83 Quantum TD Hair Dryer start

Harry · Post by **Harry** » Sat Jan 23, 2010 3:16 pm

Well this morning I got the wife to work the starter and GPs, so I took her hair dryer and a flex hose piece and crammed the hose sorta onto the air-snorkle to the air-cleaner. I had her glow it one cycle and crank it. Well it fired on first try, ran rough for about 15 secs and smoothed out. Cranked about 5-6 secs before it caught, but it's the best it's started for some time. Don't know what this proves(if anything) but thought it was sorta interesting. Heated intake air compressed reaches ignition temperature better than ambient 28F air?
Harry

82vdub · Post by **82vdub** » Sat Jan 23, 2010 3:44 pm

I believe this idea has been discussed before on the forum and the results of warming the air didn't prove to be much different. However, from somewhere else on the web............

here's a quote from Britannica.com:

"The diesel engine gains its energy by burning fuel injected or sprayed into the compressed, hot air charge within the cylinder The air must be heated to a temperature greater than the temperature at which the injected fuel can ignite. Fuel sprayed into air that has a temperature higher than the "auto-ignition" temperature of the fuel spontaneously reacts with the oxygen in the air and burns. Air temperatures are typically in excess of 526Â°C (978.8Â°F); however, at engine start-up, supplemental heating of the cylinders is usually required, since the temperature of the air within the cylinders is determined by both the engine's compression ratio and its current operating temperature."

rabbit_man · Post by **rabbit_man** » Sat Jan 23, 2010 9:08 pm

Heating the air should only help if it's waaay cold out or your GPs aren't working right, unless you've got fuel problems that also cause hard starts.

Also heating the air is just what the GPs do only they do it inside the combustion chamber, cummins diesels on the other hand only have a heat grid in the inlet of the intake mani, thus heating the incoming air........but that's a direct injected engine so it'll always start easier.

Harry · Post by **Harry** » Sat Jan 23, 2010 10:08 pm

I was just relating a single experience, does make me curious tho. I figgered if the thing fires when the compressed air temp is up sufficient, then maybe I could help up the ambient air temp entering the intake a bit. Who knows? And it's not real handy to stand out there with hair dryer raging away and a bit bitched off wife at the key, besides it could really be exciting in the rain, NOT!!!!

Fuel problems are probably part of the issue. Have no idea how old or how long unattended the injectors are. In warm weather after the engine has been run, usually have to crank once, then quit, and crank again, then it starts. Kind of like the primary pump is bringing fuel into the rest of the pump, I dunno. Have put new fuel filter on, twice, took the last filter apart and didn't see any crud in the filter, but maybe it's microscopic. Maybe the injectors are drizzling off fuel after shut off? Maybe it's the pump and the injectors. Thing is, it sure runs good once it's going.

It is interesting that the Cummins uses the heat grid in the intake stream, albeit it is direct injection, to start.

surfcam · Post by **surfcam** » Sat Jan 23, 2010 10:53 pm

I can certainly say that the Cummins is a different beast. I have a 1989 4 clylinder with no preheater. It has liquid intercooler so apparently it can't have a preheater. At 15 to 10 below Celsius it will start. In the summer it will start before it even makes a revolution. It also has good power and mileage. I think the down side is the noise and vibration.

rabbit_man · Post by **rabbit_man** » Sun Jan 24, 2010 2:30 am

In warm weather after the engine has been run, usually have to crank once, then quit, and crank again, then it starts.

I bet your ignition switch is bad, mine went bad so I swapped it out with my parts bunny and now 90% of the time, whether hot or cold it'll crank and crank........let off the key and crank again and it fires instantly.

My theory is that during cranking the fuel is shut off.
My Dad's eurovan did that since he bought it in '05, crank forever, let off key and try again and instant startup.

It eventually got so he had to hold up on the key for it to crank, he bought a new switch a month ago and I don't think he's drove it enough yet to see if it fixed the "crank it again" problem.

Harry · Post by **Harry** » Sun Jan 24, 2010 6:24 am

The ignition switch is a possibility I'd not thought of. Will wire around the switch with a jumper to the solenoid valve today when it gets light out. Will try it both starting and after it has run awhile on a restart. It's a possibility worth checking out.

JAMES ADKINS · Post by **JAMES ADKINS** » Tue Jan 26, 2010 6:55 am

I guarantee you that i now always suspect ign. switch. I had a restart prob. on my 1.6 na and finally after checking to make sure it was getting voltage to solenoid during running position, i tried an experiment and hooked up a meter during cranking and sure enough there it was, an extremely intermittent voltage during the cranking phase. Cure ? a new switch.

Harry · Post by **Harry** » Tue Jan 26, 2010 2:40 pm

Sneaky ignition switch, I'll be darned. I jumpered off the batt into the cockpit, then a switch and then a wire to the solenoid hook-up and it definitely starts better, not great, but noticably better. Rabbit-Man which Cummins in what vehicle/equiptment has the pre-air heater grid in it? Has me curious, guys up here in the hills mostly Ferds and Grammas Motor Company and aren't that familar with Cumminses.
Thanks, Harry