tery

I have 320 engine i enlarge the throttle boy from 68mm to 71mm. Put it back on car is not running smooth, sometimes can't even accel. What is the problem how can i fix it ?

mig888

Pictures would help tremendously - did you install this yourself and where did you have this done? Then we can all help you further (if it's not too much of a hassle to pull that throttle body out yourself).

flip

tery

i took it off myself and let a local machine shop bore it and made a new plate also. Install it back myself and now check engine light is on, rough idle at low rpm. car runs okay but check engine light is on. How can i fix this ? air fuel ratio ? i thought our ECU will reprogram itself. I jsut check the code its
P0104 ( Mass, Volume curcit intermitted ) anyone know what this means ?

pshek

Your mass air flow meter is supposed to measure a certain amount of intake air. You bored out the throttle body, so now the amount of air entering the intake manifold has changed, so your computer is throwing codes now. Unless you reprogram the ECU and tune it to the increased airflow, your engine won't run correctly, probably running too lean now. If your car is running lean, then potential damage may occur to the engine, like detonation.

Anybody else correct me if I'm wrong....

BTW, 3 mm is a lot of metal to grind away from the inside diameter of the throttle body.

Brian Felts

Go give up on it yet. Try to unplug the power to the ECM for about 10 minutes and give it a chance to reset. It will relearn the extra air coming in the motor and the MAF will be just fine. The problem is you are still running on the stock learned setting..........Just reset the ECM, they have an excellent ability to learn but give it about 20 minutes of idle and drive time.

Hey how much did it cost to do that job, I would like to do the same.


Brian Felts

mastermind

two possible reasons:
1) air mass sensor: the wiring got somehow damaged or disconnected, or the the hot film itself got damaged.
2) there's an air leak after the sensor

I suggest to closely inspect the assembly once more to exclude the obvious (disconnected wires, leaks). After that, the mechanic should check the voltage signal from the air mass sensor which may have to replaced (~$400).

tery

thanks everyone i try all those methods. engine still running werid and have check engine light. I order a new throttle body. at least i can drive this car.

tery

thanks everyone i try all those methods. engine still running werid and have check engine light. I order a new throttle body. at least i can drive this car.

OJwerks

very interested on the outcome on this as I too have a 320 engine and have been wanting to do this for quite some time now...... hope everything turns out fine and gains can actually be achieved!!

OJwerks

any updates???

aecasasus

Bump...Any Updates?

tery

not much, went to MB dealer check the code out. 3mm is too much. I have to use stock throttle body or remap my ECU to do new air/fuel ratio. Car runs very good on high rpm. but during low rpm or city driving check engine light will come on. and car jurk like crazy.

hubert

Here a fellow member has done it and no problems, also one of my friends enlarged it on his Jaguar V8 and he had no problems he gained 7HP to the wheels on this upgrade.
https://mbworld.org/forums/showthrea...light=throttle

mastermind

Hi

look at this posting - this guy seemed to have succeeded with a larger TB.

http://www.benzworld.org/forums/r170...=throttle+body

Cheers

vrus

From the look of the picture, it seems like you didnt leave enough room between the top and bottom of the butterfly and the wall of the throttlebody. The plate seems to be very close to the same diameter as the opening.

At idle, there has to be enough air passing by the plate to keep the car idling. You would have to remove the plate and grind the bottom and top a bit to expose more gap OR you can reduce the size of the plate by 1mm.. That should provide enough airflow.

Another trick that is used is people drill holes in the plate itself but I dont like that idea myself.

speedybenz

One last thing to look at is the diameter of the intake tubing connecting to the throotle body. If there is a big step it maybe cause lots of turbulance and drivability problems

Jeff

steve872

Send your throttle body to RVMorse Machine in Orange County. Talk to Roy first. Before I had my t/b I did a ton of research and got lucky when I found Roy. He knew how much he could take out. Almost 3mm. I drive a 2003 SLK230 which has different engine management system than your car. My ECU has had no problems with any of my mods. The t/b made my car run rough for about 10 minutes then smooted right out. Power increase was very noticable and I ran 2 dyno runs the next day and had a 4whp increase.

My stock t/b was 57MM and I had it bored out to 59.82. I still have not got around to having the lip on the plastic intake manifold sanded down to match the t/b. I am just going to buy a new intake and sand it down and then have a shop install it for me. What are you going to do with your bored out t/b. If it is of no use to you please email at steve872@hotmail.com. I may be interested.

From now on do not attempt to install parts that have been altered without having the original stock part right by your side. That is my way which may not work for some. It cost a lot of money to do it my way but I am assured of having that stock part ready to go right then and there.

OJwerks

tery, have you resolved this yet???? I havnt done anything on my own waiting for you to finish your project so I can get the full insight on it...lol.
Meenwhile, im searching on different places to get a good used throttle body and camshafts....

hubert

Just got my second throttle body, will be sending it out to Roy this week when i get it bac will let you guys know if i had any problems.

OJwerks

awsome!!!
I just baught a used one from Potomoc German Auto for $250.
Will wait and see how it goes with you guys before I decide well im getting this thin done

tery

hi i installed the stock one back on runs okay now. I try the method letting more air in when its at the close position. I file it down by starting from around .1mm to .5mm. Install it back on and let it run for a while if still no good keep filing it down a bit. It works but car still picking up check engine light. I went back to the MB dealer again for code checking. They said the ECU can only adjust its air fuel ratio to some %. My opeing is too big which is out of the % the ECU can. I am wondering if i bore it to 2mm it might work.
I even put the stock 68mm plate on with the 71mm body. Engine only last about 10sec and stall.

hubert

Damn i just got mine from them for $114 shipped to NY.

steve872

Hubert,

Did you tell Roy about the previous problems with the throttle body that you had with your car?

OJwerks

guys, so how did all this work out for you guys.... I still havnt done mine...got busy doing some other things and kind of neglected the project, but now that im free with some other stuff....i want to go back to doing this..... .

so anyone have the final specs on HOW much can you actually bore...or even better...A place that has done it for a 320-car and got it right?>???

Ghostrider

Hey tery,

How goes it with the throttle body? When you ported yours did you do the intake manifold also?

By the way, love the new setup, the fiske's are awesome.

-Ghost