RB25DET Conversion Help

[rb25detcalais]

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.

[someonestolecc]

I'm no expert but...

Check AFM?

Also my friends GTiR came up black on boost and we thought it was rich ... turned out the wastegate actuator "stick" (lever?) had worked it's way lose... (unlimited boost).

Good luck.

[gatty]

my mate had a similar issue on his 33 - turbo spooled and boost was fine until onje day on a test run after some 'fix it' things we tried BAM - no boost

[rb25detcalais]

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

[gatty]

well we tested my mates, opened and re-soldered pins etc

it was his turbo - seal inside it going - then it finally went - now he's trying to get another

[BHDave]

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]

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]

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...

[gatty]

yes - different ecu for auto and manual - both quite different

[rb25detcalais]

I don't suppose you know if the difference can be told from what's written on the label.. as I said mine says "G8" and I have no idea what that means...

[gatty]

no idea about that one mate....

remove the line from the wastegate actuator that goes to your boost controller (i presume you have one there) and see if it has oil in it - if so same prob as my mate - blown turbo

[rb25detcalais]

Does anyone know what they have written on their computers and what sort of car (manual/Auto) they have?

[gatty]

i could look on one today and report back tomorrow but i'm sure someone on here knows - i tried a search but came up with nothing

also i see you signed up at filejunkies

[blind_elk]

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).

[rb25detcalais]

filejunkies is all good

Also the ecu has been reset HEAPS, I have always got the battery off for long periods of time, this should rectify the CAS problem.. I will have a fiddle with advancing and retarding tonight....

[blind_elk]

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)

[rb25detcalais]

Found out what it was guys. Turns out its the ecu. I think if have an rb25e (or de) ecu. Tested mine in a mates and it blew out black smoke and misfired etc.... put his in mine... worked orsm.... so for future reference G8 is not for a turbo!