also, installing headers will lean you out since it increases flow through the engine. i have seen supercharged cars go way lean after installing headers to the point of engine damage.

Is this engine damaged?

O yea forgot I got those changed as well , no help


try and flush that rail though, il take you 5 minutes , worth a try

Have engine on, put plastic bag around the rail to dump fuel into and push the nipple and let it squirt fuel out for a bit.

Also is your MAF Bosch original with matching part numbers?

IF it is you might try and get the MAF re-calibrated like I did

I removed the intake manifold today and one of the parts inside was loose and blocking the airflow in the manifold. I disassembled the manifold and glued all the parts together and re-installed it. I made sure I had no vacuum leaks or anything and installed the new 02 sensors....yet I still get +22 in my LTFT's after resetting them.

I also did a compression test and everything was fine.


I've checked everything guys, The maf is new and oem, the 02 sensors are new and oem as well, the plugs are new and the car still feels like a turd and it still runs lean.

Can anyone do a quick experiment? There is a black plastic actuator to the right of the secondary air injection pump. This valve is what actuates the flaps inside the intake manifold.

Can anyone remove their engine cover and see if this actuator moves by revving their car in park? I see it has a solenoid so I don't know if the car will activate it in park.

What exactly was loose? Any pics?

Maybe you need to contact the guy who signed the airbox and give him a call. He should lead you in the right direction.

It seems like you have checked everything.. Idk what to tell you..

No pics, but if you've seen one of these intake manifolds open, it was one of the runner sets that rest on top. The are kinda just placed there and apparently it worked it's way loose.

The car came with a renntech airbox so no signature on it...lol.

What's the fuel pressure?

I haven't actually connected a fuel pressure gauge because I don't have one, but if the car is running so lean that it has to add +22% fuel to be able to idle and drive part throttle, then the car would not even be able to supply enough fuel to make a combustion at WOT and it can and it even put down almost 300whp so the pump can't be the problem. I also removed it and it was super clean and have NEVER heard or read of a fuel pump actually going "slightly" bad. Either they run fin, or crap out all together.

If someone can give me a logical explanation as to how this could be an issue I will purchase a fuel pressure gauge and install it ( or just point me in the right direction to a really cheap one...lol ).

Swap the motor out and than put it on the dyno.

Excellent idea....lol.


I would honestly check the fuel pressure but I would hate myself if I purchase a $100+ gauge only to find out it's fine.

Can anyone please check this for me?

BTW- I bought a fuel pressure gauge. Will check tomorrow the pressure and see. What is the pressure suppose to read? In my E55 it reads 80ish psi.

According to this... http://www.benzworld.org/forums/r129...witchover.html the M113 service manual says the diagnostic check for the manifold solenoid is performed while stationary. From what I understand, it's supposed to occur at 3900 rpm...

Can you check yours?

Anyone know what the fuel pressure is?

Alright guys, I checked the fuel pressure at idle and it was 38psi. Is this normal for this car? My E55's pressure is 80psi but it's a different setup so I don't know what to think.

Thanks.

My C32, stock fuel system at idle 58 psi. i tested a friend E55K stock fuel from long time i remember 70Psi, i don't know how you get 80psi. but remember the C55 is N/A.

That is low, should be 50-60 psi.

My E55 says 80psi and a few people with E55's say that it is normal. The C55 is what surprised me. It would say 38psi and go down to 25-28psi when accelerated in park.

This would explain all the symptoms...sucks I had to wait to get pissed off enough to buy a fuel gauge just for this but it seems to have been worth it.

I need someone to be SURE it's low before buying a fuel pump...they are hella expensive...lol

BTW- which pump feeds the actual engine? Can I assume it's the driver's side pump?

It does sound low. If you are going to open up your pump, first check the filter. I think it is around $50-$70. Depending on the gas that you get, some formulations (more ethanol) cause crap from the tank to rise and clog up the filter.

I checked the tank and it was sterile clean...it looked brand new inside. I checked the pump and far as I could without breaking anything and it looked clean as well. C55's don't have separate filters either...to change the filter you have to change the pump...the $400 pump...ouch.

How can I find out what MB specs are for the fuel pressure? I've searched EVERYWHERE with no luck.

Fuel pressure should be 3.8 bar to 4.5 bar. 38 psi is way too low. My car holds a rock steady 4 bar at any RPM. Check for a good ground and power signal at the pump. I've seen the ground pin at the pump melt or the connector at the rear sam melt causing low voltage/current. Which will cause the pump to have a low output.

Thank you!

I checked voltage and had my friend turn the ignition on and it read exactly 12V. I had the pump unplugged to check so I couldn't turn the car ON but I guess having 12V off the battery is pretty good right?