Please help! 190e engine idling sometimes engine turn off A couple of years has driven without air controller not connected (IAC) was set on the screws manualy I recently changed the airflow potentiometer. And now the cold start 1-2minute 1100 rpm and drop to 750rpm sometimes goes off when the engine idling. My question is why ?? instructions LMM POTI (air flow potentiometar) Engine idling ________________________________________________ PIN ________________________________________________ 1,2 : 0.75 V +- 0.20 V ________________________________________________ 1,3 : 4.85 V +- 0.25 V ________________________________________________ Engine off _________________________________________________ disconnected connector PIN: 1,3 4Kohma +- 400 ohma
SOURCE: Radiator coolant
first question is after you changed your hose and refilled while the car was running with the radiator cap locked but loose with the heater on high and set on hot run the car till the thermostat opens shut the car down once it does anti freeze level will drop and air will rise and (extreme caution taken with drain pan below ) start the car use two people run it shut it down let air escape threw cap start again run a couple of minutes shutdown again let cool down take cap off restart car with cap off watch radiator level will somone lightly increases gas peddle refill level to top reinstall cap completely tight then let idle down some vehicles have a small bleeder mounted in the thermostat houseing or in line with the radiator circulation system
SOURCE: Delay reaction of cold start and idle
Sounds like your cold start valve has an issue go to www.benzworld.org or peachparts.com for some good info on it.
SOURCE: mercedes benz 190e 1900year /air flow meter connections
Guys i just bought my first car and its a Mercedes 190E 1.8L 1991. Now i noticed an digital meter just above my steering wheel with 2 knobs on each end. I dont know what is it for can u tell me plzz. Thanks :>
SOURCE: while in park 1988 mercedez benz 190e idles rough and sometimes
This is an interesting part, and I spent quite some time to fix the problem. I list it here those steps in the order could fix the problem ranging from least expensive to most expensive steps. It just happened to me the last one really eliminated the problem. 1- Make sure it gets turned up first. 2- Adjust cables to increase idle. There are two cables. You remove the air filter to see them clearly. a- one for the gas, the other for transmission. b- clean the area well so you can see a micro switch. This switch called cut off switch. c- whatever adjustment you make, the level of the switch has to press on the switch to maintain the idle. If you see it off, you can bend the metal part to keep it in place 3- Take off the Fuel distributor to clean the throttle below it. 4- Replace all the injectors. These are not Electronic Fuel Injectors so you don't have to deal with Injector module. 5- Replace the fuel distributors. Good luck.
OPERATION
The Idle Air Control (IAC) is a bi-directional motor driven by two coils. The purpose of the IAC valve is to control engine idle speed, while preventing stalls due to changes in the engine load. The IAC valve, mounted in the throttle body, controls bypass air around the throttle plate. The PCM controls engine idle speed by adjusting the position of the IAC motor pintle. The PCM pulses current to the IAC coils in small steps (counts) to extend the pintle into a passage in the throttle body to decrease air flow. The PCM reverses the current pulses to retract the pintle, increasing air flow. This method allows highly accurate control of idle speed and quick response to changes in engine load. If RPM is too low, the PCM will retract the IAC pintle, resulting in more air being bypassed around the throttle plate to increase RPM. If the RPM is too high, the PCM will extend the IAC pintle, allowing less air to be bypassed around the throttle plate, decreasing RPM.
Fig. Typical Idle Air Control (IAC) valve components
During idle, the proper position of the of the IAC pintle is calculated by the PCM based on the battery voltage, coolant temperature, engine load and engine RPM. If the RPM drops below a specified value, and the throttle plate is closed (TP sensor voltage is between 0.20-0.74), the PCM senses a near stall condition. The PCM will then calculate a new IAC pintle position to prevent stalls.
If the IAC valve is disconnected and reconnected with the engine running, the idle RPM will be wrong. In this case, the IAC has to be reset. The IAC resets when the ignition switch is cycled ON and then OFF . When servicing the IAC, it should be disconnected or connected with the ignition switch OFF in order to keep from having to reset the IAC valve.
The position of the IAC pintle affects engine start up and the idle characteristics of the vehicle. If the IAC pintle is fully open, too much air will be allowed into the manifold. This results in high idle speed, along with possible hard starting and a lean air/fuel ratio. A Diagnostic Trouble Code (DTC) may set. If the IAC pintle is stuck closed, too little air will be allowed in the manifold. This results in a low idle speed, along with hard starting and a rich air/fuel ratio. Again, a Diagnostic Trouble Code (DTC) may set. If the IAC pintle is stuck part way open, the idle may be high or low and will not respond to changes in engine load.
TESTING
As with most all engine control sensors used in your vehicle, a thorough and proper test can only be performed by a qualified technician using a scan tool to read the data stream from the PCM. There are a few items a non-professional should check before taking the vehicle to a qualified technician for diagnosis and repair.
Check for a poor connection at the PCM or IAC motor. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connection.
Inspect for a damaged wiring harness, especially if heavy work has recently been performed (intake manifold removal, engine removal, etc.) where the throttle body has been disturbed.
Inspect for a restricted air intake system. Check for a possible collapsed air intake duct, restricted air filter element or foreign objects blocking the air intake system.
Inspect the throttle body. Check for objects blocking the IAC passage or throttle bore. Excessive deposits, especially on high-mileage engines, can build up in the IAC passage and on the IAC pintle. Excessive deposits can also build up on the throttle plate, so check for a sticking throttle plate.
Check for vacuum leaks such as disconnected hoses, leaks at the EGR valve and EGR pipe to the intake manifold, leaks at the throttle body, faulty or incorrectly installed PCV valve, leaks at the intake manifold brake booster hose connection, etc.
REMOVAL & INSTALLATION
Fig. The Idle Air Control (IAC) valve is mounted on the throttle body-3.8L (VIN K) engine shown, others similar
NOTE
Before installing a new IAC valve, measure the distance that the valve is extended. The measurement should be made from the motor housing to the end of the valve cone (pintle). The distance should be no greater than 1 1 / 8 inch (28mm). If the pintle is extended too far, adjustment is required, otherwise damage may occur when the IAC valve is installed. Adjust the IAC valve by compressing the pintle to achieve the correct length.
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