300e fuel injection

[MikeNJ]

my idle/stalling problem on the '87 300e is becoming intolerable. having adjusted the lambda tower and eha to no avail, i am at my wits end. i want to drive the car without electronic fuel injection, but i'm not sure what to pull or where to look. i know you can disconnect the whole system and run mechanical fuel injection, i just don't know where to start. where is the cis-e unit located and what plug(s) do i pull to achieve this? anything you could do to help would be very... helpful.

[Duke2.6]

All the cold start functions are part of the "E" portion of the system, so if you disconnect it the car won't cold start. You can test this by removing the OVP relay, which provides power to the various "E" portions of the system and the ABS computer. See for yourself - remove the OVP relay and try to start it cold.

If the duty cycle and EHA current are in the correct range, then your problem is somewhere else. Disabling the "E" part of the system is not a viable course of action.

Did you ever check the TVS and CIS temp sensor?

Duke

[cnctony]

First I would get some basic information on your cars condition.

1. Remove spark plugs one at a time and examine or replace. 12.00
2. Remove dist. cap and clean or replace, 85.00 rotor 30.00.
3. Measure spark plug wires with ohm meter or replace. 100.00 wires,

4. Check and or replace air cleaner.
5. If everything looks good then on to the next step. Its still good to do a tune up.
6. Fill up with Chevron with Techron 93 superU and take it out on the highway.
7. Smell exaust. NOT FOR TOO LONG! to see if it smells like gas.too rich. Could be a sign of a bad oxygen sensor or misfire or stuck cold start valve. Could be a multitude of things. DO NOT USE BOSH PLATINUM spark plugs as they all have resistors in them and should not be used on your car.

8. Oxygen sensor test Using a Oscope or borrow one from a friend remove floor cover and mat in passenger side you will see two connectors one has 2 white wires(disconnect then start engine and check voltage. You should have 12vdc.) The other connector is a single black wire very carefully using the sharp oscope probe tip puncture the black wire and connect the ground to chassis ground around door or lighter. You should see a nice sine wave around 0.2 to 0.8vdc. The frequency should be equal to or faster than 300miliseconds. if slower replace sensor.


I don't believe you can disconnect the KE Fuel injection system and still pass emisions and keep from damaging your cat and keep the car running well. The connector to the KE unit is behind the battery. Just disconnect the OVP relay and the KE unit will not function. Try it. I dont think it will solve your problems though. Here are a few items to check:

Cold start valve Check
Idle Speed control valve Check
OVP relay Check
Temprature sensor defective check
Electro-hydraulic actuator catches check
Fuel pressure incorrect.

Keep trying youll get it or just bite the bullet and pay pay pay.

Good luck
Anthony

[MikeNJ]

the car has always started fine, the problem is once it gets warm. it will often stall immediately after a warm start, and also when decellerating. recently it has begun losing power at low speeds before stalling.. the engine is still running with no responsiveness before it cuts out altogether. the other interesting development here is that now it is hard to restart her, where before she had always started right back up after a stall. you are correct though, i pulled the ovp and the cis-e unit separately and no change. i have had a hunch about the airflow sensor potentiometer or the airflow temp sensor. cap, rotor, plugs, have all been changed in the last 10,000 miles. i doubt it's the injectors themselves, it has something to do with idle at warm temperatures, which leads me to believe it is an airflow issue. back to the mechanic with her, i guess. i've had it up to here with the mb "specialist" i have been seeing, he doesn't seem to care. this was my fear when purchasing this car, a seemingly simple problem that becomes complicated and expensive..

[Duke2.6]

One thing to look for is a hot vacuum leak - a vacuum valve, hose, or some component that doesn't leak when the engine is cold, but leaks when it warms up to operating temperture.

Some problems can be very difficult to troubleshoot, but once found the solution may be simple/inexpensive.

Remove the air cleaner, hook up a vacuum gage at idle and start pinching off vacuum lines near where they join the inlet manifold. Also carefully check all vacuum lines and components for any obvious damage or deterioration.

Normal idle vacuum should be about 15-16" at 700 RPM (neutral) idle speed, and there is some fluctuation, but if you pinch off a vacuum line and get a slight surge in speed or sudden transient in the vacuum gage, you may have found a problem. Even if you don't have a vacuum gage a sudden transient in idle speed when you pinch off a hose will give you a direction to follow.

You can often hear them, too, and you can make your own "stethoscope" with just a length of vinyl or rubber tubing. Stick one end in an ear, plug your other ear, and use the other end to probe around.

Duke