Another cold starting problem

[JohnnyD]

All right, heres the problem. 1998 B-21 TLB 2400 hrs. only likes to start when the temperature is above 45 F. Here is what I have done and checked. New battery. Cleaned battery connections. Cleaned main ground frame connection. Voltage at battery cold 12.6 volts. Voltage at glow plugs in the preheat position 10.5 volts (wiring lead connected to the bar, I did not measure it off yet). Glow plug resistence - all three measure 1.3 - 1.5 ohms (factory spec. is "approx". 0.9 ohms). Do these values fit the definition of "approx"? I have purchased a block heater, but have been unable to locate a tool center that carrys a 17 mm allen head wrench or rachet end.

Other info...I have heated the glow plugs for greater than 2 mins. without results. The key switch used to get stuck in the preheat position, and this being owned prior to me by a rental place, I am sure at times was left in this position with the engine running for hours. The engine dose have what is probably considered a fair amount of blow-by smoke.

Am I unrealistic to believe my baby should run even in non-tropical conditions? Any help will be appreciated.

John

 

[hwp]

You should be able to start that machine in much colder temperatures than you are experiencing. My machine has over 5000 hours on it and it starts at tempertures down to 0 deg F without the block heater plugged in and about 10 seconds of glow plug heating. Yours should do at least as well.

It sounds to me like the spray pattern of the injectors is not right. There should be a full circle of a nice even fine spray. A stream coming from a single or few points will cause hard starting and low power. I'll bet a lot of the "blow by smoke" is in fact unburned diesel caused by a poor spray pattern in the injectors. If you don't have the mechanism to do check the injectors yourself, take the injectors to any shop that works on diesels to have it done. Most injectors can be taken apart and cleaned or rebuilt. I have done this many times on Benz diesels but haven't had to yet on my Kubota.

It may also be that the glow plugs are not doing the job and need to be replaced. Again I don't know about Kubotas as yet, but the tolerance on Benz glow plugs is quite limited.

 

[Inspector507]

www.sears.com
Item #00946666000
17mm Hex Wrench

AND they deliver /w3tcompact/icons/smile.gif

 

[JohnnyD]

Thanks for the reply. One thing that supports the injector theory is that when while attempting to start the engine (throttle about 1/4 - 1/3) a lot of smoke and fumes are coming out of the exhaust. If and when it does start, it is similar to a gasoline engine that was flooded,-alot of smoke and ?? unburnt fuel. I will look up what is involved in servicing the injectors in the service manuel. If I can't do it myself, then I/ll take your advice and send them out. I'll probably also try replacing the glow plugs first if they are not that expensive. Thanks again. I will post in a few days.

John

 

[JohnnyD]

Thanks for the reply. I'm going to that web site to order it know. John

 

[kujaneckinga]

Sounds to me that with quite alot of blowby that the compression could not be up to spec. Low compression will cause hard starting in cooler weather. Just a thought.

 

[B7500]

This is probably not your problem but isn't there a summer and winter type fuel. Maybe yours is the wrong type? Just a thought...
-T

 

[JohnMiller3]

<font color=blue>… (wiring lead connected to the bar, I did not measure it off yet). Glow plug resistence - all three measure 1.3 - 1.5 ohms (factory spec. is "approx". 0.9 ohms). Do these values fit the definition of "approx"?...</font color=blue>

Not exactly familiar with your setup, but I’m assuming you disconnected the “B+ bar strap” connecting all three glow plugs and measured the glow plugs “individually”… from B+ input to chassis ground to have some continuity…~~ varies from less than an ohm to a few hundred ohms. (glow plugs are miniature heating elements… I’d be more concerned with an “open” element as in infinity resistance or extremely high resistance as in mega-ohms. The point being, you want some continuity)

On most units, leaving the “B+ bar strap on” will have all glow plugs in parallel… so you can essentially have (1) one good glow plug and the rest all defective and still “read” some low resistance with the “bar strap” in place causing only one cylinder to “pre-heat” and the rest “dead”…

 

[JohnnyD]

Thanks for the reply John. Actually, what I did was remove the plugs from the engine, and measure the resistance from the lead tip to just above the heating element. Perhaps removing them was anunessesary step? One things that dose point (I think) to the glow plugs being OK is that essentially the same reading came up on all three. As far as the fuel, I have already ruled that out, but thanks. Keep the advice coming! John

 

[karmakanic]

John,

Have you checked the valve clearance? You've got a good handle on the other usual reasons for hard starting.

I hope it's not the problem, but your mention of this has me worried; <font color=blue>
The engine dose have what is probably considered a fair amount of blow-by smoke.</font color=blue>

Often these are the signs of low compression in diesel engine; excessive blowby, and can't get it started when it's cold. Definitely install the block heater if you can't find any other "smoking gun". Or you could use the procedure one of my old bosses used on his dozer in cold weather. Start a good sized fire under the oil pan, and brew a morning pot of coffee while the thing warms up. /w3tcompact/icons/grin.gif

Dave