How to start a barn find

[Frank Deutsch]

I recently purchased a 1966 230SL. I would like to fire up the engine to evaluate it before I begin the restore.

I have drained the fuel tank, let the fuel pump (at the tank) push the new fuel out the disconnected fuel line at the injector pump. I get a spark at the plug, I get some fuel at the #6 injector fuel line.

It won't fire up. Just barely running while the starter is running.

I hope a member can give me some help.

Frank Deutsch

1966 SL230
1998 SLK230
2006 ML350

[merrill]

Frank,
does the motor not fire or do you think there is a fuel starvation issue?

try jumping the ballast resister so a full 12 v gets to the coil.
once the motor is running remove the jumper.  the new bosch starters have a new connection for this purpose.

also, are you sure you are getting fresh fuel to the motor?
I replaced my fuel lines and tank a while back.  I actually used a vacuum pump to pull the fuel thru the system.  I made the connection on the return line from the inj pump.

hope this helps
matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[Frank Deutsch]

When the new filters arrive I will vacuum the fuel out of the injecter pump, and resume the starting process.

Perhaps there is old fuel in the injecter lines. I have read that the amount of fuel delivered at the injecters is minimal, this would make the "pipeline" seem long to purge.

Would opening the return line at the tank let me see if the lines are open (when ignition key is on)?

I will try jumping the ballast resister. Should the jumper work what would that indicate?

Frank Deutsch

1966 SL230
1998 SLK230
2006 ML350

[mdsalemi]

Frank,

An important issue you need to find out is if this car has been sitting for a while.  Is it truly a "barn find"?  As in, it was put away x number of years or decades ago in unknown condition?  Or was it running last fall?

If sitting for years, you really need to go through the entire fuel system from the tank up to the injectors.  It's not pretty, it's not cheap, but you have to do it all.  I would not be surprised in the least if you find troubles all along the way...plugged injectors; faulty FI pump; marginal fuel pump; corrosion and crud in the tank; crud in the flower pot, plugged lines, etc. Rather then simply try and get it started, I'd start at the rear of the car and work your way forward, cleaning everything.

Do a search for fuel issues here and you'll find so many...it's a complex system that does not like to sit unused.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[Sven]

Warning from a novice.  I had a somewhat similar start to my rehab.  Not knowing any better, I drained the tank and replaced with fresh, then proceeded to start the car.  It ran for a while (20 minutes idling) until the fuel pump seized up. Afterwards, I went to refresh the fuel filter and found the fuel filter canister to be full of rust and crud, apparently that I had pushed through the system during those 20 minutes.  I got an inside deal for a new MB fuel pump, but still ended up paying $450 for it.  A fuel injector pump rebuild followed shortly thereafter.

Assume there is crud/rust in the tank, and refresh the fuel filter.  I added an inline aftermarket fuel filter between the tank and the fuel pump for additional safety.  All is good now thankfully.

[ja17]

Hello Frank,

You will need to make sure that the rack is not suck in the injection pump. Do this by removing the access cap (10mm bolt and round cap) at the front end of the injection pump. You can refer to "injection pump tour" for more details. The end of the rack is threaded so you can thread a screw in and push and pull the rack, it most move freely. The rack must also move slightly when the accelerator linkage is moved.

After the fuel tank and the fuel tank screen are drained and cleaned, change the main fuel filter. The electric fuel pump should operate with the ignition on.  A fuel pressure and volume check should be taken to verify a good fuel supply.

Joe Alexander
Blacklick, Ohio