M44 Engine Vacuum Leak Help

[qube 3568]

the E36 318ti I picked up recently was idling a bit rough, thought it might have been a sensor but I have noticed now the following symptom:

when you start the engine the idle is a bit jumpy, when driving it is smooth and not misfiring or anything.

If I open the bonnet and turn off the car, straight away there is a very loud and noticeable HISS (for maybe 3 seconds or so) from the passenger side/rear of the engine.

Any ideas on which part I am looking for?

[Statek 87]

Not sure about the hiss, but i found that lumpy idle on M44 engines is fairly common, and is caused by timing - you can adjust the sprockets ever so slightly when you take off the rocker cover and it resolves that issue. I'd have to find where I got information on this... but it definitely helped the Z3 i used to own, as the lumpy/shaky idle was driving me nuts.

[qube 3568]

I think the vacuum leak is causing the car to run rich causing the lumpy idle, definitely smells a bit more than it should out the back.

Also, I believe the fuel consumption is much higher than what it should be.

I will sort out the obvious leak first then look at the timing also. Let me know if you find the information for it but all good if not I can have a search later on

 

[BM WORLD 1258]

pcv /ccv faulty , vac hoese around it too 

 

[Eagle 1514]

+1 on PCV and hose but you should really do a smoke test. I usually do a MAF clean and a check of the plugs if you haven't already.

Part no 2 and 17 are other leak locations which are hard to see without smoke.

http://bmwfans.info/parts-catalog/E36-Compact/Europe/318ti-M44/R-A/jun1997/browse/fuel_preparation_system/fuel_injection_system_injection_valve/

I find old\worn engine mounts in these contribute quite considerably to the feel of the lumpy\rough idle.  If all parts are in good nick and working as intended the idle quality isnt bad enough to adjust timing imo.

[qube 3568]

Waiting on some parts to come in to do the VCG and OFH gaskets etc so will check plugs and do a maf clean.

but i think the loud hissing noise is definitely a big enough sign of a bad vacuum leak so will need to order in a new PCV and hose as Brent mentioned. And I have a feeling that this is a good indication of the lumpy idle since the fuel smell is quite bad indicating that its running rich also.

Will check the mounts and other pipes also.

sometimes i laugh at why i bother with this as a “daily/runabout” when i can just buy a civic and just drive it for $40 gas for a week..

[Eagle 1514]

TBF the average equivalent civic isn't much (if any) better. My daily Ti a $30 a week car now after spending twice what ive paid for it on a thorough refresh. It's close enough to factory running and driving spec that its far more dependable than anything in the ~5k bracket that didn't have the equivalent work done on it (basically everything for sale) 

 

 

 

[qube 3568]

^ that’s pretty much the plan, I’ve always liked the practicality of the 318ti compact with the hatchback you can carry quite a bit. Easily fits 4 wheels for example

Also a big fan of the performance of the M44 engine, have only owned 1 previously which didn’t need any work so its a first time experience for me with this one.

Only flaw with this car is the 4 speed auto box, revs a bit high when cruising on the motorway but it is what it is.

[NZ00Z3 186]

This thread came up recently in a Z3 forum.  It may be of interest.  https://www.bimmerforums.com/forum/showthread.php?2446662-Second-of-two-problems-DISA-valve-vacuum-leak

[qube 3568]

^interesting.

However, my hissing sound only comes on for about 3 seconds after turning OFF the engine.

[Statek 87]

2 minutes ago, qube said:

^interesting.

However, my hissing sound only comes on for about 3 seconds after turning OFF the engine.

Charcoal canister venting?

[Statek 87]

@qube imagine my surprise when i found a thread on the timing issue with my name on it haha

 

[Eagle 1514]

On 3/22/2021 at 10:43 PM, qube said:

^ that’s pretty much the plan, I’ve always liked the practicality of the 318ti compact with the hatchback you can carry quite a bit. Easily fits 4 wheels for example

Also a big fan of the performance of the M44 engine, have only owned 1 previously which didn’t need any work so its a first time experience for me with this one.

Only flaw with this car is the 4 speed auto box, revs a bit high when cruising on the motorway but it is what it is.

Yeah pretty much why i bought one even though ill never fully sold on the their looks. Performance more than enough around town if in given their weight and reasonable output. Auto isnt too bad at all shifting wise once its had a fluid change and adaption reset.

[qube 3568]

^definitely, the front end is typical e36 so all good, and interior is basic but its fine. The rear looks kinda funny sometimes but practical so all good. Good call on the trans fluid and adaptation reset. Will look into that after i get the idle right.

[qube 3568]

So actually the cars idle is steady and doesnt bounce around but there is still a fair bit of exhaust rattle. 
 

also quite a bit of steering wheel vibration especially around 60-80km/h roughly. 
 

Im thinking engine mounts next for sure and probably a wheel alignment.

 

I still havent found the cause of the air hissing noise. 
Ccv and hose has been replaced already. 

[qube 3568]

With the help of @M3AN managed to get a bit of info on the car. 
 

First scan showed a bunch of error codes mostly related to misfiring cylinders. Cleared it and after a 5 min drive around the block these three codes came back. 
 

the car “drives” okay but when stopped the engine is “pulsing”. The idle needle doesnt jump up and down like crazy or anything. 
 

also when i shut off the car the air hissing noise happens every time from somewhere around the CCV. 
 

other than this there is also quite a loud tinny metallic clang type of noise when accelerating from under the car maybe the exhaust. 
 

 

[KwS 2372]

Other than the smoothness values being uneven, the only thing that stands out is that the "needed air i.s controller" is maxed out. Thats the idle control valve, so im guessing its wide open at idle just to keep it running. Does that value fluctuate?

Do these have a manual base idle adjustment on the throttle?

Have you tried disconnecting the MAF and seeing how it runs?

Edited April 30, 2021 by KwS

[qube 3568]

Will check and report back

[BM WORLD 1258]

11 hours ago, qube said:

Will check and report back

bring it around here sometime

, also have you done a compression check?

[qube 3568]

47 minutes ago, BM WORLD said:

bring it around here sometime

, also have you done a compression check?

Havent had much time to do anything with it lately. With 2 other cars both needing attention also this one is just sitting here. 
are you around today @BM WORLD

[dirtydoogle 383]

You air consumption/maf reading looks much to high for my liking, that's around 3.5gm/s and I would expect nearer 2gm/s or 7-7.5kg/h

 

[qube 3568]

CCV replaced and now much smoother. 

Still does the hiss when i shut the engine off.

Also it seems like the metallic tinny sound is coming from the cats. They were probably ruined from the oil due to being driven with the faulty CCV.

might just get an exhaust shop to chop them out