Ignition Problem

**tazsgtr** · 11-16-2011, 02:20 PM

So my GTR starts and runs fine for a while. But it seems that once the engine warms up enough, I lose a cylinder or two. Starts to sound like a subaru. The engine runs fine once it has cooled down enough. I thought I had an ignition problem such that once something warmed up enough it would cause a short. I have swapped out the igniter, ignition coil harness, ignition coils and spark plugs but no change.

I'm pretty sure I have an AAC valve problem as the engine hunts for idle when the AC is on. But I have not had a chance to clean it. I am also just about to swap out my injectors but I don't think this is the problem since it seems to run rich, especially when it drops a cylinder.

I have a Power FC that has never been tuned and would always get knock so I have never really run it hard.

Any help would be appreciated. Thanks. Jeff

**r33_gtst** · 11-16-2011, 02:36 PM

May be a stupid suggestion, but I had a bit of a similar issue but not as bad. Turns out my jdm battery terminal connections are different than the usdm battery. My tuner stretched them out and tightened them down so hard they dont move. My problem was my audio wires attached to my 10" sub would pull on the bettery connection as the box from time to time slid around during spirited driving. After being tightened immensely, car idled better and the 6th cylinder doesnt sound like it missfires upon start up. You seem to have covered all the obvious possibilities, hopefully it works out

**DarkCaporaL** · 11-17-2011, 08:35 AM

Could be

1. AAC valve
2. Air-Fuel ratio - engine temp sensor could be faulty and making the mixture change
3. Ignition - could possibly be the CAS, the one thing you haven't checked with ignition
4. Cylinder compression

**tazsgtr** · 11-17-2011, 01:45 PM

Thanks for the input guys.

**gtst_type_m** · 11-18-2011, 06:42 AM

whats your timing set at? mine was out and sounded like a subaru

**Pete-R33** · 11-18-2011, 06:51 AM

if its your AACV just remove it, honestly I know about 5 guys running without and it does not have a negative effect what soever. People always say" aw your car will stall" , or classic "when you turn your radio on the car will stall" etc ,etc this is not true. Just cover it I know people on this forum like Nelson etc aren't running them , I have 2 buddies with 240's with over 400whp each that run them, etc etc. Its not a big deal, the worst part is sometimes you have to feather the throttle upon start up , but most guys don't even have to do that!

could be a coil pack as well

good luck though mate!