Hi! I got my RB30DE engine conversion in & going in my VL and seemed to go o.k. until the engine warmed up (we revved it out a bit to get the oil flowing through the motor),the idle deteriorated then the engine wouldn't rev out past around 2000 RPM. My experience on the matter when it happened on my RB30E motor was a slightly loose clamp onto the induction clamp which then made the engine rev out to 2000 RPM then let out these bursts of revs like this motor is doing now. The thing is also the mixture is running rich as I can smell it,the motor is more difficult to start than I think it should be as well. Thoughts were going through my head like a stuffed AFM,but I did do an air leak test on the intake manifold,my brother stood behind and noticed blue smoke coming out when it was revved and I sprayed CRC around the intake where it meets the head. When I fitted the manifold I noticed it used like a metal gasket so I used some gasket cement on it being used and so it seals it up better,I tightened up the intake bolts but that hasn't made a difference. When I got the package the AFM had a green tag on the side whereas I am aware the RB25DET's have a purple tag. It may look like I have to remove the intake and seal it off with a bead of silicon and it is a prick to remove the bolts with this motor in a VL as there is a lot less room to play with as compared with the RB30E. I was just wondering if anyone can shed some light on the matter.

blue smoke = burning oil, doesn't it? i think, having read some of your posts, that you may know a lot more about the RB30 than other people on this site. however, it may be something you missed, something small. mixture settings, thermostat not reading right? but if it won't rev past 2000 RPM then it's generally and AFM problem i believe.

Quote: Originally Posted by StockyMcStock blue smoke = burning oil, doesn't it? i think, having read some of your posts, that you may know a lot more about the RB30 than other people on this site. however, it may be something you missed, something small. mixture settings, thermostat not reading right? but if it won't rev past 2000 RPM then it's generally and AFM problem i believe. I try and look at a broader picture as I did look at some ECU fault codes,I have some but I am not sure if they are for an RB25,I have read in the older Zoom magazines where they say the fault codes are the same for an RB30 as an RB20DET (NICS motor),so the same "may" be the case for an RB25 as compared to an R33 type RB20DE(T),the fault code did say there was a code 41 which is a fault in the intake temp sensor signal system (diagnostic term),disconnection or short circuit in intake sensor signal system (error state),I know from doing a bit of surfing on the net that a lot of cars have their MAT sensor located in the AFM as the VL does,cars such as the V6 Commodore have it located in the intake. As many know the ECU doesn't tell you everything as I was reading on a classic example where a bloke who owns an RB30DET powered EH Holden was helping a mate do a CA18DET conversion into his car and they spent days trying to find the fault via the ECU fault diagnosis,figured o.k.,there is spark there,the continuity of the injectors are fine,fuel pressure is fine ,injector pulse is fine so he suspected jammed injectors and sure enough it was then he felt like pegging the ECU across the room. When I mentioned the blue smoke I figured it was from the CRC being sucked into the intake,the motor running as rich as it has been and is still on its run in period will a little blow smoke when cold and the rings haven't quite seated in yet,I have had an RB30E blow blue smoke and the problem was a corroded CAS connection.

Check your air flow meter dude, this is a classic example of either the afm being buggered or the plug connected to it. Run a diagnosis on the ecu and if you get error 12 if you do its an air flow meter problem. Check terminals one and six on ther air flow meter, thier should be aprroxiamtly 382 ohms between them. WHen you do this test make sure the cable is unplugged from the air flow meter otherwise the reading will be inaccurate. Other thing you can do is disconnect the air flow meter cable and start the car, but do not rev it and see how she idles. A good way to check your tuning is to start your car and looking at the two leds on the ecu in between 1800rpm and 2200rpm the leds should flash together. If not your oxgen sensor maybe bugged. Alot of people bag the ecu saying the error in the ecu are very inaccurate, but mine were spot on when diagnosed in the correct manner. give that a try and see how you go.

Quote: Originally Posted by wagon01 Check your air flow meter dude, this is a classic example of either the afm being buggered or the plug connected to it. Run a diagnosis on the ecu and if you get error 12 if you do its an air flow meter problem. Check terminals one and six on ther air flow meter, thier should be aprroxiamtly 382 ohms between them. WHen you do this test make sure the cable is unplugged from the air flow meter otherwise the reading will be inaccurate. Other thing you can do is disconnect the air flow meter cable and start the car, but do not rev it and see how she idles. A good way to check your tuning is to start your car and looking at the two leds on the ecu in between 1800rpm and 2200rpm the leds should flash together. If not your oxgen sensor maybe bugged. Alot of people bag the ecu saying the error in the ecu are very inaccurate, but mine were spot on when diagnosed in the correct manner. give that a try and see how you go. I am using an R33 computer which is different to the VL computer as it is a bit smaller in size,uses only one LED for its fault codes,the codes are layed out differently like each fault has a different number to the VL computer and from what I have read there are 2 different codes,one for an open circuit hotwire and one for the intake temp sensor,the R33 also uses a completely different AFM to an RB30E powered VL as from what I can see it is non adjustable. I am starting to think now I have been sold a dodgy AFM which wasn't with the package,they had to scrape one up. I just did another test on the computer which showed up a code 12 which is the hotwire circuit and a code 41 which is the air intake sensor so it does look like the AFM is buggered,but as I mentioned to someone else I have had a situation where a hoseclamp was only a little bit loose and this caused the airflow meter to act like it was faulty but it wasn't the fault of the AFM at all.

If the AFM is dodgy, the ecu goes into limp home mode. Limiting fuel injector pulse width so the motor wont rev past 2000rpm. Also it will be running rich as ****, because it doesnt actually know how much air the motor is using, so it uses the limp home value which is very rich to protect the motor of course. (This happens on all Nissan RB Motors) Does the hotwire look ok inside the meter? (Piss the mesh off so you can see what your looking at) Head over to SDU and do a search, you might find some info to identify the AFM. Mick

The R33's have a different sort of hotwire sensor to the RB30E's as they look like a really small wire wound resistor unlike the VL types which are just a string of nichrome wire which can blow very easily from a backfire through the intake. I have had this sort of AFM trouble on my last VL only that the car didn't cut out past 2000 RPM,the idle on it was crap,it surged all over the place and had a rotten egg gas smell from the exhaust. The hotwire in mine looks o.k.,actually,with the R33 AFM it is totally different to the VL Bosch unit which I may have already mentioned. I have searched and asked someone who I know is really Nissan mad and what he basically said is the AFM from an RB20DET is the same as the one off an RB25DE,apparently the series 2 (Neo spec engine I take it as) has the pink label AFM as do the RB25DET's whereas mine has the green label type.

Quote: Originally Posted by StockyMcStock blue smoke = burning oil, doesn't it? i think, having read some of your posts, that you may know a lot more about the RB30 than other people on this site. however, it may be something you missed, something small. mixture settings, thermostat not reading right? but if it won't rev past 2000 RPM then it's generally and AFM problem i believe. I have quite an idea when the motor is overcooling as well,when I had this motor in single cam form before the rebuild it always stood on the second mark,it turned out to be the thermostat was crook as the jiggle valve had literally rusted away,it ran on 1/3 regardless after fitting the second single cam motor,this twin cam motor uses cars original block and I used the R33 thermostat which is apparently set higher than the RB30E unit,the unit did work as I brought some water to the boil with it hanging on a bit of string,then the valve opened it fell off the string which apparently from what radiator specialists,etc do so I have been told to test the thermostat. The thermostat actually runs at pretty much the same temperature as the old unit according to the guage,and if it was overcooling why would the problem still be there when the motor is cold?. The R33 AFM units cannot be adjusted,the fault is not with the AFM because I tried 2 more today,the fault is not in the ignition which is what the bloke at the wreckers hinted,the fault has ended up being a tiny air leak as I ran some RP7 around the intake gasket area on the head which made it blow white smoke,running automatic transmission fluid around the join made it blow light pink smoke after a few hard revs so there's the air leak.