[Inpulse]

Hi all
I have a small problem if anyone can advise my skyline runs fine on first start up but when hot it will start to run lean on idle and sound a bit lumpy if I rev it up and hold the revs it's still lumpy but when I get down the road on boost it then runs perfectly, I've not as of yet been able to do a diagnostic check yet as the plug seems dead

 

[Tricky-Ricky]

Are you sure its running lean? As hot starting problems are usually down to the ECU coolant temp sensor failing, the default setting if the sensor is dead is to run a permanent rich mixture which results in hard hot start and lumpy running on idle.

The other possibility is that the FPR is faulty or there is a vacuum line off or damaged.

 

[Inpulse]

Are you sure its running lean? As hot starting problems are usually down to the ECU coolant temp sensor failing, the default setting if the sensor is dead is to run a permanent rich mixture which results in hard hot start and lumpy running on idle.

The other possibility is that the FPR is faulty or there is a vacuum line off or damaged.

Hi ya yes definitely running lean i have a aem wideband installed, so far I've changed spark plugs, checked all vacuum hoses ,checked tps and put a adjustable fuel regulator on , next things I was looking at is MAF and CAS sensor

 

[Tricky-Ricky]

Have you fitted or changed anything recently, and what is the fuel pressure set to? I would normally say it's a lambda problem, but default for that is rich, is the ECU STD?

 

[Inpulse]

Have you fitted or changed anything recently, and what is the fuel pressure set to? I would normally say it's a lambda problem, but default for that is rich, is the ECU STD?

Nope haven't changed anything, I've just put a new lambda in just to rule it out even put a fresh tank of v-power in as it was running on tesco fuel thought I might be bad fuel ,I've had the cold start valve out today and it's working fine, no ecu is not standard it's still my nissan one I'm mapped to just shy of 400 bph ,fuel pressure is at 3.5 bar ,do you think it could be a coil pack or maybe MAF

 

[Tricky-Ricky]

Coil packs usually break down under load and not idle but if cracked I suppose its possible as is the MAF, is the ECU a std but remapped version? Or something else I am wondering if it's possible that the replaced lambda is causing the problem somehow, otherwise I would say its down to start map.

 

[Inpulse]

Coil packs usually break down under load and not idle but if cracked I suppose its possible as is the MAF, is the ECU a std but remapped version? Or something else I am wondering if it's possible that the replaced lambda is causing the problem somehow, otherwise I would say its down to start map.

Yes ECU is std and remapped by rising sun ,I've just found my original maf so gonna try that I know it's not good enough for the power in running but might rule it out, do you know much about the diagnostic plug my ignition pin seems to be dead was wondering about putting a new live to it ? It's getting annoying now she runs perfect when on boost

 

[Tricky-Ricky]

Found this.