Rb20 R32 Still Sounding Like A Wrx

[sama1500]

so ive had this problem for quite some time now, the sound comes and goes while driving at random except for the first couple minutes on a cold start, so far i've replaced coil packs, spark plugs, serviced injectors, these have all helped the car run a bit better but the problem is still lingering around, help?

[GH05T]

leak down test and return

[sama1500]

what exactly is a leak down test?

[Sinista32]

Compression test first. Identify variances across the cylinders.

You may pinpoint it down to one cylinder. If it's 2 with a low reading could be head gasket

Leak down test will further Identify in more detail the specific issue in the cylinder/cylinders

Head, rings, valves. Depends where the air is escaping. Exhaust, PCV or head.

The % low reading may also indicate valves.

Id let someone who knows what their doing. Can be time consuming.

It costs a bit more and takes a bit longer. Some shops will avoid like the plague as they don't know what they're doing or don't have the tools/experience.

Many on here can do it tho.

Edit: Where I've heard the WRX sound has normally been a single cylinder not firing.

Edited January 2, 2015 by Sinista32

[blind_elk]

Older R32 ignitors are prone to cause problems when they get hot. If you find the problem goes away after the engine has had a chance to cool a bit, then that will tend to confirm the ignitor as the culprit.

[Sinista32]

that's^very true too.

[GH05T]

or the coilpack loom

[sama1500]

actually now you mention it, when cold started it does run fine until the engine starts warming up and on cold nights the sound does come and go much more often than during the day, should i take it somewhere to get compression tested first or just chance it on it being the ignitor module and buy a new one?

[Sinista32]

Test the ignitor with a known good one

[sama1500]

the only way i'll really know is if i go buy a new one which is more expensive than a second hand one (no point getting second hand if unknown condition)

[Sinista32]

Cheapest you will find http://www.kudosmotorsports.com/catalog/genuine-nissan-pitwork-transistor-ignition-unit-ptu-nissan-skyline-r32-gtr-gts-gts25-gts4-gtst-r33-gtr-p-717.html

$500

Just get a mate to come around with one and spend 5 minutes swapping it over. Take your car for a 30 minute run

If it doesn't play up order one

These Skylines all use the same R32 GTR / GTS / GTS25 / GTS-4 / GTS-t & R33 GTR

Speak with Andrew at Kudos as there is a cheaper alternative as well

http://www.kudosmotorsports.com/catalog/genuine-nissan-pitwork-transistor-ignition-unit-ptu-nissan-300zx-z32-091993-skyline-r33-gts4-gts25-gtst-series-rb25de-rb25det-p-1298.html

needs a little bit of a change in the wiring but is more reliable/long lasting

$330

Edited January 2, 2015 by Sinista32

[GH05T]

mine got worse when hot.. head was warped.
leakdown test will rule out allot but yes you have one cylder failing.
take out the new plugs and see which one looks different.
have you done a compression test?

[sama1500]

i'll check the plugs again, i know there is a cylinder failing thats for sure, and no i havnt done a compression test, if the test shows a low compression would i be looking at head gasket most likely?

[Sinista32]

To hard to be certain with a single cylinder

If you had 2 side by side with low compression most likely.

With a single cylinder could be valves or rings.

To me it sounds more likely one piston is not firing.

Get onto checking the ignitor and doing the compression test

[sama1500]

ill get those two things done for now, also i dont know if this will help but on a cold start while idling it backfires every couple of seconds, nothing big no smoke or flames just a small backfire every second or two, the order is also random its not like it backfires every second consistently one second it might do it twice, not do it for another few seconds etc

[Sinista32]

A car backfires because unburned fuel is getting to the muffler

A backfire can be caused by incorrect timing of the spark (ignitor) or bad Tune as it's a balance of Air and Fuel

Leaking gaskets, seals, rings as this keeps the gasses in and the air out

Edited January 3, 2015 by Sinista32

[GH05T]

yeah thats the cylinder failing, thats unburnt fuel

[sama1500]

*sigh* so much shit i have to fix to just find out what the real problem is, would it be a better option to just go compression test it and put it on a dyno to see exactly what the problem is, or at least narrow it down by a fair bit?

[Sinista32]

dyno will just tell you it is underpowered.

Compression test a definite to check health of cylinders - but does not tell you about spark

Ignitor first - as easiest to check and I believe you have already said you've done the plugs, coilpacks, loom etc...

Need to make sure you have spark to each cylinder.

As ghost said if you pull your plugs you will see that one is not like the others. That's the likely culprit causing the WRX sound and backfire.

[sama1500]

ok will do this afternoon, i havnt yet replaced the loom so could it be possible also the wiring is at fault and its just old and needs replacing?