how does the injector solenoid work on a CK20S?

[ritcheyvs]

Ordered a new solenoid and O-ring from MIE. There's another part, the solenoid guide that was out of stock but I don't think I need that so didn't get it; anyone know what that is?

You almost certainly don't need the "guide." The guide is a plastic part that fits between the solenoid plunger and the injection pump rack. It also provides a place for the manual stop lever to push against to stop the engine; the lever in your photo is the manual stop lever. You need to remove more than just the SS to get to the guide. Don't worry about the guide.

By the way, the engine should be able to start and run with the SS removed. But you would need to use the manual stop lever to stop the engine and oil mist and drops would come out the open SS hole while the engine runs (messy).

 

[ritcheyvs]

This photo shows the view into the engine with the stop lever plate removed. The white plastic thing is the guide. The SS is on the right and the SS plunger pokes into the guide. The guide is pushed out (as seen here) by the injection pump rack as it moves forward (more fuel injected) providing the SS plunger is retracted.

 

[DroppedAxle]

Ok, this is turning into more of a mystery.

Thanks for your response Ritchey; and sorry for the delay. I got a new solenoid from MIE and it has exactly the same symptoms. Does not retract as I move the switch from off through to crank. Both solenoids do not retract automatically, but with them removed and engine cranking, I can nudge them into the "run" position and they lock there until the key is turned off again. Here's what I've checked:

1) Fuses are good. Pulled and inspected all of them. Swapped the 25A solenoid fuse with the spare. Same results.
2) Battery is good and on a trickle charger so always 100% when I work on this. Tried with an additional booster battery; same results.
3) Using an LCD voltmeter set to 0-20VDC range, I see a pulse go from 0-11V between the red and black wire as I move the switch through to cranking. There's some lag in the voltmeter so it may not peak there. This pulse is approximately 1 second, maybe a bit less.
4) Using same voltmeter, I see 10.5V while cranking and 12.4V when not (but key not off) between the white and black wire.
5) Cleaned the contacts best I could on the connector to the solenoid; didn't change anything.

It is still possible there is an electrical problem. If you measured voltage pulse with the SS disconnected it is possible to see a good 12v even when failing relay contacts will not pass enough current. The acid test would be to jumper the SS "pull" contact to the battery + terminal momentarily (less than a second).

SS relay failure is common but SS failure is rare (although it has happened). The SS relay is the same as the starter relay and temporarily swapping connectors between those two relays is a common troubleshooting method. The actual relays are common automotive parts available at any auto parts store (and very cheap in quantity on ebay).

I'm guessing I may be looking at SS relay failure? Can you (or anyone) describe where this thing is located?

Thanks.
DA

 

[ritcheyvs]

Good guess.

There are (usually) three relays on the vertical "fire wall" near the back of the engine. The starter and SS relays are identical and you can swap the connectors (leave relays in place) between them for troubleshooting. The third relay has a higher current rating and it powers the glow plugs.

These are common automotive relays available at any car parts store. Or you can get several cheap on Amazon.

In the future, spend more time isolating problems and less time buying and swapping parts.

 

[DroppedAxle]

Here's what I'm looking at:



This is the stop solenoid "pull" relay I think:



(There are more relays along the top; not shown in the pics.)

And here's a diagram for a ck20s workshop manual:



I'm going go look for a part compatible with T2185-69971 now.

 

[ritcheyvs]

I suspect the only available CK20S service manuals show the previous version. That's the situation with my DK45s. But (in my case) the EX45 manual does show my engine, although nothing else in the EX manual applies to my tractor.

Often, the online parts manuals (which tend to be updated) are better information sources. This one may appears to show the correct parts locations for your machine.

I think either #16 or #20 relay (in parts diagram) is the SS pull relay and the other is the starter relay. I also suspect the timer relay generates the 1 sec 12v pulse to activate the SS relay. I don't have a schematic so I can't be sure.

First, verify you have found the SS relay. Pull off the connector and make sure the 12v pulse you observed is gone but the engine still cranks. Then substitute another relay, either a new relay or the start relay.

The CK20 relay locations are totally different from the larger tractors so swapping connectors between start and SS relays does not look practical on your model (too far apart). Best bet is probably to buy a new relay and try it.

 

[DroppedAxle]

The engine diagram is from a CK20S(H) workshop manual and does seem to match what's on my firewall. Here's another pic after a bit of rodent cleanup:



I pulled off the connector on the T2185-69971 "pull" relay (the black one on the far left in the above pic). No longer seeing a 1s pulse between R&B at the SS. Still seeing 12v constant with key on between W&B as expected I think.

Here's a schematic of the electrical starting system from the same workshop manual:



Absent any recommendations for relays compatible with T2185-69971 from auto parts stores, I'll order one (or two) from MIE.

Thanks.
DA

 

[ritcheyvs]

MIE is a fine operation but this is a standard automotive part.

If you are in a hurry, take the old (suspect) relay to Autzone, Advance, OReilly;s, NAPA, Pep Boys, etc. and they'll find you a new one.

 

[DroppedAxle]

The mystery deepens...

If you are in a hurry, take the old (suspect) relay to Autzone, Advance, OReilly;s, NAPA, Pep Boys, etc. and they'll find you a new one.

I did this and got a replacement which has all the pins labelled the same and is 30A:



However, with that new relay, there's no pulse at all! (Recall, the old relay showed a pulse but the suspicion was that its contacts are bad and not able to carry enough current to set the SS.)

How to proceed now? I guess I can wire the SS directly to the battery briefly to see if the SS plunger moves to verify that the SS is ok -- it really should be since I have two of them and they both act identically.

Thanks!
DA

 

[ritcheyvs]

I think I'd start by making sure the new relay was OK. Unplug the connector from the starter relay and plug the new relay into that lose connector. Then check if the starter cranks. If not, you got a bad relay.

You can also unbolt the known-good starter relay and plug it into the SS relay connector to verify the problem is not the SS relay

If the new relay checks out OK, and the starter relay doesn't "pull" the SS, I'd go back to the beginning. Do you have a volt meter? If so, use the schematic you included in post #17 and start by ensuring the SS fuse is really good. Verify 12v power gets to the "hot" input contact of the SS relay whenever the key is ON. The contacts should have the bigger wires and you should be able to slide a meter probe into the back of the connector to take measurements. You'll need a helper to turn the key as you use the meter to verify power gets to the output SS relay contact briefly after the key is turned on. See if you can feel or hear the relay activate and deactivate when the key is turned to ON (easiest if relay not mounted. In short, just follow each "link" in the electrical chain to see where the problem is.

One other thing (and maybe check this first): These key switches are famous for developing poor electrical contacts from dirt and corrosion. So squirt a bunch of WD40 in the keyhole and cycle the switch several times (and maybe repeat) to clean these contacts. I had that problem several times.

When you get it fixed, note the sound of the SS retracting (key on) and extending (key off) so you can diagnose SS function by ear in the future.