4AGE 20V fuel problems

[70XIN]

** This is also in my build thread, but i thought more people would notice it here **

Okay so my engine is basically done. I'm getting spark and compression - but definitely no fuel. I can't hear the fuel pump priming at all when the key is on accessories, and neither of the two wires going into it have any voltage - so something isn't right. I've checked all the fuses, i haven't/don't know how to test the relays. EFI main relay gets fairly hot.

I don't think any of the engine loom i've messed with has anything to do with the fuel pump - i cut the diagnostic plug, that's the only thing i'm suss about.

Any ideas? I feel (am) retarded

[ke_70]

standed ecu?

[70XIN]

Yes sorry, should've mentioned that :)

[slide86]

I believe it is.

Fuel pump still in JDM tank? Using original ae86 harness in the boot?

[70XIN]

Yep and yep. The only wiring i have screwed with (since it was running) was all of the ECU loom in the engine bay, the wiring that runs along the firewall, and the diagnostic plug wiring - just if that helps anyone.

[slide86]

This is all pending on how factory the loom still is.....but:

Ive had a look at the wiring diagram, basically the 12v fuel pump circuit runs through the EFI main relay, into the COR (circuit opening relay) and then onto the fuel pump.

The COR should be located next to the ecu, you need this as a fail safe so the fuel pump doesnt keep running when the engine isnt turning. Its triggered by the ECU and the pin out is on the 22 pin connector near the batt +ve wire. This SHOULD be working ok as you have spark, which indicates the ECU has power and also is receiving a crank signal.

Find this COR down in the kick panel and ensure that there is 12v when the ign is on........then at least you know it will be signal to the COR fault and not a main wire fault ie unplugged or now cut

[swcustoms]

quickest fix is to wire up your own efi pump loom , standard looms are inefficient as the core size of the wire is often too small and in many vehicles they are incorrectly wired an efi pump really needs charging volts to work that little bit better .


its a simple process only one extra wire is needed to run from battery to pump , with a relay in the system so it obviously isnt running all the time , if you need to know more hit me with a pm and ill let you know how to wire it up

[70XIN]

Thanks so far lads - swcustoms, i'd like to stick to the toyota factory stuff as much as possible, but if that doesn't work i'll get in contact :)

slide86 - my good friend google has possibly pointed out that i have no COR - just the plug - and it appears though the previous owner/workshop in japan has spliced the BATT wire on the 20V 22pin connector to the 2nd pin on the COR plug wiring (both wires red/white), and the FC wire on the 22pin connector to the 4th pin on the COR plug wiring (both wires green).

[Matt]

Thanks so far lads - swcustoms, i'd like to stick to the toyota factory stuff as much as possible, but if that doesn't work i'll get in contact :)

slide86 - my good friend google has possibly pointed out that i have no COR - just the plug - and it appears though the previous owner/workshop in japan has spliced the BATT wire on the 20V 22pin connector to the 2nd pin on the COR plug wiring (both wires red/white), and the FC wire on the 22pin connector to the 4th pin on the COR plug wiring (both wires green).

That is correct the ecu provides the earth to the FOC and often the ign power to the ecu is often shared...

http://forum.4age.org/index.php?/topic/1741-toyota-fuel-open-circuit-relay-4age/page__pid__29602#entry29602

Run the blue/black wire straight to the pump from the COR, that is how it is done factory and it also goes to the diag box

[slide86]

how did you fix it bud?

[70XIN]

The way i had my igniter/coil setup wired up, the coils weren't "sending" an IGF signal to the ecu. So i just ran the IGF wire from one of the coils straight to the ECU, started up straight up - IGF was stopping the injectors from firing :)