230TE Power loss

[Derm]

I have a mercedes 230TE, 1991, 2300cc Bosch KE -Jetronic which has two problems.
When it rains it runs normally for a while then power shuts down to a rough tickover. It will then only accelerate if the throttle is opened fully.
This fault could be there the following day and then will suddenly clear.
I have checked the HT circuit while this is happening and there does not seem to be any tracking. This fault has occured for over a year now and always behaves in the same way.
I do not think it is electrics but a fuel restriction.
The car also pulls away slowly sometimes.
I would really appreciate any suggestions.

 

[turnipsock]

It sounds like the electrics. When you set of in the rain, it takes time for the water to get into the offending area.

Similarly, when you set off, the next day in the dry, it takes time for things to 'dry out'.

You haven't said if you have changed any of the parts over the year...plugs etc.?

 

[dirtydiesel]

Start of by changing plus, plug leads, distributor cap and rotor arm this should cure your fault, as turnipsocks says it sounds electrical

 

[Derm]

Thanks for the comments I will give it a try I think rotor arm and cap would be worth a try even though they look ok plugs have been changed.

 

[jberks]

Hi,
I agree its electrical, but the symptoms you describe (rough idle, no power) are a lot like the engine management 'get you home' mode.
If it pulls away slowly but smoothly, it would imply that the ignition system is ok as you don't have a obvious misfire, but the injection system is not supplying enough fuel (running lean). I am wondering whether there is a problem on a sensor in the air intake system, getting wet, or a short on the wiring to the O2 sensor underneath, getting wet. A couple of fault free restarts and it will go back to normal.

 

[Derm]

I was thinking it is like engine management shut down . Someone has cut O2 sensor wires and fitted a terminal block in line but I'm not sure what happens if these wires went short, did not put tape around it because of the heat.

 

[jberks]

Basically, if the sensor signal is out of range - either open or closed circuit, the management can't tell how rich or otherwise the mixture is, so it goes into default "get you home" mode. I lost my O2 sensor (though the air mass sensor went at the same time!?), it shook like a bag of spanners at idle so much so that I daren't turn it off until I got to the garage as I didn't think it would start again, and on full throttle, it got to 30 in about 15 seconds.

I don't know the management system on a 230e but I imagine it has a memory for faults that can be interrogated - would save a lot of searching - after I'd taped up that block though - there are heat proof tapes available I believe.

 

[turnipsock]

I tend to stay away from doing dodgy electrics like terminal blocks (and crimps for that matter).

The best way is to solder the wires together and cover them with heat shrink.

 

[Derm]

Thanks for the comments I'll post a reply when I get a result