PeachParts Mercedes-Benz Forum - 1969 280SE (108) .... just won't start now

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1969 280SE (108) .... just won't start now - help please ....

hi All,

Could someone please help me out.

I have a 1969 280SE (108) which I bought almost 18 months ago.

Its been running beautifully since, and unfortunately for the past 6 months it is rarely getting out of the garage.

So not much driving .... but the battery has held up.

It was due for rego last week - so I took it for the pink slip, drove back and parked the car.

Two days later I go to start the car, and the battery is flat out.

Called NRMA - and they hooked up the leads - but no luck. Starter motor cranking over - but the engine just wouldn't kick in. NRMA guy suggested that the flat battery was probably pulling all the power, and suggested that maybe I get the battery charged. He also checked the fuel pump and said all good.

So I bought a battery charger, and charged tha battery up over the weekend. Put it back in, and tried to start. Same again - enough power to get the starter motor going - but engine didn't kick in.

Put some fuel in - just to make sure it wasn't out of gas .... but the engine just won't start.

Does anyone have any suggestions or ideas.

I'm a novice - and when I bought it, I was hoping to learn how to maintain the car. It's just a dream to drive, however i've been caught up with renovating the house, whilst keeping the kids busy.

Any help would be appreciated.

Many many thanks in advance.

Cheers
Arun

:rolleyes:

If capable, do these two simple test and repost.

#1
Take fuel line off cold start valve at middle of intake..put a plastic hose over the line and put the end in a container..turn key to run position..

Do you have a stream of gas coming out that hose??

#2
Pull center wire off fromdist cap and hold it near [ 1/4 " ] an engine ground..turn engine over w/key..
Do you see a good spark ???

**Do not do this test until you have put the fuel line back on from the first test.

hello Arthur,

Thanks for the quick reply.

Have already done the 2nd test - and the spark is good.

I'll try the 1st test when I get home tonight.

Thanks and I'll post asap.

Cheers
Arun

First, I would check the fuse, just roll it in its holder to make sure you have good contact.

First I would check the fuse for the fuel pump by rolling it in its holder.

I had a similar problem tunr the key and the engin tries to start but just when i let the key go the engine stop, the problem was was the fuse.

thanks guys,

just been stuck at work till late for the last couple of days.

have yet to check the 1st tip about the gas and also the fuse.

BUT - thanks for your help ..... I really appreciate it.

Weekend is almost here - so will repost after I've checked.

Thanks
Arun

clogged fuel filter-replaced mine and fixed this problem. But Also replaced the fuel pump-the old one was not putting out constant pressure.

hello Arthur & fellow helpers,

I'm finally reporting back that I performed the 2nd test as suggested by Arthur to check the cold start valve.

Fuel is coming through nice and strong .... which is kind of a relief because I am assuming that eliminates a fuel pump issue - which I understand can be expensive to replace.

So electrically there is a spark coming from the centre wire, and there is fuel entering the CSV.

Now hoping you have other ideas towards troubleshooting this issue.

Thanks in advance again.

Regards
Arun

OK

So, we have fuel pump output to CSV...good

Next test:

You will notice a small 7mm cap screw plug on the side of the CSV.
This is a Test Port.
Take the plug off and turn key ON to run position..you should have NO fuel from this port.
Now, place a rag over the port [ loosely] and have someone crank the engine over [ key in START position] I recommend removal of coil primary wire for this test,.
Fuel should now run out this port under pressure from the fuel pump.
If it does then the electrical circuit for CSV has been verified and the valve is opening.
If NO, then put plug back on and test for 12v at CSV when someone cranks engine

report findings for next step.

hello again Arthur & fellow helpers,

Unscrewed the plug from the side of the test port, and then turned the key to ON - run position.

No fuel as expected.

Then I turned the key to start position .... engine trying to crank over, and fuel coming out of plug as expected.

Battery is really low at the moment - but I still double checked the 2nd test that you suggested ....

good spark coming from center wire of distributor cap.

With my limited knowledge ..... I'm curious as to whether the distributor and the rotor arm are prone to having an effect on this problem.

I have to be honest - I have not checked to confirm if the leads going to the spark plug are carrying the charge from the distributor to the spark plugs.

I'll await your advise whilst I charge the battery up.

Many thanks again for your time and advise.

Regards
Arun

<<I have to be honest - I have not checked to confirm if the leads going to the spark plug are carrying the charge from the distributor to the spark plugs.
>

That would be next test..and if OK, pull a couple of plugs and see if they are gas wet/fouled
If so , clean them up and retry.

If not wet , then take the CSV off the manifod as a unit and see if it squirts from the jets into a jar when cranking. The port test is before the actual jets and they can be plugged.

I am assuming you have check for compression.

Hi Arthur,

I'll be checking the spare plugs tomorrow morning as you have advised.

Also - I have not checked for compression.

Something I have not mentioned earlier is that there is water in the oil - which I understand is a sign off a head gasket issue.

I'll be in touch after the spark plug test.

Cheers
Arun