Running "lumpy" on start up.

[smayles]

My 04 E85 runs a little "lumpy" when I fire it up, but settles down within a couple of minutes. I have had it serviced recently and they diagnosed a slight misfire which they put down to problems that I was having with my battery (which was constantly going flat). I have replaced the battery, but the "lumpiness" prevails. It doesn't get as much use as it deserves, though the current heat wave will put that right. Any thoughts please?

 

[andystone]

Air intake?

 

[ph001]

I would start by checking the rubber elbow pipe between the airbox and inlet manifold, splits here are a common cause of air leaks that lead to lumpy idle.

 

[Peter-E36]

I would start by checking the rubber elbow pipe between the airbox and inlet manifold, splits here are a common cause of air leaks that lead to lumpy idle.

True but that would cause it to be lumpy all the time. Air leaks are awful!

I wonder if it could be a coil?

 

[andystone]

Mine would do the same initially but improved when warm, but as the split worsened the idle just got awful.

 

[AveZ4coop]

I had a similar issue, led to occasional misfires. Ended up changing all spark plugs and coils, sorted the problem.

 

[ph001]

True but that would cause it to be lumpy all the time

At idle, you have vacuum so splits cause more of a problem, with open throttle the entire intake is more or less at atmospheric pressure so any air leaks don't dominate.

 

[smayles]

Thanks for the feedback. Will get the split looked at initially - certainly before I go down the route of plugs and coil. Cheers.

 

[Peter-E36]

True but that would cause it to be lumpy all the time

At idle, you have vacuum so splits cause more of a problem, with open throttle the entire intake is more or less at atmospheric pressure so any air leaks don't dominate.
split elbow.jpg

Makes sense

 

[w1ndsurfnut]

Seems I am having a bit of a problem period. Not only will my car not start. It’s been a bit lumpy on start.
Just checked the rubber hose pictured by previous poster. Split.

 

[w1ndsurfnut]

True but that would cause it to be lumpy all the time

At idle, you have vacuum so splits cause more of a problem, with open throttle the entire intake is more or less at atmospheric pressure so any air leaks don't dominate.
split elbow.jpg

Anyone know the part number for that. Thanks.