E36 lumpy idle & sticky throttle...

[Mobrem]

Hi All,

on our little 'Babe' it has a lumpy idle and sticky throttle. The car itself is a '97 318is with an M44 engine. I'm fairly certain the lumpy idle must be something like an idle control valve that must be gruby? I'm thinking it couldn't be an air leak because the lumpiness is intermittent whereas an air leak would be a constant... My question regarding this is how would you go about cleaning an idle control valve and what would it look like? Or instead of cleaning it would you just buy new??

Secondly, the throttle pedal on our little vehicle is sticky... it's only sticky when you when you just start to push down on the pedal... such as when you're taking off at the lights. Once underway and driving then it's absolutely fine. Could this be that the cable needs lubricating? Do the cables dry out?? Or again, would you need to replace said cable with new? Or could it be something else??

thanks all for your help
Mo

 

[mart37]

Hi,
I had this sticky throttle problem, and ended up removing the plenum (butterfly flap) and cleaning it inside with a toothbrush and paint thinners. The thinners seemed to be the only stuff to get rid of the brown gunge around the edge of the butterfly and in the bore. I also stuck the throttle cable up vertical made a funnel and poured thin oil into it whilst I was cleaning the plenum assy. This cured the sticky throttle at idle.

 

[Mobrem]

Hi Mart

Thanks for your reply. I had a play yesterday and ended up finding two things... 1 - AFM boot cover was split in 3 places (new one due tomorrow so just put gaffer tape around it for now) and secondly the throttle cable was very slack. TI also cleaned the two butterfly flaps and after this took it for a drive... throttle response was great, no stickyness and overall much better. I also jet washed the engine clean and I can now see that I have a valve cover gasket leak so that's another job for the week. I put some photos here to show if you're interested...

 

[Mobrem]

nice clean tb... for a happy idling car

 

[mart37]

Great! glad the stickiness has gone, mine came back again however about 3,000 later.
My throttle on the side of the plenum has a outer thread adjuster to take up slack, however my engine is a S.O.H.C 8 valve.
I have pressure washed these computer engines before and you can run into electrical problems. with ingress of water into various components. I know it's nice to have a clean engine though. I have just had the cyl.head off mine to do a head gasket which was leaking. My engine only has 119000 miles on it and I am ticked' off that the gasket went! I mean it's a B.M.W. I thought they were reliable!!! Anyway I ported and polished the head, cleaned and ground the valves in, and had it refaced. I am in the process of putting it all back together if I can remember were all the bits go!!
Regards. Martin

 

[T9 man]

Greetings mart37 and a Warm Welcome to our TorqueCars Forum my Friend!

Good to have you along with us

 

[mart37]

Thanks Tman
I am in trouble with my m43 b18 head job. After putting it back together today I find I have two problems. One it will not start, feels like fuel starvation it wants to go but dies! after a second or two. I have bled the fuel rail, but am tired now so have come in. (on the wife's orders)
Second problem is a coolant leak from the front of the head/block it seems to come from just above the a/c compressor. Anyway tomorrow is another day.
Mart37

 

[Mobrem]

Any other ideas then Mart on what it could be if you've bled the fuel rail?

 

[mart37]

Hi mobrem,
No more ideas! yet. I was most careful rebuilding /fitting the head and the inlet manifolds, and making sure all the electrical connectors went where they should. I'm more concerned over the head gasket. Which I performed like a medical operation! .The plugs were moist with water as I could not smell any petrol on them I did the first 90degree torque freehand but bottled out with the second;' torqueing the bolts down to 70 lbs ft with my torque meter, maybe I should have gone to 75. At least I know all the bolts are the same torque. I know bmw say do two 90degree torques but if you doing it freehand there is room for error, and I was worried I'd snap a head bolt.
Anyway I'm going to inject petrol into the plug holes and a squirt or two into the plenum and warm the plugs up before trying again. I will also remove the front timing cover and check around that area,
regards. Martin

 

[Mobrem]

Hope today's gone better for you Mart! Let us know how you're getting on!

 

[mart37]

Hi,
Well I am no further forward, although I do have fuel pressure now, however still the same problem. I've taken the front timing cover/thermostat off (re the leak) 'trying to detect a leak between that front gasket and the very front off the head, I can see a place where the gasket is and coolant flows so have gently sealed the the edge with sealant. This is behind and below the thermostat. I'll build it back up tomorrow. I also torqued the head down to 75ft/lbs.
I'm not too hot! on diagnostics not so bad on obd11 as I have a code reader but of course it's different on the bmw. so I cannot scan for fault codes. So I'm down to the guessing game which isn't much good.
regards. Martin