Running Terrible - BMW Forum

Bimmer95 · 06-15-2009, 06:06 PM

Hi guys, glad to have found this forum.

Ive got a 95 325i, 2.5L auto, and am having a serious issue with it, I hope you guys can help.

Basically, it runs terrible, stumbles, sputters, and backfires thru the intake manifold. You have to floor it to drive down the road, it runs somewhat smooth, but has nowhere near the power it did before. At idle, it misfires, backfires thru the intake, stalls, and just runs very rough. You have to keep your foot on the gas most of the time to keep it running at idle as well.

The other problem I have is no vacuum. The power brakes quit when this happened, and I unplugged the hose to the booster, and the intake has virtually no vacuum at idle, or any speed. I have to stand on the brakes to stop it. Nothing at the other vacuum hoses either, and everything is connected, including the one under the intake, I havent found any broken hoses yet.

It sounds like a timing issue to me possibly.

I have one code, 1221, for the O2 sensor. The sensor is new, but I still have the code.

The fuel pump was replaced about 3 months ago. It would not run at all before that. It has had a weird stumble on acceleration as long as I have had the car, just hadnt had time to look into it. Now its not driveable.

So far, I have checked the vacuum hoses, and the compression, was 172-178 on all cylinders.

Hope you guys can help!

marti5 · 06-16-2009, 03:29 AM

Sounds like the MAF, unplug the MAF while its running if theres no difference then its shot.

Bimmer95 · 06-16-2009, 06:51 AM

Quote:

Originally Posted by marti5

Sounds like the MAF, unplug the MAF while its running if theres no difference then its shot.

Tried that quick this morning. It ran slightly smoother with the MAF unplugged, then stalled when I plugged it back in. It was backfiring thru the intake either way.

marti5 · 06-16-2009, 08:15 AM

when its running pull the oil dipstick out, do you hear slurpping noises ??

Bimmer95 · 06-16-2009, 03:05 PM

Quote:

Originally Posted by marti5

when its running pull the oil dipstick out, do you hear slurpping noises ??

I pulled it out, got a little oil vapor, then it started pushing oil (quite a bit) out of the dipstick tube, no noise to it really.

Bimmer95 · 06-17-2009, 05:31 PM

Any ideas? Ive checked everything I know how to on this, and am at a loss as to what it is. Thanks for the help so far.

marti5 · 06-18-2009, 02:38 AM

If you have oil coming out of the dipstick the n you have pressure building in the crankcase, I would go for the PCV , as the crankcase is not venting correctly.

Bimmer95 · 06-18-2009, 02:55 AM

Quote:

Originally Posted by marti5

If you have oil coming out of the dipstick the n you have pressure building in the crankcase, I would go for the PCV , as the crankcase is not venting correctly.

I will check that, thanks.

Where is the valve located? I saw the breather hose at the front left of the valve cover, but it doesnt look like a valve where it mounts, just a fitting to attach the hoses.

marti5 · 06-18-2009, 03:15 AM

Im not sure where its located on your model, but it looks like this:

BMW Crankcase PCV Valve E46 E36 E39 528i 328i 323i M3 Z:eBay Motors (item 350152462189 end time Jul-11-09 10:07:43 PDT)
And should be replaced every 30,000 miles.

Bimmer95 · 06-18-2009, 03:29 AM

Quote:

Originally Posted by marti5

Im not sure where its located on your model, but it looks like this:

BMW Crankcase PCV Valve E46 E36 E39 528i 328i 323i M3 Z:eBay Motors (item 350152462189 end time Jul-11-09 10:07:43 PDT)
And should be replaced every 30,000 miles.

Thanks. I have a look at it and see what I can find. I have a feeling its down under the intake.

Bimmer95 · 06-18-2009, 05:59 PM

Looks like I found the issue.

Today, I started digging a bit deeper into it and found a 1 inch breather hose in under the intake directly behind the throttle body that was broken off. A plastic adapter that connects the hose to the intake had snapped.

The starter was replaced by a shop recently, and I think they may have damaged it or broken it, hard to say.

At any rate, I plugged it back into the intake, and the car is running good again.

After that I removed the intake, and ordered all new breather hoses and vacuum hoses.

Thanks for your help guys, I'll let you know how she runs once the parts come in.

Bimmer95 · 06-19-2009, 07:32 AM

On further inspection, it looks like this is the IAC system, not the breather.

I'll throw up some pics in case anyone else runs into this.

I'll post the results once the parts come in and shes running again.

bmwfrmga · 06-24-2009, 09:52 PM

I currently have the same problem with my 1993 325i. Unlike yours, I can't start the car if the AFS is connected. Just curious if thats my same problem...

Bimmer95 · 06-24-2009, 10:36 PM

Quote:

Originally Posted by bmwfrmga

I currently have the same problem with my 1993 325i. Unlike yours, I can't start the car if the AFS is connected. Just curious if thats my same problem...

Very well could be. Big vacuum leaks can cause havoc.

Check the big IAC hose thats directly under the middle of the air intake and see if its broken, or cracked.

Im posting some pics now, I got her fixed up today. Running like a champ again!!

Bimmer95 · 06-24-2009, 10:47 PM

This is the broken IAC hose that caused all the grief:

Intake had to come of to replace it easily:

Found a ton of other dry rotted/cracked hoses, along with the MAF boot:

Also, changed the plugs, coil boots, both serpentine belts, and all of the vacuum lines under the intake, and the two plastic fittings, the one for the valve cover breather, and the other for the iac.

She runs like a top now, no issues.

Here's a pic of the car just for grins: