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Discussion Starter #42
I’m also wondering where on earth I would find the wiring schematics for a 1987 Mercedes caret limo! It’s a real shot in the dark, but someone must know! The fuses and wiring on the RHS of the rear trunk panel is absolutely overwhelming!
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1999 500SL, 1988 SEC
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I would be remiss on not letting youknow that all the old flexible fuel lines are a disaster waiting to happen. If you have not done them I suggest you do. You seem capable of doing them yourself so its really cheap. There are tons of posts on this. Your car is stunning and some inside pictures later please
 

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Discussion Starter #45
Stutz, I’ve already replaced any fuel lines that were cracked, or seemed weathered. Now That I’ve got the car mechanically working, I’m working on a couple little things, like installing a new TV, and getting the window between the driver cabin and passengers working. Other than that car seems legitimately mint! I’ll be posting photos of the car polished up soon!
 

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Discussion Starter #46
I’m also wondering where on earth I would find the wiring schematics for a 1987 Mercedes caret limo! It’s a real shot in the dark, but someone must know! The fuses and wiring on the RHS of the rear trunk panel is absolutely overwhelming! View attachment 2626735
Stutz, I’ve already replaced any fuel lines that were cracked, or seemed weathered. Now That I’ve got the car mechanically working, I’m working on a couple little things, like installing a new TV, and getting the window between the driver cabin and passengers working. Other than that car seems legitimately mint! I’ll be posting photos of the car polished up soon!
Does any else with a 560 have electrical components in the trunk like this? Or is this a limo thing?
 

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Discussion Starter #49
On the highway when your travelling about 70-80 KM/hr I can’t seem to get any kickdown to go faster. I noticed an arrangement of fuel pump relays in the trunk, I noticed one said “kickdown” on it, so I exchanged it, and the car wouldn’t even start. I crossed the terminals 7 and 8, it was a little better and accelerated up to 80 a little faster, but wouldn’t allow me to go any faster. Almost like it wanted more fuel, but just couldn’t get it! Any suggestions? It idles and runs very smoothly, acceleration good up to about 40kms, then sluggish until max speed at 80. On step at a time I guess,,,,,going to start back at square one testing the fuel pressure,,,,
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Discussion Starter #50
I just discovered a few interesting items. The fuel pumps that were “New Bosch fuel pumps” were actually cheap knockoffs! With “Bosche” written on them. There is a lot of you tube videos on what to look for. There will be comparison photos once my new pumps arrive! I also went looking for that tiny fuel filter up at the end of the fuel line, by the fuel distribution centre, and discovered it was plugged solid, see attached photo. I also read that a fuel strainer from a diesel tank has a different screen on it than a gas tank, not sure if this is true, but hoping someone on this website would know? I’ll get this car to 100 mph yet!
 

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1986/1990 W126
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Ha, Bosch with an E 😂

I wouldn't trust those. Bet you're glad you checked that screen too. I bet that's it.

Does the car kickdown? Kickdown is managed via the fuel pump relay. When I got my SEC it shifted down as necessary but no actual kickdown. Changed the fuel pump relay and it was night and day. A whole lot more fun 😁
 

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Discussion Starter #53
There is absolutely no kickdown, actually the opposite of kickdown, completely bogs out and almost stalls, “Bogdown”! Have to feather the fuel very carefully. I’m getting there, the more I learn about this car, the more I’m intrigued by the engineering! The FPR that I have with “Kickdown” on it, won’t even start the car! There was 4 or 5 FPR’s in the trunk when I got the car.
 

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1991 560sec. 1991 560sel 1969 280SL
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Get someone to look up the correct part number for your particular model and install that FPR. There are differences in model years.
 

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Discussion Starter #55
Well folks, back to the drawing board,,,, new fuel pumps, filters, fuel strainer, fuel pump filter, all new hoses, clamps, tank etc. I installed new injectors and changed the spark plugs. Same 2k RPM bog!!! Cleaned all the injection lines and all the tiny little fuel filters in the K-Techtronic system, I’m open to any and all suggestions, I’m getting ready to throw in the towel! See pictures and please don’t hesitate to help out, maybe I’m missing something simple!
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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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There is absolutely no kickdown, actually the opposite of kickdown, completely bogs out and almost stalls, “Bogdown”! Have to feather the fuel very carefully. I’m getting there, the more I learn about this car, the more I’m intrigued by the engineering! The FPR that I have with “Kickdown” on it, won’t even start the car! There was 4 or 5 FPR’s in the trunk when I got the car.
Hey J.P,

This is a fascinating saga you unfold for us here.. Great images.. terrific!

Fuel Pump Relay notes for you.

My'87 560SEC calls for and had the A0035450105 relay which would, if starting in first & foot to the floor would cut off the fuel pumps at 6,000 instead of an upshift to 2nd.

My '91 500SEC Euro came with the A0035452505 relay, which repaired last year, works fine and cures the upshift issue in the other car too.

There are a ton of aftermarket A0035452505 relays available these days and I'm pretty sure most of the bunch are manufactured in Asia, rebranded, and resold under different names.
All of the reproductions I've seen do NOT carry the Mercedes logo before the part number.

There is one reproduction FPR thats been around for as much as 10 years now, and made in Germany by a company KAE or KAELER & currently it retails for around $80 give or take..

I have purchased & used the KAELER one with good results and also unwittingly bought an Asian A0035452505 knockoff which also worked well for the week or so that I used it a year ago.
I resoldered two cracked solder joints in the original and reinstalled it.

You might have very good luck with the innards of your x.x.x.x. 52505 relay.

Good luck

M

The first pic is for the '87 USA 560SEC, the 2nd is for the '91 Euro.


Screen Shot 2020-06-30 at 5.59.14 AM.png Screen Shot 2020-06-30 at 6.04.32 AM.png
 

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Discussion Starter #58
Weird question, If I bypass the FPR with crossing 7 and 8, would this problem still exist if a “correct” Fuel Pump Relay was installed? It has the same bog at 2000rmp with the bypass installed on 7 and 8. You would think with the fuel pumps on full time, it would be able to rev past 2k RPM!
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My experience with this kind of thing in my MB, I’d expect if the fuel pump relay were the issue it would disappear with that jump.

If this were me and my car, with all you’ve done, a bog down at 2000 rpm, I’d look at the EHA. And air flap and the tower. But, given all the crap you had in your system, it wouldn’t surprise me if the EHA is toast. The air flap and tower (referenced earlier as why there’s that hole in your air intake) basically control idle. The EHA basically controls acceleration.
 
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