HELP! I just replaced my intake manifold (includes unplugging injectors, spark plugs, MAF, TB, etc). I fixed 2 loose injector connections and it still runs like this. One injector came out of the fuel rail and I had to lube the o-ring and reinstall it.

What can be the problem here? Can any of you tell by listening and watching? Thanks!

http://www.youtube.com/v/zhKqnB6LKio

 

My newest bet is a vacuum leak.... but how do you find it on our cars? it sounds like a whistle in the video

 

You can check for vacuum leaks by spraying electrical contact cleaner, brake cleaner, or use a bit of propane around the intake manifold mounting surface. If a leak is present you will hear the rpm increase. All the breather hoses are good? You can also spray vacuum lines and their mounting areas like above to see if there may be a leak there. Try not to spray directly at the air mass sensor, and try your best when spraying around it to not get it in the air mass. Best of luck and keep us posted.

 

definately a vacuum leak. just go over EVERYTHING once again. theres something loose somewhere.

 

does the car feel like its gonna shut off, because it doesnt quite sound like a vaccum leak it sounds like a knocking. but if it feel like it's gonna shut off then i'm pretty sure it is vaccum leak. check the hose that goes to the elbow connector betwwen the MAf and the throttle body, that one has a tendency of coming loose more than others. also since you removed the head chances are when you re-installed the hoses specially if they were old that they might cracked.

 

Thanks guys, I'll go over it again tonight. Pretty sure it's a leak bc it tries to stall. Can I do the test without the air filters?? Otherwise the airbox is in the way

 

Yea, its best done with the airbus off. Just spray around the manifold mounting areas, back around the maf (but not into/at it it will make ya think you found it but ya didn't). And spray where vacuum hoses are and where they connect to see if they are loose or split.

 

Yes you can, there are i think 4 hoses on the top of the valve covers 2 on each side my bet is on one of those. Good luck brother.

 

I just did valve covers and the two vacuum hoses on the drivers side were both hard and split when I pulled them off the barbs. Id start with those two. The large one connects below the MAF and if it's leaking, will throw the ecu into a tailspin.

 

This is not getting any prettier.

Tried the spray test and somewhere near the TB it calmed down. I'm deciding on whether it's the throttle body or if the open MAF just found a small amount of the spray.

And then it got worse. Something started smelling like smoke and the idle is lower than before now.

I posted this pic on the AMG side w/ no response. Can one of you with the 430 look and see if you have this same open spot?? Drivers side, just in front of the intake manifold. Thanks! https://mbworld.org/forums/4282734-post5.html

 

Yea thats there on mine. If the idle changed in TB area, then it may be a cracked/loose breather hose in that area. Poor TB gasket seal? Is the airmass pushed all the way down into the elbow? Is the elbow securely on the TB?

 

i say leave it , sounds like u have a sick cam shaft.... try looking at the o ring that seals the plastic line going to the brake booster. they tend to harden up from the heat.

 

I had my throttle body open up by couple of mm and port inside the manifold before. And I had the same problem. after spending a lot of time and testing with a local tuning shop. we found out that there are too much air mass going into the engine. The adjustment ECU trying to make is out of fuel injector's range. and the throttle position needs to be re calibrated also. Hope this help.

 

In the end, i put the stock one back on and have no issues. There must be a leak in the modified manifold solicone/rtv somewhere near the back (throttle body area)