help please! - diagnosis port

would someone know a bit about the diagnosis box in the engine bay?

I had a jumper wire installed by Kranz which provided constant voltage to the fuel pump at the back but its come loose and dont know where to plug them back in.

Would anyone be able to help?

stuck with the breakdown service scratching our heads...

My mobile is 07818285747 - peter

thanks!

It was more than likely a bridge from B+ to FP. There should be a little diagram on the inside of the lid.

Just spoke to Matt@AFR and he will give you a call in a bit

Here is the info I gathered over the phone.

Fuel pump works when directly connected to a power source..

B+ and FP bridge doesn't work

EFI #1 fuse has blown and been replaced (hasn't appeared to blow again)

Initial guesses are that the Fuel ECU is faulty or that a wire that runs to the FP has been nicked/cut.

Gavin thanks so much for your help earlier just got a ride with the tow truck...cringing thoughts of the van flying over speed bumps but then remembered the car was on a flat platform...have attached a coupla piccies

your update is spot on:

Fuel pump works when directly connected to a power source.. (Yep)

B+ and FP bridge doesn't work (its plugged in properly but not making a difference)

EFI #1 fuse has blown and been replaced (hasn't blown again)

going to try swap the fuel pump ecu over and see if that makes a difference.

any other thoughts from anyone else?

http://www.slipstreem.net/mkivsupra/manuals/Wiring%2520Diagrams.pdf

But here is an extract...

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=70493&d=1202347661

Also see here...

http://www.mkivsupra.net/vbb/showthread.php?t=139672&highlight=fuel+12v+mod

http://www.slipstreem.net/mkivsupra/manuals/Wiring%2520Diagrams.pdf

 

But here is an extract...

 

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=70493&d=1202347661

 

Also see here...

 

http://www.mkivsupra.net/vbb/showthread.php?t=139672&highlight=fuel+12v+mod

thanks for the diagrams buddy.

Just tried replacing the fuel pump but still no luck.

Looking at your diagrams do you think it could be relay related?

Something to do with the EFI relay 2?

With the jumper wire in place we should bypass the fuel pump ecu totally so it has to be something further down the line I guess... what do you reckon?

Pete, the jumper wire between B+ & FP was only a temporary solution to get the car running again (and driveable to a place where it could be repaired properly).

I'm guessing that the permenant connection of power through the FP test wire (only should really be used as a diagnostic connection to sense voltage to the pump, not provide full current!) has burned something out.

Initial diagnosis was the fuel pump ECU or wiring. If that can be fixed properly then it may work without fixing the jumper wire?

just noticed as well that the blown fuse for EFI #1 must be unrelated.

do you know what EFI#1 is for?

Pete, the jumper wire between B+ & FP was only a temporary solution to get the car running again (and driveable to a place where it could be repaired properly).

 

I'm guessing that the permenant connection of power through the FP test wire (only should really be used as a diagnostic connection to sense voltage to the pump, not provide full current!) has burned something out.

 

Initial diagnosis was the fuel pump ECU or wiring. If that can be fixed properly then it may work without fixing the jumper wire?

steve, any ideas on what might have burnt out?

have replaced the fuel pump ecu which i believe supragirlie bought new so am presuming would be fine but not sure how to test?

my money is now on the wiring or maybe the EFI#2 relay, does that sound about right?

Not sure, without studying the wiring diagrams I wouldn't hazzard a guess. I'll take a look.

Not sure, without studying the wiring diagrams I wouldn't hazzard a guess. I'll take a look.

See post #6

The wiring diagram shows the fuel pump ECU being fed by the EFI2 relay, which is fed by the EFI2 fuse.

On the fuel pump ECU:

Pin 1 is the 12v supply from EFI2 relay

Pin 2 is the power to the pump (also connects to the diagnostic port FP pin)

Pin 5 is the FPC.... Fuel pump control from the engine ECU? Probably shows a voltage when ignition is on and ECU ready to allow engine to start

Pin 6 is DI - Signals that the engine is running, so won't show an output until the engine actually runs

Pin 8 is earth.

I'd check for voltage at all the supplies to the fuel pump ECU. If that's all ok then its not the EFI2 fuse or relay

Then check that there is a signal getting to the FP ECU on pin 5. Don't forget that when you turn the ignition on the pump only runs for 1 second or so.

Check the output to the pump too when checking pin 5. If there is signal at pin 5, but no output to the pump, then possibly its the FP ECU.

If it all works out ok, and there is output from the FP ECU, but the pump still does not run, then it could be the wiring.

The wiring diagram shows the fuel pump ECU being fed by the EFI2 relay, which is fed by the EFI2 fuse.

 

On the fuel pump ECU:

 

Pin 1 is the 12v supply from EFI2 relay

Pin 2 is the power to the pump (also connects to the diagnostic port FP pin)

Pin 5 is the FPC.... Fuel pump control from the engine ECU???

Pin 6 is D1 ??????? Whatever that does

Pin 8 is earth.

 

I'd check for voltage at all the supplies to the fuel pump ECU. If that's all ok then its not the EFI2 fuse or relay

Then check that there is a signal getting to the FP ECU on pin 5. Don't forget that when you turn the ignition on the pump only runs for 1 second or so.

Check the output to the pump too when checking pin 5. If there is signal at pin 5, but no output to the pump, then possibly its the FP ECU.

If it all works out ok, and there is output from the FP ECU, but the pump still does not run, then it could be the wiring.

DI, from what I remember working out was the signal to say the car was idling (safety thing I assume)....

Steve/Gavin wanted to say thanks for your help with this, sorry about the silence just got back to the office and have been absolutely manic.

Will take a look at the voltage situation this weekend and let you know desperately hoping its something simple to fix!

hey guys I just realised I failed to mention I have an N/A, so think we've been looking at the wrong wiring diagram.

The one we need to look at is on pg.82 of gavin's pdf.

http://www.slipstreem.net/mkivsupra/manuals/Wiring%2520Diagrams.pdf

and the connector is on pg.90. Would you guys possibly know what each of the pins is for?

Suddenly the blown fuse at EFI#1 makes sense now, but also worrying...

can't believe how simple this was but definitely a lesson learnt.

Seem to have gained a few bhp through the standard wiring too

for those who might have a similar problem in the future, check the wiring loom connector under the rear right speaker, includes wires to the the fuel pump ecu. Seems the connector came loose when the speaker was being changed..doh

cant say thanks enough gav, a real privilege to have people like you to help on the forum

CASE CLOSED

Good new to hear it's all fixed. Sometimes the simplest fixes cure apparently complex problems.

Nice one Gav Top bloke

Here was the fix....

http://www.mkivsupra.net/vbb/showpost.php?p=2050581&postcount=43

You might find you have slightly better fuel pressure hence the slightly better top end performance (not because we have found more, but rather freed the existing ones ), purely because wiring can supply the current a little bit better.