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

[2fpower]

So to be clear I’m putting a 1FZ in a car that has a standard transmission.

I pulled an entire engine and interior haness from a LX450, deleted the alarm, and am trying to get the car runing before I start stripping out wires down to what I need.

As you can see in the pics, I have the harness laid on the plywood and all grounding points have been connected back to a common point (steering column) then back to the battery.

I had to do a jumper between the two large plugs on the NSS, neutral safety switch, and I jumped two more plugs to make sure that the computer knows it is in neutral.

The car starts up, runs for about two seconds then stops. I do have check engine light CEL, it does have spark and fuel at initial startup.

Things not currently hooked up.......

All transmission and transfer case wiring is unplugged. Are there any sensors that would shut down engine?

The EGR sensor is unplugged

the oil pressure light is unplugged.

Exhaust O2 sensors are plugged in, but sitting on the ground.

no coolant in the system.

 

[mct75]

VAF circuit opening relay?

 

[2fpower]

VAF, is that the Mass airflow sensor? that is hooked up. Am I correct that if I take off the MAF and the oxygen sensors it will run... badly, but run?

 

[mct75]

I'm not an expert, but I know that there's a system where if the engine doesn't detect airflow after cranking the fuel pump shuts off. It will start but not run (turning the starter overrides the safety)

 

[LINUS]

Random things, take w/ grain of salt.

EFI relay & fuse in block - are you hearing the fuel pump charge in “on” position, then cranking over to fire?

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Do you / have you pulled an alarm enough before that you know you’re keeping power to both fuel pump & spark the entire time, or does it die the exact minute tou let the starter off & let the key return to ‘on’ position?

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Is this a known good harness - Ideally I’m thinking tou cranked/quick ran the powertrain before removing the entirety of LX450 goods in the swap.

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Longshot - any possibilities the fuel filter is old/dead?
-Or did you install one since you had the motor out & the underside of the intake right in front of you?

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When it dies, can you pull a plug & find decent fuel vapor / wet tips? - I am heavy on the thought the fuel isn’t getting either there in volume or by control, anything from the hard parts like the pump, relay, fuse, or even the ignition tumbler if you can’t keep “on” position functions.

———

Are you still in functional OBD2 enough to toss codes?
-If so, anything interesting happening?

 

[2fpower]

Great ideas... that is what I need to think about this.

EFI relay & fuse in block - are you hearing the fuel pump charge in “on” position, then cranking over to fire?

.... I took a jumper hot wire and hit the fuel pump after the initial start, and no difference, so fuel supply is not the issue. It does not sputter, so I think that the computer is turning the spark off.... and likely the injectors.

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Do you / have you pulled an alarm enough before that you know you’re keeping power to both fuel pump & spark the entire time, or does it die the exact minute tou let the starter off & let the key return to ‘on’ position?

... this is the lx450 wiring harness, so the alarm is integrated with only the ground wire interupted, I have done one before, and I followed the best step by step known to man. HOW TO: Detailed DIY for Remote Start/Alarm/Keyless Entry

——

Is this a known good harness - Ideally I’m thinking tou cranked/quick ran the powertrain before removing the entirety of LX450 goods in the swap.

.... yes, pulled from running engine(knocking pretty bad), no rodent damage...

——

Longshot - any possibilities the fuel filter is old/dead?
-Or did you install one since you had the motor out & the underside of the intake right in front of you?

.... yep, new filter. note, when I hotwired the fuel pump it sounded like it was overpressuring the system and running the return line. so I don't think fuel delivery is the issue.

——

When it dies, can you pull a plug & find decent fuel vapor / wet tips? - I am heavy on the thought the fuel isn’t getting either there in volume or by control, anything from the hard parts like the pump, relay, fuse, or even the ignition tumbler if you can’t keep “on” position functions.

....at this point not headed to fuel.

———

Are you still in functional OBD2 enough to toss codes?

... tried to get codes, does not get any. Not sure if it is not running long enough.

 

[2fpower]

This thing is shutting down after a second, so I am thinking that some sensor is not giving the computer a signal, and thus it is shutting down....

Maybe the crankshaft position sensor? I really don't know what that does in this car....

Here is video.

 

[LINUS]

OK, so you have gas enough at least to crank, and spark enough to fire for that few seconds - can you swap a MAF off anouther rig in the yard to rule out a metering issue?

CPS as I know them is primarily to ‘see’ rotational position mainly as it related to RPM. Once running it is a used for timing spark.

Can you hot-swap a CPS or your TPS sensors with a known runner in the yard?

I know the TPS has a ohm value for a good unit - but I think as many 1FZ things as you have, maybe trading a known sender off one of those is as fast as thumbing the FSM.

If you swap all 3 and still have the issue - then I’d rewind to pulling a Mason jar of gas (delivery spec in book, I forget the CC’s they want off my head) - or check a plug / see if it’s dying wet & we’re back to a spark/air/choke -realm of things.

 

[LINUS]

Why I keep favoring the ‘swap sensors’ over ‘checked out by the book’ - comes from a issue I had with a S52 BMW motor that is a I6 and alot like a 1FZ.

I checked mine & chased my 6 another few days before finding mine had a ‘dead spot’ barely off the throttlebody dead-shut zone - ohm value was perfect in open / closed.

A $35 TPS sender made me crazy for most of a single weekend.

————————

So - if you swap a sensor / MAF & the motor idles, then try the LX450 part into say the SC’d 40th, etc - see if it ‘kills’ that motor as a doublecheck.

The upside - you’re getting initial spark.
So it’s not like you have a permissive issue or fawked engine harness (at least as I can play odds here) - where you can’t even get the initial air/fuel/spark to work whatsoever.

 

[mct75]

Is the COR a thing on these motors? I know they torment the 22RE crowd with the exact same symptoms, engine cranks but only runs for a second.

 

[LINUS]

As a final thought before any new info, it looks like you have the 80 cluster live & you mention the ‘check engine’ light - if you key to on, let it sit does it drop off in 2-3sec like when your 80 is code-free, or does it stay lit?

If it stays lit, then there should be a code pointimg to something that may be of value (Not like a PO402 or 420 - whatever the evap/EGR one is).

Just a thought going back to your 1st photo & trying to think if you were working with the LX450 ignition switch / tumbler.

 

[LINUS]

Is the COR a thing on these motors?

IDK ‘COR’ - definition?

 

[mct75]

Circuit Opening Relay, it shuts off the fuel pump if there is no airflow, to prevent the fuel pump from continuing to run if the engine stalls or is in a collision. On the 22RE and 3FE it works off the VAF sensor, and is a common culprit for the "engine cranks but doesn't run" scenario.

 

[Tank5]

I had a 92, i know not the same engine, I damaged the MAF and it would not start as a result. It would fire up and die just as you describe. I replaced the MAF and it started right up and ran. That is all I can offer good luck.

 

[2fpower]

Swapped out the MAF and it ran for a good 5 to 7 seconds before shutting down. Going to swap out the Throttlebody, my main thought is the idle circuit.

still no codes.

 

[mct75]

Can you watch a spark plug and fuel pump current to see which is dropping off?

 

[2fpower]

Update:

last night I ohm tested per the FSM the Crank position sensor, it read fine. I don't think that you can put the ring on the crank backwards, but can drop the sensor to see if that is possible. That would be terrible answer.

This morning, here are exact steps taken.

I replaced the MAF with a third MAF, no change, have about 6 seconds of run time.

I unhooked the MAF and the o2 sensors, to have an "open" system no change.

I put a new 02 sensor in, no change.

I replaced the throttle body, no change.

I hooked up the oil pressure sending unit, no change.... Strange fact, the headlight harness that runs across the entire front of the car has to be connected with the harness coming from the passenger firewall for the sending unit to work.

Good news is that I have good oil pressure.

I checked to make sure that the crank bolt was tight, and it is.

What is next?

 

[tornadoalleycruiser]

Plug in the shift lever instead of the jumpers.

 

[2fpower]

Circuit Opening Relay, it shuts off the fuel pump if there is no airflow, to prevent the fuel pump from continuing to run if the engine stalls or is in a collision. On the 22RE and 3FE it works off the VAF sensor, and is a common culprit for the "engine cranks but doesn't run" scenario.

Although I have discounted it... maybe this is a fuel pressure issue... I just don't know why it ran for two seconds initially, and now runs for 5-6 seconds.

How can I test for continued fuel pressure? or should I just check for power to the coil during the process?

 

[2fpower]

Plug in the shift lever instead of the jumpers.

You coming over to help haul a transmission up the hill?