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Rb25 Hot Start 3,000 Rpm Rev Cut?

1400r

By 1400r,
in Engines & Forced Induction

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1400r Veteran

1400r

Posted
Posted

noticed this mainly after getting fuel or stopping for a few mins somewhere

start the car up again (its at op temp already)

pull out of the driveway give it a little squirt in 1st to get in front of traffic grrrrr rev cut

(sounds the same as when Ive hit the higher rev cut before while drifting although not as hard)

then it seems to go away once I back off shift up stop try to acc over 3,000rpm

is this normal?

I have a feeling my ecu's not happy with one of my sensors or something

o2 ?(rb20 one meant to be the same)

afm?( it said it was a 25 one?)

purple plug thing near plenum? (its a s14 one)

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Jmaac Proficient

Jmaac

Posted
Posted

Sounds like the car is in R&R mode, you'll need to reset the ECU and also find the problem causing it. Try an ECU diagnostic that'll tell you which sensors are gone. (O2 is quite common for this)

1400r Veteran

1400r

Posted
  • Author
Posted

so to clarify

cutting on start up but them being fine a min ior two later does that mean its still in R.R

I would have thought it would limit rev's to 3,000 continuously?

(looking up ECU diagnostic now hope the 25 into 32 thing wont casue me any extra issues)

1400r Veteran

1400r

Posted
  • Author
Posted

buggar just did diagnostic on the ecu came up 55 all ok

which is weird seeing

1. as it doesn't start well

2. appears to have no VCT (solenoid doesnt pulse)

3. is running a rb20 02 sensor

4. a s14 purple plug near the plenum sensor

does anyone have the rb20 series ecu code numbers compared to the rb25 ones ( you know the sticker on the ecu i.e 52 -64 are R33 etc)

my ECU only has one led and was seperate to the engine package although it was marked rb25

would a stock unremaped 20 ecu even run a rb25?

green 33 Explorer

green 33

Posted
Posted

Have you checked your ignition coils, they will give you a fairly bad miss (feel like rev limiter) and a more prone to breakdown at higher temperatures, if you pull them out and have an inspect and if they have very fine cracks (normally whitish in colour) they are on there way out, running engine without coil pack cover will keep them a bit cooler for longer, also i have known people to have insulated their mounting rail and have aleiviated the problem, how ever only true way of fixing is new coil packs definately reccomend the splitfires

green 33 Explorer

green 33

Posted
Posted
missing would occur on que would it?

Im already not running the cover and I check the coils for cracks etc when I fitted the motor

they seemed fine

When mine started to go they would start breaking down between the 3000-4000rpm range and if i kept into it would again break down at the 5500 - 6500rpm range guess all dependant on temp, engine load, coil wear etc etc, the cracks can be extremely difficult to see at first thought crack was just a thin spider web.

If you are sure nothing is wrong with coils check your sparkplugs, sometimes aged or too largely gaped plugs can have same feel espeacially when running higher boost

renoR33 Rookie

renoR33

Posted
Posted

heY MATE MINES DOIN SORTA THE SAME THING, mine is sittin on about 8ok/hr in 5th then if i accelarate it starts missing and i loose power and can accelerate, i have to pull off the road and the car dies then, and it takes a bit to get goin again, now its been in the shop for a couple of days and i keep gettin it back in the same condition it was in, they have replaced the spark plugs, cleaned oil out of the afm, and they have just now replaced the fuel filter which was 90% blocked, but mines revein at about 3thou when it starts this prob, and auto elec tested it and electrically its rrunnnin fine, anyone no wat it could be??????

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