I just ordered a new bosch thermo from Fastlane, but will whis work until I get the part...

What if i clog up the threaded hold, and adjust the idle screw so that it wont die. Will this simulate the thermo closing (or getting longer), and even out my mixture?

NO! You are missing the point. The very simple test of the airflow allows one to make decisions about where the mixture problem comes from. It is cheating so to speak. It only tells us something because of the relationship between the mixture mechanism and the air mechanism. Screwing with the airflow will only change the engine speed.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Rad-Man.
We professionals don't mind helping a week-end mechanic, who has mechanical abilities,with some problem.For some guys,tinkering with their cars is relaxing and provides a sense of accomplishment.You on the other hand do not even have a clue.I can't believe we have spent as much time on you as we we have.I have 3 of the SLs like yours,and they are expensive toys.Now quit being so CHEAP and take it in.I've already given you all the clues on how to find the right person;reread my earlier posts.There is a limited number of professional mechanics on this site,and it is unfair of you to monopolize their time trying to get your car running for FREE.Others appreciate the help.I will be glad to answer tech questions for you in the future,since I know that car from end to end,but only after you've taken it in and got it running.
Good luck,
Peter

__________________
Auto Zentral Ltd.

autozen,
I really appreciate all the help you guys have given me, but you need to cool down. I'm 22 years old and this car was my dad's baby. Now it's mine and I want to get her running again. I do ALL mechanical work on my jeep, but I guess I'm being extra careful with this thing. I'm sorry if you feel like you have wasted time on me.
I'm paying for college, and trying to maintain 3 cars. I really cant afford taking this car into a shop right now........

ANyway, I just got my new FI thermo. (# 1 287 230 002)
I'm hoping this will finally fix the stupid mixture problem. If it dosent, I wont ever post here again.


as for the install, stevebfl gave me a pretty good idea of what i need to do: "They are easily cleaned/freed up. Drain your coolant and pull the t-stat housing (cylinder) - two screws. With the t-stat removed push on the piston where the t-stat plunger sat. It should be spring loaded up. It should easily push down and spring back. If not remove the other two screws and take the housing to the bench to free up. "

anything else i should know?
I'll let you know how it goes. Peace

Rad Man;
The cold start valves were famous for leaking into the intake manifold.
The valve is located on the far right side of the intake manifold,it has an elect. solenoid ,and a fuel line to it.
On the valve assy. find and remove the 7mm screw,have someone turn on the ignition but don't crank,if gas comes out of the screw hole then the valve is bad!
M.F.

Rad,

Don't let one person giving you a little lip ruin your experience here.

You may not get the problem resolved right away, but you will get it resolved.

Don't think that people here wont help you, because they will, sometimes its best to post and wait for a response for a few days, then check back and see what you have gotten.

We would hate to see you leave our community because you and one other person had a disagreement.

Alon

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'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon

After pulling off the housing and taking it apart, I've gotten a better idea of how this thing is supposed to work. I noticed how when the piston is all the way down the threaded hole (where the little filter attaches) closes and stops air from being sucked in. This explained why you guys asked me to check it at operating temp...
After putting in the new thermo, the amount of air being sucked in droped considerably after the engine warmed up, but it never stopped. After 15 mins of driving around, the engine would still die if I put my finger over the hole.



I know I said I would try not to waste any more of your time, but I feel soo close to fixing the thing.

Here is a pic:


I'm pretty sure my engine has been replaced with an SE engine (supposedly a direct replacement), but I can't help think that someone before me knew there was a problem around here and tried to rig something up.


If you look at the pic, you can see 2 brass-colored rings. The one on the left is part of the thermo, and the right (thicker one) is some kind of washer. Is this the normal setup? Call my dumb (oh wait, some of you already have ) but is this the way is should be?

I'm thinking that since the amount of air being sucked in actually changed from a lot (I left the little filter off, and the sucking was LOUD) to less... the thermo is actually moving in there. But I'm thinking that either that little 1/4" washer is stopping it from extending all the way down or the thermo just isnt strng enough to push all the way??

I guess thats about it. I think I'm going to put the old thermo abck in to see if it does the same thing. Maybe the piston just needed to be freed up.

Thanks in advance...

If you have it moving and have a new t-stat you are almost there. I think the pieces in the picture are right. The t-stat does need a place to seal against and the piece below it is beveled to accept the roundish shape of its bottom. Since you are now experienced at getting this apart and back together, you need to try some adjustments.

As I was saying before the relationship between the airflow and the mixture control is such that when you get the airflow right you will have this area of mixture control within tolerances most likely. Let me point out that when the airflow is right it will still suck your finger in but it will not drop engine rpm by more than 50. I personally like to get it to nothing as these systems are often rich for more than one reason. Also beware that almost evry time I fix one of these so simple problems, someone has already messed with all the other adjustments (which absolutely should not be messed with till the temp mixture correction has been corrected.

With all that said lets shut off the airflow. You have noticed that to finish closing off the airslide you need a longer t-stat. Well make it longer. Add small washers to the area where the end of the t-stat sits. Start small as we do not want to go to far. Remember that when its all done you are going to have to open the airscrew as it will not idle high enough when the add air is properly shut off as you realized. The most important point with this additional air/cold enrichment adjustment is getting the warm setting right as this is where the car is mostly driven and is almost always the cause of way rich mixtures.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I think thats the cold start valve. Take the fuel line off and plug it too be sure it is not leaking.

You may have gone too far with the t-stat. It was probably so loaded up that it took a while to appear lean. Just a thought since you got this down now.

While you are eliminating other things (cold start valve leaks) disconnect all the electrical to solenoids on the rear, I have seen the starting enrichment solenoid be hooked up improperly and throw the rack rich. When warm none of the solenoids are necessary for proper running.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Well, I finally added enough spacing, and the piston gets pushed all the way down at operating temp. There is no air being sucked in, and the engine is not affected when I put my finger over the hole.
Then I took out the plugs and cleaned them with some gasoline and an old toothbrush, and after putting everything back together, the engine was running wonderfully!

After 10 mins of idleing in the garage and another 15 mins of driving around, she started acting up again. The engine started sputtering and would try to cut off under high acceleration.

I took one of the plugs out when I finally made it home, and it was BLACK! DagGUM carbon fouling!

One thing I noticed... Before I had the theromo working correctly, a lot of black residue would be shot out of the exhaust pipe (a clear sign of rich mixture, as I have been told), but now there is none.

Whatever the problem still is, I know the FI thermo was a big part of it. Thanks to all who have helped me eliminate one of the culprits.

Ok, I just unscrewed the little 7mm screw and turned the key to the on position. I could hear the fuel pump working (I let it run for a good 3 minutes), but I never had any gas come out.

whew.

One thing I thought of... a few months ago I put a bottle of STP fuel injection cleaner in the gastank. I figured that she had been sitting for a while, and needed a little cleaning. Could my problem be in the gas itself?