1980 450SL - Help with installing fuel distributor - pics attached

[supercanuck]

Good day!

I have a 1980 450SL that apparently needs a new fuel distributor. I found an old distributor that I was told would work as a replacement, but when I went to install it, I noticed a few minor, but prohibitive, differences.

I have marked and labeled the differences in the attached photo and noted them below. Can somebody please tell me if there is a work around considering these differences, or am I just SOL with this particular piece?

1. The old distributor has an input that is not on the ‘new’ one.
2. There is an electrical connection on the ‘new’ one that is not on the old one
3. There is an adjustment nut on the top of the ‘new’ one that is not on the old one.
4. The vacuum input on the old one is blocked, but not on the ‘new’ one
5. There is a springy part on the old one that is not on the ‘new’ one

Sorry I can’t be more descriptive with the parts (obviously I’m a newbie at this), but is there anything I can do with the ‘new’ one to make it work with my car?

Thanks!!!

[Nascar Fan]

Totally different. You have lambda control on an 80. That is the lines that you are missing on the old one. You have a CPU under the pass side footboard that is attached to an O2 sensor that control the freq. valve that is under the fuel lines on the driver side. All this adjust the lambda to 1 or AFR to 14.7. If you wanted to **** can the lambda system you could maybe make it work, but with extra cost of changing out lots of other stuff like the WUR to match the new FD. Cheaper to buy the correct FD and get the lambda system working right.
I am chasing a problem with my O2 sensor on my 80 also.

[supercanuck]

Damn. But thanks!

Where would you recommend tracking down a replacement FD? Affordably

[Nascar Fan]

Germanstar has pretty good price. What is it that makes you sure thats your problem? Those FD get blamed for lots of other bad parts.

[Deltacom]

The FD for your car OEM is 000074043 and the Bosch number is 0 438 100 041.

I agree with Nascar Fan that the FD is always the fall guy. How have you established the problem lies with the FD?.

In any case, there a few of those FDs on ebay

[Lexxani]

you know all you really haveto do is swap out the actual distributor (the octogon piece that the hardlines attach to). That piece has the diaphrams inside of it. If you just swap that one part (remove the three torx screws that hold it down) you wont have to mess with the differences with the throttle body, thus not having any issues with your lambda sensor.

my appoligies with forgeting about the '80 addition of the O2 sensor. That FD is from a '78.

[supercanuck]

Can the solution be as simple as that? Just swamping the distributor out with the throttle body? Assuming I do that, everything else should work as-is?

As for the issues I had had beforehand that led to the FD as the culprit, it's all laid out in this thread: 1980 450SL - Mechanic says I need new fuel distributor - advice appreciated

Thanks!!

[Nascar Fan]

Can the solution be as simple as that?

No. Where are you going to connect your freq. valve? You are mixing two different type systems. As I said before, if you abandon your lambda computerized system you might get it working. There are ports on a 1980 and later FD for the freq. valve that are not on the FD you want to install.

[supercanuck]

Lexxani -

Do you have another FD that you can get ahold of that will fit the 1980? Or anyone else, for that matter?

Is anyone interested in a swap for the one I have?

Thanks!!

[Lexxani]

next week I'll go to the local yard where I get most of my parts from and hunt for an '80.

if this were a diesel we'd have it sorted out by now, parts for the old 617 are so plentyful down here in orlando.

does anyone know if one from a 380 or 560 would interchange? I can almost bet there is a 380 one to be had.

We are at the point where the 450's are becoming rather rare, seemingly.

[Richard Wooldridge]

After reading the entire two threads, my comments are that I believe he has a leaky injector on the #8 cylinder, and the WUR has lost it's spring tension, which causes the car to run rich. I have a '79, and when I first got it, it was running quite rich - excellent power, but terrible mileage. I took the wur apart and adjusted it a bit so as to have more spring tension against the diaghram, which made it run leaner and better. You really need a pressure gauge to accomplish this. Checking the pressure tells the whole story. And, if only one cylinder is running rich, that HAS TO BE THE INJECTOR! (leaky injector, or broken spring, causing it to open at too low a pressure.) However, I'm a bit concerned that maybe there is really a water leak into the #8 cylinder, due to that white smoke. Running rich doesn't cause white smoke. White smoke comes from water, or brake fluid, or transmission fluid, but water is the usual culprit. Running rich causes black smoke! Look at the inside of the tailpipe - is it rusty, or black? If it's black it's running rich, if it's rusty it has a water leak. If you start the car after it's been run for awhile, then has sat for 1/2 hr or so, does it crank for awhile, and seem to be flooded? That's indicative of a leaky injector, or several.
As I say, these are my comments based on the ownership of two SL's and 45 years of backyard mechaniking.

[supercanuck]

Thanks Richard!

I am now separated from the car (I'm in IL and it's in TX), but the project may now have been transferred to my brother who is going to look after it on my behalf. I will definitely pass this info along and keep you posted on what we find out!