OK all of you experts out there, does the Idle Control Valve operate while the engine is running?
Mine clicks off after 10 seconds when I turn on the ignition or start the car. After that, it does absolutely NOTHING! When I unplug it there is no click, no change in idle, plug it back in and no click or change in idle.
If I apply a hard ground to pin number 1 of the ICV, it clicks and the idle goes up to 2700 rpm's.
Help if you know the answer.
Thanks,
Dave
__________________
If it ain't broke, BREAK IT.....and make it better.
Idle Control Valve controls idle speed under load such as:
- cold start
- in gear
- when heavy loads are on, eg. air conditioning, extra heavy electrical loads
- depending of the vehicle speed
The overvoltage protection relay receives the loads present in the electrical system by means of overvoltage response in the associated electrical circuit or electrical control by the fuel pump relay and closes the power circuit from the power feed hot at all times (usually pin 1 on the OVP relay and the pin 2 on the ICV, if it has 2 pins, if it has 3 pins it also receives activation from the TPS or the fuel cut-off microswitch or the automatic transmission upshift delay relay) with the idle speed control on the computer (which acts like a controlled resistance ground, controlling in function of all imput factor it receives, that's why when you grounded the computer idle speed control its role was replaced and it tried to adjust the idle to a higher value, probably sensing a load condition and adjusting the other engine controls such as the ignition mole or the fuel distributor's electrohydraulic actuator which increases the lower chamber fuel pressure and increasing the idle). As the valve closes after cold start operation or after a heavy load is disconnected, the air excess needed for the engine to support the load and maintain its idle speed, is cut and the engine returns to its normal idle. A faulty Idle Control Valve could have the following symptoms: worn solenoid valve inside, dirty stuck plunger inside, excessive resistance in its internal circuit that prevents the solenoid to close for the same applied voltage.
In conclusion, the Idle Control Valve receives control voltage (to keep it open to supply additional air supply to the engine) only when it's needed (cold start, temporized 10 or 28 seconds, under a certain vehicle speed, when the AC is on, in gear, or any other excessive load). Think of it as the classic carburetor choke, only that in this case is electronically controlled and participtes in the engine management.
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Mercedes 190 E 2.0 (1983) 102.961 engine
"In giving advice, seek to help, not please your friend." - Solon (638-559 BC) Greek lawgiver & politician.
Last edited by Samoila Stefan : 10-18-2007 at 04:07 PM.
A couple of forum members sent me information stating that their idle changes when the ICV connector is unplugged while the engine is running and warmed up.
According to the test procedures, with the engine running after 28 seconds, and at operating temperature, the 2 pin ICV like mine should be pulling 580mA, +/-50mA. This tells me that the ICV should be operating and pulling current.
Like I stated, mine does nothing when the connector is pulled off the ICV with the engine running.
So either the ICV is defective or the ICV is receiving the wrong information. When I check the voltage at the ICV connector, there is no change in voltage after the ICV clicks off after 10 seconds when the ignition is turned on. A steady 11.15 volts across pins 1 & 2 of the ICV connector, and 9 ohms across pins 1 & 2 of the ICV. 12v from Pin 2 of the ICV connector and ground.
I'm going to go back over some test procedures with the wiring going to the CFI control module from various components. OVP relay, Temperature Coolant Sensor, etc.
By the way, where is the Crankshaft Position Sensor (L5 on the schematic) located on the '93 2.3?
OK all of you experts out there, does the Idle Control Valve operate while the engine is running?
Mine clicks off after 10 seconds when I turn on the ignition or start the car. After that, it does absolutely NOTHING! When I unplug it there is no click, no change in idle, plug it back in and no click or change in idle.
If I apply a hard ground to pin number 1 of the ICV, it clicks and the idle goes up to 2700 rpm's.
Dave
Hey Dave
So what is the idle on cold start and what is it warmed up? I don't think you have mentioned your symtoms.
Should be around 1000 on start, 28 seconds and it should drop to 750 ish
With mine having no voltage - 750 cold and slowly rises to 1000 by 80 C
If you are at 1000 warmed up , then there won't be a change in RPM, that's your Limp Home mode if the ICV or the OPV failed.
You have 11-14 Volts at the connector w/key on. So you are good there.
9 ohms across the connector - 12 +- 3, That means the Heating coil is also good.
You also did the Click test, applied 12 v - Audible Click - Coil is moving the slide. But it could be still sticking.
Assuming the above is correct, below is from the CD " Test Start Device" which includes the ICV and the Electronic Idle Control which gets info from a number of sources, but that's another story.
IF the slide is sticking, mmmmm I think it was Yal posted a nice fix on HOW TO clean it properly and lub with ATF.
Regards
Dan
a) If engine speed is too low after the cold
start
Compress shaped hose (arrow).
If engine speed does not change, the idle air
control valve is jamming and must be replaced.
b) Engine speed too high at normal
operating temperature
Compress formed hose (arrow).
If there is a significant change in engine speed,
the idle air control valve is jamming or is not
electrically heated.
Last edited by Logon_Bob : 10-20-2007 at 01:35 AM.
1. When engine starts up cold, idle is low and rough. After 2.5 minutes it runs perfect and the idle climbs up to 1000 rpms.
2. When shut off at operating temperature, (80C) and re-started, it idles low (500 rpms) for 10 seconds or so, then climbs to 1000.
3. When warm, the car runs perfect, although the idle is 550-600 in drive with A/C on.
4. I checked the ICV, when ignition is turned on it operates for 10 seconds then clicks off. I took off the top hose and I can see the valve open when the ignition is turned on and close after 10 seconds, so I know it's not sticking. When car is warmed up and running good, if i squeeze the top hose of the ICV, the idle speed will drop.
5. *NOTE* When I checked the cold start up yesterday morning, I discovered that when the vacuum line is disconnected from the Ignition Control Module it makes no change in idle speed. But, after 2.5 minutes when the car is warmed up and running smooth, if I pull the vacuum line off of the Ignition Control Module, the idle speed drops. Now I'm wondering if I might have a problem with the Crankshaft Position Sensor going to the Ignition Module. The resistance is 924 ohms, so I know that it is the correct range of 680-1200 ohms, but the coil end at the Flywheel might not be functioning correctly. I read an interesting article concerning the CPS and it goes into detail about how it is overlooked and causes the engine to miss, shut off, etc.
6. I know that the Temperature Coolant Sensor (mine is the 4 prong) is an important part of the warm up stage. Mine checks out ok resistance wise and I checked continuity of the wiring, but something is not happening correctly during the warm up stage.
I know that the engine used to start up and idle a little high, then drop down to 750-800 after a few minutes, but now that isn't happening.
7. I checked the Throttle Position Sensor/Switch and it is telling the system that the throttle is closed (0 ohms at idle). The Micro-Switch tests ok, and is closed at idle.
8. My car has 88,200 miles and still has the original OVP relay, Fuel Pump Relay, Temperature Coolant Sensor (4 prong), Crankshaft Position Sensor, and all fuel related parts except for the Fuel Filter and Fuel Injector Seals.
9. In conclusion, when the car is started cold, it acts like it is not getting enough fuel for 2.5 minutes. It has the 2 fuel pump configuration and both are operating and the filter is new.
10. Any ideas? OVP Relay, Crankshaft Position Sensor, Fuel Pump Relay, Ignition Control Module, Coil, CFI Control Module, EHA, Fuel Pressure Regulator???
If I can't fix it after my vacation, I think I'll have to swallow my pride and take it to a friend of mine that has an Indy MB shop.
Dave
Last edited by slk230red : 10-20-2007 at 07:47 AM.
Hey Dave
OK, just for you I pulled my Air Cleaner again :-) to see what mine does. You need to go back to my above post and read the a) & b) I am 99% sure what is going on is the Heating Coil on the ICV is not working shutting down the slide even further. See b) and your #4 below. Unfortunately, that unit is just shy of $ 300 ON Line!! Try Ebay if adventurous.
My only doubt is your OHM test of the Coil showed good. I don't know how to check that under voltage to see if it failing.
Think of it as 3 positions.
1. On Key, full open for starting along with extra fuel from the Start Valve.
2. 28 seconds and the Heated Coil closes further than it does at rest without voltage.
3. Slightly Open mode , Limp Home- Default position, No Voltage or bad coil, 1000 RPM Warm, 750 Cold.
1. When engine starts up cold, idle is low and rough. After 2.5 minutes it runs perfect and the idle climbs up to 1000 rpms.
2. When shut off at operating temperature, (80C) and re-started, it idles low (500 rpms) for 10 seconds or so, then climbs to 1000.
3. When warm, the car runs perfect, although the idle is 550-600 in drive with A/C on.
4. I checked the ICV, when ignition is turned on it operates for 10 seconds then clicks off. I took off the top hose and I can see the valve open when the ignition is turned on and close after 10 seconds, so I know it's not sticking. When car is warmed up and running good, if i squeeze the top hose of the ICV, the idle speed will drop.
**** OK, I tested mine. Key on but not starting the motor. Same deal, Full open and after 10 seconds it CLICKS off. Of course you can both Hear the Click and you can FEEL it. Now when I started the engine, run back around and put finger on it, I can't FEEL nor Hear any Click at anytime, let alone at 10 seconds. At 28 Seconds, the idle drops as it should but I still can't FEEL any Click. I suspect the unit acts different under Vacuum with the engine running.
5. *NOTE* When I checked the cold start up yesterday morning, I discovered that when the vacuum line is disconnected from the Ignition Control Module it makes no change in idle speed. But, after 2.5 minutes when the car is warmed up and running smooth, if I pull the vacuum line off of the Ignition Control Module, the idle speed drops. Now I'm wondering if I might have a problem with the Crankshaft Position Sensor going to the Ignition Module. The resistance is 924 ohms, so I know that it is the correct range of 680-1200 ohms, but the coil end at the Flywheel might not be functioning correctly. I read an interesting article concerning the CPS and it goes into detail about how it is overlooked and causes the engine to miss, shut off, etc.
**** OK, I am going to install my new Heater Valve today so I only tested as Cold. I will let you know about Warmed up later today. Cold or Warm UP stage, pulling the VAC line off the ICM does nothing to RPM's. If you put your finger across the VAC line even at idle, you can feel a slight Vacuum.
6. I know that the Temperature Coolant Sensor (mine is the 4 prong) is an important part of the warm up stage. Mine checks out ok resistance wise and I checked continuity of the wiring, but something is not happening correctly during the warm up stage.
I know that the engine used to start up and idle a little high, then drop down to 750-800 after a few minutes, but now that isn't happening.
7. I checked the Throttle Position Sensor/Switch and it is telling the system that the throttle is closed (0 ohms at idle). The Micro-Switch tests ok, and is closed at idle.
8. My car has 88,200 miles and still has the original OVP relay, Fuel Pump Relay, Temperature Coolant Sensor (4 prong), Crankshaft Position Sensor, and all fuel related parts except for the Fuel Filter and Fuel Injector Seals.
9. In conclusion, when the car is started cold, it acts like it is not getting enough fuel for 2.5 minutes. It has the 2 fuel pump configuration and both are operating and the filter is new.
10. Any ideas? OVP Relay, Crankshaft Position Sensor, Fuel Pump Relay, Ignition Control Module, Coil, CFI Control Module, EHA, Fuel Pressure Regulator???
If I can't fix it after my vacation, I think I'll have to swallow my pride and take it to a friend of mine that has an Indy MB shop.
Dave
I had another idea for you to check but I don't think I proved anything. Before I knew the ICV clicked off at 10 secs as normal, I thought maybe your voltage was dropping off before the ICV Heating Coil was warmed up enough to close down the Slide or a bad OPV. I mounted my Volt Meter on the windshield, Key on motor NOT started. Voltage remains the same even past a minute. I did that 3 times with the same results. I tried to attach my meter leads to the ICV and still have the connector on, but the lead clips are just too large.
There is a test for Shift Selector Position. As you pull into gear, the idle drops a bit then comes right back up. Test says, Parking brake applied, Select Drive, Voltage to the ICV drops. It doesn't say Drop to what voltage. IF it doesn't drop, the problem is Starter Lockout and reversing light switch circuit. Not your problem.
NOTE: See inserts in your above Quote.
Last edited by Logon_Bob : 10-21-2007 at 11:01 AM.
I had another idea for you to check but I don't think I proved anything. Before I knew the ICV clicked off at 10 secs as normal, I thought maybe your voltage was dropping off before the ICV Heating Coil was warmed up enough to close down the Slide or a bad OPV. I mounted my Volt Meter on the windshield, Key on motor NOT started. Voltage remains the same even past a minute. I did that 3 times with the same results. I tried to attach my meter leads to the ICV and still have the connector on, but the lead clips are just too large.
There is a test for Shift Selector Position. As you pull into gear, the idle drops a bit then comes right back up. Test says, Parking brake applied, Select Drive, Voltage to the ICV drops. It doesn't say Drop to what voltage. IF it doesn't drop, the problem is Starter Lockout and reversing light switch circuit. Not your problem.
NOTE: See inserts in your above Quote.
Thanks Dan,
I also put my VOM on the windshield and monitored the ICV voltage with the connector on, and the voltage does not change, yet the ICV clicks off after 10 seconds with ignition on, or with the engine running. After that, the ICV does not operate or change the idle speed at any time, yet the MB manual states that the ICV should be pulling 580mA, +/-50mA after 28 seconds at operating temperature.
When I start the engine when cold, the vacuum hose at the ignition control module does nothing for 2.5 minutes, then as the idle speed goes up, it makes a difference when the vacuum hose is pulled off...the rpms go down.
Thanks for checking your ICV,
Dave
Last edited by slk230red : 10-21-2007 at 01:31 PM.
I won't be working on my 190 2.3 idle/start problem again until I return from vacation.
One more note***
The low idle in drive with the A/C on is still a problem, but the cold/start, warm/start problem didn't start until last Thursday. I was cruising along on I75 at 55mph, and there was a strange vibration sound behind the glovebox that lasted about 3 seconds. I'm thinking that it might be the OVP relay or the Fuel Pump relay failing.
The way it starts now is like when the OVP relay is removed. When cold, it takes about 2.5 minutes to smooth out and the idle climbs to 1000 rpms in park, and about 10-15 seconds to smooth out when hot.
Although I've searched this forum and other forums for this same type of problem, the members that had the same problem didn't post the solution. The closest fix is usually a blown OVP relay fuse, OVP relay, or a defective ICV.
Linear Mode
