Injector Pump

[Rolf]

At the end of the injector pump, towards the firewll, there is a connection. It has 2 wires coming from it. I have only one  wire connected. If I connect both wires, the car stalls. It runs fine with only one wire connected. What is this connection for? Please help. I have attached a photo. I hope it is helpful. Please help, thank you.





Rolf
1966 230SL Auto
1992 300D
1991 FLHS

Download Attachment: 100_0531.jpg
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[graphic66]

One wire should go to the starting aid relay and should be black and pink, the other wire should be brown and just go to a ground. You may just need to ground the one wire to get your mixture control on your injection pump to work correctly.

[glennard]

Rolf, Welcome to the wacky world of MB relays, solenoids, timers, etc. and fuel management.  Assuming your 230 has only one solenoid on the FI pump.   The solenoid should only be energized in Start(by the relay) as evidenced by the click of the coil, etc.  The solenoid moves the rack to enriched as evidenced by the movement of a 5mm(?) bolt you put in where you have removed the cap on the front of the pump(for test purpose).  You say that connecting the wire to the other solenoid screw stalls the car.  Sound like this powers the solenoid, i. e. enriching the mix and stalling. Sounds like the solenoid circuit is hot(which it should not be with engine having run for a while). Find out how your car's starting circuitry is wired. Dig, dig, dig with your VOM. These cars are victims of 'Shade tree' revisions by who knows.

[Rolf]

Thank you ...If it's a lil warmer tomorrow. I'll take a real good look. All I know now is both wires disappear through the firewall. If I connect the second wire right after I start the car, it stalls also.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[Cees Klumper]

So if this solenoid's only purpose is to aid in (cold) starting, and your car starts up allright (cold), then no need to wory about hooking up the solenoid? The later style pumps (e.g. mine) do not have any solenoids, yet the other (cold) start systems are the same, so I guess the engine can do without.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[glennard]

Thought all FI pumps had at least one, the 'Start' solenoid?

quote:Originally posted by cees klumper

So if this solenoid's only purpose is to aid in (cold) starting, and your car starts up allright (cold), then no need to wory about hooking up the solenoid? The later style pumps (e.g. mine) do not have any solenoids, yet the other (cold) start systems are the same, so I guess the engine can do without.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[Rolf]

When cold, it takes two trys to start the car. It will start on the first try, run for about  two seconds and die. On the second try it will keep running. When warm, it takes two or three tries. When it starts, it sounds like it starts on 1 cyclinder. then the the second, third, fourth and fifth kick in. After that it runs fine. The dwell, timing and plugs were checked and are set according to specs. It idles fine in gear, automatic. It doesn't miss on acceleration nor backfire when revved.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[ja17]

Hello Rolf,

Let's be sure your car has the original injection pump first. Can you let us know what the "R" number is on the metal label on the injection pump?

Joe Alexander
Blacklick, Ohio

[Rolf]

Hello Joe,

  The only number I found on a metal plate is PES6KL70/20P1 and under that number was 611 19400. There is a number on the piece, attached to the end of the injector pump, that has the 2 wire connection which is 0330101009. I did not see any "R" number.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[Cees Klumper]

Glennard - the 'cold start solenoid' we always talk about is located on the intake manifold, or at least that is my understanding. My FI pump does not have any solenoids on it, and I've seen many other ones that are the same. Then there are pumps with one, and pumps with two solenoids on them.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[glennard]

Cees, Two different solenoids.  CSV(cold start valve/solenoid) is indeed on the common intake manifold. It is controlled by the temp switch/timer.  The start solenoid on the FI pump throws the FI pump rack to full position when ignition switch is in start.  BUT, as 2nd, 3rd, 4th....... owner/mechanic(?) of MB FI engines, these puppies can be wired and piped any which way.   Perplexing Pagoda Paradox vs Perfect Pagoda Paragon
Still, never seen a FI pump w/o a start solenoid.  Take another look at yours.  May have been 'modified'.

\

quote:Originally posted by cees klumper

Glennard - the 'cold start solenoid' we always talk about is located on the intake manifold, or at least that is my understanding. My FI pump does not have any solenoids on it, and I've seen many other ones that are the same. Then there are pumps with one, and pumps with two solenoids on them.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[Rolf]

Glennard,

  So the start solenoid on my car may be bad since the car stalls when I connect it while it's running?

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[glennard]

No, No.   Wait, wait.    Need more test evidence.  Sounds like the solenoid moves with 12v on it, so that means the solenoid responds to 12v- hence, ok.  There is no telling what 'modifications/improvements/ fixes/quackery/etc has been done to these analog FI systems by 'well meaning' owners/mechanics.  First, you gotta know how its 's'posed tobe'.  Look at a wiring diagram and compare that with what you have.    From the little evidence presented, I'd say the relay picking up the solenoid is wired wrong or the relay contacts to the solenoid are in 'trouble'.  If my memory is correct, the 'Start' solenoid picks up while the ignition switch is in 'Start'.  This throws the FI pump rack to full enrichment until released to 'Run'.  Have to get out the BBB and other references to check. Over the years MB played with these systems, along with the owners/mechanics.  So caveat emptor.
    Back to your original question- if you connect the wires-that energizes the solenoid, moving the rack to full enrichment i. e. too much fuel and too little air-then engine stalls.  Same as disconnecting the fuel rod from the cross over arm and then moving the fuel arm to rich-stalls.   Yada, yada, yada

quote:Originally posted by Rolf

Glennard,

  So the start solenoid on my car may be bad since the car stalls when I connect it while it's running?

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

 

[Rolf]

I wasn't going to rush and just get a replacement without first sucking some more knowledge from the "Pagoda educated" people here.    I have to find a wiring diagram and then proceed with the search. What if I started by testing the wires going to the solenoid to see when/if they power up on starting and then power down when the car is running?


Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[glennard]

Sounds good.  Put the M5 bolt in the front end of the rack(after you take the cap off) to see if the solenoid moves the rack.

quote:Originally posted by Rolf

I wasn't going to rush and just get a replacement without first sucking some more knowledge from the "Pagoda educated" people here.    I have to find a wiring diagram and then proceed with the search. What if I started by testing the wires going to the solenoid to see when/if they power up on starting and then power down when the car is running?


Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[ja17]

Hello Rolf,

I suspect the "20P1" in your serial number is actually a "20R1" or "20R" pump which is correct for your car. This pump should have one enrichment solenoid.

The 230SL is the most confusing model with two possible variations and a third variation which is a factory modification of the first.

The first version for the 230SL is refered to "Version II" in the early BBB. At coolant tempatures below 45 deg. F , the starting valve on the engine intake is engaged the entire starting period (with starter) via. the "thermo switch sensor" and one of two relays (relay #2).

The injection pump starting solenoid is activated for only one second during starting at coolant temperatures above 5 deg. C. (this happens via the starter and the "thermo time switch" and relay #1). In addition at coolant temperatures under 5 deg. C., the injection pump solenoid is activated up to 17sec. max @ -20 C.

The second version on the 230SL,  is designated "Version III" in the BBB. In this version both the intake starting valve and the injection pump starting solenoid operate for only one second at coolant temperatures above 35deg. C. via the "thermo switch" the "time switch" and "relay".

In addition at coolant temperatures below 35deg C. both these starting devices operate for up to 17 seconds max. at -20deg. C.  

The third possibiliy for your car  is a factory approved modification has been made to  the early version of the 230SL. This conversion involves converting the early version to the later version by replacing the original 5 deg. C. thermo time switch with the later 35deg C. thermo time switch, detaching the thermo switch and switching some wires.

It is confusing! There are a couple other versions for the later W113 cars. Read the "Starting aid tour" for more details.

In any case, you can begin the process of checking the system by checking to see if one of those wiress are hot when the engine is running. If so you may have a faulty thermo time switch, thermo switch, time switch  or relay. Start by disconnecting the wires on the thermo time switch first. Then the relays to isolate the bad componant. I can attach photos or elaborate.

Glennard and Cees, the latest version US injection pumps did not have the enrichment solenoid. The US cars kept the fuel cut off solenoid as far as I know for emmission purposes. Possibly the Euro cars had no solenoids at all?



Joe Alexander
Blacklick, Ohio

[Rolf]

Joe,

  Thank you for the information. I shall peruse through the "Starting aid tour". I take it the BBB is the Big Blue Book. I have one although I think it is not complete. I could not find the group that refers to the injection pump. I will go through the book again, with a fine toothed comb. The Pagoda is new to me and it seems more involved than even my diesel. I will let you know if I find anything or if I have to pick brains again. Thank you also Cees and Glennard for your help.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[Rolf]

I disconnected the wires from the injection pump starting solenoid and connected test leads. I got 12 volts only when I started the car. While it was running, the needle stayed at zero. I guess my next step would be to test the injection pump starting solenoid. But, if it gets no power, why would the car stall if I connected the leads to it? I did check resistance, on the wires going to the injection pump starting solenoid, to ground and get zero on one lead and two and a half ohms on the other. Does this seem right?

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[ja17]

Hello Rolf,

Yes the wires to the solenoid should read 12 volts only when cranking the starter. Do these two wires come out of the same harness loom. Maybe these wres are reversed, not sure it would make any difference, the later cars only had one wire to the solenoid.

Joe Alexander
Blacklick, Ohio

[Rolf]

Hello Joe,

  Sorry about that, I was referring to the 12 volts when cranking the engine. When it started, the volts dropped to zero.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[ja17]

Hello Rolf,

Skip back to my previous post, I was editing when you posted. Seems we are on line at the same time.

Joe Alexander
Blacklick, Ohio

[ja17]

Hello Rolf,

My concern is that possibly your second wire may be for another connection. You may need to tell me what wire goes 12 volt positive or if they both do, test each separately and make sure one stays ground while the other goes 12 volt positive when cranking. Next we can figure out what configuration of starting aid is on your car.

If both the wires come out of the same wiring loom, they probably go to the same solenoid. If not they may go different places. Maybe you can get the color code of the wire for identification also?

Joe Alexander
Blacklick, Ohio

[Rolf]

Hello Joe,

 I tested each wire separately. One wire looks like a ground, I get nothing on the voltmeter, when cranking, and zero ohms for resistance. That's right to ground. The other wire, I get the twelve volts when cranking and it has 2.5 ohms, right to ground. One wire looks brown and the other looks pink. It is hard to tell the exact colors due to some schmutz on each wire. They are in the same jacket, which only has those two wires. I can remove some of the jacket and maybe get a better handle on the colors. I have no idea what or where the other connection would be. The wire that is not connected is about as long as the one that is connected.
Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[George Davis]

Fascinating problem, Rolf.

I don't think you should be getting 2.5 ohms resistance on the one wire, it should be infinite resistance (i.e., a completely open circuit).  I suspect the relay contacts are dirty or burned or not opening completely, allowing them to barely make contact when they are open, thus allowing a small flow of current which activates the solenoid.  OK, sure, this doesn't make much sense, but then again, neither do the symptoms .

If you can identify the relay, I'd suggest opening it up and cleaning the contacts and then reinstall and see what happens.

George Davis
'69 280 SL Euro manual

[Rolf]

Hello George,

That situation puzzled me also. I worked with solenoids and relays, a little, when I was employed at Generous Electric.  
These are the wires that go to the injection pump starting solenoid. When the ignition is off, I get no reading on the voltmeter at all. I only get a reading when the started is engaged. After engagement, the reading returns to zero. One thing I didn't do, and probably should have, is check the readings with both wires disconnected. I will do that tomorrow and see if there's a difference. This Pagoda engine is like a puzzle to me and I have to get all the pieces properly aligned.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS