Rb25 Breaking Down

[JFK33]

Recently had a track day and managed to blow a manifold gasket, upgraded to a steel gasket and put the car back together.

took it for a drive to make sure she was running right and it runs terrible, hesitating coughin when boost starts to come on. sort of like the coil packs are shafted but ive only replaced them about 3 weeks ago.

any body got any ideas?????

[jjman]

is it blowing/ coughing any smoke?

black, white or blueish?

[blind_elk]

Which gasket (inlet / exhaust)?

If inlet, maybe you swapped two injector connectors.

Did you clean the manifold face and head surface properly before reassembly?

[DVS JEZ]

Make sure te cooler pipes are tight and secure also.

What coil packs did u get?

[JFK33]

exaust gasket, its not blowing any smoke that i can see, i got fuji spark coil packs as it is a budget car at the moment, but i checked coilpacks last night and there all fine so i changed plugs and still runs like ass.

ive narrowed it down to a "boost leak" but question is how to i find it??

[Moodles2]

I think I've heard of Fuji coilpacks before, someone else put them on and they were misfiring straight out the box or soemthing.

Although I just found the link, the person in question actually had one of their new coilpacks die: http://www.skylinesaustralia.com/forums/topic/407220-help-r34-rb25de-changed-coil-packs-ran-well-for-approx-40kms-then-started-misfiring-again/

[JFK33]

ive checked coils and there all good i ve checked for leaks and could find nothing at all, i am ganna pull the turbo off tonight and check for cracks. i am startin to think there might be a crack in the waste gate maybe..

[jjman]

how are you coming to the conclusion that the coils are all good?

Just because they look fine doesnt necessarily mean that they are fine...

Had a friend who bought yellowjackets barnd new have them fail after 3 months. 'Looked fine' still tho...

[JFK33]

^{while car was running i un clipped each individual coilpack with change in idle for each one}

[jjman]

ok thats a good start n fair enough

But you say in the OP that the issue is when you are driving it and coming on boost.

So while the coilpacks might be able to work fine at idle they might still be having issues under load. Which is of course their usual point of issue- under load, coming onto boost and in particular at 4500rpm WOT....

[JFK33]

good point there! i am lookin at gettin splitfires for it any way, but when it starts spooling it sound like its realising the air from the same side as the turbo. its hard to explain it is very weird

[jjman]

splitfires ftw.

[mystery_kid]

sounds a lot like a boost leak, just because it does it coming on boost doesn't mean it's coilpacks

the pipe can be holding together enough which lets the car idle and drive off boost but when you put some pressure there it the leak opens up and cause your issue, sounds like a silicon hose joint not done up properly

[JFK33]

I changed the turbo last night to make sure there wasnt any cracks or leaks, re gaped sparkies to .6. Ive checked and checked for leaks. The car runs rough as guts on idle. Doing a compression test tomorrow just to make sure then will start the elimination process again

[DVS JEZ]

Put the stock coilpacks back in. Or try another mates set of coilpacks just to diagnose

[JFK33]

Compresstion test= 120, 135, 135, 140, 145, 135

Last cylinder has i tiny bit of oil in it..

Any suggestions?

[jjman]

120 is certainly getting a bit rough and in difference to the others.

Is that the cyclinder with the oil in it? if so i think you have probably found ur problem.

[JFK33]

No cylinder 6 is the one with oil in it and tested at 135. Cylinder 1 is the one that tested 120 either way still think we've found the problem. Rebuild!

[Dobz]

There would have to be a fair bit of oil to be getting past the rings to make it run rough as guts, it would also be chugging out white smoke. Best to rule out the coils being he problem first.

With those compression numbers a rebuild would be on the horizon but it doesn't mean you shouldn't properly diagnose the problem first.

[ima_slap_joO]

A good way to check the coils is just to have a look at night with the car idling, usually the bad one will arc a bit giving you a little flash of light, but my rb20 was doing the same thing, kept trying different things, spark plugs and gaps, but it just turned out to be the coils, when I had vacuum leaks it would usually start missing much earlier than what yours seems to be.