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Registered
W124, 230E 5 speeds Manual, 1987
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187 Posts
Discussion Starter · #1 ·
Hello,

I have a very strange ICV Behavior with my m102, Car starts directly and no running problems at all no stalls either.
The problem is when I start the car in the morning I don't have that Idle Raise that should happen for some seconds on cold start and it starts just fine with the normal Idle 750RPM. no stalls and no idle fluctuation after giving it gas either.

The funny thing is sometimes and especially on sudden weather and temp changes it acts normally and has the idle up thing and even when the car is hot.
I traced the wiring from ICV to OVP and from ICV to ECU. in order to find any bad contact if any but I couldn't find anything wrong. the ICV Pin 1 is getting +12v from the OVP and the other Pin is getting ground from ECU.
the voltage between pin 1 and battery ground is 13.5.
The voltage between pins 1 and 2 is around 5.45v when the engine is running.

if I disconnect the ICV while the engine is running I have a slight increase in idle which should be a good sign.

I cleaned the ICV once by soaking it for 1 hour in carb cleaner and it acted nicely for just 2 days and back to usual.

The question is: does it needs more cleaning or it is a bad sticking ICV and needs replacement?

It is not causing any driving reliability that s why I m frustrated if it is a bad one or not. could it be somehow mechanically damaged and locked to a certain position preventing it from opening further?
 

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Registered
1989 W124 260E
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2,804 Posts
You might be on the right path . You say after cleaning it ran fine but returned after a time . These ACV are not that expensive to purches ,,even go good second hand . Also your engine temperature sensor could be faulty . It could be sending the wrong information to the computer . Like computer thinks its hot engine so weakens the mixture. But its on a cold start and needs extra fuel to bring the revs up. You could check the cold start injector to see if its working at cold starts . Pull the hard line ,,to csi and remove the injector refit the hard linre and hold it in a jar and get someone to spin the engine over ,,this way you can see if its working ... If the csi is not working go from there ..Remember it musty be cold to check this cold start device . And the ht system needs to be 100% and in tip top condition .
 

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Registered
W124, 230E 5 speeds Manual, 1987
Joined
·
187 Posts
Discussion Starter · #3 ·
You might be on the right path . You say after cleaning it ran fine but returned after a time . These ACV are not that expensive to purches ,,even go good second hand . Also your engine temperature sensor could be faulty . It could be sending the wrong information to the computer . Like computer thinks its hot engine so weakens the mixture. But its on a cold start and needs extra fuel to bring the revs up. You could check the cold start injector to see if its working at cold starts . Pull the hard line ,,to csi and remove the injector refit the hard linre and hold it in a jar and get someone to spin the engine over ,,this way you can see if its working ... If the csi is not working go from there ..Remember it musty be cold to check this cold start device . And the ht system needs to be 100% and in tip top condition .
my cold start injector is correctly working and it is being driven by an external circuit designed by me 10 years ago due to a certain problem I can't remember now. I checked the Temperature sensor resistances at different temps and it is good according to the manual. I guess I m gonna try a second-hand ICV and see how it behave.
 

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W201 Moderator
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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4,318 Posts
In a working system if you unplug the ICV connector the rpms will rise quite a bit, generally from 750rpm to 1000+rpm.
Hopefully the ICV replacement will work better. They do last a long long time.
 
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