Super Glow for 3B - 12v

[bj70alex]

Hi,

Trying to figure out if my superglow system works. Replaced both ground cables and positive cable with welding cables. Looks like I have continuity between each glow plug and the block. I was looking thru FSM to find out the voltages for the 1st cylce (Glow Plug Relay #1) and the voltage for the 2nd Glow plug relay. What should be the voltages?

Thanks,
Alex
85 BJ70
93 FZJ80

 

[lumpy70]

You'll get a disappointing 8.5V on the first cycle, and 4.5V on the second. That's what I got on my '85 BJ70. I asked around and it's pretty standard to get those readings.

That's one of the reasons the Superglow went into the garbage for me...not enough heat for a proper start.

Craig.

 

[dieselcruiserhead]

What are you replacing it with?

 

[Radd Cruisers]

I have to admit the super glow system is bunk, you should get the 8.5 on the super glow for the first glow and then the secondary glow kicks in at 6.5 and watch it drop slowly.

As always mentioned myself and others have replaced the system with a rocker switch and 10.5 glow plugs.

Lately I have wondered about the single stage 1HD-T engines and thier single stage plugs, I guess they super glow and then hold the heat in the tip of the plug. My other guess is the direct injected engines need little heat to start in the first place???

 

[bj70alex]

Well, he is latest on my super glow test. I disconnected both #1 and #2 relays and checked for continuity and it's according to specs in FSM. Checked the current sensor and resistor, there were continuity according to specs. Cleaned the contacts on the #1 main relay. Hooked the voltmeter to check the voltages. On the super glow, got about 8.7 volts and when I heard the second click, ZERO volts, looks like #2 relay didn't even kicked on. Where do you think the problem is, wiring, resistor or??????

Thanks,
Alex
85 BJ70
93 FZJ80

 

[bj70alex]

Well, he is latest on my super glow test. I disconnected both #1 and #2 relays and checked for continuity and it's according to specs in FSM. Checked the current sensor and resistor, there were continuity according to specs. Cleaned the contacts on the #1 main relay. Hooked the voltmeter to check the voltages. On the super glow, got about 8.7 volts and when I heard the second click, ZERO volts, looks like #2 relay didn't even kicked on. Where do you think the problem is, wiring, resistor or??????

Thanks,
Alex
85 BJ70
93 FZJ80

I think that I was checking the wrong # 1 relay. I checked the one that is located on the front of the battery support bracket (with two insulators!!!). Are the #1 and #2 relay located side by side inside the fendor, right????

Thanks,
Alex
85 BJ70
93 FZJ80

 

[Radd Cruisers]

Hey Alex, did you just do a voltage at the glow plugs first, should be 8 or so volts for a couple of seconds then kick down and to the second glow at a lower voltage.

If you have the FSM you could look at eh chart for 12V system and get the voltages and time they should be active (timer characteristic diagram).

I must admit that my earlier statement on the super glow system being bunk was not really true, you have to figure it worked pretty much flawlessly for 20 years.

Good luck with your trouble shooting.

 

[bj70alex]

Hey Alex, did you just do a voltage at the glow plugs first, should be 8 or so volts for a couple of seconds then kick down and to the second glow at a lower voltage.

If you have the FSM you could look at eh chart for 12V system and get the voltages and time they should be active (timer characteristic diagram).

I must admit that my earlier statement on the super glow system being bunk was not really true, you have to figure it worked pretty much flawlessly for 20 years.

Good luck with your trouble shooting.

Yes, I did check the voltage and what I noticed that it was between 8.5 - 8.8 volts until the second click and then it was ZERO volts. I don't think I hit the second cycle at all. What do you think?????

Alex
85 BJ70
93 FZJ80

 

[Radd Cruisers]

Okay sounds like your second glow is not workng and for what reason I am not sure.

Usually these systems go due to the amount of moisture in the cab, in my area the body tub tends to leak and the floor boards and carpet ar saturated. The seam sealer under the hood on the main body shrinks over time.

Second glow would be either the timer or the relay, this is a simplified example and of course there could many smaller problems underlying that could contribute to this issue.

Rob

 

[crushers]

huh?!?
i am trying to understand what you are saying Rob, in your second paragraph. are you saying the controler is defunct because of moisture from the floor and a leak from the firewall? when i drove a BJ42 as an off road buggy i used to immerse the controller in wate on a regular basis, only once did it ever act up. and that was after being buried in the water for a couple of minutes. i can not see how vapour can cause the problems that you describe. i have never seen one rusted inside, ever. and i have seen many over the years.
i would say the over all wiring under the hood needs cleaning or one of the sensors needs replacing. check ALL the conections for contamination, loosness and the one i hat ethe most is a male end that has scurried back and no longer resides in the holder but not far enough back to fall out of the conector. everything looks find till you take a close look. i have spent hours trying to find those little buggers.
take your manual and follow it step by step and you will find the problem.
cheers
Wayne

 

[Radd Cruisers]

So in your expierence Wayne, you have never seen many timers pack it in?

If this is the case I will be trouble shooting the BJ42 I purchased as the super glow is not working, it clicks for a a milli second and then shuts off.

Thats the nice part about this forum, I get to learn new stuff from the guys who have been it longer than myself.

 

[bj70alex]

Okay sounds like your second glow is not workng and for what reason I am not sure.

Usually these systems go due to the amount of moisture in the cab, in my area the body tub tends to leak and the floor boards and carpet ar saturated. The seam sealer under the hood on the main body shrinks over time.

Second glow would be either the timer or the relay, this is a simplified example and of course there could many smaller problems underlying that could contribute to this issue.

Rob

Rob,

I will have to follow the procedure for testing the timer. I disconnected the #2 relay and check both the continuity and applied voltage, it checked OK. I'll post the result of the test later today.

Alex
85 BJ70
93 FZJ80

 

[Radd Cruisers]

That test will eliminate any question and is very simple to do, I have found the majority of the time that the timers were shot.

In opening up the timer box it is simple old style circuit boards, too bad nobody trouble shoots or repairs them anymore. I have found on occasion some darkening almost black on some diodes.

Good luck.

Rob

 

[crushers]

i have never seen a board shot due to water contamination from a leaking cowl or moisure from wet boots excettera...
the one that was under the water packed it in. i have seen some where the board was cracked (not sure how that happens, i am guessing when a PO took the unit apart...)
cheers
Wayne

 

[bj70alex]

That test will eliminate any question and is very simple to do, I have found the majority of the time that the timers were shot.

In opening up the timer box it is simple old style circuit boards, too bad nobody trouble shoots or repairs them anymore. I have found on occasion some darkening almost black on some diodes.

Good luck.

Rob

Rob,
I decided to take the timer out and open the cover and visually check for obvious burned diodes, resisters etc. But couldn't really find anything wrong. I am trying to find someone localy with good electonics knowledge and see if that person will be able to test the circuit board. The input for the timer is the resistance from the water temperature sensor, which can be easily replicated on the bench. I will post results.

Alex
85 BJ70
93 FZJ80