I've got an 82 Mercedes with CIS Basic/K-Jet), it doesn't have an O2 sensor or Frequency Valve.

Any how I've been geting pretty crappy Cold Starts over the last few months. Today I finally started running down some troubleshooting suggestions outta my old VW Rabbit Bently. Sure enough Cold start Valve wasn't pumping any fuel (this is while cranking the car over), and then when I hooked up my Multi-meter I didn't get any Voltage outta the plug for the cold start either?

Any ideas?

TIA

What was the coolant temperature? The CS valve is controlled by a "thermo time relay" and I think you need to have a coolant temp of less than 50 degrees for it to activate the valve.

What happens if you disconnect the wire and give it 12V?

Some other stuff to check:

- fuel pressure when cold
- thermo time relay
- coolant sensor (tells relay what the coolant temp is)
- aux air valve
- warm-up compensator (power to it, and resistance across contacts)

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

I'm also not getting any power to the Thermotime swtich.

I'm guessing that something is going wrong here with the wiring. Any ideas on what to track down????



This thing has been pissing me off for so long now.

I am travelling and don't have a wiring diagram with me.

If memory serves, the relay needs power with key on. Then it gets a signal from start and it fires the valve for the appropriate amount of time depending on coolant temp.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Cold start injection HAPPENS only in COLD weather & only when the starter is operating.

IF that car is having cold starting problems then HAVE the system fuel pressures tested...warm-up regulator is a common problem

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Just curious, what is a warm up regulator?

Thanks,

Mike

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

warm up regulator is attached to the block, it has fuel lines that run into it, and as the motor warms up it it lowers the fuel pressure (or raises it) all it is a bimetallic wound up strip. It is also known as the control pressure regulator.

I have a serious doubt that my problem is the warm up regulator though. I wrapped my cold start sensor in ICE and tested it while cranking the engine (had it pulled and placed it in a cup to collect the fuel), didn't get any fuel spray into the cup. After that I tested to see if there was Voltage to the CS Valve, by hooking up the multimeter to the plug then cranking (no volts). I then checked the ThermoTime switch in the same manner (hooked up meter when cranking and got no voltage).

Anyone have anymore info on this Relay??? I've dealt with CIS Inj on VWs before and it can be a PITA! I didn't see a relay in the fuse box, where can I find it?

TIA

I've owned several "euro" 280E's & the cold start works the same on all of them!

LOOK at the wiring & see that the thermo time switch doesn't allow ground to injector above 59F.

No relays involved..power comes directly from ignition switch durning starter operation...circuit 50.

Attached Files

208E fuel.pdf (36.7 KB, 641 views)

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Hmmm all this time I thought the problem was the Cold Start System (either the valve or thermotime), but my cold starting problem last longer than 8 secs.

What happens is you start the car and it has a hard time continuing to run after you start it up, sometimes it stalls out and you gotta recrank it and then it'll run at idle (can't accelerate past idle without massive hesitation), sometimes it'll start up and then kick into a little higher idle; once the car is warm (Water Temp gauge starts climbing) you can drive it. The car runs normally and fine as long as the engine is warm.

I read the troubleshoot procedures for checking the "Auxilliary Air Valve" and my symptoms are similar to those of a faulty "Auxilliary Air Valve". The only problem I'm having is locating this on the Merc! This seems to be the only component that looks radically different than the ones on the VWs. Here's a pic -> http://www.***************/secure/PartImages/0280140037.jpg of what's available for the US 280Es, but I can't find anything that looks like that on Mine.

Does that sound possible? Is there no Aux Air Valve on the Euro 280Es? I really don't wanna spend the $$$ on a new Warm Up Regulator, and I have a BRAND NEW one for a 86 VW with CIS that I paid $250+ for and didn't end up using it (if need be could that work on the Merc?)

TIA

The Valve In The Pic Is The Correct One, And Your 280e Does Have One. If You Stand In Front Of Your Engine With The Hood Open, On Te Left Hand Side, Behind The Intake Manifold, To Front Of The Engine, It Bolts To The Block Of The Engine. Much Easier To See From Underneath, Remember It Is To The Front Behind Intake Manifold, Not Visible From Top.

cool,

I was looking towards the back of the engine. I've gotta test it and hopefully if it's bad it'll cure my problem

All the air valve does is let air in....

What needs to be done to find your cold starting is have the CONTROL fuel pressure when the engine is cold..

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator