I hope maybe one of the pros here have some input on what I am about to do. I have a old 1973 450SL and I'm not having too much success getting my D-jet injectors firing. I checked the relays and neither the fuel pump or the ecu seem to be working. The car runs if you hand feed gas to the intake and it ran fine last year and the pump runs fine with a jump. The engine is a 95. I can tell because it says 95 in yellow junkyard paint on the valve cover. The whole D-jet system looks old crusty and brittle. Any way, the engine smokes a little and I have a 76 450SLC CIS engine form an old parts car sitting in the corner that runs fine. I was wondering if I could swap the engines. This would mean that I would disable the D-jet and run the CIS. Is there anyone out there that could help me with this swap. Maybe brain storm what things I am missing and would need to make provisions for?

If your D-jet has good compression and oil pressure,
It is easier to make the injection system on the car to be perfect.
Than swap it into a frankenbenz

I cannot imagine it needing that much work.

CIS is a mechanical set up so all you should need is the fuel pump, correct fuel , vacuum lines and linkages.

There is at least one person on my Mercedes W108 yahoo group that is putting a 560SEL engine in a W108 which had d-jet.

__________________
With best regards

Al

Yea, I was thinking off the top of my head that that might be all I need. Anybody else got any input????

Hate to go off-topic, but isn't there a relay that powers the ECU so it can in turn supply ground to the fuel pump relay? Did you check that?

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

It sounds like your D-Jet is not getting power. There is a seperate small wire that connects to the (+) on your battery to power the D-jet system. Make sure it's not corroded and it is connected to the system on the other end, still getting power!

If you do want to swap, easiest way w/o an engine lift is to swap the heads (with cams), intake manifold and everything bolted to it, and the fuel pump.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

I'd Megasquirt it before I'd swap in an old CIS system which hasn't run in who knows how long. Do you really want to have to deal with the 30+ year old fuel distributor, WUR, cold start injector AND most likely the wiring problem you already have?

The MS will control the Djet injectors and you already have an O2 sensor. A CLT sensor, a TPS and a intake air sensor is all you'll need.

The "smoking" part of the equation will probably be the decider.

That's all good info but I don't want the old engine cuz it smokes and I don't want the d-jet cuz it is corroded (ECM) and rhe injector and points harnes is so brittle and cracked that I just cant trust it anymore. The mega squirt sounds good but I am trying to get it to run decent without a lot of fuss and cost (I got alot of other things that need more attension on it). Any other ideas as to what I would need to look out for? I would probably need to fix whatever is screwed up with the fuel pump relay. I will check that wire to the battery (I think I hooked it back up when I put the new batt in). Any other problems you can think of doin the D-jet to CIS swap?

Without seeming to sound like a smart ass, I'm going to give you some advice.

Get a different car.

I'm serious. You are trying to shortcut your way into the SL and it ain't gonna happen.

No No No No NO!, if you can keep this car running with duck tape and chicken wire, keep on trucking. Most of these cars that we now admire were scrapped when they were worth pennies because people were not interested in finding innovative ways to fix them.

If you're having ECU or Map sensor issues, hit my up. I have more spares then you can shake a stick at.

__________________
With best regards

Al

FWIW, the D-Jet 4.5 at 8.8:1 is a perky, happily-revving engine with about 230 hp @ the crank. The 8.0:1 is not too bad at 190-200 HP depending on cams.

The CIS 4.5 is a slow, heavy hunk that eats more gas and spits out 170 wheezing HP.

It's up to you, but the smoke is probably (almost surely) just valve stems and/or seals, an easy fix; I'd rebuild the harness myself and pick up an ECU and MAP if they were both shot even!

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

The car is a junker. I spent last years vacation replacing a totally rotted out trunk and the trunk lid and the rag top lid. I am 1/2 way through repainting the black interior which is mostly sitting in the corner of the shop. I had the rusty old spoked rims sand blasted and painted them silver like the old MGB rims. All the other rust is accepable in a structural sense. I have 4 of these cars and this was the worst. I have a 96 500sl, a 85 380sl, a 73 450slc, a 76 450slc parts car and this repainted rusty no folding top 73 450sl. I will get it back in shape as a non numbers matching top down no smoking reliable roadster without buying even 1 gasket or valve seal. I'm a path of least resistance and money kinda guy and all my free change goes to pay off my 96 500sl. Lots a labor is OK but spending is not. The engine has to come out to clean and paint the compartment anyway. Ya know, not every 450sl is worth total restoration. I will leave that for my sweet 380sl. That being said, It is true that it would be easier to fix the D-jet and valve seals but I am dumping the A/C, the stock exhaust and seats for flomaster and a set of late model buckets that lay down further since I am 6'2" and never fit in the stock seats. I just wanted some input as to whether this swap was do-able and things to look out for.

Ahhhh! THAT'S a different kettle of fish! You know what you're doing. I was under the impression you were trying to make it a dependable car for transportation. My mistake and I take back my last post.

Yah, the swap is pretty straight forward and you shouldn't have any problem with the exception of maybe having the exhaust header pipes custom made. I think you might have a couple of extra brackets on the SLC block but they're easily removed.

I've got the CIS stuff from my 500SEL (I'm Megasquirting the car) if you want. The distributor is probably crap but you can have the injectors, lines, WUR and the other stuff.