RTH engine starts then stops. What safety system is there?

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I tested power at the coil and it stays at 12v, so maybe this is fuel delivery issues.

I need to pull an injector wire and make sure that keeps gettting power.
 
I would but doggo appointment at vet today. You have a tractor! U got this. You are so close. Start running redundant grounds just in case. I've had lots of cruiser issues with grounds. I'm rooting for ya. If you do need help I can head over later. Second set of eyes and all.
 
I’ll circle back to yesterday - pop a plug & see if you have excess gas on a plug / vapor.

I was thinking in the fuel arena yest, so pulling a plug or 2 a few times in a row to see would see if you’re getting a dry/starve situation.

I get this is going in a 70 platform - where does the harness stop being FZJ80 & start being 70 platform in at least as it related to the fuel pump?
 
LINUS said:
I’ll circle back to yesterday - pop a plug & see if you have excess gas on a plug / vapor.

I was thinking in the fuel arena yest, so pulling a plug or 2 a few times in a row to see would see if you’re getting a dry/starve situation.

I get this is going in a 70 platform - where does the harness stop being FZJ80 & start being 70 platform in at least as it related to the fuel pump?
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At this point, the 70 harness is not connected at all to the engine. I am using the complete lx harness.

I am not sure I understand, pull a plug after it runs to see if it is wet? Not sure I understand what I am looking for or what that would mean.

I should add that this engine was fully rebuilt, and this is the initial run... I am using parts from two different engines to put it together, so any part can be swapped out.
 
I’m wondering with all the cranking, and esp if it went dry after any fuel got there - the arm would be tan & dried out, not the normal color.

At worst, the other direction it’s wet as all get out, black - but that’s unlikely as you proved good spark thru the entire cranking cycle, as I read your post.

Coming back to fuel - if that’s where you’re thinking at rhis point - are you hearing the fuel pump ‘charge’ the pressure if you pause in ‘on’ position before cranking EVERY time you repeat the cycle, or just occasionally/ let it sit/crack a banjo bolt/etc?

I don’t hear the pump EVERY time I crank the80, so if you catch it pulsing the pump more than a ‘bump’ between cranking cycles, that would make me wonder if the fuel volume is there after more than just a few seconds.

Bad pumps can often build pressure but not hold volume flow, best said.
 
thatcabledude said:
Pretty sure the answer is no, but I’m not 100% so I’ll ask.... The Lexus doesn’t use a chip key right?
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Nope, they were those internal cut keys, but no EWS feature to the LX450.
 
This may sound simple, but you say the pump runs when you jumper it. Just because it runs does not mean fuel
Is being delivered. Sure she runs for 5-6 seconds and the it's fuel supply is exhausted. I would look for a steady flow of fuel from the feed line to the rail with the pump running. Maybe the fuel sock is plugged, maybe pump can't feed volume to maintain pressure.
This should only take 15 mins to perform, I know you are convinced it's not fuel, but until you see volume flowing you are not totally eliminating fuel as an issue.
 
Sounds like we are all pointed to the fuel supply. Before I test it, I will swap out the distributor tonight before I do anything with fuel, just to eliminate this, or might just put the light spark thing in line and make sure it keeps sparking to the end.

@tornadoalleycruiser has banjo bolt fuel pressure gauges, so I might grab those from him tomorrow and be able to test pressure at the rail.
 
If the airflow meter is disconnected a 1FZ will start normally and run for a couple seconds.
 
cruiserdan said:
If the airflow meter is disconnected a 1FZ will start normally and run for a couple seconds.
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Maybe I should uncover the wiring harness there and see if any wire is cut.
 
Or try another known-good airflow meter.
 
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I think there is a resistor up by the antenna motor originally. It has a heat sink.
This is for the low speed on the fuel pump.
Not sure, but start might use high speed and or switches over to low once running.
 
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blkprj80 said:
I think there is a resistor up by the antenna motor originally. It has a heart sink.
This is for the low speed on the fuel pump.
Not sure, but start might use high speed and or switches over to low once running.
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that's an excellent point, that is used for fuel pump control. the vehicle will start, run for a few seconds and shut off due to poor fuel supply
 
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heres some resistance values that you can check from the ewd
 
@bigredmachine - I’m just going to own the fact IDK anything about that unit.

Congrats - you’re running the ‘clinic’ at this point.

No salt, I’m not familiar with this piece, so tou’re teaching me on that specific piece.

While we keep coming back to fuel as the broad arena, I never had my PS fender out to see this unit.
 
@blkprj80 and @bigredmachine .... I know what you are talking about, but I thought that was for radio.... hmmmmm.. Don't even have that installed right now.

Here is what I tried tonight.

plugged my harbor freight spark plug in line light thing in and started the engine, I saw it continue to fire, slower and slower until motor stopped, so distributor is off my list.

I bolted a few more boxes to frames in case they need grounded, most items are internally grounded, so as expected no change.

changed back to the second MAF sensor, as it had the shroud attached. no change. pulled back and checked the wires, no seen issues. Started, no change.

Decided to unplug the computer and move it so it could be upright in the same position as it is in the car. Plugged it back in. VROOOM.... that was it!. Runs great now. Not sure if it was just unplugging it to reset it, or if it needs to be upright, but she runs.

Thanks to all for input, this was a challenging one!
 
2fpower said:
Decided to unplug the computer and move it so it could be upright in the same position as it is in the car. Plugged it back in. VROOOM.... that was it!. Runs great now. Not sure if it was just unplugging it to reset it, or if it needs to be upright, but she runs.
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may have been a pin fitment issue, the harness may have just been getting pulled in an odd direction. that's a better solution than shooting the parts cannon at it to see what works
 
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LINUS said:
No salt, I’m not familiar with this piece, so tou’re teaching me on that specific piece.
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no worries, its an easly overlooked connector and controller that can have you banging your head trying to figure it out. this set up is more of a resister set up (similar to a blower motor resister) for fp control. full voltage to the the pump when the fuel pump relay is is sending power to pin 3, less voltage when at pin 2 due to the resister inline with the pump.

newer cars and that magic box in an ecu that will duty cycle the pump for the appropriate fp control. slightly more fancy way of doing the same thing

and the more you know, the farther you go gi joe
 
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