(SOLVED!) 1HD-FT fuel starved at startup (1 Viewer)

[overpakd]

SOLVED (again... no really this time)!

TLDR: 12V starter replacement (and conversion from 24V) solved it.

I'll wait the requisite 3 days to be proven wrong again before updating the thread title with the same claim... but the Land Cruiser is again starting beautifully! I only need to *think* about turning the key to start and she purrs to life.

I was indeed fooled by the good bench tests of the 24V starter. I'm assuming now that the starter was not new at the listed mileage but actually an original but rebuilt starter. Likely, the rebuild was just contacts/brush replacement/adjustment and the clutch assembly (#28011-17020) was not considered and was original. I've swapped in the new Toyota 12V starter (part #28100-17061). READ ON FOR THE SIMPLEST 12V CONVERSION ON MUD.

So... now we speculate on what was the *original* problem. Originally, the truck would crank and turn the motor over a couple good times and then start. The 24V starter was a little loud and raucous as this happened. Having nothing to compare to, I thought this was normal, and maybe it was or maybe it was an early indicator of something. The suspects in order have been: Fuel filter, fuel cutoff solenoid or wiring, fuel hoses, fuel filter priming pump, air in injector pump or lines, batteries, fuel hoses again, 24V starter, insanity, bad grounds, 24V starter again. My best guess is the original problem(s) was actually a combination of aging weak batteries, cracked fuel hoses allowing *some* problematic air into the system between starts, and a (slowly) failing starter pinion clutch. So... having replaced ALL of that, I should be good for a while


Now, a quick note on 24V to 12V conversion. Every thread I read on this is to some degree complicated with the owner's simultaneous move to isolate one of the batteries as a house/accessory battery while keeping the other as a dedicated starting battery. So wiring changes can be significant (isolators, fuse boxes, moving fusible links, removing relays, etc.). I may still isolate one of the batteries in this way in the future, but I didn't *need* to do that to replace the starter with a 12V as a troubleshooting step (and I already have a 3rd LiFePo4 battery running the house electronics). I finally read another thread from landcruiserclub.net (my grey 80 - https://www.landcruiserclub.net/community/threads/my-grey-80.133289/page-12#post-1278138), which provided the easiest 12V conversion:

1. Disconnect the Voltage Converter Timer Relay (VCT) inside the passenger (LHS) footwell kickpanel. This stops the Voltage Converter Relay (VCR) from doing it's serializing job even though it's still all connected.
2. Jumper pins 3 and 7 (RW and BW) on the female connector to the VCT. This provides necessary ground to the starter relay even though the VCR won't do that anymore.

That's it. Starter receives 12V instead of 24V on key start.

Thanks all for your help and ideas and participating in this saga. I'm proclaiming this resolved loudly and proudly because a) I'm sure it's fixed this time and b) Being this sure it's fixed is the best way to speed up the next failure that will prove me wrong

Incidentally, having fixed this and test driven a little today, I am now exactly 10km from 250,000. So "Fifty Shades" and I will celebrate our push through her mid-life crisis on the way to the office tomorrow while rolling a quarter million kms.

 

[Satoshi808]

SOLVED (again... no really this time)!

TLDR: 12V starter replacement (and conversion from 24V) solved it.

I'll wait the requisite 3 days to be proven wrong again before updating the thread title with the same claim... but the Land Cruiser is again starting beautifully! I only need to *think* about turning the key to start and she purrs to life.

I was indeed fooled by the good bench tests of the 24V starter. I'm assuming now that the starter was not new at the listed mileage but actually an original but rebuilt starter. Likely, the rebuild was just contacts/brush replacement/adjustment and the clutch assembly (#28011-17020) was not considered and was original. I've swapped in the new Toyota 12V starter (part #28100-17061). READ ON FOR THE SIMPLEST 12V CONVERSION ON MUD.

So... now we speculate on what was the *original* problem. Originally, the truck would crank and turn the motor over a couple good times and then start. The 24V starter was a little loud and raucous as this happened. Having nothing to compare to, I thought this was normal, and maybe it was or maybe it was an early indicator of something. The suspects in order have been: Fuel filter, fuel cutoff solenoid or wiring, fuel hoses, fuel filter priming pump, air in injector pump or lines, batteries, fuel hoses again, 24V starter, insanity, bad grounds, 24V starter again. My best guess is the original problem(s) was actually a combination of aging weak batteries, cracked fuel hoses allowing *some* problematic air into the system between starts, and a (slowly) failing starter pinion clutch. So... having replaced ALL of that, I should be good for a while


Now, a quick note on 24V to 12V conversion. Every thread I read on this is to some degree complicated with the owner's simultaneous move to isolate one of the batteries as a house/accessory battery while keeping the other as a dedicated starting battery. So wiring changes can be significant (isolators, fuse boxes, moving fusible links, removing relays, etc.). I may still isolate one of the batteries in this way in the future, but I didn't *need* to do that to replace the starter with a 12V as a troubleshooting step (and I already have a 3rd LiFePo4 battery running the house electronics). I finally read another thread from landcruiserclub.net (my grey 80 - https://www.landcruiserclub.net/community/threads/my-grey-80.133289/page-12#post-1278138), which provided the easiest 12V conversion:

1. Disconnect the Voltage Converter Timer Relay (VCT) inside the passenger (LHS) footwell kickpanel. This stops the Voltage Converter Relay (VCR) from doing it's serializing job even though it's still all connected.
2. Jumper pins 3 and 7 (RW and BW) on the female connector to the VCT. This provides necessary ground to the starter relay even though the VCR won't do that anymore.

That's it. Starter receives 12V instead of 24V on key start.

Thanks all for your help and ideas and participating in this saga. I'm proclaiming this resolved loudly and proudly because a) I'm sure it's fixed this time and b) Being this sure it's fixed is the best way to speed up the next failure that will prove me wrong

Incidentally, having fixed this and test driven a little today, I am now exactly 10km from 250,000. So "Fifty Shades" and I will celebrate our push through her mid-life crisis on the way to the office tomorrow while rolling a quarter million kms.

Thank you and appreciate you sharing the 12V conversion info. I also have a 1996 HDJ81 and also have plans to convert to a 12V starter. Do you have photos of the wiring that required the disconnect and jumper? Also, which battery would now be used to start the 80, is it still the primary located on the left passenger side (JDM)? What then happens to the second battery once converted to 12V start?

 

[overpakd]

Thank you and appreciate you sharing the 12V conversion info. I also have a 1996 HDJ81 and also have plans to convert to a 12V starter. Do you have photos of the wiring that required the disconnect and jumper? Also, which battery would now be used to start the 80, is it still the primary located on the left passenger side (JDM)? What then happens to the second battery once converted to 12V start?

Sure! The VCT module is tucked way up behind the dash above the LHS (our passenger) kick panel. Here's a picture of the area and then a picture zoomed in on the VCT module and the now disconnected harness. I didn't have a picture of the actual jumper wire, so I labeled where I jumped it. Just make sure you're jumping the pins connected to the Red-White wire and Black-White wire (which are pins 3 and 7 on the connector).

I had to unbolt the VCT (2 10mm bolts if I remember correctly) and tug it down a little to access the connector and disconnect it. Once the jumper was in place, I wrapped a zip tie over the jumper wire to hold it in (intended to be temporary while I tested, but it's held for months ), tucked the VCT back up where it should be and bolted it back in.

As for the batteries, with this simple method, they are still wired in parallel to the starter (and everything else), so both batteries are technically in use all the time (providing 12V). This gives you additional current capacity over a single battery (when cranking), but isn't strictly necessary. Both are used when starting, both get charged by the alternator and both are supplying voltage to the rest of your 12V system/accessories when running. I didn't need to do anything else for my setup because my "house" battery is a 3rd, lithium battery in my drawer/platform setup in the back (charged by the alternator when running through a DC-DC charger). Many people doing a 12V conversion also separate and isolate one of the factory batteries, but that's why you always read through more complexity in the 12V conversion. If you want to isolate them, you'd need to decide which battery is the starter and then potentially disconnect/rewire the starter positives, alternator positive, the fusible links, etc. to be on that battery, add an isolator, fuse panel for accessories, etc.

Hope that all makes sense and the pictures help, but happy to answer any other questions I can.

 

[Satoshi808]

Sure! The VCT module is tucked way up behind the dash above the LHS (our passenger) kick panel. Here's a picture of the area and then a picture zoomed in on the VCT module and the now disconnected harness. I didn't have a picture of the actual jumper wire, so I labeled where I jumped it. Just make sure you're jumping the pins connected to the Red-White wire and Black-White wire (which are pins 3 and 7 on the connector).

I had to unbolt the VCT (2 10mm bolts if I remember correctly) and tug it down a little to access the connector and disconnect it. Once the jumper was in place, I wrapped a zip tie over the jumper wire to hold it in (intended to be temporary while I tested, but it's held for months ), tucked the VCT back up where it should be and bolted it back in.

As for the batteries, with this simple method, they are still wired in parallel to the starter (and everything else), so both batteries are technically in use all the time (providing 12V). This gives you additional current capacity over a single battery (when cranking), but isn't strictly necessary. Both are used when starting, both get charged by the alternator and both are supplying voltage to the rest of your 12V system/accessories when running. I didn't need to do anything else for my setup because my "house" battery is a 3rd, lithium battery in my drawer/platform setup in the back (charged by the alternator when running through a DC-DC charger). Many people doing a 12V conversion also separate and isolate one of the factory batteries, but that's why you always read through more complexity in the 12V conversion. If you want to isolate them, you'd need to decide which battery is the starter and then potentially disconnect/rewire the starter positives, alternator positive, the fusible links, etc. to be on that battery, add an isolator, fuse panel for accessories, etc.

Hope that all makes sense and the pictures help, but happy to answer any other questions I can.

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This is awesome and appreciate the clarification, brother! Where is the best place to order the 12V starter compatible with our diesel 80? -Ed

 

[overpakd]

This is awesome and appreciate the clarification, brother! Where is the best place to order the 12V starter compatible with our diesel 80? -Ed

Hey! Sorry I was late to reply. You can get the 12V starter at your local Toyota dealer. I used part number #28100-17061 and my dealer had it in 1 day. I will say the connector on the body for the relay connection is different. I spliced an old connector to the existing harness to make it work. I looked for the actual connector part number to build a proper cable and got the wrong one at first. It's out of sight out of mind right now, so I haven't pursued it further. Unfortunately, I don't think I have pictures of that. (This is for the low current relay connection. The full current, heavy gauge wire connects to a giant lug in the same way as the 24V starter).

 

[Satoshi808]

Hey! Sorry I was late to reply. You can get the 12V starter at your local Toyota dealer. I used part number #28100-17061 and my dealer had it in 1 day. I will say the connector on the body for the relay connection is different. I spliced an old connector to the existing harness to make it work. I looked for the actual connector part number to build a proper cable and got the wrong one at first. It's out of sight out of mind right now, so I haven't pursued it further. Unfortunately, I don't think I have pictures of that. (This is for the low current relay connection. The full current, heavy gauge wire connects to a giant lug in the same way as the 24V starter).

No problem and thank you for the part#.