R34 Engine Problem

[Grey]

Okay, this is the problem. Last week the car was fine and all of a sudden it has no more power and misfiring really bad. Check engine light DID NOT come on or any other light that was out of the ordinary. Went to a exhaust shop because I thought it was the catalytic converter, turns out, I'm running on only FIVE cylinders.

Other symptoms include:

- Loss of acceleration

- When holding both window buttons down or up on idle, the RPMs drop from about 700-800 to 300rpm.

- Unburnt fuel smell coming from exhaust

- Exhaust making a 'chug', 'chug', 'chug' sound

Just then, I took apart all the coilpacks and sparkplugs to do a compression test and it turns out that cylinder no.2 is giving a drastically lower pressure reading compared to the rest of the cylinders. Now I've been told that this could be due to a valve problem within the engine. I really need a diagnosis on the problem so I can fix it and drive again, so if anyone on these forums could give me some advice it will be well appreciated!

Car: 1999 R34 Naturally aspirated coupe - remains stock as rock.

EDIT: I forgot to mention that I've replaced the coilpacks and sparkplugs 9 months ago with the best and longest lasting ones eg Yellow Jackets and iridium spark plugs i think, so it's definitely not the coil+sparkies.

EDIT2: Forgot to mention the compression test results (dry) from cylinder 1-6: 125, 80, 117, 113, 110, 115

Thanks!

[DVS JEZ]

Haha best and longest lasting ones. Because its running on 5 cylinders its easier to diagnose.

Start by:

Starting engine, then 1 by 1 disconnect a coilpack and see which one doesnt affect the engine sound.

Whenu find which cylinder is it. Try swapping a coilpack from another cylinder to the dud cylinder. Then if it doesnt fix the issue, try swapping a spark plug from a different cylinder.

Pull all the spark plugs out and keep them in order. Is there one that is different to the rest?

[Grey]

No, unfortunately, the cylinder that isn't working rules out spark plugs and coil packs because I did the compression test, which means it's an engine problem and not a peripheral coil pack and spark plug problem.

[mad082]

all cylinders seem a bit low on compression, other than just number 2. time for a rebuild i'd say. but would be much cheaper just to buy a second hand engine and bolt that in

[DVS JEZ]

Never rule anything out until u test it. Takes 15 minutes.

Do a wet compression test to see if the compression rises.

Did u do a test at operating temp? Was the throttle held fully open when cranking?

80psi should still be enough to run. If its a valve issue causing a missfire u would expect no comp in that cylinder.

[Grey]

Yes the throttle was held full when cranking....and i never did the wet compression test since the battery ran out after 5 cranks at each cylinder. So I just put it all back together and it's still running really crap =[

[DVS JEZ]

A discharged battery doesnt really help the situation either

[Grey]

would a dirty injector cause misfire at that cylinder?

[Hanaldo]

would a dirty injector cause misfire at that cylinder?

You would notice it on the spark plugs, the cylinder would be running lean so the spark plug would indicate as such. I'd start with that, pull the plugs and check that they are all the same. Always start with the things that are the cheapest and easiest to check and then work your way from there

[DVS JEZ]

What Hanaldo said as an echo to my 1st post.

Pull the plugs out in order and check them. Post a photo if u want us to help.

[Grey]

okay, i will take it apart again and do a wet compression test, and at the same time I'll post a pic of all the coils and sparkies so you guys can help see if they are the problem. if not then the engine might be failing and it's time for a transplant =[ results soon to come....

[Grey]

Okay, DRY compression result tests again since my friend did it wrong the first time.

150, 145, 148, 149, 144, 146

WET compression test result on cylinder 1 and 2:

168, 171

So from these results it's DEFINITELY NOT the engine itself, but the coilpacks and spark plugs. They are new yellow jacket coilpacks, probably 9months old and has about 8000kms on them. They are also NEW iridium spark plugs NGK BKR5EIX-11. After 8000kms do the spark plugs normally screw up? Cause I'm seriously not looking forward to buying new coilpacks after 400 ish spent on yellow jackets last year....

Here is the pics of the spark plugs:

From LEFT to RIGHT spark plugs 1->6

Let me know if you guys need more photos. Wiring, connectors and coilpacks look fine.

[Grey]

Additional info:

I just used nissan datascan to shut each individual cylinder off after replacing the spark plug in cylinder 2, when i shut cylinder 2 off, nothing happens, which means it's still cylinder two. I'm thinking it will be either the coilpack cable now, or just the coilpack itself. Any suggestions?

I just had a thought, I'll be swapping the coilpack from cylinder 2 to cylinder 6 to see if cylinder 6 fails, if it does, GREAT. If it doesn't it rules out spark plugs, coilpacks and leads to coilpack wiring.

Is there a voltage meter test I can use on the coilpack to see if it's working properly?

Thanks!

[DVS JEZ]

So i saved u the cost of a rebuild. Thats why u always recheck and diagnose.

Yes as i described before swap cylinder 2 coilpack with another ie cyl 1 coilpack and see which one is misfiring. If cylinder 1 is misfiring then u need another coilpack. Yellow jackets are known to fail. U can get the 1 replaced or save up and get some splitfires for $550ish.

If cyl 2 is still missfiring then the issue may be in the wiring, the spark plug or the injector.

Let us know how u go when u swap the coilpacks

[Grey]

I swapped cylinder no.2s coilpack with cylinder no.1, after reassembling, cylinder 1 has stopped working based on my ECU test from Nissan Datascan. So it's definitely the coilpack issue like 99% of the other issues here, I was too blind to think it was since I got them new about 9months ago. Trying to get warranty off performance wise now....Thanks for everyone's help!

[DVS JEZ]

Good luck with it buddy, let us know how u go.

I just had a look at the photo u posted earlier of the spark plugs. Can u see how cyl 2 is very wet of fuel. This tells u the fuel has not been ignited

[itshimdazza]

• i had the same problem with a yellow jacket as well less than one month from performance wise. asked me to send that coil back and I said I had nothing to replace it with and in good faith (after many emails) they sent another box of 6 so I could send back my originals to them...
  In the end good service..
  

Dazza