RB25Det Problems, Please Help

[Yum-Yum]

Hey, recently put an RB25DET in my 91 240sx. Has multiple little problems, but the one I want to focus on now is some sort of power loss problem.


Has FMIC, Walbro 255LPH, Exhaust, Adjustable FPR, Intake

Since I got the motor put in the car it would pull fine Sometimes (1st gear and 2nd gear) ... now it just goes under full boost and makes no power, and hesistates. It also bucks some too. Ive checked boost leaks, and it has new o2 sensor and plugs... I'm really lost.. The problem gets worse the more I drive the car.

Any suggestions/help is much appreciated!

[Yum-Yum]

One thing that really is getting me is that I can't find how to check for error codes on this damn thing.

Also Its almost like the VTC is not operating (its definitly not cracking in all the time)

[yokotas13]

id say intercooler leak personally

[street240]

You can get consult from ebay and read codes with it...

[Yum-Yum]

Well good news, threw the ecu in to diagnostic mode, got code 34, knock sensor. The rb25 has a knock sensor for cylinders 1-3 and one for cylinders 4-6.. So i dont know which one is bad.. How can I check, by testing continuity?

Also does anyone know a way to cheat the ecu temporarily to disable/eliminate the knock sensor(s)?

I am considering wiring the wires from the bad knock sensor to the good one to see if thatll work

anyways anyone know how to disable it?

[Z U L8R]

it's not the vtc, you can unplug the vtc and see if it makes a difference but that's not your problem.

first thing i'd do with ur car is double check the timing. if timing is perfect i'd put ngk 3330's in there and have a good look for burn marks on the sides of the coil packs, cause that may be your bucking issue.

continuing with this loss of power, try a coolant temp sensor, it's $19, get one for a 1996 maxima.

you can clear the ecu by disconnecting the battery....but you can also get a knock code if your car is knocking...ie...because of low grade fuel, incorrect plugs, fubar timing.

please check your timing

[Yum-Yum]

it's not the vtc, you can unplug the vtc and see if it makes a difference but that's not your problem.

first thing i'd do with ur car is double check the timing. if timing is perfect i'd put ngk 3330's in there and have a good look for burn marks on the sides of the coil packs, cause that may be your bucking issue.

continuing with this loss of power, try a coolant temp sensor, it's $19, get one for a 1996 maxima.

you can clear the ecu by disconnecting the battery....but you can also get a knock code if your car is knocking...ie...because of low grade fuel, incorrect plugs, fubar timing.

please check your timing\

You should have read my last post b4 posting all that, thanks for the suggestion though,, anyone??

[Z U L8R]

ya, check your timing, and use better gas. just because your ecu throws you a code related to the knock sensor, doesn't mean you have a bad sensor.

[Yum-Yum]

Actually it means its the knock sensor is faulty if you reset your ecu and run it for 30 seconds under no boost at idle and still get code 34.. I will check timing though

[Tranzporter786]

i have the same problem did you ever figure it out ?

[Okidamage]

May sound stupid but Check the wastegate pluming and make sure it's correct. I had the same problem with my s14 and totally over looked it.