LJ78 mystery connector

[Cascadia]

Hi guys. I can’t believe I’m posting such a simple question but I’m a little stumped.

I’m reinstalling my engine and there’s a female connection on my wiring harness I’m stuck on. Every other connection has been painfully obvious and I’m feeling foolish here for not seeing the male counterpart to this.

Round black plugs in to my alternator, small grey plugs into my A/C compressor, but what about the third one?

 

[John Young]

My HZ has a plug for a rev counter in the loom, but no pick up in the IP, so it hangs loose.
Could this be your problem??

I seem to have a bunch of connectors hanging loose in Golden Boy, the HZJ pickup. Just starting to try to figure out what is what....

 

[roscoFJ73]

I seem to have a bunch of connectors hanging loose in Golden Boy, the HZJ pickup. Just starting to try to figure out what is what....

Do you have the body and chassis FSM? The diagrams show you the wiring and connectors for each market and sometimes individual countries, laborious but its the only way. There may be connectors in there solely for the Islamabad police dept. (they have their own sections in the parts diagrams)

 

[John Young]

Do you have the body and chassis FSM? The diagrams show you the wiring and connectors for each market and sometimes individual countries, laborious but its the only way. There may be connectors in there solely for the Islamabad police dept. (they have their own sections in the parts diagrams)

LOL! I think so. I have the RM183e and the 1990 1HD_1HZ FSM.

As it happens I was just looking at a 14-in-1 AUS gauge product in a posting over in the 80 Series Tech that seems pretty economical. Looks like about 250 or 300 AUD (230 USD) for a package of display, plus sensor box, plus sensors and does not rely on OBDII. Most critical for me are:

• tach
• oil pressure
• oil temp
• maybe water temp

My truck came without the RPM meter, and the oil pressure idiot light is kind of dimly on all the time. I'd really like to know that I have oil pressure. The old guy has 560K km on the clock.... I also was thinking of just putting in discrete cheap stand-alone meters. Also thinking of putting the display, whatever I end up with, in the binnacle, taking out the OEM plastic next to the sub tank meter. The tach in particular I'd prefer to be a needle or bar graph than digital. I really have no idea how fast the engine is going when I'm at 110-120 kph. The cabin noise is great enough that it really is hard to tell.

EDIT: I know from fooling with our 77 and 80 how hard it is to figure out what is going on with the OEM gauge cluster, let alone fix it. That's why I'm thinking more about aftermarket solutions.

 

[Cascadia]

Glowing requires a fair amount of juice....80A or so for our motors I think? Sometimes smaller batteries have too much internal resistance and have a lot of voltage drop when producing high currents. But if you have a battery intended for 'starting' you should be fine. We have tons of old SLA UPS batteries at work that I use for all sorts of stuff. One thing I found is they're more suited to energy storage than high peak currents.

Probably a pretty obvious thing that you've got covered, but that new crank had a magnet on it for the crank sensor right?

Wish covid wasn't a thing, as I could come out and give you a hand.

What sort of work do you do outta curiousity?

I never figured the current would be that high, more than I’ll get from what I have. Best to just use the starting battery. I’m a fire alarm technician. Always bringing home stray batteries and wiring from failed panels.

Regarding the crank sensor. The magnet you’re talking about, is it the out of place looking tab adjacent to where the second connecting rod connects? Picture is my old crank, new one had the same feature.

Ah no worries. The advice on it’s own is a massive help.

 

[GTSSportCoupe]

I never figured the current would be that high, more than I’ll get from what I have. Best to just use the starting battery. I’m a fire alarm technician. Always bringing home stray batteries and wiring from failed panels.

Regarding the crank sensor. The magnet you’re talking about, is it the out of place looking tab adjacent to where the second connecting rod connects? Picture is my old crank, new one had the same feature.View attachment 2566103

Ah no worries. The advice on it’s own is a massive help.

Yup, thats it. Glad you have it on the new crank too!

 

[roscoFJ73]

LOL! I think so. I have the RM183e and the 1990 1HD_1HZ FSM.

As it happens I was just looking at a 14-in-1 AUS gauge product in a posting over in the 80 Series Tech that seems pretty economical. Looks like about 250 or 300 AUD (230 USD) for a package of display, plus sensor box, plus sensors and does not rely on OBDII. Most critical for me are:

• tach
• oil pressure
• oil temp
• maybe water temp

My truck came without the RPM meter, and the oil pressure idiot light is kind of dimly on all the time. I'd really like to know that I have oil pressure. The old guy has 560K km on the clock.... I also was thinking of just putting in discrete cheap stand-alone meters. Also thinking of putting the display, whatever I end up with, in the binnacle, taking out the OEM plastic next to the sub tank meter. The tach in particular I'd prefer to be a needle or bar graph than digital. I really have no idea how fast the engine is going when I'm at 110-120 kph. The cabin noise is great enough that it really is hard to tell.

EDIT: I know from fooling with our 77 and 80 how hard it is to figure out what is going on with the OEM gauge cluster, let alone fix it. That's why I'm thinking more about aftermarket solutions.

Can you get a an oil pressure tester and how does that 14-1 thing fit into your gauge pod?

 

[Cascadia]

Yup, thats it. Glad you have it on the new crank too!

This has obviously gone off topic from the mystery connector some time ago, but a follow up on the glow plug situation. Definitely no voltage to the rail. Probably sums up the no start. However I seem to have a dead short to ground on the rail.

Surely I should be seeing more resistance than that.

 

[Gengis]

Plugs have a very low resistance so make sure that you are on the correct scale on the multi meter, if it was a dead short, your heating system and/or fuse would blow. Me thinks.