C220 front engine sensor ID please. also, some other questions about cold starts and speedometer

[95c220]

would like to just know the sensor names/duties in the picture below (1,2,3, and the vacuum junction at 4).
2657




on a cold start (not weather, just after the car has sat for a day), I need to throttle the gas lightly to keep the car idling. once the temperature gauge starts to climb, the car idles perfect on it's own, and drives like a champ. no engine codes thrown. I have 2 MAF sensors, but one is used (40K miles on it) and the other is out of a parts car. using either MAF sensor, I get identical results.

last question is where should I check for a speedometer that turns off at random? will come back at random as well. slapping the top of the dash above the gauges doesn't affect this at all.

thanks in advance. :)

[RemoLexi]

1 2 3 sensors are all coolant temp related. Not clear on which one is which but you have a coolant temp sensor, fan switch for cooling fan ect.

The idle problem I would try and clean the throttle body first.

Speedo problem, probably the unit itself is failing. Becoming more common this day and age.

[95c220]

The idle problem I would try and clean the throttle body first.



thanks for the ID, I picked up all 3 sensors/senders to swap out. got another MAF sensor as well.

I've cleaned the throttle body, but from the outside...I know there's a tear-down procedure, but before I jump into that, would it actually get better from only a 20 degree rise in temp? that's why I figured a sender was bad, telling the car to dump more, or less, fuel than it needs at cold start.

[RemoLexi]

Anything is possible.

You need to clean the throttle plate with throttle body cleaner. Over time it gets gunked up and won't allow much air to pass at idle (throttle closed). But it's just a guess. It wouldn't hurt to clean it.

[95c220]

Anything is possible.

You need to clean the throttle plate with throttle body cleaner. Over time it gets gunked up and won't allow much air to pass at idle (throttle closed). But it's just a guess. It wouldn't hurt to clean it.

thanks. all help appreciated. but the plate is actually 100% clean, inside and out, as well as the TB entrance. I'm sure there's buildup in the tiny channels deeper inside the throttle body, so that's a step I'm going to try this weekend. symptoms just didn't click with me as a TB carbon issue.

swapped sensor 2 (1 pin, gauge sender) and 3 (2 pin, have not figured out what this one controls yet). will swap out sensor 1 today (I thought I had it onhand, but nope). also installed another MAF. the car displayed the exact same symptoms with the "newer" parts, but only took 30 seconds of throttling the pedal to get perfect idle (it usually averages 2 minutes to get standalone idle). soooo close.

funny thing, when the car idles I can unplug all 3 sensors and no change (except no temp gauge). so probably barking up the wrong tree. I may just spray down this junkyard MAF, as the car's behaving the best with that one to date. if it improves with that, i'll buy a new MAF.

[RemoLexi]

Have you looked at fuel pressure?

[95c220]

Have you looked at fuel pressure?

not with a gauge, but lines cleaned out, new fuel pump/filter, clean injectors that fire correctly, new fuel pressure regulator.

[95c220]

car sat for 4 days. car needed some throttle pressure for only about a 1/2 minute today, then idled fine on it's own. sat for another 5 hours, and started right up tonight. so I am leaning towards fuel pressure. maybe i need to buy an OEM bosch fuel pump? I have a new, but generic, one in there now. check valve new, fuel regulator new. only thing I'm thinking is the initial fuel pump PSI is just low when the car sits for days.

no ECU codes. another MAF, same results. down to about my last guess, that it's just low pressure from the new generic fuel pump.

[95c220]

quick question...only 1 fuel pump used in the gas engine c220, correct?