MEP-003A

[Guyfang]

Look at the comment #117. The wire diagram. Look at the S1 master switch, pin 26. Wire P66D16 runs from S1-26 to TB 5-9. During start up, you should have at S1-26, 24 VDC. At TB5-9, you should have 24 VDC. From TB5-9, the wire goes through J2 and J3 and comes to the K5. It should have 24 VDC there also. so you need to measure the path to see where you are losing volts?

 

[Johncar48]

Could that be pin #28 on S1

 

[Guyfang]

Could be the switch.

 

[Johncar48]

Pin 28 also has a jumper to K3 relay

 

[Johncar48]

Only getting 19.9 volts between pin 28 & K5-9 and K5-9 to solenoid

 

[Ray70]

Not to side track you away from the solenoid voltage issue, but if you wire the solenoid up ( or even remove it ) and it still won't even smoke out the pipe there are other things going on.

Couple questions are:
Do you hear the loud click of the glow plug solenoid when you turn S1 to the left to pre-heat?
Do you hear the fuel pumps running when you turn S1 to Aux and Prime/Run?
And have you tried running the pumps in the Prime / Run position for a few minutes before warming the glow plugs and trying to start it? ( if you have a stuck open check valve your fuel system may have drained back and / or pulled in some air ) while it was sitting all that time.

 

[Johncar48]

Ray fuel pumps come on like usual in prime position, heard glow plug relay kick in and glow plugs are heating up. I jumped a wire from positive battery terminal to positive input of IP solenoid and it pulled up perfectly and the starter motor engaged. I did not have CB2 pushed in when I did this. Guess when weather permits I'll check fuel flow to injectors. Where does S1 get it's 24V from please.

 

[Guyfang]

Look at comment #123. Its also shown here in the schematic. Look at the S1 schedule for START. Measure at terminals 11,13,15,25,27 and 28, while holding the S1 in the Start position. You should get 24 VDC.

Look at the schematic above. The power comes into the S1 on pin #11.

 

[Johncar48]

So after studying your schematic (with colored lines...and thank you for that) the only thing between the batteries and S1-11 to bring the voltage down from 24V would be CB2, if I'm reading the schematic correctly. Would you agree?

 

[Guyfang]

Yep. And I have seen it where the CB2 was the problem. So what we did, was to "jump" the CB2. We used a wire with two roach clips on the ends to jump from CB2-1 to CB2-2. If that changes the voltage readings, you may want to exercise the CB2 a few times, (at least 40-50) and then see if that changes the readings.

 

[Johncar48]

So now everything I test goes from 24V before starter engaged from S1 down to 17.8V
it's 28 degrees F outside and probably time to put a charger on the batteries.

 

[Johncar48]

Not sure what to do next. Charged batteries, jumped CB2 and nothing. Solenoid still doesn't pull up. So I've got 25v going in to CB2-1 and 25v coming out of CB2-2 but when I move S1 to start position CB2-2 drops to 18.7v. When I apply 24v directly to solenoid it pulls up like it should and when I manually hold the solenoid in the up position and crank the engine....nothing, not even a little smoke.

 

[Guyfang]

But the engine turns over?

 

[Guyfang]

Look at TB5-9. There should be two wires hooked up there. One of them is P66F. It goes from TB5-9 to the K5-1.
Disconnect the wire P66F at TB-5-9.
Disconnect the wire P66H at K5-1.
Measure for ohms between the two ends. What do you get?

 

[Johncar48]

Zero ohms

 

[Guyfang]

You mean no continuity? Or continuity?

 

[Johncar48]

There is continunity yes.

 

[Guyfang]

The other wire on the K5-2. It is P55T. It goes to J1/P1, The wire number changes to P55R and goes back to TB4-13,14 and 15. They are all hooked together. Find the wire P55P55R. Measure at the end of P55T, (disconnected from K5-2) P55R, (disconnected from TB4-13, 14 and 15.) You should get continuity.

 

[Johncar48]

Yes Sir, have continuity

 

[Guyfang]

Do you have any voltage on S1-28, when you turn S1 to the Start position?