Intermittent no start, dead batteries (1 Viewer)

[djsolution]

What’s up gents? I’m having some issues with my 1993 KZJ78 Prado, 1KZ-TE with a 12v dual battery setup. Been dealing with hard start or no start over the last few days. Drove from VA to NC for thanksgiving last week. Morning after the long drive, started up and made a quick 1 mi trip up the road. Tried starting up about an hour later and no dice. Cranked in about 10 sec bursts for a few minutes and finally she sputtered to life, very hard start. Ran for about 20 mins while I checked everything I could think of; loose wires, connections, battery terminals, etc. Couldn't find any issues. Ran a bottle of diesel additive in case it was fuel related. From that point last Thursday through yesterday, she’s been a little sluggish on startup but no big issues. Then this morning she didn’t want to start. Cranked again in 10 sec bursts until the batteries/starter were barely turning the motor. No start. I brought the batteries to an auto parts store, both tested good but with low charge. They’re going to charge them overnight.

I plan to try to start tomorrow with a fresh charge and test the alternator if I can get it running. What else can I be looking for? I have plenty of LC experience but this is my first diesel, could definitely use some help here. Thanks!

Pic for fun:

 

[Waikato Willy]

run another big earth just to test?
I know when I mucked around with batteries I forgot to tighten one of the earths and it caused slow sluggish start
also always check the useless primer, the black pump thing should be rock solid, maybe be lucky to get half a pump out of it from overnight sitting, this was a cause of my hard start for a while
oh and dont forget glow plugs, but I found duel batteries and good earths masked all these problems I had and made the wagon start a heap easier
(mine was originally a single battery set up)

 

[djsolution]

run another big earth just to test?
I know when I mucked around with batteries I forgot to tighten one of the earths and it caused slow sluggish start
also always check the useless primer, the black pump thing should be rock solid, maybe be lucky to get half a pump out of it from overnight sitting, this was a cause of my hard start for a while
oh and dont forget glow plugs, but I found duel batteries and good earths masked all these problems I had and made the wagon start a heap easier
(mine was originally a single battery set up)

Thanks for the info. I just went to pick up the charged batteries and one of them tested bad after all. Bought two new batteries, group size 24. Can anybody confirm that’s the right size? I couldn’t find any info online for US equivalent battery sizes.

I’ll run another earth cable for good measure too, seems like a good idea. Going to test the alternator too still for good measure.

 

[Radd Cruisers]

Found this thread randomly after searching for something else, then had to go and update my login... guess I haven't been on here in a while

Group 24 batteries are ok, however Group 27 batteries are the correct ones. Larger is generally better in a diesel.

If your KZJ (or any import for that matter) had Japanese batteries still in it, then they should almost always be replaced. I've imported a number of JDMs, and almost all of then had ancient, weak batteries in them and need good, healthy batteries for reliable starts and to keep the starter and alternator happy.

For starting your KZJ78.

Allow the glow plugs to light. The idiot light should be on according to engine temperature - if warm, you may not even see it, if cold out and the engine is cold it will glow 6-7 seconds.

With a healthy glow system - relays working, glow plugs working, fusible links intact, clean batter terminals and so on - for a cold start, wait a few seconds after the idiot light has gone out and then crank the engine. It should start relatively easily.

If it starts but sputters, apply light throttle or use the hand throttle to bring the revs up to the point it runs smoothly.

If the glow plugs are not working well, and your engine is otherwise healthy, you can crank it until it starts. The "10 seconds of crank" then off and repeat, is probablynot going to be long enough. Though most of these little diesels will start ok when cold, others need more cranking time than that to do a few things: builds fuel pressure in the injection pump (there's a small centrifugal lift pump in there), builds heat in the engine from cranking (that whole PV=nRT thing) where compressing a gas generates heat which, in some diesels, will cause them start even if other things are a bit dodgy. Crank it for longer, up to about 30 seconds, and then give your starter a good rest to cool down after that. If it doesn't start easily, then figure out why.

Glow plugs are best tested by removing them from the vehicle. Ohm-ing sort-of works ok some of the time, but doesn't tell you how they are glowing.

Use a battery charger that puts out about 10A @12V. Connect glow plug, it should fully light in about 5-6 seconds. It will get hot, don't burn your fingers. The glowing part should be close to the tip and progress towards the tip, and not back and closer to the body of the glow plug. They should all glow about the same. If not, replace them.

Note: the starter needs maintenance from time to time. There are contacts in it that wear out. These need to be replaced, and are relatively cheap to do. Weak batteries (low cranking voltage) will wear the starter solenoid contacts out even faster.


~John

 

[djsolution]

Found this thread randomly after searching for something else, then had to go and update my login... guess I haven't been on here in a while

Group 24 batteries are ok, however Group 27 batteries are the correct ones. Larger is generally better in a diesel.

If your KZJ (or any import for that matter) had Japanese batteries still in it, then they should almost always be replaced. I've imported a number of JDMs, and almost all of then had ancient, weak batteries in them and need good, healthy batteries for reliable starts and to keep the starter and alternator happy.

For starting your KZJ78.

Allow the glow plugs to light. The idiot light should be on according to engine temperature - if warm, you may not even see it, if cold out and the engine is cold it will glow 6-7 seconds.

With a healthy glow system - relays working, glow plugs working, fusible links intact, clean batter terminals and so on - for a cold start, wait a few seconds after the idiot light has gone out and then crank the engine. It should start relatively easily.

If it starts but sputters, apply light throttle or use the hand throttle to bring the revs up to the point it runs smoothly.

If the glow plugs are not working well, and your engine is otherwise healthy, you can crank it until it starts. The "10 seconds of crank" then off and repeat, is probablynot going to be long enough. Though most of these little diesels will start ok when cold, others need more cranking time than that to do a few things: builds fuel pressure in the injection pump (there's a small centrifugal lift pump in there), builds heat in the engine from cranking (that whole PV=nRT thing) where compressing a gas generates heat which, in some diesels, will cause them start even if other things are a bit dodgy. Crank it for longer, up to about 30 seconds, and then give your starter a good rest to cool down after that. If it doesn't start easily, then figure out why.

Glow plugs are best tested by removing them from the vehicle. Ohm-ing sort-of works ok some of the time, but doesn't tell you how they are glowing.

Use a battery charger that puts out about 10A @12V. Connect glow plug, it should fully light in about 5-6 seconds. It will get hot, don't burn your fingers. The glowing part should be close to the tip and progress towards the tip, and not back and closer to the body of the glow plug. They should all glow about the same. If not, replace them.

Note: the starter needs maintenance from time to time. There are contacts in it that wear out. These need to be replaced, and are relatively cheap to do. Weak batteries (low cranking voltage) will wear the starter solenoid contacts out even faster.


~John

Thanks for the reply!! Sorry I had missed this before, just read today as I went to reply to this thread again.

So like I mentioned before, I replaced the batteries with no real change. I ended up bringing the truck to a reputable Cruiser-friendly shop with lots of experience with these JDM vehicles. They said they couldn’t replicate the issue during the 2.5 weeks they had the Prado . It’s been struggling to start with every cold start since I picked it up from the shop and today after some very cold winter… no start at all.

I went to check the glow system fuse in the drivers kick panel and there was no fuse! I figured this must be the issue so I tried to plug in a 7.5a fuse but there was no circuit to plug into (see pic). Same for ECU-B which I thought was weird.

Any thoughts as to why the glow system would not have a fuse in the stock fuse box? Should I be looking for some aftermarket controller or relay?

 

[djsolution]

Did some more searching and I think the glow system on this model of KZJ78 didn’t have a glow fuse, but rather uses a fusible link. Does this check? I think I found the fusible link just upstream of where power is connected to the glow plug bus bar.

I tested power at the bus bar and on the top of plugs 1 and 2 during the glow cycle, constant 11v until relay clicks at the 10ish second mark, then drops.

So if the relay seems to be working correctly and the bus bar/plugs are getting correct voltage, does that point to worn Plugs?

 

[Radd Cruisers]

There is no fuse because on some models the glow timing function is controlled by the engine ECU and not a separate timer.

It sounds like your glow system is working as it should with the time periods you mentioned.

A few things come to mind: incorrect or out of spec glow plugs will not return a correct circuit resistance signal to the glow ECU and the pre or post glow cycle may be cut short or not happen at all. If you are getting a full 10 seconds on pre-glow, you should be getting a healthy start-up of the engine.

A few things do come to mind: incorrect glow plugs = pull them and check the manufacturer, part number, voltage.

While the plugs are out, glow test them with a battery charger and check for HOW they glow (see previous reply).

When putting the glow plugs back in, make sure the glow buss bar (connector that goes across the top) is clean and making good contact with the glow plugs.

Perhaps when your vehicle as in the shop, it was warm enough for the issue to not show up (?)

Does it re-start ok once it's been warmed up and been left for a while?

Also, is this in fact a glow issue? Could it be a fuel supply issue? Reason is that in cold weather, it is not uncommon for old injection pump or fuel filter-primer assembly and/or fuel heater o-rings (if equipped) to get hard, shrink and leak a small amount air into the injection system which prevents a start up.

~John

 

[Roastchestnuts]

this happened to my old fj80 two times. (I do have a kzj78 now). On the fj80 it would crank and crank and crank but not start. It turned out to be a bad battery ground the first time. (the previous owner literally electrical taped the negative batteray terminal on with electrical tape.) A few years down the road the second thing that caused this was the fusable link off the positive battery terminal. I believe these kzj78 land cruisers have a fusable link too. On the fj80 the fusable link would power the ecu as well and when it went bad it would cause the vehicle to just keep cranking and not start. I will add that I am very new to the kzj78 and am not sure if this is any help.

 

[djsolution]

There is no fuse because on some models the glow timing function is controlled by the engine ECU and not a separate timer.

It sounds like your glow system is working as it should with the time periods you mentioned.

A few things come to mind: incorrect or out of spec glow plugs will not return a correct circuit resistance signal to the glow ECU and the pre or post glow cycle may be cut short or not happen at all. If you are getting a full 10 seconds on pre-glow, you should be getting a healthy start-up of the engine.

A few things do come to mind: incorrect glow plugs = pull them and check the manufacturer, part number, voltage.

While the plugs are out, glow test them with a battery charger and check for HOW they glow (see previous reply).

When putting the glow plugs back in, make sure the glow buss bar (connector that goes across the top) is clean and making good contact with the glow plugs.

Perhaps when your vehicle as in the shop, it was warm enough for the issue to not show up (?)

Does it re-start ok once it's been warmed up and been left for a while?

Also, is this in fact a glow issue? Could it be a fuel supply issue? Reason is that in cold weather, it is not uncommon for old injection pump or fuel filter-primer assembly and/or fuel heater o-rings (if equipped) to get hard, shrink and leak a small amount air into the injection system which prevents a start up.

~John

Ok so I think I have it pinned down finally, and it looks like your last paragraph is spot on. I waited for ever for the damn parts but I replaced glow plugs, valve cover gasket and intake manifold gasket a few days ago. Went to start and still didn’t want to turn over. Tried hand pumping the primer and noticed it took a ton of pumps to build pressure and when it finally did, I had fuel leaking around the top of the filter cap and heater. Once the system had good pressure it started right up and has been starting and running great since. I think that leak is just enough to bleed pressure over a day or two and cause issues starting.

I had tried this without success before so I still think the plugs were part of it, but I think the leak is the final piece of the puzzle.

 

[djsolution]

Final update… installed a new fuel filter, primer cap and fuel heater and it’s finally fixed. Fires up without issue now every time. Thanks everyone for all the help!