| Author |
Message |
Justin Dortignac (3of14)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 24, 2006 - 9:58 am: | |
For those familiar with the 8.2L...we were told that this engine doesn't have glow plugs but rather, uses some type of engine preheater.
Can anyone verify this?
Where is the preheater?
How does it work?
Where does it get power from?
Thanks in advance! |
Mark R. Obtinario (Cowlitzcoach)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 24, 2006 - 10:41 am: | |
You are correct the 8.2L does not have glow plugs.
If the engine has a preheater it is some kind of heater in the cooling circuit. The heater usually plugs into house current, usually 110VAC.
If your 8.2L has a preheater you will find it somewhere in the lower hose or in the side of the block.
If your engine is in decent shape and it isn't below 40 degrees your engine shouldn't have to have the preheater plugged in. It should start right up with very little cranking. The warmer the ambient temperature and the lower the humidity the less cranking it should take.
Mark O. |
Phil Dumpster2
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 25, 2006 - 5:11 am: | |
Some have an electrical heating element in the intake which is powered by the battery. You turn the key to run, leave it there for 30 seconds to a minute, and then when the "wait to start" light goes out you give it a crank.
Below 10F, with no external power and no glow plugs, you may have to use "the unmentionable substance." |
Justin Dortignac (3of14)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 26, 2006 - 12:47 am: | |
Thanks, I think what Phil mentioned is what I was talking about.
We are having a hard time starting, even in 70 deg. whether! We have to crank it (on and off of course) for over an hour to get it to start. The mech said it's 'cause the preheater isn't working???
I have verified that the pre-heater is not working and will be trying to remedy that. Not sure if this will fix it...any advice? |
Mark R. Obtinario (Cowlitzcoach)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 26, 2006 - 12:02 pm: | |
A diesel engine is very sensitive to cranking speed. The faster you can crank the engine the easier it will start because the faster you crank the faster the combustion chamber will reach the heat of combustion. All that a pre-heater really does is it warms the air in the intake manifold to make the heat necessary for combustion to occur easier and quicker when starting.
If you have been cranking the engine a lot your starter may be getting fatigued. The starter may not be spinning at the desired RPM.
Old batteries and old battery cables can slow the cranking speed down as well. They may look okay but in reality they probably are not.
If the ambient temperature is 70 degrees and it takes an inordinant amount of cranking you have something far more serious wrong than just a poor pre-heater.
What can happen when you crank and crank the engine is the unburned fuel will wash the cylinders. It can dilute the lube oil and effectively lower the compression ratio and make it harder to start.
If you know for sure the pre-heater is not working, pour a little lube oil into the intake.
On tired engines that have been overcranked this can help you get things started. But it won't cure what is basically wrong.
Fuel, air, and compression is all it takes for a diesel engine to run. If any of those elements are not present in the proper amounts you are going to have a hard time getting the engine started.
Good luck with your boat anchor.
Mark O. |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 26, 2006 - 10:35 pm: | |
The 8.2 in Thomas School Bus I had did not have the preheater and always started fine down to 40 F. It was very well worn out "and I assume by the blow by and oil burning it had very low compression" so I think you need to seek a second opinion before replacing the preheater as the poor start cause, even if it has been tested as not working.
The next question is the how well (fast) is the starter turning it over,is the fuel system losing prime with a air leaking into the suck side when shut down and draining back into the fuel tank??? It is hard to tell if the engine is dry or flooding on these long crank times if you have a long exhast pipe on a front engine bus. Then maybe a "tune-up time if there appears to be only fuel system related problems left to eliminate". |
Justin Dortignac (3of14)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 26, 2006 - 11:06 pm: | |
Thanks for your help!
The bus is a rear engine and the exaust is right by the engine, when I crank it, it pours out significant amounts of white<?> smoke The engine is a recent rebuild with less than 6000 miles on her...and yes, it's a boat anchor...but I would think that a new engine should start easier...
I can always get it started, it just takes about an hour. once it's warmed up, I can shut it off for a couple hrs. and it will start up first try, no effort...
Still confused although I greatly appreciate your input. I may have to seek a second opinion. |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 26, 2006 - 11:22 pm: | |
Justin, there is a good chance that the engine is not yet broken in; this will cause hard starting.
When you say that the engine puts out significant amounts of white smoke, that's a little ambiguous. If an engine is injecting a normal amount of fuel because it is cranking normally, then there will be LOTS of white smoke.
If air is getting into the fuel system, it's not uncommon to see significant smoke when the engine refuses to start.
Probably a more reliable indication of a low cylinder or two would be smoke that doesn't clear up after the engine has been running a couple of minutes.
Another possibility with that design of fuel system is a damaged pump. It's not at all uncommon. If the engine will not behave properly after it has been running for a bit, then the pump may well be tired.
A lot depends on what the rebuild was trying to cure.
Good luck running down the problem.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
Justin Dortignac (3of14)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 27, 2006 - 12:34 pm: | |
Thanks Tom, all the smoke clears up shortly after the engine starts and then it runs fine. It only struggles on a cold (not reffering to temperature) start.
The rebuild was actually a complete out of frame exchange for a rebuilt that came from Pedco. |