002a voltage regulator

[dangier]

Working on sorting out electrical problems on a 002a and have a burned R11 resistor (1/2 watt, 330 ohm), on the voltage regulator. Is this an indication of Q2 also being taken out? Voltage goes high when board is installed in a working unit.
Thanks
David

 

[Triple Jim]

David, if R4 also looks like it got hot, I'd say Q1 might have failed. Q2 could also be the problem, because if it fails, it could cause Q1 to fully conduct. If it's just R11, I'd suspect the 18V Zener diode, CR6. Any more detective work would require some voltage measurements while in operation.

 

[dangier]

Triple Jim,
The only piece that looks burned is R11. Still working on getting the engine running. Starts hard (even hot). Have to use starting fluid (sparingly). Once it gets up to starter dropout, I get some smoke and then it takes off. Have had the ip apart several times and everything looks ok to me. Timing is right on pc mark. Storeman checked out the injectors and reset to spec. Once I get the engine running, I have no power on any terminals on the vr. Looking at tracing wiring from schematic.
Thanks,
David


























avid

 

[1800 Diesel]

Triple Jim,
The only piece that looks burned is R11. Still working on getting the engine running. Starts hard (even hot). Have to use starting fluid (sparingly). Once it gets up to starter dropout, I get some smoke and then it takes off. Have had the ip apart several times and everything looks ok to me. Timing is right on pc mark. Storeman checked out the injectors and reset to spec. Once I get the engine running, I have no power on any terminals on the vr. Looking at tracing wiring from schematic.
Thanks,
David

David,

A couple basic questions about the 002--(take no offense if you're 100% familiar with these units.)

1. Prior to starting, you are holding the preheat switch for 45 seconds, right? I'll assume your response is yes, since you stated the starting problem also occurs when the engine is hot.

2. Did you verify that the check valve is installed between the secondary filter & the IP? Even if it is in place, you should take it off and clean/test it for proper function without any leakage. If it leaks past, then replace the valve.

3. Have you cracked the fuel line fittings on the injectors and verified good fuel flow while cranking?

4. If everything checks out & Jerry setup your injectors & the IP is known good & you are getting good fuel flow, then that leaves low compression. (I think it's safe to say the engine is getting air.) I suggest that you do a compression test to isolate the problem. There's a fellow on this site who can machine an adapter for this purpose. I believe Jerry may have one if you live close to him.

5. An afterthought--did you check valve adjustment? Too little lash will open the valves too far and too long and could lower compression also.

Hope some of this helps.

Kevin

 

[dangier]

Hard starting 002a

Kevin,
Appreciate the response:

1. Prior to starting, you are holding the preheat switch for 45 seconds, right? I'll assume your response is yes, since you stated the starting problem also occurs when the engine is hot.

Yes, I have preheated for up to one minute. Also, have verified that the heaters and glow plugs are being powered and are actually heating.

2. Did you verify that the check valve is installed between the secondary filter & the IP? Even if it is in place, you should take it off and clean/test it for proper function without any leakage. If it leaks past, then replace the valve.

This unit came without the check valve. To test to see if the fuel is bleeding back, I pinched the line with a refrigeration line clamp at hot shutdown and then tried to restart immediately. No go-would not start. Plan to get into Advance Auto for a #CV8000 check valve when I can.

3. Have you cracked the fuel line fittings on the injectors and verified good fuel flow while cranking?

Yep, bled until I have plenty of fuel. This ip came on the unit. Have taken it apart and replaced the plunger guide as well as cleaned/checked everything inside. Kind of wondering if it is worn enough so it is not making high enough pressure to pop the reset injectors on start-up cranking. Before the injectors were cleaned/reset, it would start ok, but ran crappy. Bought a new ip from Gimpyrobb, but ended up putting it on another unit. May have to buy another ip-just want to see if it is actually needed.

4. If everything checks out & Jerry setup your injectors & the IP is known good & you are getting good fuel flow, then that leaves low compression. (I think it's safe to say the engine is getting air.) I suggest that you do a compression test to isolate the problem. There's a fellow on this site who can machine an adapter for this purpose. I believe Jerry may have one if you live close to him.

I have a diesel compression test kit, just need to have an adapter made. I am a couple of hours from Jerry. There is a local machine shop I may contact to have one made. Would be nice to have one on hand. I pulled the head to check the head gasket, cylinder, and valves. Looks good-cylinder still has machining cross hatching. There are 163 hours showing on meter. Head gasket was ok. Valves had been adjusted and checked again (.007 exhaust and .010 intake).

5. An afterthought--did you check valve adjustment? Too little lash will open the valves too far and too long and could lower compression also.

I have one operating machine for backup. It is going to take some time to iron out problems as there are electrical issues. Just have to get it running first....

Thanks,
David

 

[1800 Diesel]

Kevin,
Appreciate the response:

1. Prior to starting, you are holding the preheat switch for 45 seconds, right? I'll assume your response is yes, since you stated the starting problem also occurs when the engine is hot.

Yes, I have preheated for up to one minute. Also, have verified that the heaters and glow plugs are being powered and are actually heating.

2. Did you verify that the check valve is installed between the secondary filter & the IP? Even if it is in place, you should take it off and clean/test it for proper function without any leakage. If it leaks past, then replace the valve.

This unit came without the check valve. To test to see if the fuel is bleeding back, I pinched the line with a refrigeration line clamp at hot shutdown and then tried to restart immediately. No go-would not start. Plan to get into Advance Auto for a #CV8000 check valve when I can.

3. Have you cracked the fuel line fittings on the injectors and verified good fuel flow while cranking?

Yep, bled until I have plenty of fuel. This ip came on the unit. Have taken it apart and replaced the plunger guide as well as cleaned/checked everything inside. Kind of wondering if it is worn enough so it is not making high enough pressure to pop the reset injectors on start-up cranking. Before the injectors were cleaned/reset, it would start ok, but ran crappy. Bought a new ip from Gimpyrobb, but ended up putting it on another unit. May have to buy another ip-just want to see if it is actually needed.

4. If everything checks out & Jerry setup your injectors & the IP is known good & you are getting good fuel flow, then that leaves low compression. (I think it's safe to say the engine is getting air.) I suggest that you do a compression test to isolate the problem. There's a fellow on this site who can machine an adapter for this purpose. I believe Jerry may have one if you live close to him.

I have a diesel compression test kit, just need to have an adapter made. I am a couple of hours from Jerry. There is a local machine shop I may contact to have one made. Would be nice to have one on hand. I pulled the head to check the head gasket, cylinder, and valves. Looks good-cylinder still has machining cross hatching. There are 163 hours showing on meter. Head gasket was ok. Valves had been adjusted and checked again (.007 exhaust and .010 intake).

5. An afterthought--did you check valve adjustment? Too little lash will open the valves too far and too long and could lower compression also.

I have one operating machine for backup. It is going to take some time to iron out problems as there are electrical issues. Just have to get it running first....

Thanks,
David

Edit--I haven't done this on these specific diesels, but as the tubing allows it, remove the injectors & connect to the lines and then crank on the engine to observe pop-off timing and spray. Obviously follow standard safety precautions for eye & skin protection....

You'll find a drawing on this site with the details of the adapter & also the POC to build it.

 

[Triple Jim]

To correct my post above, which assumed you have a 72-5338 regulator, your 72-5020 regulator calls the 18V zener diode "CR2". If that's shorted, R11 would carry more current than normal, and get hot. The zener diode is rated at 1 watt, so any generic 18V 1W zener can be used as a replacement.

 

[dangier]

1800 diesel-talk about not seeing the forest for the trees.... I never thought about taking the injectors out and then trying them..... Oh well.

Triple Jim-Thanks for the follow-up. Electrical side is on the back burner until I get the engine running. Stopped by a machine shop this AM and they are making me an adapter to go in place of the injector for compression testing.
Thanks
David

 

[Triple Jim]

You probably know, but be sure the adapter has next to zero volume or you'll read low compression when it's not.

 

[Jimc]

hmm doesnt the adapter usually replace the glow plug? seems like a bit of a pain to pull an injector for each cyl to check compression not to mention there are gaskets involved.

 

[1800 Diesel]

hmm doesnt the adapter usually replace the glow plug? seems like a bit of a pain to pull an injector for each cyl to check compression not to mention there are gaskets involved.

You're correct, the adapter is installed in place of the glow plugs...here's the thread with the details in case he needs the info:

http://www.steelsoldiers.com/showth...on-Testing-on-MEP-002A-003A&highlight=adapter

WRT pulling the injectors, I suggested this so he can connect the fuel lines with the injector outside & in plain sight--this in order to observe spray & pressure being delivered by the IP....

Thanks for the clarification though on the adapter, since he was getting one made, I assumed he knew where it had to go...my bad...I'm curious about the outcome of this one..pretty stubborn problem; hopefully he's narrowing it down...

 

[dangier]

All,
My bad on not asking.
Thanks,
David

 

[dangier]

All-thinking about this.... I knew I had seen it somewhere. TM34, dia 7-10.1 shows an injector adapter to check compression. Point on the gaskets is well taken.
Appreciate the feed back.
Thanks,
David

 

[storeman]

There is a local machine shop I may contact to have one made. Would be nice to have one on hand. I pulled the head to check the head gasket, cylinder, and valves. Looks good-cylinder still has machining cross hatching. There are 163 hours showing on meter. Head gasket was ok. Valves had been adjusted and checked again (.007 exhaust and .010 intake).

NJTOOLNUT makes adapters and made mine. Try him.
Jerry

 

[dangier]

Ok, back from quality time with the grand kids..... I let the machine shop finish the compression adapter for the injector attachment. Pictures below. Had machine shop drill a 1/8" diameter hole through center for gauge access. Tested the adapter on a working 002 and got 385 psi dry and 430 psi with few drops of oil in #1 cylinder. Used a snug fitting o-ring to seal. Went to the down machine and did compression tests-both cylinders had roughly 380 psi cold and 420 psi with oil added. Have good compression. As suggested one possibility is to install the injectors outside the unit connected to verify they are indeed spraying. Tried this and no spray! The IP is weak enough that it does not furnish fuel with correctly set injectors (thanks Jerry). Did run rough with injectors running around 1000+ psi. Working on new ip.... Now to the electrical side. As mentioned before, I had found a bad R11 resistor on the A2 board. It was suggested that I check the CR2 diode. Unsoldered and checked. Current both ways...Bad! Have since found a burned R1 resistor on the A4 board and questionable CR5 diode (suspect overheated when R1 went south as it is directly above it). Does this combination of failures raise any red flags to the knowledgeable?
Off to buy electronic parts... Appreciate the help so far.
David

I did find the table in '34 for testing the bridge assembly diodes and the correct ohm reading (56 ohms) for the R1 resister. Anyone know the specs on the resister (wattage)?

 

[Triple Jim]

What was the resistance of R1? I wouldn't expect it to overhead unless something upstream allowed flashing current to continue when it was supposed to stop. If the 18V zener diode shorted, it would be normal for the R11 to overheat. Offhand I don't see these things pointing to a bigger problem, but when you get the parts replaced, observe the generator output voltage and it it's abnormal, run it just long enough to make measurements as needed to find out why.

Edit: You might check the output of T1, terminals 15 and 16 on the regulator board, when you get it running. Seems to me that should be around 24VAC. If something is wired wrong and a higher voltage is getting there, that could blow the zener.

 

[dangier]

Does the R1 need to be un-soldered for measurements or can it be done in place?
Thanks,
David

 

[Triple Jim]

If you disconnect the wire at terminal 6, then you've disconnected one end of R1 and can make the measurement.

 

[dangier]

No ohm reading on A4 R1-resistor broken in the middle. Got A4 board out and all diodes check out ok. Found numbers on the R1 on my working unit (V560, CM-5-5, and CV8124). Mouser has a wide range of resistors. Anyone know where I could find the wattage value? Should I just overkill and go high (50-100 watts)?
Did find a large amount of loose connections.
Thanks,
David

How extensive is a Tier 1 reset suppose to be?

 

[Triple Jim]

The parts manual shows the part number for the resistor as 5905-00-081-7350. A google search turns up several sites that say it's a 56±5 ohm resistor, rated at 6.5 watts in free air. Anything around that resistance, rated for 6.5 watts or more, will be fine as long as the problem that made it get hot is fixed.