RB25 heartbreak HELP PLEASE

[97'240sxSE]

Hello I live in the US I have an RB25det and i need to know if anyone has had a problem similar to mine so i can find a direction to start. The RB motor is not reving past 3000 rpm. It pulls hard until it hits that mark then it dies off. It doesnt die it just stops building boost. Ive check the obvious IE boost piping, maf, and waste gate i was wondering if any has had a similar problem.

[Sumo]

Is it the stock turbo? How much boost are you trying to run? Is it the stock ECU?

The more info you give us the more luck we might have trying to think of possible reasons.

Sumo

[B-Man]

Sounds like some restriction (either phsical or electronic) on the exhaust or the intake.

Check the cat converter & exhaust system (drop the exhaust from the turbo and take it for a spin)

Check that you MAF is working and is wored corretly

Are you running heaps of boost ?? Might be boost cutout from the std ECU ??

Like Sumo said - could be heaps of things - give us more info.,

[EVL-180]

i have a RB 20 in my 180sx wich is the same as your 240sx just rwd apparntly (not sure if your 240 is rwd or fwd???) i found in my car that even with the A31 saffero dash (thats were i got my engine from) the revs still drop off at about 4 grand and it is a little slow gettin up there i have tried a couple of other dashes but apparntly the only way i can fix my problem is by gettin a monter tacho or somethin like that which sux

[B-Man]

i have a RB 20 in my 180sx wich is the same as your 240sx just rwd apparntly (not sure if your 240 is rwd or fwd???) i found in my car that even with the A31 saffero dash (thats were i got my engine from) the revs still drop off at about 4 grand and it is a little slow gettin up there i have tried a couple of other dashes but apparntly the only way i can fix my problem is by gettin a monter tacho or somethin like that which sux

That sounds a bit weird - how can your dash/tacho cause RPM drop off at 4K ??? WHat happens if you disconnect your tach ??? The car doesn't work ?? I think someone is yanking your chain.......

[meggala]

I would check your timing as well 15o is where is should be at also it could be the crank angle sensor.

something else to try.

cheers

meggala

[EVL-180]

That sounds a bit weird - how can your dash/tacho cause RPM drop off at 4K ??? WHat happens if you disconnect your tach ??? The car doesn't work ?? I think someone is yanking your chain.......

nu thats just what i have noticed in my car its really weird my car still runs fine but the tacho just stops at 4000rpm but it takes ages to get up there.

[meggala]

nah pay no atention to your tacho as it was clibrated for a 4 cyylinder not a 6 cylinder

meggala

[sileighty]

ahh dont worry about the tacho... mine is not working. just keep going till she starts to stutter a bit and the engine starts to scream.. then change gear... works for me

[97'240sxSE]

Ok the wiring is fine and the mass air is new. OO and by the way a 240sx here in the states is just an s13 or s14 chasis (silvia in other words only we get the pitiful ka24de for an engine.) I havent checked the cas sooo that can be a start. The car runs the stock ecu stock boost stock waste gate stock everything NO MODS yet.... I'm trying to avoid running an AFC for the time bieng so any advice would be grand.

THanks from the states

EVeret

[r33skylinegtst]

Isn't the 240SX pretty much the same chassis as our 180SX?

[paulr33]

it sounds like the ecu is in limp home mode, wont rev past 2500rpm.

this is usually caused by dead or damaged air flow meter.

see if you can swap it with someone else that has an rb25det

failing that build yourself a consult interface or order one and do a diag on it, or do manual ecu diag which can be found on this site somewhere

[EVL-180]

Isn't the 240SX pretty much the same chassis as our 180SX?

yeah but its FWD insted of RWD apparntly.... not much of a drift car really

[r33skylinegtst]

FWD? ok...ah... why the hell did nissan do that? They took a good car and... crappified it...

Sorry, don't mean that in a bad way, just that i find it rather stupid to change a car that was good in the first place. Anyways, good luck with it mate, you chose a good engine for the conversion :wassup:

[97'240sxSE]

No the 240sx is RWD its exactly the same as a 180sx but we have the nissan frontier truck motor. Its still rwd. Its just called a 240sx because we got the 2.4L instead of the ca18det or the sr20det. AND you still can drift the crap out of it. i only wish that we got the skyline

[97'240sxSE]

Can you send me the link on the self diagnostic. Im really sure the maf is good.

its new.

[93RPS13]

yeah but its FWD insted of RWD apparntly.... not much of a drift car really

hahahaha :bs!: where did you here that(no offence)...that really funny but that would suck if the 240sx was FR

[tastyratz]

dont you mean ff instead of fr?

yea dude ive been told before that the rb25det has the same maf as a 300zx (fairlady z) but DONT QUOTE ME ON THIS. its very possible im wrong but its not a bad direction to research in for a replacement, thats an easier afm to find over here in the states. you could always do the afm correction and make this an excuse to get a q45 afm

[NewKleer]

is ur afm hooked up right? try unplugging it and going for a drive. not sure if that can do any damage, if u think it might, then try:

turn car off. remove hardness from afm. turn key to on (dont think u need to start it), measure voltage between pin 3 (middle pin of the 5?) and negative terminal/earth. if 0v then no power getting to it.

if thats ok, and u can be bothered getting to the ecu:

turn car off, test continuity between pin 4 (when holding harness with connector stub facing upwards, its the 2nd pin from left i think) and ECU pin 26

if thats ok, test continuity between pin 2 and ECU pin 27

finally u can test voltage when car is idling between pin 27 and earth. should be ~1.1v

pin 26 and 27 are the 6th and 7th pin in the top row, counting right from the middle screw thing when the ecu is lying flat (not sure which is top/bottom, try both if ur not sure

problem may be wiring rather than a stuffed afm

[Sinful]

It sounds like Air or fuel problems Now you said it pulled hard until 3000rpm then that is usualy the turbo side of things which boost is coming on. Any smoke out the back? it could be anything