1997 1UZFE 3-5 second start issue

[mrdale]

Hi all,

I am currently swapping a 1997 LS400 1UZFE into an old 50's F100 body and am having a few issues getting it to "stay started".

I am using the OEM engine loom connected into the OEM ECU with some custom wiring which i will explain below.

Basically the engine fires up for around 3-5 seconds (hi revs) and then dies, opening the throttle does nothing to prolong running time. I also have to turn the power switch off then on to start it again.

The only error code on the ECU is 12 which i beleve is related to the cam/crank sensors not giving correct timing readings, however it sounds great during those 3-5 seconds. I have checked all 3 sensors all of which read within spec and i have checked continuity all the way back to the ecu connectors to ensure there is no break in the wiring.

Now onto the wiring, i am currently using 4 relays:

1. Starter
2. Igniter power
3. Injector power
4. Fuel Pump

I have two switches, one for power, which switches on the ECU and relays 2-4 and a button switch for the starter relay (just for testing purposes) with a few fuses thrown in for safety. ECU has constant power for memory and everything (as far as i am aware) is well grounded.

I am using an after market fuel pump and i am getting fuel return from the rails.

Any suggestions on checks which i can do would be greatly appreciated as i am running out of ideas.

Appologies if this thread is in the wrong section, i am a first time poster.

 

[pajman]

Sensor power supply? Also coils injectors igniters they maybe getting power during start but cutting out , have you a diagram to trace each circuit?

 

[pajman]

Where bouts in NZ are you

 

[mrdale]

Hmm, i guess i should double check my wiring...

I will get some pic's over the weekend, i have been working off several different diagrams and Nigel Wade's documentation. We just wanted to get it started as it has been sitting for a year so the 3-5 seconds was OK but we will eventually need to get it running.

I am taking a large gauge black wire from the engine loom for the starter which is hooked to a relay and push button switch. A large gauge red/black wire which is for the injector power and a smaller red/black gauge wire for the igniters' power. The injector, igniters and fuel pump all have separate relays but all triggered simultaneously by the IG switch. The ignitors, ecu etc are grounded to either the engine or the battery.

I couldn't find the exact ecu pinout for the 1997 so i have been going on the 1994 diagram. I am not taking any output from the ecu for the relays and the only modification i have done is on the 28pin plug, providing only const power for mem and switched power, with a engine check light.

The engine loom has several connectors, 3 to the ecu, 1 for gauges (I'm assuming here) and the other larger connector where i pull the above wires from. I had great difficulty tracing everything thus far as all the wiring was stripped out of the car before i could mark everything up.

Apart from the 3 wires i have already taken from the big connector are there any more i need to look out for?

We are also running it with no radiator or coolant as we don't plan to run it for more than 30 seconds and no gearbox oil (its an auto) but we don't plan on putting it into gear. We have plugged unnecessary accessory vacuum ports so there are no leaks.

I live in Auckland.

Cheers

 

[Bushwhacker]

Your ECU is immobilised.
Replace it with one from '95/'96 and swap the IGT wires around

 

[mrdale]

I figured it wouldn't start at all without the Immobilizer connected, there is one and i do still have it... Interesting, i will try and source on older ecu, if all else fails might have to try and wire the Immobilizer back in.

 

[mrdale]

Your ECU is immobilised.
Replace it with one from '95/'96 and swap the IGT wires around

Bushwhacker, just so we are clear, my ECU does not have the immobilizer built into it, it is a separate unit, does that matter?

It Looks like this:

 

[Bushwhacker]

Bushwhacker, just so we are clear, my ECU does not have the immobilizer built into it, it is a separate unit, does that matter?

It Looks like this:

Yes, you need that unit plus the Lexus ignition key and the plastic ring that surrounds the key when it's in the ignition.

 

[mrdale]

Damn i thought as much, you wouldn't happen to know anywhere i can get the pin-out diagram or the immobilizer?

Luckily I have a key etc as this was all form a running (but written off) LS400 which is a bonus, however i will probably modify the immobilizer so there is no key required if i cant get another ECU.

 

[George_R]

If it was the immobilizer what caused the failure, the ECU would throw the 99 DTC

There's a possible problem with the IGF2 (or IGF1, can't recall) being in different location on different ECU's , but then DTC 14 or 15 would be displayed

 

[361UZ]

probably not related, but my 1UZ had been sitting for a LONG time when I tried to start it (still in the 1/2 cut).
It would fire and run for a for seconds then stop.
Not sure if this applies to your 1UZ, but the crown mine came out of has a start injector, which was working fine, but ALL the main injectors were gummed up.
So, I tapped each very lightly with a small hammer. After the first attempt, the engine ran - but on four (ish) cylinders. Then another round of tapping and more injectors came on line. Once it was running reliably, I tapped the rest (gently!) and then all eight were running fine.

 

[mrdale]

If it was the immobilizer what caused the failure, the ECU would throw the 99 DTC

There's a possible problem with the IGF2 (or IGF1, can't recall) being in different location on different ECU's , but then DTC 14 or 15 would be displayed

Initially, before i actually got it to fire up for the 3-5 seconds i got at least 5 codes from the ECU all of which were either to do with the MAF or O2 sensors being dissconnected (which they were). Now i only get one code, code 12... i have read that swapping the ignitors might give me a code 13 if the igniter is faulty so i will try that.

 

[mrdale]

probably not related, but my 1UZ had been sitting for a LONG time when I tried to start it (still in the 1/2 cut).
It would fire and run for a for seconds then stop.
Not sure if this applies to your 1UZ, but the crown mine came out of has a start injector, which was working fine, but ALL the main injectors were gummed up.
So, I tapped each very lightly with a small hammer. After the first attempt, the engine ran - but on four (ish) cylinders. Then another round of tapping and more injectors came on line. Once it was running reliably, I tapped the rest (gently!) and then all eight were running fine.

You are braver than i tapping injectors with a hammer!

If it comes down to this i will take the fuel rail off and inspect/clean the injectors.

 

[George_R]

Only dtc 14 and 15 are ignition related
12 and 13 are crank/cam sensors related, or maybe the timming is off a tooth or more

 

[mrdale]

Only dtc 14 and 15 are ignition related
12 and 13 are crank/cam sensors related, or maybe the timming is off a tooth or more

The car was running perfectly before we pulled the engine out, we only moved it 2-3m onto the new chassis so its doubtful the timing is off. All 3 sensors read within spec but im not eliminating a fault with them at this stage.

 

[361UZ]

You are braver than i tapping injectors with a hammer!

If it comes down to this i will take the fuel rail off and inspect/clean the injectors.

Yeah, I should have been more explicit.
If you are careful, you can use a SMALL hammer and a long screwdriver to tap at the base of each injector while the engine is running (albeit on whatever injectors do fire).
I posted this a long while ago, and the advice was, as I tried (sucessfully).
Bearing in mind MY engine had been out of service for a long time, and this was only a test firing to make sure the whole package was operational before I dismantled it all.
When it's all together again, I will be removing said injectors for a more thorough clean and test.

 

[Bushwhacker]

The car was running perfectly before we pulled the engine out, we only moved it 2-3m onto the new chassis so its doubtful the timing is off. All 3 sensors read within spec but im not eliminating a fault with them at this stage.

It's not any of the sensors or injectors, it's the ECU.

 

[mrdale]

It's not any of the sensors or injectors, it's the ECU.

Thanks Bushwhacker I will try eliminating the immobilizer over the weekend and post back my findings. Thanks for all your help.

 

[George_R]

btw, as for the code 12
it's normal in some cases
for example when you turn ignition on and not crank the engine. Or if you crank it but there's no input to STA pin. In short, check that there's +12V at STA when cranking

it will not cure the 5sec start problem but that should eliminate the DTC so you don't suspect it any longer

 

[mrdale]

btw, as for the code 12
it's normal in some cases
for example when you turn ignition on and not crank the engine. Or if you crank it but there's no input to STA pin. In short, check that there's +12V at STA when cranking

it will not cure the 5sec start problem but that should eliminate the DTC so you don't suspect it any longer

Thanks George, i will double check this but as i mentioned in one of my previous posts i have only modified the 28pin plug from the ECU, the STA signal is on the 34pin plug which is part of the unmodified OEM engine loom. I will report back with my findings over the weekend.