Hello,
My bmw e30 m10b18 was idling pretty high, i don't have a rev meter but im guessing 1200rpm.
So i went searching for my idle control valve for a cleanup. turns out i don't have one... to my knowledge every engine should have one, right?
Next i started googling where it should sit with an m10 and saw that it connects in between the chocke injector on the inlet manifold and the some air enrichment regulator just above the valve cover (on mine this is just a single hose connecting the two). And secondly thecontrol cable is hanging in the rear of the engine bay.
Now normally i would just order the valve and install it. but it seems that there are a (at least) two different choke injector bases, and i'm finding a lot of pictures that have exactly the same setup as mine. without an ICV...
example :https://www.google.nl/imgres?imgurl=htt ... mrc&uact=8
Example with ICV (m20 engine, but it's the same system) :https://www.google.nl/search?q=m10+IDLE ... X9OyjWM%3A
Could somebody enlighten me ?
IdleCtrlValve deleted?
Moderator: martauto
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guuskolo
- E30 Zone Newbie
- Posts: 53
- Joined: Thu Oct 06, 2016 11:00 pm
- Location: limburg, the netherlands
maybe a good thing to add:
the idling speed seems to increase when the engine gets up to temperature.
when i start it it runs pretty close to normal. and with about 15 minutes of driving (could be more or less) it gets up to around 1200 rpm.
A thing that also seemd strange to me was the fact that when i pull the oil cover cap off it runs almost normally (at temperature). i'm used tot engines stuttering and stalling when one does that.
the idling speed seems to increase when the engine gets up to temperature.
when i start it it runs pretty close to normal. and with about 15 minutes of driving (could be more or less) it gets up to around 1200 rpm.
A thing that also seemd strange to me was the fact that when i pull the oil cover cap off it runs almost normally (at temperature). i'm used tot engines stuttering and stalling when one does that.
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Jona1971
- E30 Zone Regular
- Posts: 474
- Joined: Sat Mar 15, 2014 11:00 pm
- Location: Staffordshire Moorlands
My M10b18 doesn't have an idle control valve. It has an air slide valve instead.
Have you had a look on realoem.com to see diagrams of what you should have?
Have you had a look on realoem.com to see diagrams of what you should have?
Moredoor autos with small engines are cool - but my new m20b25 is awesome!
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guuskolo
- E30 Zone Newbie
- Posts: 53
- Joined: Thu Oct 06, 2016 11:00 pm
- Location: limburg, the netherlands
yeah thats the one.
But why do i have the cable that hooks up to the idle control valve ?
And how do i start fixing my idling problem?
i pulled the hose from the left side of the valve and closed it off but that did nothing.
this is the system:https://www.google.nl/imgres?imgurl=htt ... mrc&uact=8
But why do i have the cable that hooks up to the idle control valve ?
And how do i start fixing my idling problem?
i pulled the hose from the left side of the valve and closed it off but that did nothing.
this is the system:https://www.google.nl/imgres?imgurl=htt ... mrc&uact=8
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Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
I know absolutely nothing about these weird old systems, but I'd guess that the electrical connection is for some primitive kind of idle speed increase mechanism for the warm up phase.
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guuskolo
- E30 Zone Newbie
- Posts: 53
- Joined: Thu Oct 06, 2016 11:00 pm
- Location: limburg, the netherlands
Small update: disconected everything today to make absolutely sure there is no vacuum leak. And there is none. If i close off the main hose going to this system then it stalls when i dont rev it manually. So i guess i'm on my way.
Got some spare time this weekend which i'm probably going to spend on fixing this little problem.
I'll be sure to share!
Got some spare time this weekend which i'm probably going to spend on fixing this little problem.
I'll be sure to share!
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guuskolo
- E30 Zone Newbie
- Posts: 53
- Joined: Thu Oct 06, 2016 11:00 pm
- Location: limburg, the netherlands
i just came across something rather disconcerting disconcerting. e30 zone "jetronic page" says:
Jetronic cars were also equipped with an idle valve, used to stabilize the engine speed when the throttle is depressed. Unlike the electric ICV in Motronic systems, the Jetronic Idle valve is driven by engine vacuum to hold the throttle position at a fixed position when you let go of the accelerator pedal. On early systems this was 1200rpm, although it was later dropped to 1000rpm for economy reasons.
i still find it weird that there is such a big variation in idle speed, and the fact that there are two different systems on the same engine.
i hope i'm not trying to fix a problem that's not there.
Jetronic cars were also equipped with an idle valve, used to stabilize the engine speed when the throttle is depressed. Unlike the electric ICV in Motronic systems, the Jetronic Idle valve is driven by engine vacuum to hold the throttle position at a fixed position when you let go of the accelerator pedal. On early systems this was 1200rpm, although it was later dropped to 1000rpm for economy reasons.
i still find it weird that there is such a big variation in idle speed, and the fact that there are two different systems on the same engine.
i hope i'm not trying to fix a problem that's not there.
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guuskolo
- E30 Zone Newbie
- Posts: 53
- Joined: Thu Oct 06, 2016 11:00 pm
- Location: limburg, the netherlands
okay, last Friday i took apart (i guess) everything that has to do with the idling system.
i came to the conclusion that every component is doing it's job properly.
this means that around 1000/1200 rpm is normal for an m10 engine...
now my only option is to adjust some things so i will lower this number. which is something i'm planning on doing some time in the future, and i will post my findings here.
in the mean time you guys could help me figure out what exactly to do.
a quick summary of the system:
-a smaller hose is attached to the main inlet hose.
-this hose divides into two hoses at the next T piece.
-one hose is unrestricted and has no valves. (we'll call this hose 1)
-the other is connected to the component (component 1) above the valve cover. (hose 2)
-these two hoses com together at the metal T piece attached to the main inlet body which has the choke injector attached to it.
i tried disconnecting both hoses to see what happened, in both instances i closed of the hose that ran to the vacuum to ensure there is still flow going trough the MAF sensor.
-disconnecting hose 1:
Idle speed goes up a bit above 1200, and once every 5 seconds it stalls for a second and then revs up to a bit above 1200.
-disconnecting hose 2:
does nothing in particular.
-disconnecting and closing off hose 1:
Causes the car to stall
-disconnecting and closing off hose 2:
very small variation in idle speed which balances out ( almost too small to notice )
-removing the component 1 and connecting the two hoses:
Causes the car to idle in a wave like pattern, up to about 1200 rpm and then dropping down to about 800 and going up again. (when i partly close off this hose the dropping down goes a lot slower)
-disconnecting the cable going to component 1:
does nothing
now i'm guessing the component above the valve cover is some kind of vacuum detector. But i don't know how it works. and the wave like pattern makes me think there is some other thing in the system that i'm missing.
now the only thing that is still on my list is restricting the flow in hose 1 to see what this does.
if anyone has any ideas on what to try i'll be glad to hear them.
side-note: i'll be installing a tachometer in the near future, which will also allow some more accurate reading of the idle speed.
i came to the conclusion that every component is doing it's job properly.
this means that around 1000/1200 rpm is normal for an m10 engine...
now my only option is to adjust some things so i will lower this number. which is something i'm planning on doing some time in the future, and i will post my findings here.
in the mean time you guys could help me figure out what exactly to do.
a quick summary of the system:
-a smaller hose is attached to the main inlet hose.
-this hose divides into two hoses at the next T piece.
-one hose is unrestricted and has no valves. (we'll call this hose 1)
-the other is connected to the component (component 1) above the valve cover. (hose 2)
-these two hoses com together at the metal T piece attached to the main inlet body which has the choke injector attached to it.
i tried disconnecting both hoses to see what happened, in both instances i closed of the hose that ran to the vacuum to ensure there is still flow going trough the MAF sensor.
-disconnecting hose 1:
Idle speed goes up a bit above 1200, and once every 5 seconds it stalls for a second and then revs up to a bit above 1200.
-disconnecting hose 2:
does nothing in particular.
-disconnecting and closing off hose 1:
Causes the car to stall
-disconnecting and closing off hose 2:
very small variation in idle speed which balances out ( almost too small to notice )
-removing the component 1 and connecting the two hoses:
Causes the car to idle in a wave like pattern, up to about 1200 rpm and then dropping down to about 800 and going up again. (when i partly close off this hose the dropping down goes a lot slower)
-disconnecting the cable going to component 1:
does nothing
now i'm guessing the component above the valve cover is some kind of vacuum detector. But i don't know how it works. and the wave like pattern makes me think there is some other thing in the system that i'm missing.
now the only thing that is still on my list is restricting the flow in hose 1 to see what this does.
if anyone has any ideas on what to try i'll be glad to hear them.
side-note: i'll be installing a tachometer in the near future, which will also allow some more accurate reading of the idle speed.
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guuskolo
- E30 Zone Newbie
- Posts: 53
- Joined: Thu Oct 06, 2016 11:00 pm
- Location: limburg, the netherlands
FOUND THIS:
http://www.verrill.com/car/e30_idlefaq.shtml
Good info for anyone with real problems.
Add to wiki maybe ?
http://www.verrill.com/car/e30_idlefaq.shtml
Good info for anyone with real problems.
Add to wiki maybe ?
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guuskolo
- E30 Zone Newbie
- Posts: 53
- Joined: Thu Oct 06, 2016 11:00 pm
- Location: limburg, the netherlands
AND WE'RE DONE!
I first used the penny trick to figure out where i needed to be.
then used some different diameters to see what rpm they achieve.
then machined a piece of nylon PA-6 which i could fit into the hose.
i have a m10b18 and the hole i used was just above 3mm and that got me around 800 rpm.
Pictures:
Original rpm: (1250-1400)
The hose that needs to be closed off is the one that is attached to the bottom of the metal piece connected to the inlet manifold:
The piece of nylon in place:
And finally the new rpm ( 900 cold 800 warm):
Can really recommend doing this. makes you engine a whole lot more quiet. and it was about 15 minutes of work.
If people agree: Maybe this should be added to the wiki?
I could make a more detailed guide with better pictures and more detailed diameters etc.
I first used the penny trick to figure out where i needed to be.
then used some different diameters to see what rpm they achieve.
then machined a piece of nylon PA-6 which i could fit into the hose.
i have a m10b18 and the hole i used was just above 3mm and that got me around 800 rpm.
Pictures:
Original rpm: (1250-1400)
The hose that needs to be closed off is the one that is attached to the bottom of the metal piece connected to the inlet manifold:
The piece of nylon in place:
And finally the new rpm ( 900 cold 800 warm):
Can really recommend doing this. makes you engine a whole lot more quiet. and it was about 15 minutes of work.
If people agree: Maybe this should be added to the wiki?
I could make a more detailed guide with better pictures and more detailed diameters etc.