Rb25det Problem Under Boost

[NicsR33]

Hey, i did a search but i wasn't sure on what to look out for.

basically i just put a few mods on the car. heres the story so far:

Bought the car completely stock with a leaking bov, was only running 4psi. i didn't mind cause it was going to be replaced soon. used to shudder after 7000rpm.

put a 3" turbo back exhaust, fmic, pod, GFB atmo bov and the bleed valve from eBay. now under low boost the car is fine up until around 6000rpm then it starts to shudder. i then up the boost to around 10psi and it shudders after 4000rpm pretty bad, it starts jumping and eventually i just ease off.

what could be causing the problem? someone told me it might be the injectors might on the way out but im not sure. the car was completely stock before i got to, it has around 90,000kms on it too.

any help will be great guys! cheers.

:sorcerer:

[Link]

Its misfiring - check your plugs and coilpacks

[NicsR33]

Its misfiring - check your plugs and coilpacks

so this is misfiring hmmmm.

plugs are 100% checked them when i bought the car around 1000kms ago. are these coilpacks much? could these be the only reason why its misfiring or are there other reasons?

[AdamsR33]

could be R+r, do a search on rich and retard.

[Abo Bob]

so this is misfiring hmmmm.

plugs are 100% checked them when i bought the car around 1000kms ago. are these coilpacks much? could these be the only reason why its misfiring or are there other reasons?

How do you know they are 100%? What gaps are you running?

Also do a search for misfiring or look in the forced induction quick referrence.

[NicsR33]

gf's dad is an engine pro he checked the plugs for me when i bought the car. not sure about the gap however.

cheers for the thread reference.

[AdamsR33]

also do you know if the boost is spiking over 10psi? also., why the hell are you revving it over 7000rpm?

[Tangles]

sounds like Rich and Retard. may be time for a SAFC or a better piggyback / full ecu.

at same time add a larger fuel pump....... would be all good (hopefully) then

good luck

[NicsR33]

i never thash the car, i only did it for a test (and on the bangor bypass going up).

if it only shuddered at 7 then i dont care but the fact it happens really bad on 10psi then its starting to worry. i might drop it back down and get it tuned up.

[Race_Bred]

ive seen plugs that look perfectly fine do all sorts of wierd shit throughout the rev range in jap performance cars trying to push horses, when you start going fast even the more simpler things become important

the coil packs could even be breaking down, get some new plugs and regap them to 0.8mm it will reduce the load on the coil pack therefore creating a happier working environment for your tired coil packs.

[J_Red33]

Bought the car completely stock with a leaking bov, was only running 4psi. i didn't mind cause it was going to be replaced soon. used to shudder after 7000rpm.

If your running the stock ECU, just over 7000 rpm is the rev limiter. It won't go any further.

[cameron]

Factory Rev limiter is at 7000rpm not above.

As others said re-gap plugs to .75

[AdamsR33]

What series is it?looks like S1 if thats the one in your pic, s2 stock ECU's don't like boost near or over 10psi, thinks car is overboosting so puts it into R+R, then again some s2 owners have run 10 or more without R+R kicking in. S1's i think can go to 12psi before R+R kicks in.

Next question, is the shudder erratic or even, like a beat?

[NicsR33]

im pretty sure it went to 8000rpm yesterday, i was surprised cause i didn't think a stock 6 could go as far as 8. ill take a video of it on my camera phone next time.

yeh its a series 1. its going on the dyno today so i guess they can check what might wrong with it!

i got a feeling too it might have went over 10psi. i dont have a boost gauge other than the factory one which only reads up to 7 so i might have gone up to like 12+ by mistake. ill drop the pressure and see how it goes on the dyno.

as for the shuddering its its pretty erratic.

Edited October 20, 2006 by NicsR33

[mad082]

sounds like it has a remapped ecu, so that means that there will be no r&r.

probably either the plugs need to be gapped down, or are the wrong heat range, or the coils need to be taped up.

get a set of new plugs just to be on the safe side. the ones you want are NGK BKR6ES or BCPR6ES. the first ones are just the v groove option. they should be gapped at 0.8mm, and will set you back about $4 each.

[kjb_r33]

im pretty sure it went to 8000rpm yesterday, i was surprised cause i didn't think a stock 6 could go as far as 8. ill take a video of it on my camera phone next time.

yeh its a series 1. its going on the dyno today so i guess they can check what might wrong with it!

i got a feeling too it might have went over 10psi. i dont have a boost gauge other than the factory one which only reads up to 7 so i might have gone up to like 12+ by mistake. ill drop the pressure and see how it goes on the dyno.

as for the shuddering its its pretty erratic.

Driving it like that its not going to last long. The 7 on the stock gauge one my series one r33 is actually 1 bar, 14 psi.

Knock boost back and keep it under 7000 rpm

Edited October 21, 2006 by kjb_r33

[govich]

im pretty sure it went to 8000rpm yesterday, i was surprised cause i didn't think a stock 6 could go as far as 8. ill take a video of it on my camera phone next time.

The factory redline is set at 7000rpm for a reason. I don't recommend taking it to 8000rpm often without an engine built for it, though pictures of rods through blocks etc are fun to look at.

Edited October 21, 2006 by govich

[NicsR33]

problem diagnosed as coils, should be fixed up within the week. car managed to pull 160 rwkw on 5psi thou so thats a promising sign for things to come!