RB20 sputtering/vibration

**feyd182** · 12-07-2011, 03:56 PM

Soooo long story short, I was running down the hiway today cruising along at about 140kph and my car seemed to develop a sputter. It's not really noticeable while cruising, but as soon as I get on the throttle the car seems to be sluggish and has a noticeable vibration. There is no smoke or anything of that nature coming from the exhaust and oil pressure and coolant temp are normal. My first thought was coil pack/s. I am currently setup with an RB25 turbo, Turbosmart MBC set at 12psi, FMIC, 3" turbo back exhaust, and fuel pump has been rewired and fuel filter is new as of 3 days ago.

Anyone else experience this issue? It feels like I have a dead cylinder and I get a semi-burnt fuel smell while idling. The car will still drive and idle on its own. Acceleration feels like I'm pulling a piano behind me.

Any thoughts would be greatly appreciated!

BTW it is an RB20 powered GTS4.

**feyd182** · 12-07-2011, 04:28 PM

Just tested coilpacks and all are coming in at 0.8ohms while hot.

Sent from my iPhone using Tapatalk

**feyd182** · 12-07-2011, 04:40 PM

Pulled all spark plugs, all seem fine and I noticed the tops of the pistons in #1 and #6 holes are wet. The rest are dry on top.

Sent from my iPhone using Tapatalk

**feyd182** · 12-07-2011, 05:02 PM

Found this when I inspected the coil harness:

You can see the plug is mashed, there is a good one in the background. The yellow plastic piece broke and fell apart when I removed the plug.
I'm really hoping this is the problem. Gonna pick up some newer GTR coils and hopefully harness from colinr33 tonight and I'll see how it goes.
Sent from my iPhone using Tapatalk

**Micho** · 12-07-2011, 05:43 PM

Hope you figure out what's wrong because this is the exact thing that happened to me and I haven't fixed it yet.

**feyd182** · 12-07-2011, 06:12 PM

Did some tinkering, removed individual coil wires w/engine running and found little to no change with number 1 coil disco'd. Coil tested fine hot and cold so I'm leaning towards the harness. Surprisingly enough the car runs fine now that it has cooled off.
Coilpacks and harness it is!

Sent from my iPhone using Tapatalk

**Supraclean** · 12-07-2011, 10:22 PM

Good choice, honestly thats 95% on the questions/ problems on this site with skylines are coil/ connections related problems I figure.

**feyd182** · 12-07-2011, 10:31 PM

Peeled open my coil harness only to find this crap:

Nice hack job! Being a mechanic, seeing that crap makes me hate do it yourselfers even more. If ya don't know what ur doing, take it to a pro or at least ask for advice.

Sent from my iPhone using Tapatalk

**feyd182** · 12-08-2011, 01:10 AM

So I replaced my crappy R32 coil harness and coils with R33 GTR coils and harness and the car runs way better. Got it up to operating temp and then took it for a good hard rip on the hiway and it still runs good after coming back onto city roads. Problem solved till the next thing breaks, lol.

BTW, huge thumbs up to colinr33 for selling me his OEM coils and pulling the harness out of his car right in front of me. Best $100 I've spent on this car yet!

Sent from my iPhone using Tapatalk