ghamazy

Hi all.

I have a 2005 manual 350z and am trying to diagnose a problem. I’ve read through the posts here and am trying to narrow down the cause. Here goes:

6 months ago, my car will stall when idling – this happens occasionally. Somehow, after a couple of months, the stalling went away, and there were no issues for 6 mths.

Stalling and problem restarting – engine vibrates violently
A few days ago, after pumping a full tank of gas at a new gas station, the problem returned. While idling at a red light, the engine just died. It took some time to restart the car.

1) I switched on the ignition and the engine started and vibrates violently, but it died immediately after.
2) I switched the ignition a 2nd time and car didn’t start.
3) 3rd time, car started and died again.
4) 4th time, I throttled lightly - but the revs didnt go up no matter how much i throttled and engine died again!
Took a few more tries before it finally started and when it did, the revs went up to 4k-5k, before dropping back to normal and idling was stable.

Jerky acceleration at high rpms
After the stalling saga, I drove for a bit and all was ok. But when I accelerated on the highway at about 4k-5k rpms on 6th gear, it wasn’t smooth. The car felt slightly jerky – the feeling you get when you engine brake. The jerking stopped only when I throttled further. This happened on and off during my journey.

And the problem continues…(jerkiness, stalling and engine vibrates after restarting)
Since that day, the problem recurred almost everyday – at odd unpredictable times.

Starting up problems
Since that also, I now have problem starting the car sometimes. Sometimes, the car wont start as easily. I can hear the starter motor running and the fuel pump working, but the it takes about 2-3 seconds before the engine starts. Normally it takes < 1 second.

My mechanic cant troubleshoot the problem cos I cant replicate the problem. There are also no codes thrown out, and no CEL. Based on what I’ve read in this forum, I’ve tried to narrow down the cause to the following:
1) bad gas – the gas station I filled up at was not the normal one I use.
2) fuel filter or fuel pump
3) crank sensor or throttle position sensor

Did I miss anything out? Has anyone experienced this?

I love my Z but I hate it when I don’t have peace of mind enjoying my drive….

Thanks for hearing me out..

quick5oh

iTrader: (15)

Are there any mods done to the car?

ghamazy

Hi, thanks for the response. I'm running on a HKS GT Supercharger with Walbro 255l Fuel Pump. Unichip piggyback.

Thanks again

Jarred@Z1

iTrader: (4)

sounds like a boost pipe may have blown off. check all connections form plenum to supercharger. edit have you had a clutch installed lately?

ghamazy

Thanks Jarred, appreciate your thoughts. Checked for leaks and connections etc and no issues. As for the clutch, nope- none installed recently. Out of curiosity, would a new clutch cause stalling at idle? I presume it would cause some jerkiness at high rev acceleration due to slippage. Pls let me know.

Btw, no stalling in the last couple of days. Keeping my fingers crossed and hope its because of bad fuel thats now depleted.

chromesilverz

Another possibility is a bad throttle body? It's strange that it's not throwing a code though.