My New Euro Lights Are Causing My 300SD To Be Slow (Time For a K&N Air Intake?)
 

I have a 1979 W116 300SD. I don't care for the USA style headlights so I put together a nice set of European headlights from the several sets that I have. I was so excited to install them and they look so good!

When I installed them I had to remove a black plastic "shield". Right after I installed them my car began running sluggish. Normally it drives like a rocket but now I floor it and it barely moves. It feels like it is dragging an anchor behind it!

So today I checked the fuel prefilter (which looked clean and clear) then I replaced the main fuel filter thinking maybe that was the cause of lack of power. The fuel was dark, so I am glad I replaced the filter.

Right when I was bleeding the fuel lines the starter started spinning without turning the ring gear. This would be the third time it has gone out this year. No more CSK rebuilt starters, even if they are under warranty!

I ended up installing an old, dirty Bosch rebuild and after two different Schuck's auto stores and talking to the right people I got a refund for the starter instead of another warranty for a starter that will only last 2 months!

I got the car running again but it was still slow. Then I realized the reason for the poor performance was coincidental with the installation of the European headlights. On this car the air intake comes in behind the right headlight.

The USA headlights "float" and allow air to flow behind them into the air intake tube. The European headlights fit flush against the body and seal the area behind them (where the air intake is). When Euro headlights are installed they seal off the air intake area! No wonder the car seems slower and I am amazed it runs at all!

Now I am angry because I don't want to have to be stuck with putting the USA lights back on. I don't know what to do about fixing the air intake so it can breathe. I could install an aftermarket cone filter, but all that does is suck in hot air and debris. Maybe I could route a tube from the air cleaner to the front of the car.

This is frustrating. Who would have thought installing Euro headlights would affect the engine?

pull the hood release but dont open it up, that will give it more room and do a test drive to make sure that is the prob....

go around the block, you should know if that was the prob right away

k&n wont do anything if its choking before the air even gets to the filter

Nobody would have thought...........because it cannot happen. It's totally impossible for the type of intake to affect the performance of the vehicle at lower rpm's (below 3000 rpm), unless you managed to plug the intake in some fashion. If this occurred, there would be smoke pouring out the back of the vehicle.

The intake configuration could possibly affect the capability of breathing at maximum rpm's and power..........which would increase the acceleration times a bit..........but not noticeably unless you checked with a stopwatch.

You've drawn an erroneous conclusion. The problem is probably a disconnected boost line or something completely irrelevant to the Euro light installation.

What I'm wondering is where the engine is getting it's air supply from now. The Euro headlights are blocking the air intake. The air cleaner has a hose that goes from the air cleaner directly to the back of the headlights. The back of the headlights are sealed off entirely and there is apparently nowhere for air to enter except for one pinhole on top of the headlight sheet metal area. Right now it is practically causing a vacuum because the engine cannot breathe anymore!

I am guessing but this makes me think that the Euro cars must have a different air intake setup.

This guy has Euro lights and has routed the breather hose down somewhere unless that's the stock form...?

http://www.idunno.net/300sd/?C=D%3BO=D

http://www.idunno.net/300sd/engine2.jpg

I agree with Brian, you're dealing with two completely different issues.

There is no such thing as a Euro 300SD W116; they were available in North America only and all had USA lights.

If Euro lights are blocking the intake, how is the air supposed to get into the intake? The engine won't run well off a vacuum, which is pretty much what is happening. Those pictures showing the guy rerouting the intake hose is probably what I will have to do.

...........and you know this because.......??

...........where's the black smoke..........??

I'm just wondering where the engine is getting air from. It smokes at idle but when I pull the hose off it stops smoking.

I will take pictures to show you guys what I am talking about.

AFAIK no ECE W126s were in Turbo Diesel.

Is your engine compartment tightly sealed? Isn`t it open at the bottom?

when you open the hood and look down, can you see the ground?

You don`t have a vacuum, if you did, the hood and fenders could be sucked in, now that would be scary! :eek: :D :rolleyes: Just kidding:)

Charlie

Please take a closeup shot of the end of the intake.......right behind the new headlight.

I have Bosch euro lights on my W116 300SD and they did not affect the performance at all.