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Rough Running S1 R33

Rudager

By Rudager,
in General Maintenance

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Rudager Enthusiast

Rudager

Posted
Posted

Lately my S1 R33 (RB25DET+5sp manual) has been running really rough, it idles rough and once it gets over 3000RPM feels like it's going to shake itself to peices.

I checked the coilpacks, taped them up already and checked the spark plugs, all look seemed fine, i think it might be the AFM, last mechanic i took it too tried cleaning the AFM and ended up pouring a whole heap of de-greaser or some shit into the engine causing it to missfire something chronic, so i'm guessing he may have screwed the AFM at the same time since it started not long after.

Anyway to check the AFM is working fine?

And any other ideas on what it may be, the best way to describe it would be that something feels unbalanced, so yeah any ideas would be nice :dry:

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https://www.sau.com.au/forums/topic/126074-rough-running-s1-r33/
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mad082 Grand Master

mad082

Posted
Posted

easiest way to check the afm is to borrow someone elses.

have you checked to see that each coil pack is actually firing? easiest way is to unplug them 1 at a time while the car is running, and if you unplug 1 and it doesn't run any worse then you know that is a dead coil pack/spark plug. then to check if it is the coil pack that is dead, have a spare spark plug that you know works (not one out of the motor) and take the coil pack out (leave it plugged into the loom, and the spark plug in the motor though) and put the spare spark plug in, turn off the lights and have someone start the car. if you can't see it sparking then you know it is a dead coil. we did this to a mates 33 the other day. but you once we looked at the coil we could see it was dead because there was a big scorch mark where the plug goes at the top. then we test the 6 others he had bought from a wreckers and they all turned out to be dead as well. he was not happy.

  • 3 weeks later...
Rudager Enthusiast

Rudager

Posted
  • Author
Posted

OK.

Changed, Fuel Filter and Spark Plugs and fluids.

Cleaned the AFM

Checked the coil packs again, while idling just pulled off the connector for one at a time and each time the idle noticably changed.

The other thing is it happens on throttle and off, as in it's still rough when the revs are dropping after being rough getting there.

Endless604 Apprentice

Endless604

Posted
Posted
Not yet, that was my next step actually

it sounds more like a fuel problem then electrical

hows your injectors doing? try running a bottle of redline SI-1 through, or taking them out and getting the benched....and have you checked your ecu for codes yet? this almost sounds like a problem i had :P

  • 3 weeks later...
Rudager Enthusiast

Rudager

Posted
  • Author
Posted (edited)

Well well well, been an interesting night.

Took the car out for a spin, figured it was nice and quiet so i'd give it some stick and see if i could figure out how bad this problem is.

So it gets to about 6000RPM, and BAM, i go shit that's not good, but the engine smoothed right out after that. Made a beeline for home (only about 300m) and popped the bonnet and then i got a nice surprise.

The fan has ripped itself off the block and embedded itself in the radiator, coolant everywhere, steam everywhere and i'm not very happy right now :(

Not quite sure what happened, becasue it was only 2 days ago i checked to make sure the clutch on the fan was working fine, made sure it could move both ways easily when stationary, so f**k it i dont know.

But like i said, as soon as it happened it went smooth as, so go figure.

Edited by Rudager

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