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Fault diagnosis help...


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I just want to know what the below fault is? Is it fuel pump speed? I'm very new to this, I had the G4x fitted a couple months ago and I'm having running issues. Long story short, rb25det, car is misfiring, stuttering all through the revs when warm, turned on the other day and it was sputtering from cold. 

I plugged it in just to see what codes there was. When the car is idling this is showing a fault, when I rev it, it turns to active, but car still struggle through the revs. Any help would be great.

Thanks in advance

received_678512873061236.jpeg

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Oh OK, am I correct saying it's fuel pump speed? 

I took the fuel pump out and have found that it is a GTR fuel pump. Yes the sputtering is a new problem, was tuned when I got the link fitted. The tuner mentioned it kept blowing coilpacks, so they asked me to either go ahead with the R35 GTR coilpack conversion with new harness, as it ran better. Since having it back a month or so, it slowly started to develop this problem, it's when it warms up and the sputtering/missing gets worse as the engine gets warmer. I turned it on the other day and it was sputtering from a cold start as well. 

I was told buy the tuner, to check all my earth's and loom. I cleaned all the earths and nothing. Loom is abit harder as I'm pretty sure it's an engine out job. I unplugged coilpacks on cold, each one made a change to revs, when it with the issue, I unplugged them all and cylinder 1 and 3 didn't make a change. With that fault, I thought it might not be getting enough fuel. 

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5 hours ago, rrob said:

R33 gts-t have a 2 speed fuel pump controller.

You should be able to test the speed output with a multimeter, back probed the fuel pump wires on the tank lid. From memory its 9-10v on low speed and 12-13v on hi. 

Awesome, thanks for that. Where is this located? I think I saw something on the inner rear arch. 

Could this be why it's throwing the error fault in the picture above? 

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Various things can cause the aux output to show a fault state - it doesnt always mean there is a problem or it is not working - just means the voltages arent changing as expected. For instance if the output is loaded enough that the pull-up cant pull it all the way up to 12V when off then it will show a fault.  

It would be worth checking fuel pressure also.  

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18 minutes ago, Adamw said:

Various things can cause the aux output to show a fault state - it doesnt always mean there is a problem or it is not working - just means the voltages arent changing as expected. For instance if the output is loaded enough that the pull-up cant pull it all the way up to 12V when off then it will show a fault.  

It would be worth checking fuel pressure also.  

Best way to check fuel pressure? Get a gauge? Voltages to the ecu? Or to the fuel pump? 

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I actually had another R33 Gtst map across my desk today and that was showing a fault on Inj 6 also - so I suspect there is probably noting wrong and it is just caused by the fuel pump controller holding the aux at an odd voltage.

To check fuel pressure you would usually temporarily connect a gauge.  I just have mine on a long hose and tape it to the windscreen or similar.  A tuner would typically have this kit as it is common diagnostics.  

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