Can't get air intake boot to seat - PeachParts Mercedes-Benz Forum

zhandax · #1 03-28-2010, 02:44 AM

Preliminaries: bought a 93 300SL which runs rich. Car smoked badly out the exhaust which smelled of gas. Installed a new water temperature sensor, car will now idle, but still blows a little black smoke. Removed the fuel distributor to try to clean it and notice that the part number is for a 300E, not an SL (expletives deleted).

Found an entire airflowmeter assembly complete with EHA, fuel pressure regulator and fuel distributor from a 92 300CE with correct part numbers on eBay. The body has the same part number as my old one (0438121082) but the fuel distributor has the correct part number (0438101044). Intake boot on bottom of unit has same part number as the old one (1041410090). Donor had 98k miles.

Today, I pulled the old AFM, replaced the injector holders, seals, and o-rings, replaced the intake hoses to the AFM and ICV, and tried to install the new AFM. After about an hour of trying, I still cannot get the intake boot on the bottom of the AFM to seat.

I bought the WIS for the car without thinking that I had installed Win7 on my two main systems. A few weeks ago, I spent at least 4 hours before I concluded that the WIS will not install on Win7 but since I reinstalled the AFM on my 300E when I reworked the head (although 6 or 7 years ago), decided to try it from memory. I don't remember this much hassle.

After giving up in front of an approaching storm and reflecting on what happened, it occurs to me it may work if I remove the intake butterfly, mount it on the bottom of the AFM, and then bolt the butterfly down. Is this the trick or is there something I am missing?

oldsinner111 · #2 03-29-2010, 02:46 PM

I used aluminum tape on my and others.Holds for years.

zhandax · #3 03-30-2010, 06:27 AM

This is a gasser. Has to pass emissions to get a tag. I need vacuum tight. In all fairness, by the time I got to this point, it was dark and I was holding a flashlight in my mouth to see. It may be more apparent in daylight. I just knew I would be done in two hours. Guess this will teach me to park it in the garage before I start.

oldsinner111 · #4 03-30-2010, 06:38 AM

I used it on my s320 gas.The tape is leak prooft,and sticks like super glue,I'm talking about the tape that is alminum.Not aluminum colored.Besides less air(leak thru boot should lean her).Less air over maf sensor.It can't dump more fuel with no air.
To pass emissions here a old trick,add 4 oz. acetone to each 10 gals. gas or diesel.
This raises combustion by 10 to 20%.Better mileage,power,and pass emissions.
Also the first oxy sensor controls rich or lean.I have cleaned them with carb. cleaner,and blow dry them.The'll last another 100,000.I did mine.

cliffmac · #5 03-30-2010, 06:47 PM

not easy, but it'll go back on.....

cliffmac · #6 03-30-2010, 06:53 PM

if you are talking about KE-5 CIS then I have replaced the fuel distributor on that engine....you simply have to work with the rubber valences to get them back on...tape is BAD!...the reason that it's so hard to properly replace air intake bellows and so forth is that they are incredibly important
to keep unwanted airflow out of the meterning system...tape is false economy

tinypanzer · #7 03-30-2010, 07:11 PM

Yeah, it's a pain but you can get it back on there. It's all about angle and patience. Perhaps a tiny amount of oil or light grease will help ease the lip over the flange.

zhandax · #8 03-31-2010, 06:48 AM

Yes, I would rather avoid the tape. One of the maintenance guys at work suggested WD40; won't attack the rubber and no silicone to foul the O2 sensor. I couldn't see a good way to force it with the flashlight-in the-mouth routine. Surely I will see something workable with enough light and a fresh start. I may try the acetone in the gas although the plan is for the the new AFM and a lambda adjustment to make it unnecessary.

oldsinner111 · #9 03-31-2010, 06:50 AM

In my case the PO broke the latch close to air box for filter.

zhandax · #10 03-31-2010, 07:10 AM

That would be quite workable but trying to get tape to stick to the steep curve of the bottom AFM rubber sounds like a full time battle.

oldsinner111 · #11 03-31-2010, 07:48 AM

Its the part where latch attached.I'll scout around junkyards.Or make a KanN cold air.

zhandax · #12 04-05-2010, 02:22 AM

Finally got it. I took a bamboo stir-fry stick from the kitchen, about 2 in wide x 1/4 inch thick, pressed down the AFM plate, and pushed the boot down over the butterfly flange. Since the plate will not allow access to the engine side of the boot, I squeezed on the boot and got it within a couple of mm's of the bottom of the flange. Finished plumbing in the injector lines, started it up, drove it a couple of miles, and no more gas smell out the exhaust. Hopefully it will pass emissions and I can get a tag, finally.