My New 230E With A Few Issues

[PunkJr]

Hi all

I have just obtained my Great Uncle's 1983 230E which has travelled 180,000km. It is physically in great shape but it is running rough. On Sunday when I drove it home, it was idling rough and chugging. I changed spark plugs and this made it run a lot better, however it is still idling low/rough when cold. Once it warms up, it idles smoothly, however I still feel it is idling low. I cannot tell the idle RPM's because the tacho is no working. Another issue is that the air conditioner is not kicking in. I thought these three issues may all be caused by a faulty OVP, however I cannot find an OVP - at least I cannot find a relay that looks like the OVP on my W126 (long relay with fuse on top). I can only find three silver standard size relays under a cover just in front of the fuse box.

Does anyone know whether my car has an OVP? I looked under the dash on both driver and passenger side, and cannot find anything.

PS. I found last night that the plugs I put in the car were resistor type NGP plugs. The car still seems to run fine at operating temp with these plugs in. I will try to source some non-resistor plugs today, and get a set of Beru leads next week - the leads appear to be original Mercedes.

[CraigB]

With a car that's new to me, I always think it is good to do a compression check and make sure you are not chasing stuff when there is an underlying problem - just good to know and if you don't have one I am sure somebody local would have one and takes a few minutes to check. For the rest I am sure plenty of 123 experts will chime in.

[PunkJr]

Hi Craig, I ran a compression test just to check a head gasket and it all checks out fine. Much easier to do
on the M102 than the M117!

[CraigB]

Great - other thought if car has been sitting, a fresh load of fuel in the tank can make a difference. But if it is running good warm and just rough cold, makes you wonder - are there any vacuum lines associated with the cold start part of it or the intake when cold - air leaks can often affect idling.

[PunkJr]

Thanks Craig. Yes I'll have to get the trusty vacuum guage out this weekend. I just hope that I could locate the ovp relay and find a blown fuse and all my issues would be solved. I'm just not sure if my car has an ovp relay at all, which could mean that all of my issues are individual issues that need to be addressed. Hoping for that silver bullet fix

[tsharkey]

Nice looking car.

No OVP as I am aware, tho I am more on the diesel side.

Two of the three near the fuse box are the AirCon - 1 for the compressor, another for the thermo fan.

Bad idle when cold .... New leads may make a difference there, Does the K Jet have different fuel mixtures depending on temp ?

[PunkJr]

I've changed the plugs, and that is all I've had a chance to test at this stage. I'm sure you're right regards the OVP - I cannot find one anywhere. I put new non-resistor plugs in tonight and it does run nice when up to speed - the idle is a little low I feel (still no tacho), but certainly driveable around town.

[mathuisella]

I've changed the plugs, and that is all I've had a chance to test at this stage. I'm sure you're right regards the OVP - I cannot find one anywhere. I put new non-resistor plugs in tonight and it does run nice when up to speed - the idle is a little low I feel (still no tacho), but certainly driveable around town.

See if you can get one of those timing lights, connect over cylinder 1 spark plug lead and see the rpm :)

https://www.supercheapauto.com.au/p/too ... /9702.html

also, check the air filter and put in new oil + oil filters.

if the car hasn't been serviced, or been sitting for a long time, condensation inside the crankcase can water down the oil. and make it well, like water and make things run faeces.

[PunkJr]

Yeah a service is on the cards. It has only travelled 7500km since last service but that was in Dec, 2015! I am struggling to find any online manuals online (there was no shortage of manuals for the W126) maybe because the 230e never made it to the USA. I think I may get it down to Adelaide for a checkover. I hear amazing things about Olaf but I'd heard that he had left Adelaide for sunny Qld. Is he back in SA?

[WJB]

This might help.

https://www.ifixit.com/Device/Mercedes_W123

[Ivanerrol]

Check all the rubber hoses.
Chances are some are perished and letting some unmetered air into the intake manifold.
Idle air valve hoses being particularly noticible for going hard.
If the car has been sitting - and I notice only 180 odd thousand K’s for a 1983 model. You should change out the fuel filters.

[PunkJr]

I have changed plugs, new injectors, new fuel filter,0air filter, oil change, all new rubbers on the intake including intake boot, new coolant, tightened steering box, removed air pump and pulley, new a/C compressor and adjusted timing. She seems to be running very nice now.

I still haven't got the tacho working. I have checked the continuity of the lead from the fuse box and the ignition coil so I'm thinking it's an issue with the tacho itself (seems rare). Cruise control not working however I can get the car to accelerate by holding up the stalk so I'm thinking it is the module in the drivers foot well (I tried sticking it I the oven for five minutes but it hasn't helped)

I also have a low idle on start up still. I'm working g through the issues slowly but at least the car is very driveable.

[Tony From West Oz]

regarding cruise control: If the brake light globes are blown the CC will not set. It relies on the ground from the tail lamps to enable cruise control. Applying the brake makes it +12V, so CC turns off.

[Ivanerrol]

regarding cruise control: If the brake light globes are blown the CC will not set. It relies on the ground from the tail lamps to enable cruise control. Applying the brake makes it +12V, so CC turns off.

Wrong wattage brake light bulbs will also cause the C.C. To malfunction.

Loose connections on the throttle arm affect the cruise actuator.

You may need to pull the instrument cluster to check for loose connections. There’s a hall sensor on the back of the speedo which also affects the C.C.

[brycedunn]

I am struggling to find any online manuals online (there was no shortage of manuals for the W126) maybe because the 230e never made it to the USA.

The Americans never got the 230E due to CAFE, however they did get the W123 and the M102 2.3 Engine in the 190E 2.3, so you can get close to what you want.

[PunkJr]

Thanks all, never would have thought to check the brake light bulbs! The Brooklands manual has been a handy book to have. Just ordered the Haynes for my son's W202 but have the Mercedes WIS which is very detailed, but the aftermarket books seem to have a slightly different approach that can be helpful.