Jump to content
SAU Community

Recommended Posts

Hi Guys,

I have a problem at idle with my GTR, cylinder number 5 is not running when idleing or not under load, When the engine get some load, it kicks back in and runs fine with plenty of power. I have replaced all 6 spark plugs, i have swapped over the coil packs with others and its not a coil pack issue. However when i Unplug the plug to the 5th coilpack, the revs don't change/drop. So I'm guessing it has something to do with the plug/wiring?

Anyone got any advice before i start replacing everything?

I recently replaced the whole engine and got it tuned. This started happening a day after i got it tuned. Took it back to the mechanics who installed the motor and they couldnt find the problem...

Any help would be greatly appreciated!

Swap your number 1 and 5 coil packs and see if the problem moves. If it does you know where your problem is.

Next, run the engine with the number 5 coil pack out of the head, and with a spare plug in it, sitting on top of the motor and watch for spark. If there is no spark, then its wiring or ignitor.

If there is spark you need to eliminate fuel. Swap the number 5 and 1 injectors and see if the problem moves. If it does, then injector. If not, then potentially wiring or ECU issue.

Borrow a stock /replacement ECU from someone and see how it goes. Have your tuned map uploaded if need be.

  • Like 1

Sounds like it could be a blown intake gasket on that cylinder. Get some brake cleaner or wd40 etc and while the car is idling spray around cylinder 5 inlet, throttle gasket and injector oring etc. see if the idle changes

Swap your number 1 and 5 coil packs and see if the problem moves. If it does you know where your problem is.

Next, run the engine with the number 5 coil pack out of the head, and with a spare plug in it, sitting on top of the motor and watch for spark. If there is no spark, then its wiring or ignitor.

If there is spark you need to eliminate fuel. Swap the number 5 and 1 injectors and see if the problem moves. If it does, then injector. If not, then potentially wiring or ECU issue.

Borrow a stock /replacement ECU from someone and see how it goes. Have your tuned map uploaded if need be.

I have tried swapping my number 1 and number 5 coil packs and it made no change.

I will try the rest when I get a chance this week. Thanks for the info, will let you know how I go!!

Sorry forgot to mention, also when its a cold start, the revs drop quite a bit and struggles to stay on (turns off most of the time), i need to keep my foot on the accelerator for about 15-20 seconds before it stays on..

So i tried spraying some throttle body cleaner on the injectors earlier, the revs did not change on injectors 1, 2 and 3. however the revs went higher by 100-200 rpm.. when sprayed on injectors 4, 5 and 6.... when i sprayed it on all 3 at once, the revs jumped upto 500 rpm.

Does this mean the intake gasket is leaking towards the back? Could this be the issue or is this an entirely new issue?

Yes sounds like the inlet gasket is blown. Its pretty common to happen as the gasket gets old. I normally replace the inlet and throttle gaskets with a set of metal nitto gaskets. Also check all the hoses under the plenum as they may need replacing while the plenum is out

Is that the gasket from runners to head? Shouldn't be hard. I think the rb25 plenum to runners is probably the ugliest job to do. I did it without a guide but there should be something readily available. Google change rb26 plenum gasket or intake gasket.

Its a veryfun job to do on RB26's. willtake atkeast 3hours to get off, then cleaning of old gaskets and replacing hoses etc. then atleast 3hours to get back on.

DO NOT CLEAN IN AND AROUND THE THROTTLE BODY BUTTERFLIES!!!

  • 2 weeks later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Or, is it a case of what it is like owning an R series Skyline? NFI what the previous owner has done or fiddled with... Ha ha ha After reading through this thread, I went on a bit of a research about the Q50/Q60. Now I'm quite intrigued by them! Is the AWD in them more like a WRX where it's always AWD, or is it more like the ATTESSA in the GTRs? By the sound of this TCU tuning, this sounds like a case of someone has made some real software for it, and you just need the right piece of hardware, and then you license that specific vehicle/TCU. Or is this a case of the software will be really expensive so only a few tuners have it, and you still have to pay a license per vehicle?
    • By popular demand.. it was a coil. Got my hands on 1 new OEM coil, replaced with the one that made the less noise difference when I unplugged it while the car was running and started the car up. No stutter and the engine light was gone. I guess I’ll buy the other 5 they have lol
    • No, code 21 is very straightforward. It can only be the things described in that diagnostic flow. In fact it has no way of knowing that the spark plug resistance is out of spec.
    • Hi, SteveL Thank you very much for your reply, you seem to be the only person on the net who has come up with a definitive answer for which I am grateful. The "Leak" was more by way of wet bubbles when the pedal was depressed hard by a buddy while trying to gey a decent pedal when bleeding the system having fitted the rebuilt BM50 back in the car, which now makes perfect sense. A bit of a shame having just rebuilt my BM50, I did not touch the proportioning valve side of things, the BM50 was leaking from the primary piston seal and fluid was running down the the Brake booster hence the need to rebuild, I had never noticed any fluid leaking from that hole previously it only started when I refitted it to the car. The brake lines in the photo are "Kunifer" which is a Copper/Nickel alloy brake pipe, but are only the ones I use to bench bleed Master cylinders, they are perfectly legal to use on vehicles here in the UK, however the lines on the car are PVF coated steel. Thanks again for clearing this up for me, a purchase of a new BMC appears to be on the cards, I have been looking at various options in case my BM50 was not repairable and have looked at the HFM BM57 which I understand is manufactured in Australia.  
×
×
  • Create New...