Can a gasoline engine fire on starting fluid without spark?
 

Had a weird experience at the shop today. A Hyundai sheetbox was towed in no start. It was in my upper lot, and I went to take a quick look at it to see what I was up against. One of my quick checks is to grab a can of ether to see if the car will fire , and tell me if I am chasing down a fuel problem, or something else. I shot a couple of squirts of ether down the intake, and it sputtered like it was going to start. I did this a couple of times, and it almost fired. Then I could get no more response from starting fluid. I went and pulled the covers off the coils, to find it had zero, no spark, not from any of the coils. I was holding the plug wire in my hand while my dad cranked, and there was nada spark, or I would have had my boots knocked off.
Is it possible? I did not think there was enough compression to light it without spark.
Maybe it was just a fluke, and the car did have minimum spark at first few cranks. then died. Had me wondering though.

hmmm. I think it may have had some spark but not enough. Unless I am mistaken there is not enough pressure developed to combust gas - needs an ignition source. Diesel is another matter...

How old are you guys? I remember cars in the '80's 'dieseling' for several minutes if you left them in Park after turning off the switch. Put them in drive or mashing the throttle would get them to quit.
Jim

I've seen it only if the engine was hot...probably had a little spark left

It will start on 'starting fluid'. No spark.

I chased a wrong diagnosis for a while until I actually checked spark. If it's warm, compression good... will 'diesel' on 'starting fluid'. It's not really 'running'... and that stuff is really bad for cylinder wall lube.

Yes it will run w/o spark on starting fluid. It would probably run w/o pistons on starting fluid. That's why I never use starting fluid unless I'm in danger of freezing to death in the woods of MN. in the dead of winter and I really, really need some rolling turd to start. It's bad stuff.

I think it was just a fluke. My scanner showed no signal from the crankshaft position sensor. I went in to replace it, and I was also going to do a timing belt while I was in there, the sensor is under the timing belt covers. I found that the timing belt had shed about half its teeth, and some of them were lodged in between the sensor and the toothed wheel. I could see how it could have made an occasional spark. This guy was a lucky mo fo. the timing jumped about 4 teeth, and not one bent valve. New belts, and replaced sensor, fired right up, and ran perfect
I have never seen one fire on ether without spark before, and have probably done this hundreds of times in my life, This engine was stone cold, ( well, 88 degrees here )