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Some Quick Help Please

r32drifter1

By r32drifter1,
in Engines & Forced Induction

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r32drifter1 Apprentice

r32drifter1

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Posted (edited)

hey guys iv just finished putting an rb25 into my VL, and yesterday on first start up it hunted at idle quite badly, then sometimes the revvs dropped really low and it made a bit of a tapping or knocking from near the fuel reg. then i started it again last night, i didnt let it warm all the way up to running temp so not sure if it would have begun hunting again, but it just idled a bit high and not very smooth, with a very slight hunt. i have checked everywhere for a vacuum leak etc, i am only left with rather a sensor is screwin round or my BOV is leaking or something. any other causes of this? anyone who knows about these would be a huge help!

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moobaque Rising Star

moobaque

Posted
Posted

Could be your air flow meter is not working properly (that's asuming your setup is still using an airflow meter) are you using a nissan ECU or an aftermarket item?

other possibility is the AAC valve is dirty..maybe.

r32drifter1 Apprentice

r32drifter1

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thanks heaps for the quick reply guys, yeah airflow meter im not sure, i am using one of my old silver top rb20 because i was told they are the same? any chance thats the problem. and lol i dont know alot about these engines. the ACC were is it? there is a sensor and plug just below the idle control motor, a purple plug from memory, its a little damaged from transit, does that play a role in idling etc? oh and yer using standard rb25 ECU, ive tried spraying crc around looking for an air leak but im starting to get more convinced its not the problem

Edited by r32drifter1
moobaque Rising Star

moobaque

Posted
Posted
the import place that i bought my engine from. could it be making it run wrong?

quite possibly. i haven't looked at an rb20 motor to see if they use the same airflow meter. but if they don't it could be sending completely wrong voltages to the ecu which would definitely cause idling issues.

r32drifter1 Apprentice

r32drifter1

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yeah its a S1, iv just found that DIY cleaning the AAC valve and realised that is the part which has a damaged plug on mine, that could probably be the reason yeh? are these a part only on rb25s? cause i have an rb20 and 30 manifold in my shed i could swapping if not!

Simon-S14 Grand Master

Simon-S14

Posted
Posted

unplug the AFm and start it up... if it idles fine then your AFM is the issue

*note, with the AFM unplugged the engine willacctually run and idle very well... but wont rev more thne 2000 ish rpm, where as an AFM that is plugged in but not hooked up to the intake pipe or popped off intercooler hose will run like shit.

the ecu limp home mode works with the AFM unplugged.

r32drifter1 Apprentice

r32drifter1

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ok i have some more symptoms its got me confused now, ill try get some pics up if i dont get it fixed soon. i actually took it for a drive yesterday and it was wet so hard to really test, but it looses traction easy etc. but on grippy surface it doesnt want to go. it makes all the noises just doesnt accelerate like it should. also the idle hunting, it only does it when the car is warm, and if you gently accelerate it will stop. lastly on cold start up it wont revv at all, if you give it any throttle is just wants to die, and is a bit of a pig to get started cause of this. so yeah theres the million things wrong with it, anyone got any ideas?

r32drifter1 Apprentice

r32drifter1

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yeah i have a feeling there is a faulty plug in my loom, which is involved in giving power to the fuel pump. hopefully that will fix the sluggishness, i dont understant why it would hunt and not revv untill warmed up. maybe some of the sensors take power from it too

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