My 1990 190E 2.6 has a cold start problem...first start when not warm it will not start, always start second time, always. Car is in immaculate condition. New injectors, new holders, orings, and seals. Two new fuel pump check valves, new fuel filter, new wires, new rotor and cap. New plugs, new timing chain and all timing guides etc. Some say fuel pressure bleed down, some say it is injectors, but now they are replaced. SOme say accumulator, but I am sceptical, others say no accumulator and want me to pay them to test system AGAIN. OH, cold start valve is new too. It likes to start on first key turn in winter with new cold start valve cause it is giving it a snoot of fuel when it is cold. But once it warmed up over the temp the cold start valve needed to activate I am back to the trying twice before the car stars and runs like a champ. Help.

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Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

I'm having a nearly identical problem... with a '90 190E 2.6.

I searched the archives and found that the *cool* (not really cold)initial start-up can be hard for this particular vehicle, due to the emissions calibration. I didn't find a definite cure for it, though.
BTW, the O2 sensor was replaced (bad/check eng light) and the cold start injector was replaced for good measure.
The car runs great, once it starts. Warm starts are no problem.

Anybody have more info?

1990 190E 2.6, 135K miles

Have you checked the vent tube of the pressure regulator for leakage? It might be worthwhile hanging a pressure gauge in the fuel line to verify leakdown as the cause.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7

It seems that while you may have a new cold start injector, it still isn't passing fuel when it is supposed to. The cold start system comprises of 4 components, and EACH must work, in order for the CS injector to work.

1) CS injector.........yours is new, so skip this

2) fuse for the CS system..........check the fuse panel for a bad "cold start injector" fuse

3) CS start relay.........looks like a square box, usually along side the fuses..............there are many, so you have find out which one it is.......I don't know

4) Thermotime switch (TTS)...........usually located next to the water temp sender unit........I find them near the thermostat housing

The MOST often problem is the TTS going bad, so there is where I would check first.

Henry:

Would a dionostic of the fuel system show this component as defective?

I have a similar problem, when I start the engine hot or cold it stumbles for a few seconds before it smooths out. I have had this problem since I purchased the vehicle in 96.

I just thought it was one of those little quirks of the 103 series engine until now.

Scripley: A diagnosis of the FI system would show this, but ONLY if it is a complete one.

A defective cold start system ONLY shows itself in a cold start condition......it isn't even used when the engine is warm or hot.....this is controlled by the TTS. Hence your problem is something else..........something that is common to both cold and hot.

I would suspect the air by-pass screw adjustment is off. This is the large Allen head, knurled screw, located at the throttle plate area. Try turning it 1/2 turn one way, then the other........see if this helps. If not, then other tests would have to be performed.

Thanks, I will give it a try.

Is there a quick/easy way to test the TTS, such as with a VOM? I'm selling this car on Thurs, and I'd like to at least provide some good info to the new owner.