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  #16  
Old 12-30-2014, 05:38 PM
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Location: Ottawa, Canada
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I replaced the coil with a new one today. Still no go. Cranking but not starting. I check the spark plugs, they seem a little wet with gasoline. I also tried pressing the accelerator pedal all the way down to stop the flow of gasoline.

While cranking, the intake butterfly goes down by about half a mm and it resists when pressing down.

At TDC, the rotor was pointing at the Cylinder 1 (three scribed marks) .
Reference resistor is about 750 ohm.

Would a blocked catalytical converter prevent the engine from starting?

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'88 Benz 420 SEL
'79 Porsche 911SC ('87 Carrera Engine)
'00 BMW 540 Sports Package
'99 Land Rover Discovery

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  #17  
Old 12-30-2014, 06:51 PM
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In your first post you state that you were "accelerating from a red light". You may have to take this matter up with Santa; you have been naughty. Please, for the sake of the rest of us, restrict your accelerating to green lights.

The reference resistor will not affect starting.

If the engine was running, and the car accelerating when the engine quit, it is possible, though not not very likely, that the cat suddenly became 100% blocked. Usually cat blockage is a gradual process. Have someone hold a piece of paper against the exhaust outlets while cranking the engine with the throttle open. There should be detectable puffing of air out of the pipes.

Perchance, had you refueled just before the engine quit?
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  #18  
Old 12-30-2014, 08:14 PM
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, yeah, i meant the traffic lights

I had not just refueled at the time. I also sucked out gasoline (about the volume of small water bottle ) and checked it for water, which would accumulate in the bottom. I did not see any sign of water. I also poured on a piece newspaper and lit it. It flamed without the paper turning into ash, until fuel was burnt up and the paper started turning into ash.

BTW, outside temperature is -5 F here! I am thinking if the spark plugs are too wet that might prevent the combustion?

What would cause the low voltage (8-9 volts) at the positive terminal of the ignition coil while cranking? Before cranking I make sure the battery is charged to about 13 V.

Thanks for all the inputs.
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Zorin

'88 Benz 420 SEL
'79 Porsche 911SC ('87 Carrera Engine)
'00 BMW 540 Sports Package
'99 Land Rover Discovery

86 300E - Manual (sold)
88 260E (sold)
84 944 (sold)
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  #19  
Old 12-30-2014, 10:43 PM
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Reduced primary voltage is a normal condition when cranking; the starter motor draws so much power that the system voltage is reduced. When a battery is in top condition voltage will stay above 10V., however, with age and low temps the voltage decreases. Below ~9V. spark quality falls off quite a bit. The problem is compounded by the decreased vapor pressure of the fuel at low temps; winter blend fuels have higher vapor pressures. Wet and sooty spark plugs also bleed off spark energy.

It would seem necessary to try to describe the shutdown of the engine; was it as though the ignition had been turned off, resulting in a smooth and quiet shut off, or was there misfiring, popping, rough running, or backfiring? Although it seems obvious, if you can determine what caused the shutdown, you will probably have found the reason for not starting again. The wet plugs and weak spark may contribute to the problem, but what caused the initial failure?
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  #20  
Old 12-31-2014, 08:55 PM
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Fixed! Finally.

After a lengthy battle with problem of cranking but not starting, thanks to the input and help of members of this group, I managed to fix the problem, or I should say problems.

I guess I was so unlucky that many problems happened around the same time and the fact that cold weather arrived compounded the problem. Here is the list and the fixes:

- I had 4 defective spark plugs. I am not sure what made them go bad so quickly as they were just a year old. I replaced them. I will replace the rest after the holidays.

- There were 3 bad coils. Their resistance was few Mega ohms! I replaced them.

- Replaced the ignition coil, since originally I thought that was the problem.

- The plugs were wet and I guess the engine was flooded because of all the cranking I have been doing, even though I was occasionally flooring the gas pedal to stop the flow of gas to engine. So I pulled out all the plugs and dried, cleaned and re-gaped them. And while the plugs were out, I cranked the engine to push out the gasoline from cylinders.

- After performing all these fixes, the engine was cranking but still no start. It seemed that the battery was draining quicker as the result of cranking. So I used booster cables and used the battery from my other car while the rpm was raised and kept above idle speed. This made the engine start and keep running. Plugging the block heater helped as well. I guess the battery was no longer in top condition after all this, although I had mostly kept it charging.

In summary, the problems were: 4 bad plugs, 3 bad spark plug wires, probably a bad ignition coil, flooded engine, and a battery that was not good enough to start the engine in this cold weather.

Thanks again for all the help.
and
Happy New Year.

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Zorin

'88 Benz 420 SEL
'79 Porsche 911SC ('87 Carrera Engine)
'00 BMW 540 Sports Package
'99 Land Rover Discovery

86 300E - Manual (sold)
88 260E (sold)
84 944 (sold)
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