1996 318is will start but wont hold an idle.

[1996bmw318is]

Hey, I have a M44 engine that will run at 1000 rpm or more but anything lower it sputters and dies.

I have recently replaced the fuel pump, fuel filter, spark plugs and wires
I have redone all the gaskets for the intake manifold and cleaned Icv
The car wont throw any codes and don't know where to look next.
Any help would be appreciated Thanks.

[Benzg1818]

I'm also in a similar situation, although with a 93 M42. Looked at the same things as you. ive also had my injectors and coil packs replaced by the previous owner who also couldn't solve the shitty idle. I've replaced most of the vacuum lines and only left the ones that looked like they were in decent condition. My next move is to try and rent out or borrow a smoke machine and test for more possible vac leaks that way.

Just a thought, could it be related to engine timing, i can see that my chains have most likely been done as the front timing case gasket is just silicon, When i did my valve cover gasket the timing chain guide between the intake and exhaust cam wasn't even bolted in, the E8 or whatever it was was only sitting in the guide. This makes me think whoever did it probably didnt know what they were doing and leads me to believe that the engine could be out of time. I did drive it about 40 minutes from where i bought the car, didnt seem to lack much power (m42 power that is) once you go going and was putting some load on the engine. But as soon as i came to a stop at a set of lights it started to sputter and struggle to hold idle under 1K.

[ed323i]

* Try to run without MAF sensor (to see if MAf is causing it; in normal situations it should run perfectly fine without MAF)
* Check the fuel rail pressure. Not sure if you need 3.0 or 3.5 bar, but should be one of those. At idle it should a 0.7 bar lower more or less.

Symptoms very much seem fuel related, so fuel pressure regulator might be it.

Perhaps crank or cam position sensor?

[1996bmw318is]

M44 Engine wont hold idle on its own

I have checked all vacuum lines and have found no vacuum leak.
I have replaced the fuel pump and filter.
I have put in a new TPS, ICV, coolant temp sensor and cam pos sensor
Along with new spark plugs and wires, If i disconnect the MAF sensor the car will not start at all.
It has yet to throw a single code.
And unfortunately i'm unable to test fuel pressure but the car will run to red-line without a misfire or anything\
And because it will run from 1000-6000 rpm in neutral, i'd believe I would notice if it was out of time.
My next thought would be the fuel pressure regulator as (ed323i) had thought.
It sucks cause i'm unable to drive it because it wont hold an idle while shifting gears, and once shes under load it will sputter and top out at 4000 rpm.
The thing that is puzzling is that when it runs there is no tick or nothing.
So I will try a new fuel pressure regulator as they are pretty cheap.
My only other idea would be that the DISA valve diaphragm could be ruptured.
Would the crank position sensor allow it to even run if it was broken?

[ed323i]

I have an idea.
Disconnect the connector from the new ICV, and plug that connector in the old ICV, which you try to hold or fix in a place where you can look inside to see how the valve is acting.
Then let someone start the engine and let the revs drop to below 1000 rpm and see what the valve does. Perhaps rpm won't drop below 1000 rpm, because the disconnected new ICV will probably stall at an 'open' position, so you might have to use some duct tape to take the new ICV out of the equation, using a large piece of tape in between the ICV rubber hose and the intake boot (assuming it's comparable to M50/M52). Be sure to fold the tape down the outside of the ICV tube, so it can't be sucked into the boot and next the manifold, causing potentially big trouble.

If the valve does absolutely nothing, then the cause might be a bad DME or bad wiring in between DME and ICV..

[1996bmw318is]

Thanks man I’ll give that a shot. I’ll let you know how that goes.

So the ICV seems to be working completely fine. And at this moment I can get the engine to start easier and hold its own idle, if I use my hand or a cloth to create more air restriction.