How does duty cycle work on Bosch fuel injection?
It is suggested that before the active (engine-running) tests are attempted, some static tests should be performed to check a few of the basic components of the Bosch fuel injection controller. With the ignition on but the engine not running, the duty cycle tells which version of controller is installed.
What is the idle speed of a Bosch Jetronic?
A frequency of 43.3 pulses per second corresponds to the desired idle speed of 650 RPM. (To check your tachometer you could measure the frequency at this pin and multiply by 15 to get RPM.) This signal is derived from the ignition amplifier and is synchronized with the low side of the ignition coil. 2 GROUND 3
Where is the X11 diagnostic connector on my 1991 560SEC?
On my 1991 560SEC the “X11 diagnostic connector” is mounted on the inside of the left fender, behind the ABS controller. It has a round screw-cap. On some cars (California?) there is also an “X11/4” between the two firewalls – don’t get them confused.
Is the idle speed adjustable on the Mercedes 116 / 117?
The 116/117 does not have an adjustable idle control. Each component within the system that make up the idle control must be functioning properly. Unless your vehicle was retrofitted with the old idle adjustment valve and ICV removed (pre-84), idle speed cannot be adjusted, only affected by failed componenets.
How to test a Mercedes-Benz idle control valve?
Plug on couple at idle speed adjuster in a manner that voltage can be measured on plug. Engine at idle. If a faulty control unit is found, nowhere within the Mercedes Manual does it suggest this method but others have suggested this and it worked for me. Remove the control unit cover and lightly twisting from side to side while engine is running.
Is it normal for the idle to rise to 550 rpm?
Yes 550 rpm is normal. The idle should not rise when AC is switched on. The idle control unit supplies a signal, delayed, to compensate for the additional resistance caused by the compressor. The 116/117 does not have an adjustable idle control. Each component within the system that make up the idle control must be functioning properly.
Can a car idle speed be adjusted without an ICV?
Unless your vehicle was retrofitted with the old idle adjustment valve and ICV removed (pre-84), idle speed cannot be adjusted, only affected by failed componenets. Here are the tests quoted from the MB sevice manual.
How to adjust Bosch KE3 Jetronic fuel mixture?
Mercedes suggests that special tools are required to adjust the mixture on the Bosch KE3-Jetronic (CIS-E) fuel injection, such as is used on the 1988-91 560 series motors. The dedicated shade tree mechanic can do it, but needs to be well-informed first.
What does duty cycle on Mercedes Benz mean?
Instead, it is a constant 100 Hz pulse whose duty cycle indicates the hunting of the fuel injection for an ideal mixture by switching back and forth between very slightly rich and very slightly lean. Mercedes has chosen the less common definition of “duty cycle” in this case.
When do you change the Jetronic mixture in a car?
For California cars, starting in 1988: Press the push button switch on test connector X92 (passenger side, between the two firewalls) for two to four seconds. The LED will flash once, indicating no fault code is stored in the system. Now press the switch again for two to four seconds.
It is suggested that before the active (engine-running) tests are attempted, some static tests should be performed to check a few of the basic components of the Bosch fuel injection controller. With the ignition on but the engine not running, the duty cycle tells which version of controller is installed.
When do you need idle speed and mixture adjustment?
10.6 Idle speed adjustment screw (A) and mixture adjustment screw (B) – Ford VV carburettor 7 Adjustment of the CO content (mixture) is not normally required during routine maintenance, but if the reading noted in paragraph 5 is not as given in the Specifications first remove the tamperproof plug, prising it free using a small screwdriver.
What happens to the timing of fuel injection?
Advancing or retarding an engine’s timing is possible. Advancing an engine’s timing causes the injection process to occur earlier than the manufacturer’s settings. In opposition, retarding is when you make changes, so the fuel releases after the recommended time.
What does it mean when the duty cycle is at 50%?
If the duty cycle is at 50%, this means the frequency valve is open 50% of the time, and closed 50% of the time. Conveniently, the duty cycle can be measured with a dwell meter set to the 4-cylinder scale; the example 50% duty cycle corresponds to 45° dwell (100% being 90°).