7200 Cub Cadet Compact Tractor

[kscr4]

I've got a 1998 Cub Cadet compact tractor 7200 4WD 20 HP diesel that all of a sudden has been hard to start. I turn the switch for the glow plug and the lite comes on and then when I engage the starter it spins and white smoke comes out the exhaust. I replaced the battery thinking it was the problem. After I repalced the battery it started the first time, but once it sat over night it would not start. The only way I was able to start it was to spray starter fluid in the air intake and it started right up. The glow plug light stayed on for about 20 minutes and then went out. Once it is started and is shut off it will start back up with no problem however the glow plug lite stays on for a while and then goes out. Any ideas where to start?

 

[Bob_Bainbridge]

Perhaps one or more glow plugs have burnt out. If you have a multimeter you can measure the resistance frome each glow plug terminal to the engine block. I don't know what the resistance should be but I would think it's near the lower end of the 100 ohm scale. All glow plugs should be similar resistance. The failed one(s) will probably read infinity. If that doesn't reveal a problem you should check for voltage on the glow plug connectors while the controller light is on.

Bob B.

 

[Double Orange]

Just a safety note; It is highly NOT recommended to spray stater fluid into a diesel engine. Good Luck Frank

 

[TedLaRue]

I agree with Bob's advice, but I would try Bob's last suggestion first, partly because it's easier to test, and partly because I think it is more likely that there is no power to any of the glow plugs. If one plug went south, I think the engine would still start. The glow plugs are probably powered through a relay which may have gone bad.

NOTE: Opinions vary about using starting fluid (ether) to start a diesel engine. Some say it can cause serious engine damage. Others claim they have used it many times with no problems. I've heard that it's ok if you only spray it in when the engine is cranking. Or that it's ok if the engine is very cold (cold weather). Or that it's ok if you only use a short squirt. I've also heard of using WD-40 instead of ether since it is less volatile. Personally, I won't use ether at all.

 

[dweitzel]

I've got a 1998 Cub Cadet compact tractor 7200 4WD 20 HP diesel that all of a sudden has been hard to start. I turn the switch for the glow plug and the lite comes on and then when I engage the starter it spins and white smoke comes out the exhaust. I replaced the battery thinking it was the problem. After I repalced the battery it started the first time, but once it sat over night it would not start. The only way I was able to start it was to spray starter fluid in the air intake and it started right up. The glow plug light stayed on for about 20 minutes and then went out. Once it is started and is shut off it will start back up with no problem however the glow plug lite stays on for a while and then goes out. Any ideas where to start?

Disconnect the common piece of metal across all the glow plugs, put an ohm meter on each plug one at a time. One lead to a ground, and one to the top of the glow plug. If I recall correctly, you should have a dead short across each plug. If the circuit is open, then it is bad.

Also check the black timer relay on the firewall on the right hand side up near the top. That has gone bad on many 1998-9 7360ss cubs. I'm assuming your's is about the same. That relay is about $80. It about 1.5" by 2" and black in color with one modular plug coming out of the bottom and one bolt/screw holding it top the firewall.

Also there is a temp sensor on on the thermostat housing. that work in sync with the timer relay to tell the plugs how long to stay on depending on the temp of the antifreeze.

Also you did not mention. Does the glow plug light come on every time you cycle the key? If not I'd bet on the timer relay.

Dave

 

[kscr4]

Thanks guys for all the help. It'll be another day or two before I can get to checking but as soon as I get it going I'll let you know...once again thanks!

 

[kscr4]

Checked power going to glow plugs and am getting current to bar across the top of plugs...checked each plug with a ohm meter and two showed no reading and a third showed 4.12..I'm assuming the plug with the reading is bad..I took it out and connnected to the power source and when I turned on the swithch it did not glow...this is a mitsubishi engine..is there a online site where I can order the glow plugs? thanks for any help

 

[dweitzel]

Checked power going to glow plugs and am getting current to bar across the top of plugs...checked each plug with a ohm meter and two showed no reading and a third showed 4.12..I'm assuming the plug with the reading is bad..I took it out and connnected to the power source and when I turned on the swithch it did not glow...this is a mitsubishi engine..is there a online site where I can order the glow plugs? thanks for any help

I could be wrong, but I thought there WAS to be a OHM reading from the top of the plug to a ground (with the common rail removed from the top of the glow plugs)

Another problem was the black glow plug relay timer. I believe others have mentioned that when their timer went bad it took the glow plugs with it.

Did you use 12 volts straight from a battery, or did you use the glow plug circuit to test the plug with the ohm reading?

I also thought that the ohm reading should be infinite with good plugs. I bet if you put 12 volts to the other 2 plugs with no reading, they will not get hot either.

Can someone else chime in? Are the glow plugs suppose to have a complete circuit or not? I think they are.

Dw

 

[dweitzel]

Checked power going to glow plugs and am getting current to bar across the top of plugs...checked each plug with a ohm meter and two showed no reading and a third showed 4.12..I'm assuming the plug with the reading is bad..I took it out and connnected to the power source and when I turned on the swithch it did not glow...this is a mitsubishi engine..is there a online site where I can order the glow plugs? thanks for any help

You can look up your parts on the cub cadet web page and see what their inflated prices are, then either order from there, check out your local dealer and pay more, or perhaps look at a mahindra dealer and see if they can look them up based on your engine's serial number? Might be worth a shot if they are real expensive.

Cub Cadet Landing Page

 

[TedLaRue]

kscr4, the plug with the 4.12 reading is the good plug.

dweitzel's first post about resistance was correct, but his/her second post contradicted the first. He/she asked others to chime in, so here I go....

The resistance of a glow plug should be very low. It varies, but the resistance should definitely be no more than 100 ohms, and more likely will be around 0.5 ohms. That could look like a dead short on some ohm meters. If the resistance is low (you mentioned a 4.12 reading) then that plug is probably ok.

If you have "infinite" resistance, then no current will flow through that plug and it won't get hot. If your plugs are wired in series, and one of them has "infinite" resistance, then none of the plugs will get hot (glow).

The resistance of a cold plug will be somewhat lower than that of a hot plug, but hot or cold the resistance should be below 100 ohms.

When you measure resistance this low, it's very important to have good contact between the ohm meter leads and the plug.

When you took the plugs out and connected them to the power source, did you also connect the body of the plug to ground? If not, then they wouldn't glow.

Also, you need to be careful about applying voltage when testing a plug. If the plugs on your engine are wired in parallel, then 12V would be ok, but if the plugs are in series, 12V could burn up a plug (because it's designed to work at 4 volts if you have 3 plugs 12/3 = 4). So if you don't know which way your plugs are wired, don't apply 12V for more than a few seconds.