Jump to content
SAU Community

Recommended Posts

hey im trying to hunt down a miss fire in my rb25det

the car is a stock rb25det making 470rwhp at 26psi

last 3-4 weeks its been getting bad, now its time 2 do something about it.

basically the car from cold will start up and run on 5 cyclinders for first 10secs then clear up and run fine.

i can drive around off boost and it will run fine. As soon as i give the car a hard time and thrash it, i can pull up and on idle its back to 5 cyclinders.mind you it runs perfectly fine under load/boost

ive narrowed it down to cyclinder 6 which is the cyclinder not firing.

ive tried new injectors,coilpack wiring harness etc

injectors have been cleaned etc and new seals.

ive done a compression test and its good came back with 150-155 from 1-6

anyone else got any ideas? some ppl ive talked to think its lifter problem in cyclinder 6?

Edited by methz
Link to comment
https://www.sau.com.au/forums/topic/376360-rb25-miss-fire/
Share on other sites

4350772539_55ff96415a_o.jpg&sa=X&ei=uotlTsuKKMLOmAXolZGaCg&ved=0CAUQ8wc4AQ&usg=AFQjCNGlgx_MfDkMMdcgSkJIa3LWOkL0Zw

Simon is making 500+hp on a stock motor? Misfiring could be caused by many things but it seems you've tried the basics. I will be keeping an eye on this thread to see how it progresses. Keep us posted. What I would suspect is the spark plug or coil back. Next would be wiring. Next would be CAS(could be playing up?) Sounds electrical to me. My car had similar symptoms on startup. It would sound like its missing a cylinder or even two and after a few seconds they all kick in, my spark plugs were on their way out. Try gap your plugs closer see if that gets rid of the misfire.

Link to comment
https://www.sau.com.au/forums/topic/376360-rb25-miss-fire/#findComment-6002873
Share on other sites

plugs are about 500kms old bk7re always used them.

leak down test might be on the cards then, might ask my tuner 2 perform this.

yes 26psi thru gt35r on a stock rb25. i dont always run this boost. only turned it up for a dyno day not long ago.

running 1.75bar atm.

Link to comment
https://www.sau.com.au/forums/topic/376360-rb25-miss-fire/#findComment-6002980
Share on other sites

At that power level I am assuming normal 98 pump gas? Simon is getting away with it on an ethanol mix, petrol would probably be a bit much for the crap fuel we get in this part of the world :(

+1 on compression test.

Link to comment
https://www.sau.com.au/forums/topic/376360-rb25-miss-fire/#findComment-6003033
Share on other sites

yes pump 98 bp ultimate

car has been on big boost and 400hp for a few yrs now.

ive done 2 compression test's and both came up fine 150-155 across all 6.

leak down i have not done, i dont even know someone with the right tool 2 do it.

Link to comment
https://www.sau.com.au/forums/topic/376360-rb25-miss-fire/#findComment-6003068
Share on other sites

Try a CAS and see. Just borrow a mates one if possible.

Have u upgraded the valve springs?

Does the engine tick when its misfiring?

Any smoke?

Do a compression test when it starts to misfire if u can. Maybe a valve seat issue

Link to comment
https://www.sau.com.au/forums/topic/376360-rb25-miss-fire/#findComment-6003438
Share on other sites

Gonna try new CAS 2morrow morning.

Valve springs are stock

only ticking noise is from the injectors, as far as im aware

no smoke at all.

ill get it 2 run on 5 and do a compression test then and see wot it comes up with.

yeh my tuner thinks a lifter or valve or something along those lines in cyclinder 6

Link to comment
https://www.sau.com.au/forums/topic/376360-rb25-miss-fire/#findComment-6003477
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • For these last 7 years of ownership, I've always had to use a small scissor jack under one of the front tow hooks to raise the front just enough so my low-profile jack fits under to reach my subframe jack point. I'm beginning to get annoyed of always having to do this. Are there any lower low-profile jacks that fit under the gtr lip on a dropped car?
    • Seat of the pants assessment of the new intake: The car is way less "doughy" when hitting the loud pedal, especially off idle when stopped or in traffic, I did use a cheapo lazer thermal thingo to measure the temp around where the pod filter got its air, it was between 55 - 60°C, in saying this the car was shut off and not moving, so the OEM intake pipe was not supplying any fresh air to where the pod was when the car was at least moving A weird bonus was induction noise on the throttle in the cabin increased a bit,  I was worried that I was actually going to lose some of that induction noise I love so much, outside though, when I got the daughter to do a WOT drive by pass for me, the induction noise has increased alot when on the throttle, not quite ITB doort, but well up there I'm extremely happy with the results and have been exploring the country roads in the region  As for house mods: 1.New front fence is up and is awesome, it really upgraded how the joint looks from the street, and the added security is nice 2. Electricians have replace some interior lights, and with more lighting in the garage, a few new motion detecting lights out the front above the garage, front room, and at the front door, which I have already found heaps helpful coming and going, also now has fancy pants CCTV all round the house The only hold point for power though is the solar and batteries due to supply issues, although this will happen over the next few weeks 3. I have done a heap of landscaping out the front and I'm almost ready to do a new small retaining wall with some nice blocks to replace the brick and cemented in rocks around the raised garden beds cemented in river stone "was the fashion at the time" the house was built. I currently have a pallet of retaining wall blocks and 2 bulka bags of 20mm blue metal to replace the wood chip that is in the raised garden beds around the house 4. I now have 3 big raised garden beds for out the back to grow some vegetables, about 70cm high, 200cm long and 100cm wide 5. My 2 compost bins are already pretty full with brown, green and kitchen waste from the landscaping I'vedone so far, but they will probably take a few months to break down, so anything else that gets chopped, trimmed, and kitchen waste will just start filling the base of the raised garden beds to about 30cm before I start throwing 40cm of good compost, and stuff, for the vegetables to grow in, I'll need a few ton of compost and soil, but the local supplier can sent me bulka bags of the stuff Basically the logs, wood chips and a few strategically placed rocks for drainage, will give the beds some good organic materials down low to break down over time, and they will hold moisture during the warmer months to save the water in my big arse water tank if we don't get alot of rain So, all in all, the car and house mods are going well, and I'm really enjoying being retired, I sleep in too 0700 and slowly plod around inside until I feel like actually doing anything, and only work in the yard for as long as want, which has actually been alot over the last few weeks,  although when you look at it, it seems that not a huge amount of work has been done,  until I look at the before I started the work pics Happy days and good times indeed 
    • hahaha yeah. Plan is to get side skirts and probably just rear pods. But going to do them one-by-one. I've got a set that I really like from RHDJapen, but that one isn't shipped to AU. So need to find someone who can get it for me
    • Here's an idea, answer the questions I asked you as they are trying to work out WHY the LSD will be binding up in a straight line.
×
×
  • Create New...