7520 preheater not working, EMERGENCY!

[jrchafin]

Hey folks,
My 7520 is 1.5 years old, and works great but has trouble starting cold. The light on the dash that looks like a heater coil only comes on for a few seconds when I turn the key to on position, then it goes out and the green healthy light comes on. I try to start and it chugs white smoke if the temp is below 30. Runs fine otherwise.
I believe the preheater is thermostatically controlled, and the coil light should come on and stay lit for 30 seconds or so, when it's cold out. So first question, how can I trouble shoot this?
More important question is how can I get this thing to start. We've got a foot of snow on the ground and my tractor won't start! Is there a way I can jump from the battery directly to the preheater and just manually do it? Or could I put some heating pads on the block or fuel pump to get it going? Advice??

Thanks!

 

[manganos]

Maybe your battery voltage is low??? Might want to hook it up to a charger or try hooking it up to a vehicle. Glow plugs draw a lot of current. If it is parked in your garage (like mine is ) you can put a heater and try to raise up the temp. How COLD is it? You might have other issues such as gel'ed fuel etc? Good luck and let us know what it turns out to be.

 

[jrchafin]

It's right at 30 degrees, not cold enough to gel anything. I've checked the manual and it says the heater coil light should be on for 35 seconds after putting the key to on position, and it's just not coming on. The engine cranks ok, so I don't think it's the battery, but I can certainly try jumping it.

Looking at the wiring diagram, it looks like it should be easy to jump from the battery to the heater element. Think I'll give that a try, but right now I have other stuff going on, so it'll be a bit before I give it a go.

 

[UncleBuck01]

It's right at 30 degrees, not cold enough to gel anything. I've checked the manual and it says the heater coil light should be on for 35 seconds after putting the key to on position, and it's just not coming on. The engine cranks ok, so I don't think it's the battery, but I can certainly try jumping it.

Looking at the wiring diagram, it looks like it should be easy to jump from the battery to the heater element. Think I'll give that a try, but right now I have other stuff going on, so it'll be a bit before I give it a go.

On my 4110 I turn my key left ( like I want to listen to radio in my car )for glow plugs , After the coil lite goes out on dash I turn key to right to start. If temp is in the 20's I cycle the glow plug twice. hope this helps

 

[QRTRHRS]

I don't use my 7520 much when it's cold but I am thinking that my "coil" light stays on long after the green "healthy" light comes on. Once I see the healthy light, I turn the key and it fires right up as long as it is not down in the low twenties or teens. Then it starts hard so I put a block heater on it.

I would put some halogen lights on it to get it warmed up. If you have at least one, aim it near the injection pump. Keep an eye on it so you don't melt anything rubber or plastic. Put a charger on the battery set on a low charge for an hour or so. Crank the amperage up when you go to start it.

 

[LAWALLSTRACTOR]

First of all the 7520 doesn't have glow plugs, but they can be added as an option. The heater indicated on the instrument panel, is an intake heater which isn't as effective as glow plugs, but it helps.
At 30 degrees the 7520 should fire up without the heater, but if I were you I would install a block heater, which I think most of us dealers keep them in stock, at least I do. I have always installed the block heater at the point of sale, so I haven't had any complaints about starting. I will be in the shop tomorrow and will look in the service manual to see if I can find you any help.

 

[manganos]

There ya go! Seems like that is the ticket! (above)

 

[QRTRHRS]

There ya go! Seems like that is the ticket! (above)

You bet! Galen hooked me up. I used it once this year already. About two hours and I did not even need to preheat the intake.

 

[SPYDERLK]

The 7520 has a relay that energizes the intake manifold heater for about 45s after the ignition is turned on. Try this: Turn ignition on, raise hood and look at the intake manifold on the left side of the engine. There are wires [Ground&+] leading to it for the heater that is inside. After 30 s or so you should be able to feel some warmth on the outside of the manifold. Now try to start. It should fire right up. If no heat its probably the relay. You might try manually making the + connection temporarily for starting with a good clip lead [45 Amps] running straight from the + supply at the heater relay, then over to the + elec input stud on the heater. You should see a spark as you make the connection.
larry

 

[jrchafin]

Ok, preheater is definitely not working. I jumped from the positive battery terminal to the heater with a jumper cable, and after about 15 secs I could feel the warmth. Of course, before it wasn't getting warm at all. Also, the coil light on my dash was lit while I had the jumper in place. Correct me if I'm wrong, but that sounds like the relay to me.

It still chugged a little bit to start, but it started. I live in Virginia, and I'm not opposed to getting a block heater, but it seems like overkill. It just doesn't get that cold here. My dodge/cummins never has trouble. Do you think a block heater is necessary?

And next, the age old question, how much does it cost??

 

[LAWALLSTRACTOR]

It sounds like you could be correct about the relay, but I would check it first. One wire to the relay should have 12 volts all the time, one should go to the heater element, one should go to a grounding point and the last one should have 12 volts when you first turn on the key. If that checks out the problem could be a poor ground, timer module or any wire not making a connection. As for the block heater it could possibly help you out at times like this however few they may be. I sent you a PM.

 

[jrchafin]

So to check this relay, do I unplug it and check the voltages you mentioned, or does it have to be plugged in while testing?

How can I identify which relay it is?

 

[SPYDERLK]

So to check this relay, do I unplug it and check the voltages you mentioned, or does it have to be plugged in while testing?

How can I identify which relay it is?

On mine it is up by the PS reservoir on the frame for the removable leftside panel. There should be good sized wire [10 or 12 ga] from batt+ feeding it and a good sized wire from it over to the heater +. Also theres a connector that brings in power from the Ig sw to close the relay. Yours is either not closing or is closing but has bad contacts. You should hear a click when you turn you Ig sw to the 1st position. That is the relay closing. Now the 2 bigger wires should be connected internally by the relay and power the heater. If you have a Voltmeter you can measure the voltage across the relay-[from one wire to the other]. With the relay open it will be 12V -- closed =~0V. Be sure not to use the Ohm scale on a live circuit. I believe that the relay and timer, mentioned by Galen, are a combined unit.
larry

 

[QRTRHRS]

Ok, preheater is definitely not working. I jumped from the positive battery terminal to the heater with a jumper cable, and after about 15 secs I could feel the warmth. Of course, before it wasn't getting warm at all. Also, the coil light on my dash was lit while I had the jumper in place. Correct me if I'm wrong, but that sounds like the relay to me.

It still chugged a little bit to start, but it started. I live in Virginia, and I'm not opposed to getting a block heater, but it seems like overkill. It just doesn't get that cold here. My dodge/cummins never has trouble. Do you think a block heater is necessary?

And next, the age old question, how much does it cost??

Where I live in KY, we see an occasional single digit day and it may dip in the teens or twenties but does not usually last long. Mostly, it is just damp. Having lived and had equipment where if I did not plug it in, it would hardly if at all turn over, I have spent plenty on electricity.

I figure that for two hours of drawing 750 watts, my 30k tractor is going to start easier and get better lubrication as opposed to spitting and sputtering until it smooths out.

I would have to look it up but I am thinking that the cost is about the same as three cases of Bud.

 

[manganos]

On my vehicles with block heaters I have them setup on timers that are plugged into the outlet. I set them to start 2 hours before I plan on starting the truck/vw/tractor etc That way they aren't drawing current all night for no reason.

 

[QRTRHRS]

On my vehicles with block heaters I have them setup on timers that are plugged into the outlet. I set them to start 2 hours before I plan on starting the truck/vw/tractor etc That way they aren't drawing current all night for no reason.

I picked up a simple hot water heater timer that can handle the current draw long term with the plastic on/off clips similar to the bargain basement types. Meant to be hard wired, I wired up an extention cord so I could move it if I needed to. It is in a weather resistant enclosure. Cost me less than 40 bucks a few years back.

 

[CurlyDave]

My tractor lives in a garage which never gets below about 60 F in the winter, so I have no problems starting, but let me ask a dumb question anyway.

Why wouldn't a tarp over the tractor and a $15 Wally World convection heater be enough to heat up the engine enough to start in many places? Seems to me this would be a lot less costly than a block heater and in the same 2 hours raise the temp enough to get the job done...

 

[QRTRHRS]

My tractor lives in a garage which never gets below about 60 F in the winter, so I have no problems starting, but let me ask a dumb question anyway.

Why wouldn't a tarp over the tractor and a $15 Wally World convection heater be enough to heat up the engine enough to start in many places? Seems to me this would be a lot less costly than a block heater and in the same 2 hours raise the temp enough to get the job done...

A tarp and a heater will actually work. I will tell you that through the years, folks have actually built fires under engines to get them started.

I would say that if you cannot afford a heater that cost under 40 bucks and the power to use it then perhaps you have more issues than getting the tractor fired up.

 

[jrchafin]

Yeah, I always figured a block heater would be an expensive add on. Turns out it's about $35, so I'm going to do it. I'm sure it works better than a tarp!
Problem is the relay I need is $109. (For a frickin relay??? ) So I'm going to wire a switch between the battery and the intake heater. I'll just turn it on and off manually.

 

[SPYDERLK]

Yeah, I always figured a block heater would be an expensive add on. Turns out it's about $35, so I'm going to do it. I'm sure it works better than a tarp!
Problem is the relay I need is $109. (For a frickin relay??? ) So I'm going to wire a switch between the battery and the intake heater. I'll just turn it on and off manually.

Thats what I do. Works great! In cold weather hit it for 20-30s and starts instant. Just be sure to use one that you have to hold to keep it on... That way you dont ever leave it on. The heater draws about 45Amps.

The hi relay$ it probably because its a timer too. Too much to go wrong, I think.
larry