Motor run one second only

[n/a]

My 230 Sl is now fully restorated. I tried to start engine yesterday the first time. Motor started well but always stopped after one second.
It seems that motor don't get enough fuel.
Injection pump has not restorated but it worked very well before restoration work. Fuel pump works ok.

Any good ideas how to start search reason for my problem ?

[ja17]

Hello,
The electric fuel pump should be checked to be functioning and delivering fuel first.
The engine probably started and ran for one second on the starting solenoid circuit. This cold start device gives a momentary squirt of fuel in the intake manifold during starting. The injection system itself will take many revolutions to prime all those long empty fuel injection lines going to the injectors. It may be a good idea to loosen at least one injector line at a injector so you can see when the fuel reaches the fuel injectors. Removal of all the spark plugs during this process will enable the engine to crank easily during prime-up. Diconnect the coil wire at the coil so any fuel coming from the spark plug holes does not ignite! Crank engine with full with accelerator down. When fuel is visible from the loose injector line, tighten everything up and attach the coil wire. The engine should start and run. Good luck.



Joe Alexander
Blacklick, Ohio

[n/a]

Thanks Joe, I will test your idea tonight. It's 6 years already when injection pump was in service.
Kind regards
Timo

[J. Huber]

Could it be something as simple as fuse #4??



James
63 230SL

[rwmastel]

James,
You remind me of an old TV game show I used to watch.  "OK, do you want to take the money, or choose what's behind fuse #4....."

Maybe you could elaborate on this?

Thanks,

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[J. Huber]

Well, I feel like some gameshow music should be playing in the background... but here's what's behind door number one...

Fuse #4 controls fuel pump feed. My tech manual suggests the first place to look for difficult start is non-current. Second on the list is fuel delivery (with current). So, just a longshot guess ... I thought maybe the car is simply not getting any fuel but had enough residual to fire up for a moment.... Now after a point, it wouldn't start period. Not sure if original poster meant each time it ran for a sec then quit. Or just once.

Now if it starts briefly then floods thats another story. On this one, explore the fuel delivery and cold-start system.

Hope that helps somehow.



James
63 230SL

[tobacco]

Does it run fine after you restart?  

This may be way off, but when my car was new, every time I cold-started the engine it would stall immediately.  But when I restarted, the engine would kick over instantly and run just fine thereafter.  

My Sacramento dealer's service manager replicated the situation, found no problems internally, and was inclined to think it was idiosyncratic -- until once during a morning test drive he noticed that my pick-up (low-end torque) was exceptional for a W113.  He double-checked the cylinder compression and found it a little high, and when he asked about my oil consumption and I said there hadn't been any (how neat, I'd figured, that a Mercedes was built so well it never burned oil), he speculated that my rings were a bit too tight, and that when they loosened up the stalling would go away.

The stalling eventually did go away -- but after 30,000 miles or so, my oil consumption began to increase . . .  and increase.  At 97,000 miles, I blew rings in two cylinders (Joe Alexander would remember; he was the one who confirmed the damage).  Not bad for a lot of cars, but unusual in a Mercedes-Benz.

So, in hopes that your situation is less structural than mine (or that 97,000 miles is an acceptable gap between ring jobs), good luck in your investigation.


Bill Greffin
Chicago
#22375

[n/a]

Same problem continues. I have checked electric fuel pump and it works OK. Injection pump is getting fuel.
So every time when I am starting the motor it starts fine but run about one second. When the motor is runing it works with all 6 syliders well ( but always a moment,) When the motor is running that sort time I have tried to step accelerator down but nothing happens.
So I opened all injection lines during starting and found out that there are coming fuel from each injector lines but pressure is quite low.
Then I took away all spark plugs and started with motor accelerator down. All sylinders seems to be dry still so it seems that motor don't get fuel enough. Then I took away one wire from injection pump starting solenoid = then motor is not starting at all.
Restoration work has been taken more than 6 years and my injection pump has been dry long time. It seems that the problem is injection pump.
I have a possibility to rent special pressure meter to measure outgoing pressure to injectors.
Maybe something inside injection pump has been stucked ?

[Cees Klumper]

On the front of the injection pump (usually) is a small round black plastic cap. If you remove this, you should be able to insert a 5 or 6 mm bolt and move the injection pump rack. These can get stuck. If the rack moves freely, then this is not your problem. Unfortunately that's all I know. Do you have a Bosch service place where you can have the FI pump checked? The pumps rarely go bad but having one sit for that long without preventative measures (caps, moving it from time to time etc) I suppose can cause problems.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello alahtimo,
 Ok the fuel supply checks out. It sounds like you have a bad ballast resistor on the ignition. A circuit by-passes this resistor during starting. As soon as the ignition is released the bad ballast resistor interupts the flow of power to the ignition and the engine dies. To test, bypass each ballast resistor with a jumper wire. The engine should start and run when the bad one is by-passed. You can also diagnose with a 12 volt test light or meter. You will have power going into the ballast resistor but none coming out. If you need more details or a photo let me know. replace the bad resisitor or temporarily by-pass it to verify your diagnosis.

Joe Alexander
Blacklick, Ohio

[Cees Klumper]

Joe - would you please explain what the function of the ballast resistors is ?

[hands_aus]

the car is a 230SL and may not have 2 ballast resistors

Bob(Brisbane,Australia)

[ja17]

Hello alahtimo,
Bob is correct on this. I was thinking that yours was a 280-SL. Only the later version 280-SL had the ignition bypass circuit.  The symptoms that you are experiencing with your 230-SL (single ballast resistor and no by-pass circuit) cannot be caused by a bad ballast resistor. If your ballast resistor was bad the car would not run at all. You have something interupting your ignition or fuel supply. A volume and pressure check of your fuel supply from the electric fuel pump may help.


Joe Alexander
Blacklick, Ohio

[n/a]

Thanks Joe and Bob,
I checked that one resistors and it is OK. I also checked electric supply to ignition and it's Ok also.
Today I concentrate more to Injection pump. I took all spark plugs away and started motor with accelerator down. Fuel is coming thrue injectors only accelerator fully down or during starting. So I put spark plugs back and started motor accelerator down. Motor started immediately and picked up speed up to 5000 rpm or more. When I loosen accelerator motor stopped always.
I think that I need to send injection pump to service.

[ja17]

Hello alahtimo,
If your car ran ok before storage, you may just have something stuck in the injection pump. Check the rack as Cees mentioned, also the warm-up device on the pump may be stuck. Read the previous threads on this topic if you can find them. If you are unfamiliar with these topics or cannot find them, let us know. I can email some photos and procedures. Please make sure the tune up items like the spark plugs and ignition points are in good tune before moving into more complex and expensive areas.



Joe Alexander
Blacklick, Ohio

[n/a]

Thanks Joe,
I am starting to be quite sure that something inside injection pump has been stucked. Please could you be so kind and send some photos and procedures.
Timo

[ja17]

Hello Timo,
Here is some additional information and photos. I am using a 250-SL engine and injection pump, I do not have a 230-SL on hand at the moment. The parts are only slightly different.
If your car has been stored for a long period and now is not running properly, check these two items on the injection pump. As Cees has mentioned in a previous post, the pump "rack" must be free to move. To check this remove the 10mm head bolt and cylindrical cover (see photo). (Later engines had a black rubber cover.)

Download Attachment: Injection pump rack cover.jpg
59.23 KB

Next thread a  4mm screw in the end of the rack.(see photo)

Download Attachment: 4mm screw on rack.jpg
60.56 KB

You should be able to move the rack back and forth. In additon moving the accelerator linkage should also slightly move the rack.
If it is stuck, it must be freed. Try exercising it first.
Next the "warm up device on the rear top part of the injection pump should be checked.(see photo)

Download Attachment: warm up device.jpg
60.04 KB

If the car runs, during warm-up the coolant thermostat in this device moves an air valve and plunger which adds additional air and fuel during warm-up. This device completely closes the air valve when the engine is warm. You can check this by listening to the air actually stop flowing during warm-up. (use a section of hose for a stethescope!).
If your car does not run long enough to check, or you think it is not functioning, it can easily be removed and checked. The "air valve in the unit can easily get stuck from long periods of storage.
Remove the two coolant hoses and the one air hose going behind the engine to the intake. Loosen and remove the two top slotted screw in the coolant housing and remove it along with the thermostat. The air valve below should be free in it's housing. If not remove the air valve housing. Keep track of the adjustment shims between the air valve housing and the injection pump.

Download Attachment: disassembly.jpg
56.13 KB

Free-up the air valve and make sure the plunger is moving also. The injection pump air filter must be clear, replace it if needed. It can be left off temporarily for test purposes if it is clogged.

Download Attachment: parts.jpg
50.86 KB
 Re-assemble the unit. I like to use a very little  silicone grease to lubricate the air valve. The thermostat and housing have no gasket. A compression type fit seals the unit. A little grease or a bit of sealer here may help the parts join nicely. Top off your coolant. Good luck. Keep us up to date!

Joe Alexander
Blacklick, Ohio

[Joe]

Joe, I'm sure others appreciate as much as I do when you go to the obvious trouble of preparing the photos and posters you do. With the discussion you provide, they are more helpful than any book.
I have a question for you. What are the two cannisters on the top of the injection pump shown clearly in the Warm-up Valve" photo? Mine are as rusty as those in your photo, and I'd like to remove them for cleaning, but don't want to change any adjustments.
Do you have any photos of the inside of the injection pump?
On the photo you showed, where does one check the oil level in the IP?
Guess I had three questions!
Joe

[ja17]

Hello Joe,
Thanks, I am glad this information is useful. this new technology is amazing. I am learning as I go along here. My old computer is temporarily moved out to the garage until my new one is up and running on line in the house. So here I sit in a lawn chair in the garage surrounded by M130 engines, parts, Mercedes cars etc. You could say it is very condusive to exchanging information!

Download Attachment: P1010041.jpg
62.49 KB

The two other canisters on the injection pump are the barometric pressure sensor (mainly for altitude changes) and the oil filler cap for the injection pump on the early style pumps.

Download Attachment: injection pump canisters.jpg
53.84 KB

Naturally removing the oil filler cap is not a problem. The barometric pressure sensor must be returned to it's exact location. Also there are factory adjustment shims between it and the pump. If your car is running fine you may want to leave this alone.
The early version injection pumps all had the oil level stick on the rear pump cover (large sloted screw). The exact location on the rear cover varied depending on version.(photo)

Download Attachment: Injection pump dip stick.jpg
58.35 KB

The later version pumps had no dip stick at all.

Download Attachment: various versions.jpg
63.78 KB

I will post some internal pump photos in the next couple of days.




Joe Alexander
Blacklick, Ohio

[hands_aus]

Hey alahtimo,

Did you sort out the problem with your car only running for the ONE MINUTE?

What did you do to get it going?

Bob (Brisbane,Australia)
early 250 SL, RHD