12v Super Glow experts

[wesintl]

I'm trying to diagnose my super glow system 1985 3B 12v super glow system

Going thru the OEM manual all the relays and resistors test fine per fsm but they don't list OHM #'s

Here is what I have:

At the bus bar I have 13.3v continuous. (eventually will burn out, and did, my 6v plugs)

if I disconnect the glow plug relay #1 on the battery tray. It will glow 13.3 and then drop and stay at 5.3. After this is should drop to 0 right, but it never does. Maybe i'm not waiting long enough but I'm assuming a minutes would be sufficient. I suspect this relay because it got hot and melted the plastic around it but I think that's only because it got hot since it's always on providing the pull 13.3v to the glow plugs


I have power at the glow timer #9. what I don't understand is the 9 to 12? I have power there. when testing it is it supposed to drop off to 0 after the glow?

Does this sound like the timer is shot?

Don't bother posting telling me to go to wilson switch. I don't want to but I know how to wire one if I really have to. This thread is about fixing the super glow. thx

 

[bj40green]

Have a look at the diagram in posting #80 in https://forum.ih8mud.com/diesel-tec...-should-i-running-b-2b-3b-h-2h-diesels-4.html , maybe that shines a light on how the super glow system works and aswers your question.

Rudi

 

[lostmarbles]

I'm trying to diagnose my super glow system 1985 3B 12v super glow system

Going thru the OEM manual all the relays and resistors test fine per fsm but they don't list OHM #'s

Here is what I have:

At the bus bar I have 13.3v continuous. (eventually will burn out, and did, my 6v plugs)

if I disconnect the glow plug relay #1 on the battery tray. It will glow 13.3 and then drop and stay at 5.3. After this is should drop to 0 right, but it never does. Maybe i'm not waiting long enough but I'm assuming a minutes would be sufficient. I suspect this relay because it got hot and melted the plastic around it but I think that's only because it got hot since it's always on providing the pull 13.3v to the glow plugs


I have power at the glow timer #9. what I don't understand is the 9 to 12? I have power there. when testing it is it supposed to drop off to 0 after the glow?

Does this sound like the timer is shot?

Don't bother posting telling me to go to wilson switch. I don't want to but I know how to wire one if I really have to. This thread is about fixing the super glow. thx

To find more than 12V at the busbar you must be making your measurements with the engine running. Is that what you're doing?

(I'm confused as to why your engine would be running! Sure .... I admit that a fully charged battery may have higher voltage than 12V but it's not normal to be able to measure more than 12V at the busbar when you are drawing a lot of current off your battery with your glow system prior to cranking your engine ......... even if the battery is fully-charged and in top condition.)



Does this represent your wiring?:


If so, you shouldn't be able to get battery voltage at your busbar with No. 1 relay disconnected!

And AFAIK number 9 terminal simply tells your "timer" when your engine's running by sensing the alternator output.

 

[wesintl]

To find more than 12V at the busbar you must be making your measurements with the engine running. Is that what you're doing?

yes. sorry. doesn't make much difference though substitute 12.5 then 4.5. with #1 relay connected it stays at 12.5. I can still hear the #2 relay click to drop it down to 4.5 after ~30 sec. But still with #1 connected it's 12.5.

Does this represent your wiring?:

yes, although i have the glow plug current sensor just before the glow plugs.

If so, you shouldn't be able to get battery voltage at your busbar with No. 1 relay disconnected!

well, exactly. why is the relay fully charged all the time?

And AFAIK number 9 terminal simply tells your "timer" when your engine's running by sensing the alternator output.

I was trying to remember my troubleshooting at work :fail:

where i'm at is EM-11
check if voltage to terminal 1 of preheat timer is terminated after engine is started = NO

Start the engine and check/if there is a voltage at terminal 9 of preheating timer.
If faulty, repair charging system as necessary.
If ok, Timer is faulty and should be replaced.

I have 12-13v at 9 after starting... I'm assuming the above is saying the timer is faulty.

 

[bj40green]

I'm confused. Tom asked if his diagram represents your wiring?
You say;

yes, although i have the glow plug current sensor just before the glow plugs.[/ QUOTE]

But there is no "glow plug current sensor" in Toms diagram.
If you have a "glow plug current sensor" then you have a different diagram with a different timer IC and of course different pin configuration.

Please tell model and year so "we" can find the right diagram for your truck or post the diagram that you are using.

So far it sounds that if the #1 relay is activated after cranking the timer is faulty. Check by disconnecting the #1 relay to see what voltage you have on the busbar.

Rudi

 

[wesintl]

Please tell model and year so "we" can find the right diagram for your truck or post the diagram that you are using.

note first post 1985 3b 12v super glow oh.. sorry BJ70

So far it sounds that if the #1 relay is activated after cranking the timer is faulty. Check by disconnecting the #1 relay to see what voltage you have on the busbar.

Rudi

noted: if disconnect relay one I get 12.5v for the super glow then it drops to 4.5 to smooth the engine out and stays at 4.5v for as long as the key is on.

I should note that I don't have the bus bar connected to the glow plug. i'm taking the reading at the end of the bar where it connects to the glowplug. The system killed my set of plugs that were in it. Then I had a spare set and I put those in thinking everything checked out (except for the old blown plugs) and it killed those in 1 run to the store. Does the system need good plugs in it to troubleshoot? I really don't want to throw another $100 in plugs down the tubes testing this.

 

[bj40green]

OK, so we have a '85 BJ70 with a 3B and super glow.
We now have the right diagram so let's see.
Pin 9 detects if the engine is running. This activates the after glow time, which is calculated by the water temp sensor. Max time for afterglow is 3 minutes.
So, after 3 minutes with the key in the "on" position there should be NO voltage on the bus bar.
[Side step] What bothers me is that you keep talking of 12.5 Volt. I expect something between 11.9 and 12.4V depending on the age of the battery. A brand new battery fully charged reads 12.6 Volt after 2 hours rest. You must have a really fresh battery to get that reading. [End side step]
That brings us on measuring what you have on the g terminal of the #1 relay. The questions are: how much and how long?
Please measure what you get on the g terminals of each relay and for how long.
Did you check the #1 relay for correct functioning? It can be that the contacts stick together.

Rudi

 

[lostmarbles]

If the glowplugs are blown then the dropping resistor won't be able to drop the voltage to the busbar at all.

So at least this explains why you were still able to measure battery voltage there with No.1 relay disconnected.

What are the plug specifications?

Sorry I'm in a bit of a rush right now and have to go back to work............

 

[wesintl]

yes. brand spankin new battery Deka intimidator agm. Brand spanking new denso alt, brushes, regulator

I'd have to test g tonight. The #1 relay is working correctly per fsm. No continuity at B G unplugged. there is continuity at g e. once I put power to g e i get continuity at B G. I can clearly hear it click and function.

plug specs are toyota ND 19850-68051 6v

 

[wesintl]

I tested g real quick but i'll have to do another test when I get home. g gets 9.5.v I believe continuously. I'll have to look at the watch and count the min. The solenoid will def get warm after a while due to the current.

 

[Eric Winkworth]

I went through a lot of headaches with my superglow computer on my truck(24v cdm spec), which went from have to cycle the key muiltiple times and still getting a rough idle in cold weather... To no voltage at the busbar when cycling... Took the POS out and went manual, never had an issue since, it's so nice to feather the plugs on a cold start... Now I can feather idle and glow plugs all in the cab, perfect!

The glow computer is stupid IMO and upon inspection mine had a nasty burnt resistor on the board and was quite dusty, glad it didn't start a fire or let me down when I was out in the middle of no where... If you're going to run the old computer keep a piece of wire with you, to jump the busbar in a pinch!

 

[slowandsteady BJ]

On my 85 BJ 60 PO installed a wilson.

Funny thing is the volt meter drops to 10V as if the superglow is still working.

I give the truck 10 or so seconds on the wilson switch during that time volts drop to 8 or so. After releasing the switch the volts moves to 10V..... a few seconds later there is a big "realy type" click and the volts climb up to 12V. Wierd.

Any idea why this is?

Cheers
Cam

 

[bj40green]

On my 85 BJ 60 PO installed a wilson.

Funny thing is the volt meter drops to 10V as if the superglow is still working.

I give the truck 10 or so seconds on the wilson switch during that time volts drop to 8 or so. After releasing the switch the volts moves to 10V..... a few seconds later there is a big "realy type" click and the volts climb up to 12V. Wierd.

Any idea why this is?

Cheers
Cam

I think you don't have a real "Wilson switch set up" but an added switch to activate the #1 glow relay. Depressing the switch for so many seconds is easier then cycling the key 3 or 4 times to get the same result.

My 0.02 cents.

Rudi

 

[BreckenridgeCruiser]

Wes, as Lostmarbles I think was alluding to, the plugs being heated and increasing in resistance is part if the superglow cycle. Not having plugs in will keep the system electrified as it thinks the plugs are not hot yet...

 

[wesintl]

ya got some extra's? we'll test with yours

 

[lostmarbles]

....where i'm at is EM-11
check if voltage to terminal 1 of preheat timer is terminated after engine is started = NO

Start the engine and check/if there is a voltage at terminal 9 of preheating timer.
If faulty, repair charging system as necessary.
If ok, Timer is faulty and should be replaced.

I have 12-13v at 9 after starting... I'm assuming the above is saying the timer is faulty.

That's page EM13 of my 1988 B, 3B, 11B, 14B FSM (rather than being page EM11).

And here is that section for anyone that's interested:




From what I can see, these tests revolve around checking for the reason behind "no glow" or "insufficient glow" rather than checking for "prolonged high voltage that blows plugs".

The engine must be started and running to check terminal 9. And this suggests further that terminal 9 simply tells the "timer" that your engine has started by sensing when the alternator commences charging your battery.

I think you doný have a real "Wilson switch set up" but an added switch to activate the #1 glow relay. Depressing the switch for so many seconds is easier then cycling the key 3 or 4 times to get the same result.

My 0.02 cents.

Rudi

I agree.

The click you hear is likely to be a glow relay "chopping out" that is still being controlled by your old superglow timer device.

I think people who convert to "Wilson" should ideally go fully-manual, use fail-safe plugs (such as 10.5V plugs for a 12V cruiser or 23V plugs for a 24V cruiser), and not leave any of their old superglow system functioning.

Wes, as Lostmarbles I think was alluding to, the plugs being heated and increasing in resistance is part if the superglow cycle. Not having plugs in will keep the system electrified as it thinks the plugs are not hot yet...

Sort of...

I was referring to the fact that if no currrent is passing through the dropping resistor, it cannot possibly do its job of dropping the voltage to the busbar. This is because it drops the voltage by applying "back e.m.f".

("Back emf" here is "voltage that OPPOSES the battery voltage".)

And Ohm's Law dictates how high this back emf will be by V=IxR

So the back emf (V) must be "zero" if the current in the circuit (I) is zero. Thus "no opposing voltage at all". So the busbar will still receive "full battery voltage" via No.2 relay just as it did via No.1 relay (if you have no plugs connected or if all the connected plugs are blown).



PS. If it was me, I'd start by checking the system with a good set of 6V plugs in place. And I would be monitoring CLOSELY how long full-battery voltage remains at the busbar with those plugs there.

Depending on the ambient temperature (assuming your engine is at ambient temperature and not warm from recent use), the timer should chop out No.1 relay according to the "Light Lighting Time" graph shown here (from page ST3 of the FSM):



For example, at 10oC expect 4.5 seconds . So immediately stop the glow cycle if No. 1 relay hasn't chopped out at 6 seconds (to avoid blowing your new plugs)

Edit: I don't like responding to this thread because of its title. I don't regard myself as an EXPERT on superglow. (Hell..I don't even own a cruiser fitted with superglow.) However I do have an interest in starting/pre-heating systems used on cruisers similar to mine .. so that's the only connection I have.

 

[wesintl]

From what I can see, these tests revolve around checking for the reason behind "no glow" or "insufficient glow" rather than checking for "prolonged high voltage that blows plugs".

true, but with the plugs burned out the procedure for testing the timer should be valid. It's also the only troubleshooting procedure for the timer. I'll run the tests with the bad plugs hooked up. I did this but i've run so many tests I can be sure what the #'s are.


no one has any good 6v or 7v plugs so i gotta wait for some to come to my dealer from Canada.

 

[BreckenridgeCruiser]

Wes, I have a bunch of 14v plugs, but no 6v ones. If you think those would work, I could lend you a set...

 

[BTUMAN]

no one has any good 6v or 7v plugs so i gotta wait for some to come to my dealer from Canada.

O'reiley auto parts had the 7 v I used on my 1983 BJ42LX with super-glow. They were 14 each. Quicker and cheaper than $OR. HTK part number found i think in the thread. Also of you search on NAPA website they show this same one listed for my 1983 Toyota and actually have Super Glow listed in the description. They were just a little longer but worked. The top nut is not 10mm so I had to tighten to the bar with a adjustable wrench.

I only had 1 of 4 working. Rocked like a bronco on the first real cold start. Original are 6 volts on a 12v system like mine. But the 7 volts should last a little longer(like a 130v light bulb as compared to a 120v bulb).

Tested the glow plugs 3 different ways, but the best was hooking it up to the battery using jumper cables for a few seconds. (watch them flow fast).

 

[caper]

this super glow thing got me drove crazy also . I have a 24v system and am getting 20V on the bus for 5 seconds then a click and my light goes out then down to 11 volts for 5 seconds and then a click and 0 volts . The truck starts rough like shake apart rough. My plugs must be burnt out or something I will have to pull them and check, never done this before it should be intresting .