BMW E36 1992 M50B25 non vanos idle surge issue

Update Car was found to have many vacuum leaks from cracked ICV hoses/intake boot, missing / old injector o-rings and incorrect injectors installed. The engine has since been rebuilt and is waiting to be put into a new car.

[@ItsMatich]

Hey everyone, Small update on the M50, it’s since been rebuilt and put into a hellrot red coupe ready for a turbo. I’ve uploaded a short video for people to see it’s current state. Progress on the build has been a little slow but am happy to upload more if there’s interest in it. The main issue on why this engine didn’t want to idle before was due to loads of vacuum leaks from old cracked rubber hoses and boots, missing O-rings on injectors (also wrong injectors) and a stuck idle control valve.

[@janisozolins4999]

Idle control valve stuck and it is common! Clean the valve first and see what happens. I had exactly the same problem

[@laureanodavidangaritabecer8206]

hello there!, I have the same car but german version, not american, my problem of rich mixture is not in ralanti, is in cruising speed mainly.... any ideas? thanks!

[@mohamedmostafa-zc5ju]

you should add air filter to avoid air turbulence at opening of maf

[@sergeygr]

lmao, no.. there are plastic mesh (blades) in front of maf..

[@DrThreeEyes]

That thing has a giant vacuum leak, you can hear it.. under the intake manifold

[@mohamedmostafa-zc5ju]

these old maf are very sensitive to air turbulence

[@itsskylerrr7716]

Hey man you still have this thing?

[@ix-Xafra]

My son replaced the head on his M50 and it did this. Turned out he accidently swapped harness connectors between the TPS and ISC...

[@manuelalmonacid2048]

Put the airfilter box to the maf sensor, and thats it...

[@relaxedvideos5993]

Bro i have the same shit i cant fix it did u fix it already?

[@danielroblero5059]

mi carro tiene lo mismo como lo resuelvo help :c

[@frac3620]

Resolved?

[@jamesagilbraith4301]

Did you find a solution to this? My car is doing the exact same thing, and literally pissing black smoke out the back when you rev it. Accompanied by a misfire XD

[@ItsMatich]

not yet! need to look at the codes it's giving then I might know

[@jamesagilbraith4301]

ItsMatich are you getting a rich condition also? black exhaust smoke under acceleration?

[@ItsMatich]

it's running very rich but isnt smoking, ecu seems to be in limp mode

[@jamesagilbraith4301]

Any luck yet? Im still struggling with this

[@vova358]

the same sh@t my has ... no luck ..

[@jamesagilbraith4301]

Any luck yet? People always post a problem, but never post anything when they find the solution.

[@ItsMatich]

Haven't been spending time on it recently! Will post if i find solution

[@schnitzer3490]

what was the reason

[@ItsMatich]

Vacuum leaks + broken MAF

[@schnitzer3490]

ItsMatich new bought MAF and how much does it cost

[@ItsMatich]

@@schnitzer3490 second hand maf not new, cost me $50 off facebook

[@schnitzer3490]

ItsMatich I have exactly the same problem, but even the momentum is falling strongly on neutral

[@schnitzer3490]

ItsMatich Turnovers fall strongly down to a stop.

[@extract1n]

My car does the same thing. Did you resolve the problem ?

[@ItsMatich]

extract1n air leaks behind the MAF sensor, when air escapes it can't calculate proper fueling, there were missing o-rings on injectors etc

[@Nguyen360]

I think the port above the oil filter into the valve cover has two ports and one of them you have it open (right by the brown ground wire).

[@ItsMatich]

Jackson Nguyen that's just the PCV valve and the one under it is fuel supply, PCV is routed to the intake elbow boot. This can be vented to atmosphere if you want as long as you plug the hole in the elbow boot. In this video there was air leaks around the injectors and a hole in the break booster reservoir. Engine is going under a full rebuild so will see how it behaves when it's all fresh again

[@tips0123]

@@ItsMatich How did the rebuild turn out? I have the same issue currently. If removing and cleaning everything doesn't work I guess it will be rebuild time for me as well!

[@ItsMatich]

@@tips0123 just doing the head work (lapping valves etc) then the head should be ready to be dropped onto the rebuilt block. I have a new maf sensor but have since acquired a turbo kit so will only be breaking the engine in stock. Will upload videos once i get it in the car. Looking back now, from what i found im sure this was either faulty maf/o2 or vacuum leak. Maintenance on this engine looked non-existent from previous owners.

[@ericchen6379]

These maf issues are common to E31.E32.E34.E36 (NV ENGINES) Better way to fix that，You can find refurbished .OEM. LOWE aftermarket M50B20 M50B25 M70B50 are picky to its maf