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R33 Rb25det - Cutting Out On Boost

prawln

By prawln,
in Engines & Forced Induction

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prawln Apprentice

prawln

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hey guys so today was a busy day.

I changed the coils over with a mates ones that were working sweet and the problem was still there.

I changed the AFM to another pink sticker one, problem still there.

I decided to take a look at the ECU and to my suprise it has an odd one for it, and remembered that when i brought the engine it was out of an auto car.. and the ECU they gave us came with that engine.. so im guessing the ECU is an auto one.

The numbers are: MEC-R730 B1 6521, Ive done a search but cant find anything about this ecu.

I got a proper r33 rb25det ecu and checked the numbers on it and they are for this car but now it wont idle! its turns over and then dies straight away, if i give it some gas it i can hold the revs myself then if i slowly take my foot of the accel it will sit there idling but will be searching then pretty much die.

I unplugged the AFM and it was the same.. so while it was seaching for idle i got the mrs to plug the AFM back in and it died straight away. Would this mean its the AFM?

prawln Apprentice

prawln

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ok so today i checked for error codes on the manual rb25det ecu, i got code 12, which is AFM so i replaced it with another one and now it will idle fine and run, but again it is cutting out on boost!! im running out of ideas here!

Can anyone else think of anything to try?

Edited by prawln
Mr.Massive Community Regular

Mr.Massive

Posted
Posted

I had the same problem when I finished my conversion. It cut out exactly like in your posted videos. I changed the spark plugs, coils, afm and couldn't find anything wrong. So I lowered the boost and took it to a tuner. Got a nistune and havn't had any problems.

prawln Apprentice

prawln

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ok so have some good news.. got the car fixed and sorted.

The auto ecu was causing the car to not get above 5-5.5k rpm so replaced with a manual ecu and that fixed that problem.

i was still having the cutting out on boost issues though so today i took the pod filter off and put my hand over the AFM quickly to see if i could hear any leaks in the intercooler piping.. and to my surprise bingo herd a hissing sound. I located where the noise was coming from and found that the T bolt clamp was on tere tight but when we put the joiner on the intercooler pipe was in far enough and the T bolt clamp wasnt actully over the piping so was causing it to leak! When looking at it it looked like it was on perfect but apprently not

Took for a run on 5psi actuator and ran mint!! so put the 10psi actuator and also runs mint!!! so problem solved!

Just need to bring the timing back to 15 degrees from 20 degrees as its idleing rough!

Big thanks for everyones help and sorry for this being such a silly minor stupid thing!

  • 5 years later...
ONO2LO Contributor

ONO2LO

Posted
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Ive got the same f**ken problem its had me stumped for months changed heaps of parts and everything an stull cant get it but i dont think i have an air leak i can easly stall the motor by putting my hand over the afm. has anyone got an answer for this cutting out on boost problem? Its driving me nuts

This post should be in the hall of fame for real!

Ben C34 Grand Master

Ben C34

Posted
Posted

Ive got the same f**ken problem its had me stumped for months changed heaps of parts and everything an stull cant get it but i dont think i have an air leak i can easly stall the motor by putting my hand over the afm. has anyone got an answer for this cutting out on boost problem? Its driving me nuts

This post should be in the hall of fame for real!

Stalling the motor by blocking the afm is not an indication of anything. Good or bad.
Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

Alright this is the common problem with basic mods really my only solution is bigger afm and a play around with an ecu. got my hands on a scanner

it's not 1996, buy yourself a proper ECU

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