93 2.6L 190E Hesitation when cold
 

1993 2.6L 190E, 208,000 miles

With the car cold, using the diagnostic connector, I get a "Code 3" which I believe is saying that the temperature sensor is out of range. Replacing the temperature sensor changes nothing. Replacing the computer (the larger of the computer boxes behind the battery, I think it's the emission computer) changes nothing.

The car starts fine, and idles slightly rough for about 10 seconds. If you let it idle for about 5 minutes, the "code 3" goes away.

If you start it cold, and immediately drive it, a major hesitation happens for approximately 10 seconds. It doesn't stall, but chugs along for about 10 seconds. Then all is fine, unless you stop soon thereafter. Then it will do it once more after leaving the stop sign and nearly getting t-boned. By that time, it seems to fix itself, and all is good until the next time the car is cold again.

In looking at the wiring diagram, I'm perplexed. It looks like the only thing it could be is the wiring itself. A visual inspection of the wiring doesn't show anything, and the warmup making the problem go away makes me think the wiring couldn't be it.

Its logical that the hesitation is related to the "code 3", so I'm attempting to fix that before looking at other reasons for the hesitation.

Looking for someone with a magic bullet saying "yes, I've seen that before, it's the whatchamajigger sensor on the e pluibus unum."

Thanks in advance,
-jmjatlanta

Too bad there is no answer to this since I have the same problem with my 85 190E 2.3L.

Only when cold, it hesitates on acceleration, then once it warms up it runs perfectly fine. Weather is getting colder now here (Canada), it was 10C in the morning and the car missed a beat twice, as soon as the temp built up, it was like new.

I have a few options in mind, tune up, although it was done about 15K ago, but the car was sitting for a year in my garage as I restored it, temp sensor, I have a new one, I'll put it on tonight and see if it makes a difference, and possibly the cold start valve.

Cold start valve makes sense since it supplies fuel to the engine when it's cold, but the valve itself might be perfectly fine, it might be a sensor that triggers it, hence the temp sensor. I might rig something up to see if it clicks on or not.

Any other suggestions?

I seriously doubt it's ignition related since I've seen this before, but a tune up never hurts :)

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