I think it stems from a faliure to realize that automotive systems change periodically... and that car is not like all others.

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-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Shoveled the foot of snow off the car Friday anticipating a tow to the Mechanic today but decided yesterday morning to drag it home with the help of my son in law. Put it in the garage with a small heater blowing under the front of the car and decided to give it a try at 5 PM last night. The car fired up with no problem and ran fine (just like the old days). Drove it around the block and put it back in the garage. Cold temperatures still prevail.

Because I've purchased numerous parts, I changed the plugs and breather hose(they were easy to locate). Car again runs fine. I'm not sure but think that my old problem may arise soon and thought I'd test the situation by replacing the Air Temp Sensor first and see if this could be the culprit HOWEVER I CAN'T LOCATE IT. I pulled the Air Filter housing thinking I might see it underneath but am now at a loss.

Any assistance would be greatly appreciated.

Oh by the way, it appears that the broken thin hard plastic vacume line from the Breather Hose previously mentioned goes to the Fuel Pressure Regulator. Think this might be an issue for cold starts?

Refering to my inabilty to locate the Air Temp Sensor, I now believe it should be attached to the Air Intake Hose to the air filter.

This gets interesting. The new Air Intake Hose (which I purchased) allows for the Air Temp Sensor (which I purchased) to attach via a hole on the side of the Air Intake Hose. The old Air Intake Hose has a round plug snapped into the hole where the Air Temp Sensor should go.

Where would the Air Temp Sensor be if its not where it should be?
What would the Air Temp Sensor connect to in this odd scenario?

The Water Temp Sensor is on the block. It is easy to test and takes a whopping 5 minutes and is a <$50 part. Takes less than 20 minutes to replace as well. So go test that. It should be on the right hand front side of the block in the sensor array. It is either a 2 wire or 4 wire sensor.

http://img.eautopartscatalog.com/live/C602012903BOS.JPG

http://img.eautopartscatalog.com/live/C602012373FEB.JPG

Test that first using the table on the first page of this Thread.

__________________
~Jamie
_________________
2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

The reason you have a plug in your air intake is because the M103 engine didn't use that sensor until 1990. If that sensor is defective or unplugged on a 90 or newer, it will trigger a CEL or MIL. The temp sensor I would concentrate on is located at the rear left side of the block. It has 4 terminals and 2 or 4 connevtors depending on model year. You can swap the connectors to test, because the 2 sensors in the unit are exactly the same. Good luck.

__________________
Auto Zentral Ltd.

OK Have to recap. I checked my books and discovered that the 4 pole sensor is Ca only. If you have a 49 State car, you have a 2 pole sensor in the same location. Let me determine a test procedure for that sensor.

__________________
Auto Zentral Ltd.

I left the car out all day yesterday(high 23 low 5)and started it twice and let it get up to temperature. Turned it off and left it alone for 10 minutes and then restarted it with no problem. Drove it up the road a few miles last night to see how acceleration felt and it drove fine until I was pulled over by a County Sheriff for exceeding the speed limit by 10 (65 in a 55).

I explained that I was only a quarter mile from home and this had been the maiden voyage since the cold weather had started. He was quite nice and wanted to know if the temperature readout on the dash was accurate (showing 3 degrees at 6:30 Pm). No ticket just a warning.

Left the car out last night (high 5 low -6) and started it up with no problem this morning. Drove it to work and just restarted it after letting it sit for 20 minutes (showing 14 degrees).

And thats where we are. Plugs have been changed, new breather hose, new vacume line from the breather hose to the fuel pressure regulator, new air intake hose to the air filter and a new Air Temp Sensor temporarily filling the hole where it would be if it were a 1990.

The breather hose/vacuum line are what fixed it. Can't have vacuum leaks and expect good cold starting.

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Thanks much Kent for the early advice. Lets see how long this lasts. No problems at all today multiple cold and warm starts. Supposed to get to about 15 below tonight and I'm leaving the car out to see how it'll respond in the morning. I think tomorro may be my last post on this subject. Hope so.

Immediate start this morning, no issues, low last night -8, current temp +3.

Thank you all. This is an excellent forum. Saved myself a bundle and started learning a new car.

Looking forward using this group again.

Happy Holidays!!!