1JZ-GTE rev cutting at 0 manifold pressure

[brett_celicacoupe]

just finished putting a 1jz in a MX83 and there is an issue.

ive wired it up as per: http://www.thermactor.com/forum/view...ght=dino+flyen

everything else seems perfect so far, except....

as i accelerate, i can feel the turbos just starting bring the manifold pressure to zero and bam! its like someone turns the key off for a second. the ecu is clearly responsible for shutting down the engine because i can hear one of the relays click as the engine comes back into life.

on the road i can trigger this cut at any rpm, hence why i think it is 0 vacuum related. i can also trigger it to cut while free revving on the spot. it takes a much higher rpm though.

the ecu threw a code 21 before, O2 sensor but didnt throw it after resetting the battery and going for a spin.

hopefully someone has had this issue and its something simple.

input/suggestions appreciated

cheers
brett

[oldcorollas]

AFM or MAP?

[brett_celicacoupe]

i thought they were all map sensored, but yeh its got a map sensor.

the ABS light also comes on when driving (different toothed wheel in the gbox) but i didnt think the ABS computer was capable of interferring with the running of the engine (cutting engine to be 'safe').

under vacuum, the car runs PERFECT!

[brett_celicacoupe]

the problem was evaded (thanks to wilbo666 for help) by hard wiring the fuel pump in the diag box.

the root of the problem is still unknown. for some reason, the ECU is turning off the fuel pump as boost comes on. ive got the 1JZ fuel pump trigger wire (green with red stripe) connected to the original 7m fuel pump relay input

any ideas?

[BeRad]

i dont know if your running an aftermarket ecu but if you are is the boost cut on? pretty obvious but sometimes it slips the mind.

[wilbo666]

Hmm yeah sounds like an issue with the COR.

Does the stock JZX run a fuel pump resistor?

Cheers
Wilbo

[sideshow]

put fuel press gauge on it

if yr instrantlyloosing press then u have wiring wrong

had this prob on a 7m

[mrshin]

My guesss is it's to do with fuel pump resistor - it's trying to switch to 'high power' and there's no circuit there. Try applying power straight to the relay so it's on all the time, then go for a drive.

[brett_celicacoupe]

i dont know if your running an aftermarket ecu but if you are is the boost cut on? pretty obvious but sometimes it slips the mind.

stock ECU

put fuel press gauge on it

if yr instrantlyloosing press then u have wiring wrong

had this prob on a 7m

ive already established its an electrical issue thanks. putting a gauge on it wont acheive anything

My guesss is it's to do with fuel pump resistor - it's trying to switch to 'high power' and there's no circuit there. Try applying power straight to the relay so it's on all the time, then go for a drive.

i think your on the money shiny. incase you didnt read my above post, when the fuel pump is hard wired in the diagnostic box (Fp ->+B), there is no issue at all. it boosts away and does skids 'n' shit


is the fuel pump resistor the rectangluar one beside where the factory 7MGE coil is?

so how can i solve the problem is my next question?

thanks

[wilbo666]

so how can i solve the problem is my next question?

thanks

Wire up the COR really as per factory

Starter -> COR
ECU -> COR

COR -> Fuel pump

= skids 'n shit



Cheers
Wilbo

[JP]

from the description I'd think that maybe the fuel pump resistor isn't plugged in...

From memory it usually bolts to the drivers side of the bay in front of the strut tower.

jzx81 diagrams are here:

http://users.tpg.com.au/adsl0uxv/1JZ...1__diagram.pdf
http://users.tpg.com.au/adsl0uxv/1JZ...1__pinouts.pdf

The clicking you can hear is most likely when the ECU is trying to switch in/out the FPR as stated above.

[brett_celicacoupe]

thanks JP,

i didnt remove the resistor, it stayed bolted into the strut tower and plugged in the whole time i was swapping the engines

[brett_celicacoupe]

i think the problem is found (more thanks to wilbo)

i had the wrong wire triggering the FPR. i wired everything based on the guides on this website http://www.thermactor.com/forum/view...ght=dino+flyen

ill rewire as per below (green) tomorow and see what happens

http://img244.imageshack.us/img244/4...dwiringoa9.jpg


brett