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MBZ '87 300SDL, MBZ '85 380SL, RR '77 Silver Shadow II, MBZ '98 E300TD
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Front of car:

Data applies to post 1980 cars through 1985. Procedure differs somewhat with KE Jetronic cars in a few minor areas. Minor differences with European cars include deletion of frequency valve and minor differences in number and location of fuel dampers and some part numbers.

Parts and Supplies, Tools:

• Rubber vibration isolating mounting standoffs x4 for just the fuel distributor/air metering housing, x2 more for the the air filtering housing

• Rubber air guide boot and aluminum reinforcing rib

• New air filter so your work isn't stymied by a choked air intake

• New smog pump air filter that fits inside the air filter housing, if you have one

• Throttle butterfly housing paper gasket and non-hardening gasket sealer for same

• Full throttle/idle switch at throttle butterfly housing

• 10 mm wide by 150 mm band clamp for attaching air guide boot to throttle butterfly housing

• Frequency valve, if needed Bosch P/N: 0 280 150 306 and self-made rubber hose

• Cold start valve if condemned, Bosch P/N: 0 280 170 403 w/MBZ paper gasket

• Various fuel rated hoses fuel vapor purge canister and frequency valves

• Air breather hoses and associated injector holders and O-rings for same

• Carb and intake cleaning solvent and lots of it. 4x cans minimum or you will be guaranteed to run out.

• Five meters of 4 mm vacuum tube

• Half dozen 4 way, half dozen 3 way and a full dozen rubber vacuum elbows, with four of the elbows providing the 5 mm port on one end for the larger black vacuum tubes

• Anti-seize paste for bolts so you can get things apart again someday

• rubber-safe lubricants - rubber grease, Balisol (German gun-oil; wood, plastic and rubber safe)

• 303 Rubber protection, to give the rubber a bit extra protection

• Rebuilt fuel distributor if condemned. Insist on CIS Flowtech by name for rebuilt units. Bosch P/N interchanges for 380SL, 500SEC/SEL: Fuel distro 0 438 100 087/438 100 088. The Euro cars use a very similar part (without the fittings for the freq valve) P/N: 0 438 100 111/0438 100 112

• Bosch injectors P/N: 0 437 502 047, works for 3.8/5.0l applications 1980 up to 1985 US/Euro

• Warm up reg if condemned 0 438 140 155/0 438 140 156

• Fitted fuel return line from fuel distributor to steel line running back to tank (after-market)

• Fitted fuel line from fuel pump assembly to fuel cooler on large AC coolant house (MBZ)

• Fitted fuel line from fuel cooler at large AC coolant hose to fuel distributor head (MBZ)

• Vacuum one-way valves (the blue/black type 3 mm openings), six total in engine compartment, buy extra for doors, right side of trunk

• Assorted stainless steel hose clamps to replace the spring clamps at the charcoal fuel vapor canister

• Three way vacuum one way valve to control purge from charcoal canister

• Plastic injector line separators for routing the fuel lines neatly

Fuel Distributor, Air Distribution and Fuel Injector Procedure:

1.Label or mark the fuel lines by injector/cylinder number with tape

2.Remove fuel lines, start with cold start injector, catch all fuel with rag

3.Remove the plastic line organizing clips, if broken/brittle replace. Replacements are around $35.00 from dealer

4.Proceed to the left hand bank of injectors, which are more easily accessed than the right

5.Unbolt the allen-head bolts on the left hank bank's fuel injector flanges and collect the bolts and washers. Withdraw the injectors with seals

6.If left hand air distributor hose hard, remove from the top of the four fuel injector holders of the bank and discard

7.With the air distribution hoses on left bank removed in previous step, pull straight up on each the fuel injector. If you used penetrating oil, the injector will usually come out with the seal still attached to the injector body, the fuel injector holder will remain down in the fuel injector bore with the O-ring seal

8.Unscrew all fuel lines from the top of the fuel distributor with 14 mm spanner and set the left bank lines to the side

9.Unbolt the fuel dampers and frequency valve (if applicable) from the rear and right side of the fuel distributor/air metering housing assembly

10.Roll the loose assembly of lines, frequency valve and damper over to clear it away from the injectors

11.Remove the main air distribution feed on the right bank that drives the air distribution hoses to the injector holders

12.Clean off the injector flanges with solvent oil and steel wool to clean off corrosion. Clean off the bolts and apply anti-seize to the threads, then screw the bolts with washers in without the flanges

13.If the fuel injector holder and it's O-ring are still in the bore, use a pair of vice grips or needle nose pliers and grab the edge and withdraw. The O-ring may or may not come out with the holder

14.If O-ring still in bore, use a pick to remove it to prevent risking dropping the seal into the intake runner leading to the valve

15.Drop a light oil or alcohol moistened cotton ball into the injector bore and clean it out

16.Use a 10 mm socket and remove the 4 bolts securing the top of the fuel distributor/air flow metering housing from the top of the air intake manifold

17.Use 14 mm and 17 mm box end spanners to loosen the fuel line nuts of the return and damper in/out line

18.Use a ratchet and extension with a 8 mm socket or a long slotted screwdriver counter clockwise to loosen the band clamp of rubber air guide boot attached to throttle butterfly housing

19.With all nuts removed from the fuel distributor/air metering housing assembly and all lines and the band clamp loosened, pull straight up from the front of the assembly to dislodge

20.Once freed, set the fuel distributor and air metering housing assembly aside on the bench.

21.Replace the four rubber standoffs for the fuel distributor/air flow housing and the pair for the air filtering housing. A set of vice grips works for removal and if the jaws are taped up. Remember to hold the nut, it's not welded on

22.Many of the vacuum lines or the associated elbows, three and four way connectors will be brittle. Replace one line at a time as you start loosening fuel injector lines and so on

23.The vapor hoses leading to the charcoal canister should be replaced if cracked, ditto for spring clamps and three-way plastic purge valve

24.Three fitted fuel hoses with 17 mm nuts will likely need to be replaced, including the return line, feed line to fuel cooling jacket feed line from fuel cooling jacket to fuel distributor

25.As a mater of principle, replace all vacuum lines, connectors and so on that are hard to access when fuel/air metering housing are installed:

i.Vacuum lines: Replace one at a time with their rubber elbows/connectors. New vacuum hose is clear, no color stripes to guide you.

ii.Rubber elbow connector to the idle compensating valve takes some heat and is in the presence of fuel vapor, replace.

iii.The rubber hoses of the air distribution system on each bank that connects to the fuel injector holders should be pulled off and replaced

26.Slacken up the electrical connection (black insulated wire) for the idle/full throttle switch from the right/passenger side of the engine compartment which routes to the the throttle valve housing

27.Unbolt the allen-head panhead screws at each corner of the throttle butterfly housing - Use magnetic tools!

28.Use a slotted screwdriver or similar tool to gently lever off the rubber elbows holding the vacuum lines (one thick, one thin) off the the vacuum nipples near the full throttle/idle switch

29.Unbolt the spring hook that attaches to the post on the throttle butterfly lever above the throttle valve housing. Hold spring while unbolting to keep parts from being pulled down into the intake manifold

30.Remove the spring and spring hook, screw the retaining screw back in, keeping screw threads clean

31.Set the spring and spring hook aside, in a bag, etc. to make sure they are not lost

32.You can either detach the throttle linkage, or attempt to work around it - I chose to work around it

33.Pull straight up and remove the throttle valve housing and put flat on top of the intake manifold (taking care not to bend the throttle rods or twist it too far)

34.Use a razor blade and scrape off the impregnated paper gasket on the bottom of the throttle valve housing

35.Do the same for the bottom of the throttle valve housing at the top of the intake manifold, scraping off the gasket material and gasket sealant with a razor.

36.Remove old full throttle/idle switch from throttle valve housing via the two machine screws

37.Install new full throttle/idle switch to throttle valve housing

38.Attach two new rubber vacuum elbows, one for standard 4mm, the other for 5mm adapting to the larger black vacuum hose running to the right bank

39.It does not matter which line is top or bottom, both are ported to the same source in the throttle valve housing.

40.Use a quality non-hardening gasket sealer to the gasket mating surfaces and apply

41.Reinstall throttle valve housing onto the gasket and insert the four allen-head bolts into each corner, cinching down with increasing torque in small increments onto each allen-head screw to equalize pressure

42.Use a damp towel to remove excess sealant from the inside of the the throttle valve housing

43.Attach vacuum lines and insure elbows are well seated on the vacuum nipples of the throttle valve housing

44.Use a needle-nose pliers to attach the throttle butterfly spring from the butterfly's slotted peg and stretch the spring to the spring hook on the top of the intake manifold

45.Re-install the fuel distributor and air flow metering housing assembly onto the top of the air intake manifold using the 4x 10 mm nuts. Attach the two fuel dampers, re-attach the frequency valve holder's bolts to secure to the assembly

46. If the rubber line extending from the frequency valve is dry/cracking and/or the frequency valve had been condemned during a duty cycle diagnostic check , replace the frequency valve prior to re-attaching it's holder to the assembly

47.Attach all fuel lines in their designated positions and re-attach the fuel line routing clips between the various steel fuel lines. Ensure all line nuts are very snug, but do not over-tighten

48.Inspect rubber standoffs for air filter housing if the rubber is hard, brittle and cracking. A collapsed standoff/vibration mount will allow air to be sucked in without being filtered.

49.On the bench, unite fuel distributor head with air flow metering housing and air guide boot. Use suitable rubber grease or lubricant which will not attack the rubber o-ring of the fuel distributor. Gently insert the distributor, taking care not to use force lest the seal be damaged and cause vacuum leaks

50.Attach the fuel distributor/air metering housing to the throttle butterfly housing. Use a little rubber grease or rubber safe lubricate to push the rubber guide boot of the assembled fuel distributor/air flow metering housing

51.Tighten the band clamp around the air guide boot with an 8mm socket and extension on a ratchet

52.Re-attach the nuts of the fuel/air metering housing to the top of the new rubber standoffs

53.Replace the fitted fuel lines into and out of the fuel cooler (if applicable) and the return line to the tank if the rubber is hard or cracked

54.Use a suitable piece of hose and connect the fitted return line with the hose from the fuel cooler to fitted fuel distributor hose and apply hose clamps to secure each

55.Remove plastic rivets from the glove box liner top and bottom and remove

56.Remove the fuel pump relay

57.Prepare a length/diameter of wire sufficient to jumper the pin of the always hot 12v power from battery with the power pin to the fuel pump, you should add a 15 amp inline fuse for safety. You will be flushing the fuel system through the the fuel filter to protect the new fuel distributor

58.Jumper the position 30 (12v always hot) to position 87 (fuel pump) and the you will hear the fuel pump engage. Run this for several minutes. A 10 gallon quantity should do it, though you can add fuel cleaning additives to this. Barrymen B12 and Seafoam both make good cleaning product, the B12 is stronger and shouldn't be left in the tank when you are done. Larry from CIS Flowtech advises this procedure and the use of B12

59.Reconnect the fitted fuel lines to their correct positions at the fuel distributor input and fuel return output

60.Reconnect all injector lines to their correct positions and tighten until very snug

61.Reconnect electrical connectors to cold start injector and frequency valve (if applicable)

63.Start engine and look for fuel or air leaks in hoses and lines
 

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1985 380SL; 2004 E320; 2007 GL450
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BenzHacker, Excellent write-up. I have a spare Euro version of FD (part # 0438100111 ). Can I convert it for a 380SL?
 

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MBZ '87 300SDL, MBZ '85 380SL, RR '77 Silver Shadow II, MBZ '98 E300TD
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Discussion Starter #4
BenzHacker, Excellent write-up. I have a spare Euro version of FD (part # 0438100111 ). Can I convert it for a 380SL?
What by chance is wrong with the fuel distro on the car now? Is the *111 unit you mention having new (old stock), used or rebuilt? How many miles are on it and under what conditions was this unit stored? If you don't know, putting fuel distro in to replace one for a different application, while possible, may not be the correct approach and may require futzing with lines and removing parts from the fuel system (frequency valve, perhaps one damper pod). As far as I can tell, the fuel pressures are the same, but if this car ever finds it's way to another owner, the minor differences could mean the difference between passing a smog check or not.

Call Germanstar or AutohausAZ and inquire about making an exchange. Most likely they will give you somewhere between $50 and $100 for the core (do you still have one on the car?) and replace like for like with the correct part number for your 380SL, repleat with all the correct fittings and known good rebuilding practices (both of these folks use Larry Fletcher of CIS Flowtech for their rebuilds).

Usual disclaimer here: I have no affiliation with any of the vendors listed and no financial or other compensation for mentioning them. I mention them here because my results have been good with those I've mentioned and I have neither the time nor the patience for this sort of work, at least not with the consistency required.

Good luck.
 

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Fuel Injectors

This is a very useful write-up, I'm going to be doing this and also (I hope) removing the intake manifold so that I can install new rubber seals in between the two parts and clean out the 10 pounds of oil muck in the valley. Unfortunately, I've read that this is very treacherous, and requires PB blaster and a lot of luck to do without breaking a bolt, and breaking a bolt here is very, very tough. I've got all the big and little rubber parts, and I've replaced a few easy-to-get-to ones; it's shocking to see how hard and brittle the old rubber was. I don't think I have a vacuum leak, I have 20 very small vacuum leaks. Surprisingly, the vacuum tubing was actually in pretty good shape!

Anyway, today I tested 10 brass fuel injectors for the 380SL with an injector cleaner canister filled with kerosene and Seafoam. I only found one (two of them were new, and it wasn't EITHER of those) that exactly matched the specifications shown in the shop manual. One used one was jammed, and one used one sprayed a rope; the others took a little more pressure than you would expect to open. None actually leaked. A very experienced MB technician at a dealership told me that they routinely send back NEW injectors that don't work, and not many actually completely pass the tests as shown. Nonetheless, hopefully these are better than what I have after 136K miles.
 

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Tribute 500SEC AMG Widebody
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Excellent write up, thank you for sharing!
 

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MBZ '87 300SDL, MBZ '85 380SL, RR '77 Silver Shadow II, MBZ '98 E300TD
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Discussion Starter #7
This is a very useful write-up, I'm going to be doing this and also (I hope) removing the intake manifold so that I can install new rubber seals in between the two parts and clean out the 10 pounds of oil muck in the valley. Unfortunately, I've read that this is very treacherous, and requires PB blaster and a lot of luck to do without breaking a bolt, and breaking a bolt here is very, very tough. I've got all the big and little rubber parts, and I've replaced a few easy-to-get-to ones; it's shocking to see how hard and brittle the old rubber was. I don't think I have a vacuum leak, I have 20 very small vacuum leaks. Surprisingly, the vacuum tubing was actually in pretty good shape!

Anyway, today I tested 10 brass fuel injectors for the 380SL with an injector cleaner canister filled with kerosene and Seafoam. I only found one (two of them were new, and it wasn't EITHER of those) that exactly matched the specifications shown in the shop manual. One used one was jammed, and one used one sprayed a rope; the others took a little more pressure than you would expect to open. None actually leaked. A very experienced MB technician at a dealership told me that they routinely send back NEW injectors that don't work, and not many actually completely pass the tests as shown. Nonetheless, hopefully these are better than what I have after 136K miles.
You are ahead of the game if you are testing injectors to the spec. Its work I didn't cover but well worth it given how infrequently they are touched. The spec in the shop manual is very specific about spray pattern, opening pressure and volume of flow per minute. The added work will pay for itself down the road and may contribute to both a better running engine and longer lasting engine. I've seen spray patterns where it's clear that cylinder was not able to burn all of the fuel, much of it still quite liquid, from the poor misting pattern. Carbon buildup and oil washing together scored the cylinder bores and subsequent loss of compression.

Good luck.
 

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1985 380SL; 2004 E320; 2007 GL450
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What by chance is wrong with the fuel distro on the car now? Is the *111 unit you mention having new (old stock), used or rebuilt? How many miles are on it and under what conditions was this unit stored? If you don't know, putting fuel distro in to replace one for a different application, while possible, may not be the correct approach and may require futzing with lines and removing parts from the fuel system (frequency valve, perhaps one damper pod). As far as I can tell, the fuel pressures are the same, but if this car ever finds it's way to another owner, the minor differences could mean the difference between passing a smog check or not.

Call Germanstar or AutohausAZ and inquire about making an exchange. Most likely they will give you somewhere between $50 and $100 for the core (do you still have one on the car?) and replace like for like with the correct part number for your 380SL, repleat with all the correct fittings and known good rebuilding practices (both of these folks use Larry Fletcher of CIS Flowtech for their rebuilds).

Usual disclaimer here: I have no affiliation with any of the vendors listed and no financial or other compensation for mentioning them. I mention them here because my results have been good with those I've mentioned and I have neither the time nor the patience for this sort of work, at least not with the consistency required.

Good luck.
BenzHacker, understand what you said. However, I am an DIYer and would like to try things. I would like to re-build FD myself. And the spare FD I have is something I can start trying. One more question for you: for the frequency valve port that the *111 version deleted, does it have system fuel pressure? If it does, can I just put a adapter shown in the picture into the fuel port of the *111 version and get a port needed for the frequency valve for the US version 380SL?
 

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Discussion Starter #9
BenzHacker, understand what you said. However, I am an DIYer and would like to try things. I would like to re-build FD myself. And the spare FD I have is something I can start trying. One more question for you: for the frequency valve port that the *111 version deleted, does it have system fuel pressure? If it does, can I just put a adapter shown in the picture into the fuel port of the *111 version and get a port needed for the frequency valve for the US version 380SL?
You can obtain the rebuild kits from most Bosch resellers using the FD's part number to get the correct diaphragms and fiddley bits. I'm not sure I understand the question regarding the FD's port layout in relation to system vs. control pressure. As far as I know, the only difference is the two ports missing from the right hand side (seen from in front of car) of the fuel distributor. If you have a US 380SL, you will have an ECU, a frequency valve and an O2 sensor, precats and a large main cat/resonator. In the second case, you definitely have K Jetronic with Lambda (the O2 sensor is also called a "lambda sensor").

The added electronic control imparts limited closed loop capability to an otherwise totally mechanical system and permitted meeting or exceeding US Federal EPA and California ARB requirements. If you are not in a location with emissions inspection, you may get by. The frequency valve is critical to the operation of that enhanced emissions focused system, it will in fact run without it and that's exactly what happens when the O2 sensors stop sending signal (they tend to die at 30K miles) or the frequency valve is unplugged.

Good luck.
 

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1985 380SL; 2004 E320; 2007 GL450
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You can obtain the rebuild kits from most Bosch resellers using the FD's part number to get the correct diaphragms and fiddley bits. I'm not sure I understand the question regarding the FD's port layout in relation to system vs. control pressure. As far as I know, the only difference is the two ports missing from the right hand side (seen from in front of car) of the fuel distributor. If you have a US 380SL, you will have an ECU, a frequency valve and an O2 sensor, precats and a large main cat/resonator. In the second case, you definitely have K Jetronic with Lambda (the O2 sensor is also called a "lambda sensor").

The added electronic control imparts limited closed loop capability to an otherwise totally mechanical system and permitted meeting or exceeding US Federal EPA and California ARB requirements. If you are not in a location with emissions inspection, you may get by. The frequency valve is critical to the operation of that enhanced emissions focused system, it will in fact run without it and that's exactly what happens when the O2 sensors stop sending signal (they tend to die at 30K miles) or the frequency valve is unplugged.

Good luck.
BenzHacker, Thanks for your quick response that fills with useful info. You are a scholar and a gentleman. I was not clear regarding system pressure for the frequency valve. So I attach two pictures this time. The first picture is the FD for my US 380SL. The yellow circle is the port that is not in the Euro version of the FD (in the second picture). I am wondering if the port in yellow circle has system pressure.
 

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Outstanding Contributor , Bob's Your Uncle!
-----'83 280 SL----- 5 speed....The PIG
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I'll be honest with you.
I didn't read it............it's too early and there's no pictures to amuse me.

So, I am saving this write up for that moment in the future that I will need it.

Thanks, great efforts are appreciated.
 
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