JZX100 FC & FPR fuel pump wiring problem...

[BigWorm]

So I'm tidying up the loose ends from my engine conversion & one of the last things left is getting the ECU to control the fuel pump properly. For those unfamiliar it's a JZX100 VVTi 1J auto, in an MX36 cressida wagon.

From my research I've concluded that JZX100s don't have the variable speed fuel pump controller, and the wiring diagram I went off seemed to agree with this, however the JZZ30 VVTi 1J do have these controllers.

I've wired up 3 relays as per the wiring diagram below, the second two earthed by pins FC & FPR, but these two won't do anything.
I've temporarily bypassed these 2 to get it running, & when running neither pins seem to go to earth like I expected.

Often the AFM controls the COR, but I can't see any connection with that?
Also what's with the little 5V sybol next to the FC pin?
Have I missed something obvious, done something stupid, or what?!?




Cheers for help!!!

[George]

For vvti 1jz-gte, check this topic
http://www.toymods.org.au/forums/sho...-of-newer-ECUs

Have you connected the STA and NSW pins properly?

[BigWorm]

Yeah STA & NSW are connected ok, everything works & the car runs & drives, but only with the 2 relays bypassed.

And it was that thread that prompted me to start this one, but cheers for the heads up.

[George]

How many connectors are on the ECU? (4 or 5)
I've seen 2 kinds of vvti 1jz-gte ECU's so far. 5-connector jzs171 used 2 relays and 4-connector jzx100 had pwm output to fuel pump controller.

I would recommend to inspect the outputs with an oscilloscope (probably trying to pull them high and low with 1K Ohm) and next, try different schematics to locate the outputs elsewhere.

[wilbo666]

What's the part number on the engine ECU you have? You've checked that it's JZX100?!

First thing is that FPR looks to be the Fuel Pump Resistor control, I assume you're not going to run a fuel pump resistor? The resistor looks to be normally bypassed by the relay and is put into the circuit when the relay that is triggered by the FPC pin is energized...


Onto the FC pin, one option is that perhaps the transistor inside is broken... it would seem unlikely but anything is possible I guess...!
You could test the transistor by taking the lid off the engine ECU... Trace back to the transistor via a multimeter or tracing the tracks.

Once at the transistor (which will have three pins) one pin should be connected to the engine ECU FC output pin, one pin should be connected to Ground and the other pin should be the 'On/Off' signal to the transistor. +5V on the On/Off transistor pin should turn the transistor on and hence the relay On, so use a multimeter to check if the +5V On/Off signal is present at the transistor would be my suggestion... (or try engine ECU in another car?! )

Cheers
Wilbo

[JP]

I wired the JZX100 1J in my old GX70 wagon with the ECU triggering the COR from the FC pin the traditional way, it worked fine. I also put a relay in that was triggered by the FPR pin to get rid of the fault code that comes up if you dont have anything connected to it. There was nothing connected to the output of the FPR relay, it was only there to get rid of the fault code and you could hear it click in and out depending on engine load.

I did manage to blow one of the transistors off the PCB when I stuffed up some wiring and fed it 12V instead of ground, cant remember exactly what pin it was on but it was something to do with the fuel control, managed to salvage a transistor from another denso ECU to replace the burnt out component and luckily it was good after that.

[BigWorm]

SORTED!!!!


In about 5 minutes flat.
Cheers everyone for your help, thanks for pointing out the resistor part Wilbo, now I get it!
Once I pissed off the 3rd relay that was hooked up to the FPR pin, just like you suggested JP, it worked!
I havn't actually got around to hooking up the engine warning light yet (!), so when I do I'll remember to sort out the FPR pin, but for now it's happy hanging.

I had a really shit day at work today, you guys just flipped my mood! Thanks again!!!

[Kenny80]

Hey Bigworm. Got a very similar problem at the moment. Both of my FC and FPR wires from the ECU won't trigger it's corresponding relay. Ie not earthing. I too can get around this issue by simply bypassing these wires.

I noticed you resolved this problem using JP's recommendation. Does this mean your fuel pump is activated by the COR output? And by wiring the FPR wire to the actual fuel pump relay, with nothing connected to this relays output, will this then allow the ecu to send an earth signal to the FC wire?

I know it's been a while so hopefully u can remember. Or someone else reading this can assist?

[BigWorm]

Hi Kenny, my problem was that I was trying to use the FPR relay without the low voltage/resistor bypass, so while the FC pin was energising its relay the FPR didn't energise as it wasn't ready for the full 12v to the pump. I hadn't noticed/understood this bypass in the diagram until it was pointed out.
Basically the FPR pin and fuel pump relay are redundant, FC controls the COR, but without a relay for the FPR to control you will get an error code, so hook up a relay that does nothing beside switch open closed when the FPR pin asks for it.

[Kenny80]

Hi Kenny, my problem was that I was trying to use the FPR relay without the low voltage/resistor bypass, so while the FC pin was energising its relay the FPR didn't energise as it wasn't ready for the full 12v to the pump. I hadn't noticed/understood this bypass in the diagram until it was pointed out.
Basically the FPR pin and fuel pump relay are redundant, FC controls the COR, but without a relay for the FPR to control you will get an error code, so hook up a relay that does nothing beside switch open closed when the FPR pin asks for it.

Thanks Bigworm. Everything is now running as it should. I followed the info above and all is sweet.

Yes the fuel pump relay not energizing now makes sense! Thanks heaps 😊

[dumbass]

I never ever run the low speed pump setup
99% of the time people want more boost and power
the high voltage switches at around 4000 rpm
when u want more power its best to just run the pump at full voltage all the time
plus there is less shit to wire up