Here's a strange one.... Ignition problems

doubledutch

doubledutch

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For the last few weeks I have been having issues with the ignition on my '71 2800cs, automatic. When I try to turn off the engine (key removed...) the engine keeps running, it finally quits (while sputtering) after 5-20sec. As of yesterday the car wont start while in the Park position but it WILL start in Neutral (O). Reading the posts on this site it doesn't sound like a lot of fun changing the ignition switch (Part number: 61 32 1 357 380?) anybody have advice/suggestion or experience with any of this?
Cheers
Pieter
 
If the sputtering starts right away it sounds like a serious case of dieseling. 20 seconds is a lot. The non start in Park sounds more like the gear selector contact to the neutral safety switch and could be the result of play in the linkage.

For the first problem I would try filling the tank with highest octane gas you can find and see if it improves. If it does it is unrelated to the ignition switch.
If it doesn't there could be an intermittent contact there.

For the second I would bypass the neutral safety switch and see if it starts in P.

If both things happen you can send me a bubbly champagne half the price of an ignition switch.
 
doubledutch said:
For the last few weeks I have been having issues with the ignition on my '71 2800cs, automatic. When I try to turn off the engine (key removed...) the engine keeps running, it finally quits (while sputtering) after 5-20sec. As of yesterday the car wont start while in the Park position but it WILL start in Neutral (O). Reading the posts on this site it doesn't sound like a lot of fun changing the ignition switch (Part number: 61 32 1 357 380?) anybody have advice/suggestion or experience with any of this?
Cheers
Pieter
Click to expand...

Agree with Arde's initial diagnosis, but have slightly different initial treatment.


Before upping the octane, I would make sure the idle is not too high and check to see that the ignition timing is not too far advanced. Spark plugs of a heat range that are too hot, may also contribute to this condition. Examining the plugs for overheating is never a bad idea.

Run-on or dieseling are typically controlled by idle solenoids present in the carburetors. (Assuming that you have carburettors equipped with the same. You did not specify) With the ignition switched off, idle solenoids "cap" the flow of fuel to the engine at idle. No fuel = no run-on. The idle solenoids can be rendered ineffective if the throttle plates are adjusted poorly, permitting fuel to feed the engine via the main fuel circuitry. One of the earmarks of poor adjustment is a very high idle - which might indicate the carb/s are not running off of the idle circuit.

Per Arde, respecting a no-start condition in an automatic, the first thing to check is the safety switch that is triggered by the shift linkage. It has been addressed on the forum before. :wink:

hth
 
Ignition problems

Thanks for the quick responses. Obviously I am not a mechanic and this is all still very new to me but I think you guys are onto something. The problem of "dieseling" only occurs when the engine is hot, I do have zenith carbs and I did do some fidgeting around with them a few weeks back because she idled so low (and clearly not knowing what I was doing...)
Also I forgot the mention that I installed a period correct radio yesterday (very pleased with my Blaupunkt Bavaria) but I wondered if I might have goofed with the wiring so now it only starts in Neutral? More work to do I guess but it sounds a lot easier than replacing the ignition switch. I might have to give the local E9 guru, Mike Thompson a call
Thanks guys!
Pieter
 
OK, I am halfway into a champagne with dieseling. Simplest test may be to accelerate just before shutting down the engine. The dieseling period should shrink as the fuel left in the carb is consumed at a faster rate.

I see no way a radio installation would prevent the car from starting in P. My bets stand.
 
Champagne

Arde said:
OK, I am halfway into a champagne with dieseling. Simplest test may be to accelerate just before shutting down the engine. The dieseling period should shrink as the fuel left in the carb is consumed at a faster rate.

I see no way a radio installation would prevent the car from starting in P. My bets stand.
Click to expand...

Haha..... Ran out and filed up with 93 (highest I could find) and put a bottle of octane boost in the tank et voila......it only idlled for 2 seconds, after removing the key (i am sure it will get better with time).
Arde I think I have an old Asti Spumanti aging in the wine cellar, she's all yours once I get the 2nd problem addressed ;)

Thx again guys
Pieter
 
Disco the green wire at the coil and sub in a jumper direct to positive pole at battery.
Fire up the car and then disco the the jumper.
If it keeps running its not the ignition switch.
 
Can you not check idle solenoids by simply unplugging them and listen for idle changes?
 
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