C43 Power
 

Hi, I been looking at this site for a long time but I was never ever able to post for some crazy reason. Anyway, I have some questions for you guys.

1- In the morning when the weather is around 60-65 my c43 becomes a REAL LIFE BEAST in power. but when the outside temperature gets higher or the engine fully warms up the car loose the "morning power". WHY?

Is it possible to make the ecu think it's cool/cold out so as to keep the car running that strong? I don't mind if it wastes more gas I love that extra power. When it's cool out in the morning my car burns rubber very easily. But once it's fully warm it's very sluggish. I have already tried the resetting of the trans trick but only helps very little.

The car has had a full tune-up and like I said in the cool mornings it shows and the power is completely awesome!

2. Has anyone up-graded their c43 to a set of better fuel injectors? I think mine has the bosh mean green (something like that) which I read are nice. But if there are better ones for it that will give me some more power like in the mornings that would be great. I could do the wrok myself.


Thanks everyone and hope someone can help because I have searched through out the web and so far found nothing regarding this.

Thanks.

as for the first question.

when your car and the air out side is cold, cars run better because cold air is dencer, this is why on turbos, people put very insane CAI (cold air intakes) and diffrent cooling systems and water pumps. what YOU can do is, get a better air intake system (K&N, Green filters). so yea, its has nothing to do with your ECU (exetp it tends so hold 1,2nd gear longer to warm up the car) but other than that, heat kills cars powers.

Mark

Although I have not personally tried this product, it does come from a very reputable manufacturer. Might be worth a shot.

http://www.redlineoil.com/img/productSubCatImages/4.jpg

Redline Water Wetter:
http://www.redlineoil.com/products_c...ubCategoryID=4

Scientific Explanation:
http://e30m3performance.com/myths/mo...ter_wetter.htm

http://www.racerpartswholesale.com/redtech3.htm

Thanks for the tips guys!

It's great news that it has nothing to do with the ecu.
I do have the green air filters which works nice for me.
I'm going to try that water wetter, I will order it tonight and post results after using it for anyone who is interested.

If anyone else has any other ideas how to make the car run like it does in cool mornings PLEASE let me know!

To be completely honest, there are a number of issues that could cause your car to be slower once it warms up. What are the day time temperatures where it feels slow? A huge temperature jump would be noticeable but a normal day-to-day temp change shouldn't make a big deal. One possible fix is replacing the thermostat with a slightly cooler one, which will force the engine to run slightly cooler.

You need three things to make power; air, fuel, and spark. Your air filters could need replacement, but then your car wouldn't run any better when it is cool. Your fuel filter may need to be replaced. Again, not sure why it would run better when it is cool as it should actually run more lean when it is cool. It could also be your MAS, which is honestly what I would guess. If you get a check engine light soon and it turns out to be fuel trim left and right bank, that will be your MAS. You could also have timing issues. Who did your tune up?

One thing that you should not do is change your injectors. The injectors that are on the car were designed to work with that fuel system. You have no way of compensating for a higher flow injector and it could be difficult to find one that had the same electric characteristics and would work with the fuel system. This idea should really be shelved until all else fails. If anything, I would just replace them with stock units.

Without the car in front of us and the ability to run diagnostic testing, we're swinging at air here. I'd take it to a qualified independent or a dealer if you felt comfortable with them.

Chg the MAF if you have not done so yet. That is probably the problem!

Its called "heatsoak" that kills the lowend power.

Heat soak is a term for heat exchangers, not for engines. Your thermostat is designed to keep the engine running at a certain temperature that the engine was designed for. Once the engine reaches operating temperature and in turn a certain pressure, the thermostat opens and allows water to enter the radiator and be cooled. When the operating temperature cannot be controlled simply by flowing water over the radiator, the fans kick on and increase the convective heat transfer over the radiator. Air has a pretty poor conduction rate, so the fan really helps. If your fan weren't kicking on, that could cause you to overheat if you were sitting in traffic. If your engine temps look fine, I don't think cooling is your issue.

I still think your MAF/MAS is the culprit or possibly some kind of throttle position sensor. Cold air is denser than warm air, so when the engine warms up, it heats up the intake air. If your car is not accounting for the changes in air density and in turn the mass flow rate of air, it will deliver the incorrect amount of full and you either lean out or run too rich.

I'm just rambling here. The best way to diagnose is with the proper diagnosis tools.

Power2go... listen to Carl! I've been there. Was kicking myself I waited so long. IMPORTANT!!! Don't listen to the MB tech when he check your MAF using the most common method of "adaptation", and says the "adaptation is within spec", and they most likely will. They need to check the airflow measurement (in kg. per minute or something like that). It will idle under 20. If it's bad when the throttle is pumped, it'll only measure up near say 100. Put in a new MAF and it'll measure near 700!

Carl, been a while. I'm going to Jeffery's tomorrow to drop the SL off. He thinks the C might need another MAF... :rolleyes: he's going to check it out. Car's been real 'sluggish'.

OT but, You going to the meet Pete's putting together, Captree and RPM racing, next Saturday? (he's doig a drive up near Bear Mtn Sunday too)

Cold Air = More Speed
 

Cold air definitely makes the car run better. A few years ago, I had a Z28 convertible. Road & Track had times of 14.3 in the 1/4 mile. And the first few times I ran it down the track in 70 degree weather, that's what I ran.

One day, I was able to run it when the temp was in the high 30's. I ran consistent 13.70's that day with no mods.

I can't assuredly state that your engine has one (although every other Bosch ME system I've seen has one - including my car), but if the intake air temperature sensor has gone bad, the symptoms that you're describing would be present. Some people modify the sensor (or the signal from the sensor) to improve performance. :naughty: There is a downside to improperly doing this. :crazy: But getting back on target, you may want to grab your WIS, find the "intake air temperature sensor" or "intake air thermosensor" (which is what it's called on some Bosch systems), or IAT, and review the testing procedure.

My brother-in-law flies F-16s, he says jets fly a lot better in cold air....
He said it should be same for all engines... I guess it's because of the thinness or thickness of the air for engine to process. But that doesn't mean u can try your 0-60 right after you start the car after 24 hours of sitting in garage.. I believe you gotta get the oil traveling before you floor it..

WOW, been really busy and had no time to check the forums. Thanks for so much great info. The car has been running GREAT. I searched for the "intake air thermosensor" for the 99 c43 but NOTHING comes up. Even my mercedes parts cannot find such a sensor.

Marcusf do you have any idea WHERE the sensor may be or where I can see a picture of it?

- I will save some money for the MAF
- I did install green air filters
- I installed crankshaft sensor.cam sensor
- Still need to try the redline to see what that will do
- Still need to flush my cooling system
- Still have to try the LOWER TEMP thermostat.

Anyone else suggest I try a LOWER TEMP thermostat before I do this?