Jump to content
SAU Community

Rb25det Falling On Its Face, Just Swapped In 240sx.. Help Me Please?..

IslandBoy
 Share

Recommended Posts

IslandBoy Explorer

IslandBoy

Posted
Posted

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.

Its almost liek the vtc isnt enabling?

its a SERIES II btw.

Also what is factory base fuel pressure for this motor?

Any suggestions/help is much appreciated!

Adriano Grand Master

Adriano

Posted
Posted

Mate, i would check trouble codes, get rid of the FPR, try gapping the plugs down to .8 and stick it on the dyno. If you have get a consult, you can monitor the sensors, and for $60 they are invaluable for stock computer. How much boost is it running?

shnaped_second Mentor

shnaped_second

Posted
Posted
and for $60 they are invaluable for stock computer

$60, from where? with software and usb cable? i could only find them in the US for over $100

IslandBoy Explorer

IslandBoy

Posted
  • Author
Posted

Well good news, checked error codes, retrieved code 34, which I assume is bad knock sensor. I reset the ecu then drove for 30secs and code returned, so It has to be bad.

My question now is, where is the knock sensor located on the SII Rb25DET Engine and what is a direct replacement/interchaneable part I can use?

Will a 300zx or KA24DE or Sr20DEt/DE work?

Thanks.

InterCooL Rising Star

InterCooL

Posted
Posted

not too sure if this helps, but the sr20det and rb series are fairly similar, and the knock sensor on the sr20det is located underneath the intake manifold, a lil plug that resembles a stethoscope, screws to the top of the block. would be a bitch to get to with the intake manifold in place :D

IslandBoy Explorer

IslandBoy

Posted
  • Author
Posted
not too sure if this helps, but the sr20det and rb series are fairly similar, and the knock sensor on the sr20det is located underneath the intake manifold, a lil plug that resembles a stethoscope, screws to the top of the block. would be a bitch to get to with the intake manifold in place :D

Yeah, i have an sr20 240 too.

I am aware now there are two knock sensors so it could be either one.. How can i check which one is bad? By testing the continuity?

Is there any way of disabling knock sensors"?

Adriano Grand Master

Adriano

Posted
Posted

There is a group buy on the forum for the consult, there is no way of disabling the knock sensor, if you disconnect it, it just gives the code, you could plug an oscilloscope onto the wire and see how much noise they are getting, should be able to test them, but i would check that they both have continuity in the wiring to them first, engine conversions can do funny things to wiring.

blind_elk Grand Master

blind_elk

Posted
Posted
Well good news, checked error codes, retrieved code 34, which I assume is bad knock sensor.
It's not indicating that you have knock, it's indicating a fault in the knock sensor circuits.

Have you checked that the CAS is working properly? Have you checked the base timing? Have you tried applying direct power to the VVT solenoid to see if it activates?

IslandBoy Explorer

IslandBoy

Posted
  • Author
Posted
It's not indicating that you have knock, it's indicating a fault in the knock sensor circuits.

Have you checked that the CAS is working properly? Have you checked the base timing? Have you tried applying direct power to the VVT solenoid to see if it activates?

Or the knock sensor could be bad as well. Where is the VVT solenoid at? I'm going to get a timing light later today and check the timing. What is a direct replacement for a knock sensor?

klh6686 Explorer

klh6686

Posted
Posted
Or the knock sensor could be bad as well. Where is the VVT solenoid at? I'm going to get a timing light later today and check the timing. What is a direct replacement for a knock sensor?

Are you sure both knock sensors are in tact and plugged in? i say this only because it is a swap into another chassis and it could be possible.

IslandBoy Explorer

IslandBoy

Posted
  • Author
Posted
Are you sure both knock sensors are in tact and plugged in? i say this only because it is a swap into another chassis and it could be possible.

Problem fixed, both knock sensors were not plugged in, the damn shop.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • sonicii
      Could it really happen......

      By sonicii · Posted

      I don't know any details, but I really wouldn't be surprised if they do it as a LHD only version, at least initially.
    • Gareth87
      What should I do next to hold the head on

      By Gareth87 · Posted

      Thanks for the replies everyone. Definitely a coolant push. Oil catch can is empty and always has been. As the engine is out now I'll be having a good look over things. I do have some detonation on the piston tops from a trigger issue back about 5 years ago. I felt it and shut off then bought a new ecu and changed the trigger. Never been an issue since. It never hurt the power, its made almost 80hp more since that incident but I will pull the bearing caps to take a look. If the bearings are damaged I will do a bottom end refresh. Head is being re conditioned at the moment and the block will be cleaned and checked to ensure it's flat. I'll go with a kameari gasket and see how it ends up. The other thing I'm not super keen on is the cylinder colours. I suspect this is from the inlet manifold. The plan will be to put it back together, retune and then stick a plazmaman billet inlet on it and retune. I'm happy with the power, if it makes a little more, then great, but I would rather just make everything more efficient at this stage.
    • MBS206
      Could it really happen......

      By MBS206 · Posted

      Maybe they'll look to do a bunch of presales to help inject some cash fast for their financial issues...
    • MBS206
      R34 25GT Engine Light 21

      By MBS206 · Posted

      Does it also misfire equally when revving?   Josh is very correct in what you should do. The coilpack harness wiring loom itself is a known problem due to its age and the number of heat cycles it has gone through. Throwing parts at a vehicle to diagnose the issue isn't a smart or good way to do it. Secondly, you may have a bad coil pack, you pop replacements in, they fix that issue, but messing with the harness breaks it, so the issue persists. So now you think "well it wasn't the coil packs" and have to continue chasing your tail, potentially swapping back in your shit coil packs and returning the good ones (yes, I've seen people do this because 'it wasn't the problem' and they want to save money). And suddenly, you've got two issues with the same symptoms...   Diagnose, don't use the spare parts shotgun.
    • V35_Paul
      Could it really happen......

      By V35_Paul · Posted

      Well the articals keep saying a Q50s (Skyline in Japan) with a new Manual gearbox. I like the talk about the new looks with the round tail lights. I hope they bring back the retro look like they did with the Z
×
×
  • Create New...