Cold start problem 260e

[ecol]

Hi everyone,can any one advise,I am a newbie to the forum.my 1989 260e has a cold start problem which I have traced to the Rotary Idle Valve,it starts ok but clicks off after about 10/15secs I have checked relays and fuses to no avail ,I have to let the idle speed pick up on its own (a few seconds) before i pull away.I have replaced the idle valve with a known good unit .also now when hot and restarting it flicks up to 12/1300rpm for 10/15 seconds then drops backto normal revs Can any of the forums members advise?

ecol:

 

[television]

When you say that you have checked the relays, have you checked the Idle Control Relay, if so how ?

Malcolm

 

[ecol]

hello Malcolm,I have replaced the fuel pump relay and the ovp and it fuse,is there another hidden away that I could have missed?

Regards Eddie

 

[television]

As there are 3 variants can you confirm that it is a 103 engine with KE injection is the car a 124.007 or 026 or 027

malcolm

 

[ecol]

hello again Malcolm,it is 124.026



eddie

 

[ecol]

hello again Malcolm,it is 124.026

 

[simmo300e]

I suggest you check the voltage at the idle control valve and see what's going on. Get a multimeter set to the 12v range and bridge the connections to the ICV with the engine running. You should be seeing around 6v across the terminals. You'll also hear the unit clicking when it powers up

I've had this problem with my 300E. The voltage was not constant coming out of the ECU, sometimes it would be delivering power, sometimes it wasn't. If there's no current going to the ICV, it reverts to limp home mode which is about 600 rpm.

You can adjust the idle mixture to compensate so the engine will idle at this level without ICV support, but when the current kicks back in from the ECU, the ICV switches to a wider aperture and bumps the idle up to 1000 rpm or more.

I could switch the power to the ICV on and off by giving the ECU a thump, had to replace the unit in the end.

 

[ecol]

Thanks Simmo I was thinking along these lines but Television mentioned a relay for the Idle control unit dependant on which version,but I have not heard from him since,have you any knowledge of one?

 

[ecol]

Hi Simmo I tried a est across the icu whilst engine is running and there is no voltage at all ,but when i turn off the engine and restart I get / 11/12volts for about 10 seconds which takes my idle speed up to about12/1300 revs for that same period ,other than that the runs fine,have you any ideas?

 

[Stevie A]

I have the same M103 2.6 engine and the car automatically increases the revs to about 1200rpm for a short period after starting then automatically reduces the revs to 600-750rpm which is fine and normal for this engine.

 

[ecol]

Thanks Steve but I still think I have problem

 

[television]

Sorry, I forgot to come back to your problem, You injection for ref is KE111
The idle control is built into the N3 KE injection control. As Simon300 said he had to replace his. these can be re soldered as it is an expensive lump. when cold, tapping the unit would show up any faults.

The N3 control unit drives the electrohydraulic actuator Y1(rightside throtle body top rear) this controls sytem presure and lower chamber presure that controls mixture adaptation of
Start enrichment
post start enrichment
warming up phase
Acceleration enrichment
De cel fuel cut off
Lambada control with cat
Part load mixture control
To the left at bottom of throtle body you have a throtle valve switch for full load and idle speed recognition (worth a check)
The fuel pump relay contains the start valve actuater control and max speed control (only on KE111) with 1 or 2 it part of ignition.
When you start the car start enrichment duration 2 sec
Post start duration 20 sec
Warming up depends on coolant.

Malcolm