I need to drive it to the garage for a fix and it's 40 miles away from where my car is at work. If there is a vacuum leak will it cause any damage? Has anyone else had this crop up?

Scooba_Steve
Lifer
Lifer
Posts: 4608
Joined: Wed Feb 19, 2014 3:01 pm
Location: NW London

Random misfires on startup

Post by Scooba_Steve » Mon Jul 09, 2018 6:00 pm

Put some tape over the hole to start with and try again? P0300 isn't specific just a misfire code, maybe INPA will give a better code. I assume it was a generic code reader?
3.0si Sport: F10 Illuminated ZHP, Retrofit Cruise, OE Stubby, Gaptech RCH+, Kenwood BT73DAB + Handsfree, HIDs, LED Sidelights, OE LED Number Plate Lights, Custom LED strip bootlight.

User avatar
ph001
Senior Member
Senior Member
Posts: 1777
Joined: Mon Oct 31, 2016 5:53 pm
Location: N. Yorkshire.

Random misfires on startup

Post by ph001 » Mon Jul 09, 2018 8:44 pm

You need a garage to change a hose?
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual.

Online
User avatar
mr wilks
Lifer
Lifer
Posts: 18502
Joined: Wed Jul 04, 2012 10:02 pm
Location: Lancs or Normandy , i don't mind which

Random misfires on startup

Post by mr wilks » Mon Jul 09, 2018 9:09 pm

ph001 wrote:
Mon Jul 09, 2018 8:44 pm
You need a garage to change a hose?
Why is that so strange :? i would too :? but i could install a truss roof , construct a decent extension from scratch , screed & lay a karndean floor , convert a French barn etc all quite easily :wink: not everyone chooses to work on their own cars , i never have , perhaps i could but i don't .
Z history
E86
E85
Grey///MR
Si E85
E89 23i
Si E85
E86
3.0Si E85
Imola///MR
35i Msport 6spd
E86
E86

Silver///MR GruppeM :driving:

Image


https://www.instagram.com/andybmwheels/

JohnMRZ4
Newbie
Newbie
Posts: 8
Joined: Fri Oct 28, 2016 10:43 pm

Random misfires on startup

Post by JohnMRZ4 » Mon Jul 09, 2018 10:49 pm

Scooba_Steve wrote:
Mon Jul 09, 2018 6:00 pm
Put some tape over the hole to start with and try again? P0300 isn't specific just a misfire code, maybe INPA will give a better code. I assume it was a generic code reader?
It was a standard reader, I will get some tape and give it a go and see if it fixes it. The hose itself is quite tricky for a newbie like me to get to and change myself :?

JohnMRZ4
Newbie
Newbie
Posts: 8
Joined: Fri Oct 28, 2016 10:43 pm

Random misfires on startup

Post by JohnMRZ4 » Fri Jul 20, 2018 8:49 pm

Well, I taped up the hole but it didn't fix it. So I'm lost as to what it might be. I took a video of the engine featuring the noise it's making. Any ideas what it sounds like? The unusual sound is like a steam train - the chug chug chug

https://youtu.be/vDSYOSWPjWM

AveZ4coop
Member
Member
Posts: 136
Joined: Thu Nov 16, 2017 11:08 pm
Location: Peterborough

Random misfires on startup

Post by AveZ4coop » Fri Jul 20, 2018 11:02 pm

doesn't sound good! Hope someone on here can help you and it's not too serious.
Montego blue 2006 BMW Z4 coupe 3.0 with black interior, ZHP, stubby, 12mm front/16mm rear spacers on BBS 108's. :driving:

Gazza51
Member
Member
Posts: 153
Joined: Fri Dec 21, 2012 11:03 am
Location: Romford Essex

Random misfires on startup

Post by Gazza51 » Sat Jul 21, 2018 7:49 am

Sounds like a compression leak.
Z4 MC, M3 CSL, S54 Z3MR, Z1.

User avatar
Fox889
Member
Member
Posts: 126
Joined: Sat Jul 09, 2016 10:12 pm
Location: God's very own county.....Suffolk

Random misfires on startup

Post by Fox889 » Sat Jul 21, 2018 11:43 am

I suppose my first question is, does she run ok after a few seconds or is she running rough all the while?
Sounds very much as if she's 'inhaling' far more air than she normally should?
I would take the air filter out, remove the air filter box & make sure all the hoses etc seem ok & go from there.
I know when I bought mine [3.0] carried out a full service then blow me, the yellow engine light came on, turned out to be the air filter box 'elbow' pipe had deteriorated badly.
Carry out the simple bits first then see where you are.
Just a thought........it wouldn't be something as stupid as a loose spark plug?

Tell us how you get on.
2004 3.0 Z4 in Sterling grey metallic

JohnMRZ4
Newbie
Newbie
Posts: 8
Joined: Fri Oct 28, 2016 10:43 pm

Random misfires on startup

Post by JohnMRZ4 » Sun Jul 22, 2018 10:32 pm

I have run the engine for a good minute or two and it keeps going as-is in the video with no signs of letting up.

Looking at the hoses I taped-up the bit where I could see an obvious rip, I didn't see any other splits.

The strange thing is it drove to work fine, then I came to go home and this started.

I guess other causes maybe valve cover gasket ? Bad coil packs probably wouldn't cause this sound?

AveZ4coop
Member
Member
Posts: 136
Joined: Thu Nov 16, 2017 11:08 pm
Location: Peterborough

Random misfires on startup

Post by AveZ4coop » Mon Jul 23, 2018 3:14 pm

A bad coil pack/spark plug would cause a misfire and would first show itself under load. This doesn't sound ignition related.
Montego blue 2006 BMW Z4 coupe 3.0 with black interior, ZHP, stubby, 12mm front/16mm rear spacers on BBS 108's. :driving:

JohnMRZ4
Newbie
Newbie
Posts: 8
Joined: Fri Oct 28, 2016 10:43 pm

Random misfires on startup

Post by JohnMRZ4 » Sat Jul 28, 2018 9:10 pm

Weirdly it was the coil pack on cylinder 2, replaced it and it is now running well, I didn't think it would be that simple. Thanks for all your help and replies

AveZ4coop
Member
Member
Posts: 136
Joined: Thu Nov 16, 2017 11:08 pm
Location: Peterborough

Random misfires on startup

Post by AveZ4coop » Thu Aug 09, 2018 10:38 pm

Eating humble pie :oops:

Glad you got it sorted. :thumbsup:
Montego blue 2006 BMW Z4 coupe 3.0 with black interior, ZHP, stubby, 12mm front/16mm rear spacers on BBS 108's. :driving:

Post Reply