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Rb25det Acting Strange, Help!

ross80

By ross80,
in Engines & Forced Induction

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ross80 Rising Star

ross80

Posted
Posted

hey all,

I have just had my motor replaced and have had some vacum leaks fixed and an exhaust manifold leak fixed. Before they were fixed car wasnt boosting up. Car is boosting up now but seems to be hesitating a bit. Doesnt seem to be comming on boost as hard.

I have added a front mount and i was told to expect more turbo lag, but the car feels substantially slower. I notice it quite a lot in 3rd gear, Second doesnt seem to bad. Idle goes up or down a bit every now and then too. I have noticed when the idle does this, I can hear a clicking near the front or intake side of the head just as the idle changes?

Any Ideas anyone?

And also what does everone sugest i do to treat my newly formed car? Good oil? etc

thanks

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Tangles Grand Master

Tangles

Posted
Posted
I have just had my motor replaced

I have added a front mount

ummmm - has it been tuned as yet with the fmic on??? my rb25det was very hesitant when I put on the fmic, now after a tune is very strong.

ross80 Rising Star

ross80

Posted
  • Author
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The car has the following mods,

K&N pod filter

Hybrid Front Mount

3 inch cat back exhaust

Daikon/exedy brass button clutch

kyb struts and springs

I havnt had the car tuned after I have put motor in and the front mount so maybye that is the problem. I am confident it is not the usual coil, or spark plug issue as they are new and coils have been checked 2 weeks ago.

Noticed idle fluctuating between 800 and 100 rpm everynow and then again today. Almost sounded like it had lumpy cams.

ross80 Rising Star

ross80

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James,

The engine is out of a series two 97 model, i didnt rebuild old motor as block was screwed.

I dont have a aftermarket boost guage. I also have performed that high boost mod mod that is stated on this site, possibly a dumb move befor car was tuned.

Ant97GTR Grand Master

Ant97GTR

Posted
Posted

Sounds dumb and you've prob checked it anyway but it made my 33 idle fluctuate as you've described...

Right at the front of the fuel rail (cyl #1 end of motor) is the fuel pressure reg which has a little vac hose attached to it....this hose may have a leak or has come off....

ross80 Rising Star

ross80

Posted
  • Author
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Yeah ill try the ecu reset tmrw thanks for that. Yeah ill try injector clean too. Guy thinks that there may have been bigger injectors in the half cut i bought. May be something to look at, maybye they need better reg or pump?

paulr33 Grand Master

paulr33

Posted
Posted

it sounds like you are hitting the factory excess airflow protecition. this is usually the result of an incorrectly plumbed in actuator line. check there is a pressure line from the intercooler piping running to the turbocharger actuator (copper bubble with a nipple on it).

if its missing your are running unlimited boost and the ecu is protecting itself. what does the factory boost guage show? does it goto +7 ?

RANDY Veteran

RANDY

Posted
Posted

On that note of ECU's and motor swaps...

The series 2 motor doesn't run the ignitor on the top of it, it's run from the ECU. How did your mechanic get around this? Swap ECU's, or do something funky with another ignitor?

paulr33 Grand Master

paulr33

Posted
Posted

oh you have a series 1 ecu running a series 2 engine?

i once tried a remapped ecu and it was from a series 1 rb25

i experienced the same sorta things you mentioned, really flat gear feelings despite the car running fine.

please confirm what ecu you have and what engine (series 1 or 2)

if you have series 1 ecu on series 2 engine i would recommend buying a series 2 ecu

paulr33 Grand Master

paulr33

Posted
Posted

well if it in fact is a series 1 ecu on a series 2 rb25 engine (which seems to be the case without confirmation) then an safc will help a little but i suspect the problem will still be present or get worse. you would be better off getting a correct series 2 ecu.

the powerfc will fix it as the powerfc is the same wether its the series 1 or series 2 rb25, its the same ecu.

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