loosing power at 5000rpm

[nizmokid]

Has anyone Had this problem.

I am running fmic,bov,3.5 zaust, boostcontroler,ect, and my car seems to have pot,pot,pot noise through the zaust, noise begins at 5000 as boost starts to really get going( i loose boost also), It does this on high and low boost whats the problem? the zaust has only been on the car for a month and it was running fine for the first few weeks! ..........................help! whats wrong!!

[dAVE]

sounds like what mine was going. Was missing due to plugs being gapped at 1.1. Took them out and gapped to .8 and havent had a problem since.

Could aslo be a problem with coil packs, but best to check the plugs 1st.

[nizmokid]

took it to a mechcanic last night and i have booked it in to test the fuel mixture through the rev ranges. He looked at the exhaust and said it might be running lean. So I am not driving it at the moment until I findout whats wrong!

I don't think the sparkies have the wrong gap setting as they were just put in two months ago platnium ngk plugs gap set at 0.9 think thats what they were!

I hope it just a blocked injector or something!

[Guilt-Toy]

Take notice of what you were told dude..

I had the EXACT same problem and the HITMAN told me ALL boosted skylines have that problem with the plugs being set to 1.1 at more then standard boost.

I was told by the HITMAN to set them to .6 and it stoped straight way.

Once it passes the popping point it keeps going hey?

Take your car back and try it. or tell him to set them to .6 or .8

Worked for me.

[MegaGTS4]

maybe slight detonation might have damaged one or two of your plugs?

MEGA

[dAVE]

could be wrong but wouldnt those pot pot noises from the exhaust mean its most likely running way to rich rather than too lean?

[Guilt-Toy]

CHANGE THE GAP ON YOUR PLUGS TO .6 or .8

Try it. you will be surprised.

[adam 32]

the pop pop noise is because its running rich as the sparkies arent creating a reliable spark under high boost. ive got the same problem at the moment but have been too lazy to regap the plugs (damn uni exams)

0.6 is too close. i say between 0.8 and 0.9 should be fine. but it depends what boost u running?

[R32 Zilla]

I have a very bad miss at about 4500 rpm and after puting it on a dyno to see what was going on they told me i had 2 coils (1&5) that were breaking down, so i replaced both of them and the miss is still there. I am running 1.3 bar with a .8 gap. should i run a smaller gap ? if so, then why would it only break down on 2 cylinders ?

[adam 32]

i assume AFs are fine... other thing to check is timing advance cos this is obviously an ignition problem

i know you run a closer gap with higher boost pressure however i dont know how close your supposed to go... at 1 bar (what im running) im going to run 0.8 so i guess you should close the gap more...

why is it at 4500rpm? is that when full boost hits? does the car keep going after that point? unforunately there are quite a few things it could be

[nizmokid]

I got a fuel air mixture reading done on my car to see if it was to rich or lean but it was fine. they said it might be 2 faulty coil packs that could be the problem, same as what JAPSIX said about his ride!....... but first thing is that I am going to change the gap size on my sparkies they are 0.9 will drop them back down to 0.8 or 0.7 and see if that works. thanks for the input!

[R32 Zilla]

Yes my a/fs are fine, they checked it on the dyno.

I rang my tuning shop today and they said to try a .65 gap, so i will do that tomorrow and if that does not work then i will try a different ignitor.

If i turn my boost down below 1 bar then there is no problem and when i run over that it only misses once the car is fully warmed up. I have about 15 psi at about 4000rpm and the miss is sometimes inconsistant. Sometimes it will miss a bit then let you rev it out but most of the time it misses real bad and i back off.

[JET-RB]

mine are 0.6 gap and she's running fine I thought the same that it might be too little but its fine I'm running NGK iridiums...gotta gap em down or play with the ignition timing as well that can cause part of ur problem...

[hitnrun]

I would try advancing your timing to 20-25. I had same problems, at exactly 4500 to 5500rpm then fine until redline. Changing the timing totally fixed it.

As a quick review here are some common cause of the surgin/popping etc

spark plugs farked/gapped wrong

Timing

Air Flow metre shagged, faulty or dirty

far to rich or far to lean (on stock usually to rich, on boosted line usually a bit to lean so ecu retards the hell out of the timing)

Hitting boost cut due to leaking/inaccurate boost guage (Says 12psi, but maybe spiking to 14-15psi)

I'm sure there is other reasons, but most of these should be free or very cheap fixes.

Good luck with fixing it.

Cheers,

Tim

[SeriesIIGTST]

Hi

I don't have many mods (well cat back zorst and pod) and I noticed mine having a bit of a lumpy "pop" noise in the zorst at idle which wasn't so noticable during driving but no doubt still there. I went thru what you're experiencing. Turns out my injector in cyl 6 wasn't closing off and had overfueled the cyclinder and washed all the oil away from my valves, significantly dropping my compression in that cyclinder.

Long story short, do the following:

1) Clean out your AFM, you'd be surprised how much cr*p gets built up in that little item.

2) Clean out your injectors - probably can't do this yourself? Find someone that can.

3) Get new sparkies if necessary. I haven't gapped mine but as I said, i'm pretty standard.

4) Get someone to perform a compression test on your cylinders.

Other than that, I can't help :headspin:

Cheers!

[nizmokid]

thanks guys I regapped my spark plugs and the car has full power now!

BUT i have a miss when it Idels how can I fix this is it timing or sometinng! need info please!!!!!!!

[Kichigai]

SKYLINR,

I am interested in Iridium plugs for my line. Interested to hear if you find they made any difference?

[MYGTST]

im using iridiums they rock !!!

i also got bigger turbo si i use tem rating 5 ans gap at 0.7mm

no more mising or pinging

[adam 32]

next time use rating 6 (colder)

[JET-RB]

iridiums are really good not one ping or miss, platniums used to do it every now and then at top end rpm.