Jump to content
SAU Community

Revs Drop At 5000 To 4700 At 3rd Gear And Then Slowly Struggles To Climb. What Could Be The Problem?


Recommended Posts

Hi guys,

Can someone tell me what the problem could be?

When I rip the 34gtt, 1st and 2nd are sweet but as i put it into 3rd and once it reaches 5000 the revs drop down to 4700 and then it lags and struggles to climb back up and once it passes 5000 its normal again...

I am losing power at this point and would like to know where the problem lies? can someone please help me?

Any advice would be greatly appreciated, thank you.

Clutch dude... Between that rev range you're pulling the most amount of torque therefore a good chance it may be slipping. It's a good indication that your clutch is on the way out.

Yeah have to agree clutch is a strong chance. Not really sure why it would then struggle to accelerate once it's bitten though, bit strange. Could be just that it drops just below the rev point that the cam is meant to switch between the low & high advance setting. ECU may be getting confused since ur on full throttle & the revs suddenly drop.

^^ nope not neccessarly..

it can start to slip from 3rd and onwards, or even in 2nd.. After a while, if you dont replace your clutch, it will start slipping from 1st, and u wont be able to get past 20ks.. ahhah from experience..

I remember drivin on the last day to the workshop, with the clutch slippin in 1st, i could not go faster than 20ks..

Might not even be your clutch.. maybe a more knowledgable person, could suggest something else..

Correct me if im wrong but if a clutch was slipping, u would not be goin from 5k DOWN to 4700rpm... It would be the other way round cause ur affectively reducing load on the engine.... Maybe some sort of engine management issue for a certain load condition and rev range. U'd have to play around with diff Throttle positions once u reach that condition n see if it makes a diff, id imagine these ECU's get their load readings off the TPS.

I personally doubt that it's something electronic. How does a manual car suddenly drop 300 rpm without dropping speed at the same time? They're not like an automatic which will vary revs according to how much throttle is applied.... unless the clutch is slipping. If the revs are higher torque has less of a role to accelerate the car. I'd say chances are he's slipping at middle revs at peak torque. When power takes over the clutch bites again

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


  • Latest Posts

    • The wiring diagram for the R33 RB25 is freely available, and is essentially the same same as most other RBs (just with differences as to which pin # does which job). To get the ECU to power up, you just need to provide power to the ECCS relay, and have the other power feeds that come in from the top left of the wiring diagram (wrt the ECU) that give perma power to the fuel pump relay, the ECU itself, etc etc, all connected. When you put power on all these it will just come to life. It's pretty clear from the diagram what needs to happen. Just follow the lines from the 12V + supply stuff in the top left over towards the ECU. I've even posted snips of such diagrams (not for vanilla 25, I think for Neo and 26) to various threads here in the last few months, talking about what it takes to get the fuel pump and FPCM up and going. Search these up and they will help get you started on doing the same with the vanilla 25 diagram. Hell, for all I know, I've done the same with that one in years past and have forgotten.
    • Yep...so unless someone posts up the answer you will need to probe from the ECU connector to the dash plug with a multi meter in continuity mode to trace the wires.  Note the ECU has multiple - and + (and across different key settings - Battery, IGN and Start) and most likely the power is fed from the connector(s) that is normally near the left hand headlight.
    • Thanks Duncan, I am actually just trying to get the Rb turning and running with the RB25DET S2 original loom itself  I am just trying to get it going outside the body and not thinking about the S15 or trying to match anything to the S15 loom at all I am only trying to see if anyone has done this and what pin they found to be the ignition trigger and ECU+/- on the dash connector, that's about it. Thanks  
    • Hi Guys, Does anyone know any aftermarket part numbers for a starter motor to suit the VQ25DET? I can find lots of alternative part number for the VQ35DE, which I assume would fit, but there is a lot of conflicting information out there. Thanks..
    • I don't understand how this hasn't boiled down to - Upgrade the turbo when you have everything required. ECU, injectors, fuel pump, turbo, etc. Do it all at once.  If you don't have everything required, just enjoy the car as it is and keep saving up your pennies. 
×
×
  • Create New...