Jump to content
SAU Community

Recommended Posts

well i got my rb25det r31 and it free revs well.

But once you put load on it driving it starts to rev and then breaks down and wont rev, and starts backfiring as if it was a limiter noise...

when you change gears the bov makes a high pitched whistle instead of the normal rb25det bov noise, but thats in 1st and 2nd but from 2nd to 3rd and 3rd to 4th and 4th to 5th it makes the normal noises...

and when you do the limiter revving under load noise when you put the clutch in the revs drop down then it revs back up

free revs all the way out but wont rev under load

what could it be?

Link to comment
https://www.sau.com.au/forums/topic/160907-rb25det-breaks-down-under-load/
Share on other sites

coil packs or spark plugs. there are a few different fixes for the misfiring problem.

#1 - gap your spark plugs to .8mm (do that if not already done)

#2 - fix your coil packs, there are a few threads around on how to do this.

as for the bov sound, im not too sure if this fits the sound you described but it might be turbo chatter, where your bov doesnt actually open, the noise you're hearing is the air passing back onto the turbo blades.

Hey you are reading my mind but about four months earlier, If you have played with intercooler and a boost controller on the car you would have noticed that a nipple would be missing on the inlet part of the pipe before the bov that is the vacuum pipe that opens the actuator on the internal waste gate and if you dont have that hooked up you will hit max load causing seveire breakdown at 2k trust me i had the exact problem!!! easy way to fix it is to simply put a T valve in on the blow off valve hose that goes to near the back of the plenum!! that will get rid of your break down at 2k.. P.M if ya want a photo!

made a slight difference but still breaks down, but you can get past the banging and then it tries to pull.. could it be a fuel problem?

but what concerns me is, i gave it a boot full and then went to go into my driveway, stopped and the car stalled, then i started it again and it stalled again but started it and gave it a rev and it idled fine...

its quite farken easy u see...

u get a gapping tool, pick the gap u want, get ur spark plug out, tap them on the ground softly until the gapping ruler u are using fits between the sparking element and the underside of the tip. ur spark plugs come pregapped at 1.1 thats not enough for boost past 6-7psi. that will work, if ur unsure how to do it, go to ur mechanic.

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


  • Similar Content

  • Latest Posts

    • Right, its been a while for updating this car, but I made some small but important progress today. In the end I bought an Ecutek dongle from the Australian distributor Tunehouse (for local hardware support) but have gone with a remote tune from Racebox in the US (because they have done millions of these, and I could not find any tuner where I could access the tune anyway as they are all password locked). The App is reasonably easy to work with, but the PC software reminds me of Haltech's ECU Manager that you need to use with the Plat Pro ECUs, it is a nightmare.  Anyway, I sent the details over, got back a tune file and a request for data logs. I finally got a chance to access a private test track today as they want redline logs in 3rd and 4th, and have sent them back for the first round of reviews. The main difference in the tune is going from 1.0 (stock) to 1.3 bar (19psi), although I'm sure is a lot of other stuff in the background. Keeping in mind this is a dead stock car with 125,000klm, this is what the App's performance test claimed: Before After Interesting to note that both 400m tests had the same terminal speed (158klm/h) but different ETs. And no, the speed limiter seems to be higher than that at 186kl/h. Summary of the key logged parameters for the 3rd and 4th gear runs were: Those little turbos were certainly whizzing at 200,000rpm+.  Also I'm really not that excited about oil pressure 55psi at redline so I think I'll go thicker than 5w30 (nissan recommend 0w20....) and see if that improves it. Other than that (and the big boost spike....) everything looks good as a start to me.
    • Just one more post to show the final result and the original "janky" solution for a laugh. Everything feels really tight and no wobbling at all, very pleased 🙂
    • After drying a few days, time to put her back together 
    • The hot exhaust light will come on not from just the cat being blocked, but it's just a temp sensor, and it's designed to warn you to not do things like park in long grass.   If you've been pushing the motor a bit, it can cause the light to come on.   Second if the cat is rattling, I'd suspect it's not blocked, but instead falling apart inside.   The easiest "fix" until you can get a cat put back in, is to unbolt your one, bash the rest of the insides out, and then bolt it back in.   For a daily driver/street car, I am in agreeance of put a cat in the car. If it were race car I wouldn't care if it were removed.
×
×
  • Create New...