Jump to content
608KEB

520 H won't start. Hour meter/oil sensor

Recommended Posts

608KEB

I put in my new oil sending unit. It does not work. Also the hour meter works with the key in the on position. But when engine is running the hour meter does not work. What is the problem? When I hooked up the oil sending unit I soldered the connecters and shrink wrapped them...

IMG_20150817_110040_867.jpg

Edited by 608KEB
9

Share this post


Link to post
Share on other sites
 
Save Old Iron

Sounds like the hour meter connection to the pressure switch is hooked up to the incorrect terminal on the pressure switch. Change the wiring from the hour meter to the other terminal on the pressure switch.

Share this post


Link to post
Share on other sites
 
608KEB

Now it will not start. I turn the key and nothing. I jumped a wire from + battery to starter (blue wire) it turns over. I can hear and feel the relay when I turn the key to start. I cleaned starter switch and relay contacts. It does have constant power. What do I check out next?

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
Save Old Iron

Do you have a multi-meter or test light to do basic troubleshooting?

We also have to find out if that part # is correct for the 520H.


 

Share this post


Link to post
Share on other sites
 
Save Old Iron

and how about a little history of this issue? what was the reason you have a new oil switch?

what year 520?

we have to retrace your steps as I believe the oil pressure switch only controls the indicator light and the hour meter - not the starter function.

 

Share this post


Link to post
Share on other sites
 
Save Old Iron

one terminal on the pressure switch should be grounded with withe engine OFF - hook the oil pressure indicator to that terminal.

the second terminal on the pressure switch should ground out WHEN THE ENGINE IS RUNNING / HAS OIL PRESSURE - connect the hour meter to this switch terminal.

  • Like 1

Share this post


Link to post
Share on other sites
 
608KEB

I switched the blue and black wire at the oil pressure switch. That now functions correctly. The hour meter works. The oil light however does not come on at all. It does not flash with ignition key on. It's possible the led is not working. The next problem was the 9 pin connector. I cleaned and adjusted the pins that plug in together. It now works at all times. Prior to this I had to shake the 9 pin connector to get it to start. I found the problem and fixed it. Next I removed the 3 relays and thoroughly cleaned connectors on both ends. I used waterproof electric grease on all connections. Next I started it 4-5 times let it run maybe 1-2 minutes each time. I went to start it again and there was nothing. I can hear the starter relay click when I try to start it. Next I checked the starter. I ran a jumper wire from the +battery to where the light blue wire goes to starter. It turns  over no problem. But it did not start. Since then I checked all the saftey switches and ground connections. The seat switch is bypassed. I separatd the brown and orange wire. With the key on. I can hear the relay click when I touch these two wires together. I removed the PTO switch and bracket. I sanded the metal so there is a solid ground connection for the 2 black wires that are grounded with the PTO bracket. That is how far I got checking everything over. I also use electric contact cleaner. I do have a multimeter tester
 

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
608KEB

I also took the ignition switch out and cleaned the plug in and switch contacts

Share this post


Link to post
Share on other sites
 
Save Old Iron

to check the function of the oil light circuit

key on, engine off

jumper the dark blue wire on the TRACTOR side of the 9 pin connector to ground - the oil light should come on (checks if indicator is functional)
remove the jumper and
ground the dark blue wire on the ENGINE side of the 9 pin connector - the oil light should come on
(this checks the pins within the 9 pin connector)
then ground the dark blue wire at the oil sender to ground (checks wiring from sender to 9 pin conn) - the oil light should come on.

Edited by Save Old Iron

Share this post


Link to post
Share on other sites
 
Save Old Iron

another comment (maybe) unrelated to the oil indicator issue, once the 9 pin connectors start going bad, reforming the contacts by squeezing or cleaning them rarely solves the problem long term. Once the metal contacts loose their resilience, replacement of the contacts / and housing is the only way to go.

Share this post


Link to post
Share on other sites
 
608KEB

O.k. I will do that and report back with my findings. What should I look at in regards to getting the 520 to start?

Share this post


Link to post
Share on other sites
 
608KEB

I jumped the dark blue wire from the tractor to ground. The oil light did not come on. I'm more concerned with getting the tractor to start and run at this point. Any suggestions would be appreciated to get the 520 running.

Share this post


Link to post
Share on other sites
 
608KEB

As far as the oil sending unit another member helped me source it by cross referencing onan and Cummins manuals. I also confirmed the oil sending unit with the Cummins dealer. He also cross referenced it. So the switch should be the correct one. 

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
608KEB

I checked the voltage at the fuse block. The 30 and 25 amp fuses were at 27 volts. The 15 amp was at 8 volts. Is this good? Did I check it correctly?

IMG_20150819_203210_142.jpg

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
WNYPCRepair

Hard to see but it looks like you are using the AC voltage selection. You need DC (20v) to check the fuses
 

Edited by WNYPCRepair
  • Like 2

Share this post


Link to post
Share on other sites
 
Save Old Iron

Hard to see but it looks like you are using the AC voltage selection. You need DC (20v) to check the fuses
 

Correct

set your meter to the DC 20 volt range i pointed to in the pic below.


 

ac dc.gif

V~         scale is for AC voltages

V ___  is for + and - DC voltages
   - - -

  • Like 1

Share this post


Link to post
Share on other sites
 
608KEB

I set the tester as instructed. The 15 amp is at 12.5, 25 amp at 12.57, 30 amp 12.5

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
Save Old Iron

Kurt,

I will need to confirm you had your black meter lead on the battery negative terminal (it appears you did but I would like to confirm that).

The readings are interesting, especially the -3.96 volts at the 15 amp fuse. Is that right ? MINUS 3.96 volts?

Since the 30 amp and 15 amp fuses are not in any way related to starting, let's concentrate on the 25 amp fuse. The 25 amp fuse supplies power to the ignition switch and all the relays required to function properly to start the engine.

Place the black meter lead firmly on the battery negative terminal and measure to inlet and outlet of the 25 amp fuse. Most fuses have 2 small metal test points on the top of the plastic case where the amperage marking is. Measure both points and post back the results.



 

000086.png

Edited by Save Old Iron

Share this post


Link to post
Share on other sites
 
Save Old Iron

with the symptoms we are troubleshooting, an INCANDESCENT test light ( not LED) might be more beneficial to help find the issue.

I will be traveling until this weekend, so if anyone can jump in and help out until then, we might be able to get you up and running quicker.

Last but not least, is your problem the engine is just not cranking or is there a no spark issue also?

Edited by Save Old Iron

Share this post


Link to post
Share on other sites
 
608KEB

All 3 fuses are at 12.5 volts. Multimeter black lead on - red lead on slot in fuse. Key turned to run. I will pick up a light tester. I won't be home til sat.to check it out further.

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
Save Old Iron

Does your 25 amp fuse have two metal test points on top near the 25A marking?
If it does, is 12 volts on each point?
if 12 volts is not on each point, then we have a fuse or fuse holder issue.

Share this post


Link to post
Share on other sites
 
Save Old Iron

If the fuse holder area appears in good condition (this is a high failure area due to corrosion)
proceed on to measuring the LIGHT BLUE  wire entering at the base of the SWITCHING RELAY.

12 volts should be on the light blue wire when the ignition switch is in the RUN position.

520 crank.gif

Edited by Save Old Iron

Share this post


Link to post
Share on other sites
 
608KEB

I  checked each point on the 25 amp fuse. Both points are at 12.5 volts. So put the black lead on the - battery and the red lead on the light blue wire before the relay? Using the multimeter

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
608KEB

Can't I test the light blue wire that plugs into the starter at the end of it? 

Edited by 608KEB

Share this post


Link to post
Share on other sites
 
Save Old Iron

I  checked each point on the 25 amp fuse. Both points are at 12.5 volts. So put the black lead on the - battery and the red lead on the light blue wire before the relay? Using the multimeter

 So put the black lead on the - battery and the red lead on the light blue wire before the relay? Using the multimeter

Yes

With the red lead (or preferably the test lite) on the light blue wire into the switching relay

key on, engine off, PTO off, operator in seat and trans in neutral,

light blue wire should have 12 volts - this will check the ignition switch and all the safety switches

Share this post


Link to post
Share on other sites
 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • BrianKoch
      By BrianKoch
      Hello gentleman, 
       
      Problem: will not crank on its own, will crank with jump box—but still not fire
       
      Recent things I did prior to this issue: cleaned fuel filter, replaced battery cables, replaced cable from ignition to starter
       
      I have my test light out and am probing around. 
       
      There is no power at ignition/magneto wire or the ignition/starter wire
       
      There is power everywhere else






    • Jeff-C175
      By Jeff-C175
      Detailed wiring from the Demystification Guide #492-4509
      4 pages 1.4MB Color
      p7-67 to p7-70
       
      Onan powered
       
      1989 416-8 model 31-16O801
    • trident
      By trident
      Need some help. My 800 Special has an electric PTO. It is not working. Checked Ohms - nothing. My questions are 1) how does the PTO come off and 2) can they be rebuilt? I took the bolt out that I thought holds it on but no luck. Must be something more?
    • grasscuts
      By grasscuts
      Hi, here's what happened. I changed out 9 pin moles plug...had issues tracter quit running and changed the plugs while I was at it....got plugs from auto store cross reference to ngk they said it was the same heat range and I check electrod  length with calipers ,same...tracter started right up and ran great for about 10 min. And started back firing and quit.....going to check it out tonite anybody have an idea?    
    • jakester
      By jakester
      hello all I'm a new owner of a 312-8 tractor, have starting problems, came across a very small, what I believe is a relay between the battery and the dash,its about 2/3rd size of a cube of sugar silver on the outside blue on top with a hole bout the size of a pea, theres 6 pins with wires connected to it on the bottom do not know what this is any thoughts? I cannot determine the exact year of this machine for there is no tag anywhere only tag on engine kohler magnum md #m12s   ser# 170370459  spec#  471527  I figure its mid to late 80s to early 90s. of all the wiring diagrams ive looked at it does not show any thing like what I just described also can that little circuit board be removed that's like a test point for idiot lights? any help would be appreciated  jeff
×
×
  • Create New...