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Growing Pains For Rb25 180sx

copycutter

By copycutter,
in Engines & Forced Induction

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copycutter Experienced

copycutter

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Hello again everyone. Another day, another problem... :D

For some reason my car; an rb25 180sx, was going nuts today. On partial throttle it would sort of jerk like hitting boost cut, and would also blip like a misfire up high in the rpm on wide open throttle. On the way to work this got progressively worse - to the point where I could barely limp the thing there!

The car would buck and jerk at almost any throttle setting and backfired pretty damn loud, made quite a few people duck. I thought the airflow meter or coil packs could have become unplugged, but upon checking them they appeared fine. There are no vacuum leaks from what I can tell, and the boost gauge is reading the same vacuum it normally would on idle i'm fairly certain.

Also, just before I arrived at work, the car stalled once when I popped the clutch, and then when I slowed down to go over a speed bump and take off again the car did nothing.... and i mean like the car was barely running, so I instinctively put my foot down a tiny bit further and all of a sudden the car surged forwards. It did this in 2nd also, which alone made me unsure about the fuel pump; as i've heard that when they are dying they deliver no fuel and the surge suddenly.

Over the past couple of weeks all that i've done is change the oil, swap the spark plugs to the correct heat range and gap, taped the coil packs, and just driven it to and from uni and work. The idle went up at one stage for no reason, so a friend suggested we adjust the screw at the back of the inlet plenum, which lowered the idle, but caused problems with stalling when I used the clutch and on cold start, so I adjusted it back up to 1500rpm where it raised itself to. Then for some reason it lowered itself to 650rpm and ran fine and I didnt change anything but I still cleaned a decent amount of gunk out of the throttle body. The car still ran fine for a week after this, and those problems i've written above ONLY happened today...

Is my walbro fuel pump gone? (i can still hear it priming normally when i turn ignition)

Is my fuel filter/injectors/regulator clogged?

Computer playing up?

PS: I was suggested to change the fuel filter, as it's the same one that my ca18 was drinking from for 8-9 months and could be clogged. Today I drove it and it was only rough for a very short bit, and then it behaved itself for the rest of the 15 minute drive. I didn't go into positive boost at all for fear of leaning out/detonation. Does this inconsistency indicate anything in particular to r33 owners at all?

Thanks again

-Nick

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BlueRB240 Collaborator

BlueRB240

Posted
Posted
Hello again everyone. Another day, another problem... :D

For some reason my car; an rb25 180sx, was going nuts today. On partial throttle it would sort of jerk like hitting boost cut, and would also blip like a misfire up high in the rpm on wide open throttle. On the way to work this got progressively worse - to the point where I could barely limp the thing there!

The car would buck and jerk at almost any throttle setting and backfired pretty damn loud, made quite a few people duck. I thought the airflow meter or coil packs could have become unplugged, but upon checking them they appeared fine. There are no vacuum leaks from what I can tell, and the boost gauge is reading the same vacuum it normally would on idle i'm fairly certain.

Also, just before I arrived at work, the car stalled once when I popped the clutch, and then when I slowed down to go over a speed bump and take off again the car did nothing.... and i mean like the car was barely running, so I instinctively put my foot down a tiny bit further and all of a sudden the car surged forwards. It did this in 2nd also, which alone made me unsure about the fuel pump; as i've heard that when they are dying they deliver no fuel and the surge suddenly.

Over the past couple of weeks all that i've done is change the oil, swap the spark plugs to the correct heat range and gap, taped the coil packs, and just driven it to and from uni and work. The idle went up at one stage for no reason, so a friend suggested we adjust the screw at the back of the inlet plenum, which lowered the idle, but caused problems with stalling when I used the clutch and on cold start, so I adjusted it back up to 1500rpm where it raised itself to. Then for some reason it lowered itself to 650rpm and ran fine and I didnt change anything but I still cleaned a decent amount of gunk out of the throttle body. The car still ran fine for a week after this, and those problems i've written above ONLY happened today...

Is my walbro fuel pump gone? (i can still hear it priming normally when i turn ignition)

Is my fuel filter/injectors/regulator clogged?

Computer playing up?

PS: I was suggested to change the fuel filter, as it's the same one that my ca18 was drinking from for 8-9 months and could be clogged. Today I drove it and it was only rough for a very short bit, and then it behaved itself for the rest of the 15 minute drive. I didn't go into positive boost at all for fear of leaning out/detonation. Does this inconsistency indicate anything in particular to r33 owners at all?

Thanks again

-Nick

Could be a bad CAS? did you pull the codes of the ECU? might give you a heads up with the problem.

copycutter Experienced

copycutter

Posted
  • Author
Posted

Just before we removed the throttle body to clean it my mate (mechanic) tried to get a voltage reading from the tpd while it was off. We fiddled around for a bit and he tried to stick a paper clip through the back end of the plug to the front to get a voltage reading but i'm pretty sure we didnt damage anything.

And wouldn't the car not idle at all if it had a vacuum leak?

copycutter Experienced

copycutter

Posted
  • Author
Posted

Ok i changed the fuel filter yesterday and we also stuck on a fuel pressure gauge and started it. It started fine and read about 41psi on idle, and would move a tiny bit when we revved it. So we removed the gauge and took it for a drive and the problem still occurs.

It wasn't as bad as before, but it feels like then engine is being told to cut which makes me think it could be a sensor related problem like the Crank Angle Sensor, Airflow Meter, Throttle Positioning Sensor etc.

AGAIN... does anyone know how to extract error codes from the computer?

  • 3 years later...

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