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RB25DET Conversion Help

rb25detcalais
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rb25detcalais Contributor

rb25detcalais

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Hey ppl, well I know this comes up all the time as I have done a search and none of the solutions seem to help. I have just come by a car that I have bought knowingly not working. It has a S2 RB25DET STOCK. When I picked it up it was misfiring heaps and a crap-load of black smoke as soon as it hit boost (but only a little on idle and cruise). Running rich - definately! I found the alternator was wired wrong hence the flat battery when I got home. Fixed that.

I have tested the AFM on a mates R33 and its working fine. I have checked all the wires going back to the ECU - they seem to be correct. My next step is to test my ECU on my friends R33 to check whether the ECU is bugered.

I have done a diagnostic on the ecu - 55 - all ok. Apparently before the engine was converted into this car by the previous owner he was driving it and it was running fine. I have checked the coils (resistance varies only slightly). I have checked the grounding for the injectors and coils.... I am REALLY stumped on this one. The crank angle sensor has apparently been replaced with a newy.

I dont think its the turbo as it spools up nice and the BOV is heard... The engine seems to be OK with regards to oil being where it shouldnt (coolant) and vica versa. I just can't understand why it's overfueling unless it has something to do with the Fule pressure regulator... but then that wouldn't explain the misfiring. I am also going to check the plugs tonight...

Sorry for the bore as a lot of you may have heard this so many times over.... any help would be greatly appreciated.

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rb25detcalais Contributor

rb25detcalais

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Yeah I am a little lost for options. I have tested the AFM on my friends R33 and it has worked fine. I can't think of much else that I have not mentioned originally above that could cause it. I will have to see whether my ECU does the same sort of thing when we put it in his tonight. On top of that if I could actually drive it properly (Is really bad) I might be able to think of some other things... but I can hardly get it out of the garage :D

BHDave Grand Master

BHDave

Posted
Posted

Was the crank angle sensor replaced prior to the problem starting? there a few different types apparently.

The missfire could be a result of stupid amounts of fuel. Have you checked the fuel pressure? It may be the problem, could also be bigger injectors if you're really lucky :)

rb25detcalais Contributor

rb25detcalais

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today I just bought a new aftermarket regulator... still same prob. I am starting to think its either the injectors or ecu... my ecu has "G8" on the label, is this standard for a S2 rb25det? I am thinking maybe this isnt the right ecu and its outputting the wrong impedence to the injectors.... perhaps the ecu is outputting a high impedence signal when the injector needs a low impedence signal.. or vica versa. Can anyone help with this???

rb25detcalais Contributor

rb25detcalais

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BTW the car this came out of was auto, its now manual so I don't know whether there are different ecu's for auto or manual like the RB30's.... in other words if there is a difference then the ecu would have been changed and it's a bigger possibility that it could be that... a wrong ecu. I have no idea whether this is the same ecu out of the old car or whether its another the previous owner sourced...

blind_elk Grand Master

blind_elk

Posted
Posted

Take the injectors out and heve them tested / cleaned.

Also, was the timing reset after the CAS was replaced? If you can hardly get it out of the garage, it sounds like the CAS is out to buggery (firing AFTER TDC, maybe).

blind_elk Grand Master

blind_elk

Posted
Posted

The battery has nothing to do with the timing - disconnecting the battery will have no effect on the settings of the CAS. You need to hook up a timing light to check what the base timing is (at idle, it should be around 15 BTDC)

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