W113 Pagoda SL Group > Drive train, fuel, suspension, steering & brakes

New Engine Start up - NOT

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Tomnistuff:
Well, two days ago we got the New Engine Start Up results from Minerva - hook up stuff, crank it, it fires and runs, shut it off - what's next?  I should be so good.  Minerva apparently did everything right.  CONGRATULATIONS!!

Now it's my turn.  I've documented the planning and execution of every step in the reassembly of my car since it arrived back from the Body Restorer in Mid July 2012 on a flat-bed truck sitting on a finger tight suspension.  I rolled it into the garage on the hoist put it on jack stands and removed the suspension so I could start from scratch.

On Friday, May 10, 2019, the car was effectively done except for firing it up.  That action item is number 847 at the top of page 45 of the single-spaced bullet-point document I've entitled Vehicle Reassembly Sequence.  My smile turned upside down.

A couple of days before, I had primed the fuel injection pump and injector lines with shortened plastic pill bottles between the line fittings and the injectors.
Two ten second cranks at full throttle yielded nothing, but the third seven second crank at full throttle yielded one ml of fuel in each bottle.  After cleaning the pill bottles and repositioning them, a 10 second crank at full throttle yielded exactly 3 ml of fuel in each bottle.  The only problem seen was dark fuel in cylinder four output which turned out to be an excess of anti-seize compound on the bubble fitting from the connector nut.  All pump pistons were delivering exactly the same amount of fuel from the lines without injectors.  The injectors had been cleaned and flow tested by Robert Fairchild Industries, so I wasn't going to go to the effort to remove them and flow check them with my crude methods.

So on May 10, 2019, I tried to fire it up.
   First crank at closed throttle for 5 seconds: no firing.
   Second crank at full throttle for 5 seconds: no firing.
   Third crank at full throttle: engine started firing with starter assist but would not sustain.
   Fourth crank at full throttle: engine started running with starter help and ran at below idle speed on two or three cylinders
     at full throttle but died when the throttle was closed after another four or five seconds.

Observations and Conclusions
   Even with the garage door open, it stinks of hydrocarbon emissions (it smells like gasoline burning in an open bucket with
      lots of black smoke)
   Every spark plug is severely carbon fouled. (dry soot not wet fouled - indicates fuel rich environment, presence of spark
      and severely incomplete combustion due to overly rich mixture)
   Exhaust system was also severely carbon coated inside with dry soot. (Suggests fuel burning in the exhaust system but not
      long enough to be noticeable.  I did not check the temperature of the pipes or exhaust manifolds.)
   Every spark plug was warm when I removed it. (so they were firing).
   Engine firing did not respond to throttle plate movement while it was running. (Insensitive to air flow so there was plenty
      at any throttle setting except closed).
   Engine firing did not respond to Injection Pump throttle setting. (so there was adequate fuel, in fact too much, at all throttle
      conditions except closed.

Major conclusion:  Existence of fuel and spark is not the problem, but it is possible that the fuel injection is occurring during the exhaust/intake stroke overlap and burning in the exhaust system ignited and sustained by a slow, poor burning in the exhaust manifolds and exhaust pipes.

Distributor setup is not perfect but is close to correct based on the cam lobes and rotor position relative to the timing marks and pointer.

I will check injection pump timing next, using Joe's IP write-up.

These are my best guesses considering my considerable ignorance of the M-B mechanical fuel injection system.

If anyone recognizes the above symptoms and possible other causal factors, please don't hesitate to comment.

Thanks,

Tom Kizer

Minerva:
Tom, didn't read all you wrote but had a bit of a head scratcher, mine would fire but not run. Found that there was a 12 volt coil fitted as well as the ballast resistor so getting full 12 volts  at crank and less onve key went back to run position. Worth a look maybe..
Keith

Tomnistuff:
Hi Minerva,

I just did a search for the word "ballast" on my Vehicle Reassembly Sequence document and found on line item 563, page 27 that I bypassed the ballast resister but left it installed to make the car look original, even though it has a new Pertronix Ignition with the Pertronix recommended coil.

Thanks for the thought.  I'll check it out.  Tomorrow, I'll recheck the distributor setting (and wiring) accurately, run a compression test, check out the Starting Aid Tour and then start on Joe Alexander's procedure for checking timing on the injection pump without removing it unless it's installed wrong.

I'll keep checking this thread, as I work, to find more ideas and to provide my test results.

Tom Kizer,
Levis, Quebec, Canada

andyburns:
My money is on ignition timing.  Have you checked with number one at tdc both valves shut and the distributor rotors pointing at the appropriate ignition lead.  Is it possible your distributor cap is 180 out?

ja17:
Good guess Andy, I would go with ignition timing also. Try advancing.

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