126 Engine will turn but wont start
 

Car: 1989 Mercedes 560sel 156k miles

Problem: Car will turn over but wont start. Was working the night before.

What I have done so far:

1) Made sure I had gas.
2) I am getting no power to the fuel pump with the ignition on.
3) Removed the relay and jumped pins 87 and 30. The pump comes on but the car still doesnt start.
4) Replaced the old relay and the car still wont start and the fuel pump is not running with the ignition on.
5) Took the Relay appart and resolder any and all joints.
6) Read thru all the forum under search string "fuel pump relay" and " fuel pump".
7) Check fuse on OVP and cleaned all contacts on Fuel pump relay and OVP.
8) Replaced the Distributor cap and rotor a couple of weeks ago. Due to a stalling situation. Seems to be better most of the time.. but seems to to have rough idle problems still at times, before it completely failed to start.
9) Put gas directly in the Throttle body, car still wont start.

Car still wont start.

Question:

1) On a 560sel, Does the fuel pump run when the ignition is turn on and before it start?
2) If so, then it looks like its the Relay that is causing the problem. However, when I bypass the relay and jumped pins 87 and 30, the car still wont start. Does the relay have to be in place for the car to start?
3) Could it be the Coil?
4) Could it be the Transmission cut off switch?
4) What am I missing?

Thanks ahead of time.

I saw this happen on a 380SEL once. It turned out that the timing chain had broke. It needed a rebuild after that.

Thats easy to check.. didnt think of that. Just open the oil filler cap and look when the engine is cranking.

But would I hear a noise when cranking now?

Thanks

This should have told you that fuel is not the problem.

Update:

1) Getting not spark
2) Tried starting the car in neutral. no go.

I am down to the Coil, the ignition control module or the Crank position sensor.

How do you test those things other than swapping them out.

Changed Coil
 

Changed the ignition coil. Still no go.

Can anyone give any suggestions?

Thanks

If you do not have the 126 CD-Rom, try looking for diagnostic info at this site.

Many MB manuals are here.

http://mb.braingears.com/

...Tried the neutral safety switch???..,. Had it go on my 380....very frustrating 'cause no one thought of that as a potential problem....

Starting in neutral still not work if the NSS needs replacement!...check it out

if it were a
 

neutral switch the car wouldnt turn over.

tom w

hahaha you're right!... i guess I was having a " fuzzy" memory....

have you checked your compression? Make sure you haven't jumped a tooth?

Jonathan

update
 

Had it towed :mad:

1) 1st problem. Bad fuel. The fuel was cloudy.
2) The no spark problem was due to a bad rotor. (Just replaced it a month ago) He said its because it not MB part. It was a Sorensen part. Replaced rotor.
3) Have fuel pressure but not fuel volume. They said it should put out 1 liter every 40 seconds. Its only putting out 2/3 liters every 40 seconds.

They told me they need to drain the fuel tank and replace the screen. (I have a full tank of gas).

Replace the both fuel pump. $260 each not including labor. ( I told them I can get OE ones for $190. They said they wont install it.

Replace fuel filter.

I told them to install the new fuel filter, replace rotor and drain the tank after they check the fuel thru the filler nozzle.

What do you all think?


Thanks for all the replys.


PS. Do i need to check compression if i was not getting spark?

Nice site.. too bad the PDF files are missing. :(

Thanks anyways

Should have tried starting her w/ carb cleaner....if a car won't run on that it won't run.

Look at it this way, at least by paying their price on pumps (which isn't horrible) you get the added benefit of a warantee. I tend to not let people bring their own parts, but if I do I will Not warantee the work etc...

Didn't know you were not getting spark, sorry if I missed that bit of info...been fighting a Bad cold!

Jonathan