Supercharger Starting/Idle problem

[hyunsoo1803]

Well, flame suit on first...

Yes Stillen kit is hated by people in here due to their design flaws and maxed out power etc...

Well I got the kit and I've been happy with it... sort of

Trying to improve the Stillen kit, I did the followings

1. Custom water to air intercooler (Thanks to ANMVQ for the part info)
- Due to Stillen's heat exchanger's size being too small

2. Custom tune
- Stillen tune was running wayyyy too rich and was not friendly to my mods (Greddy Ti-C with silencer, Berk HFC)

3. CSF Radiator
- Wasn't done to improve the Stillen kit but I put it here just so that everyone knows that it's there.


Now here is the problem

When starting the car cold, it has no problem starting. Starts strong

However when warm, 3-4 times out of 10 times, it would do something like this. (Skip to 00:35)

The start sounds weak and sometimes the car struggles to start the motor. It also cranks a bit more than usual sometimes. When it stalls the Rev sweep does not happen

Now I got the habit of giving a little gas while starting the car just to make sure it doesn't stall on me

It could be the tune, but i've been there 2-3 times to check on my starting issue and after they make small adjustments it starts fine when I'm there.

Now the idling issue.

With a little research, most of the SC kits suffer a small idling problem even with a custom tune. It looks something like this. (Skip to 00:39)

Now mine used to do that these days and I stopped caring since the RPM would just bounce up itself. It was driving me nuts for the first few weeks. However last night, when I was stopped at a redlight, it stalled. I then realized my car stalled and tried to start my car right away. It took quite an effort for the motor to start my car and I had to give gas to properly start my car

Few theories on top of my friends after having a little chat with buddies. We were looking for a solution to 2 problems "starting/idling"

1. Spark plugs?
- Maybe 1 step colder might help the car starting problem...
- GTM Motorsports*::*IGNITION SYSTEM*::*NGK Iridium Spark Plugs - VQ One Step Colder

2. Tune?
- Custom tune may take several adjustments to make it right.
- Oh btw, my A/F ratio is usually at 14.4 at idle. Can anyone with stillen kit chime in?

3. Leak?
- I doubt it is... but who knows

4. AC?
- I believe AC does not disturb anything.... but I did a little testing driving with AC on and AC off. When AC off, the idle is a little more gentle and smoother than AC on. When my car stalled, I had my AC on.

Any inputs guys? I would really appreciate any help

[hyunsoo1803]

And.... I just saw this. I may have to go check my car from my tuner.

Stillen supercharger and engine fail. :(

[jpritche]

If it makes you feel any better whatsoever, before trading my Z it did that. I just had an intake and exhaust.... I know it's nowhere near the same setup, but my rpms would do the exact same thing. The car would shudder also.

[ANMVQ]

Hey man ! You are very welcome. Have the answer for this too. LOL Mine did this a few times also. Its the HOT start and idle set on the tune. My First issue was mine wouldnt start after it was warm, Too much fuel( hot and cold starts where set the same?)
I had one step colder plugs too, along with bigger injectors, My tuner ironed that out if 20 mins


An to be really honest. I LOVED my Stillen kit, Wish I could have kept is, The 457WHP is made was MORE Than enough for me.

[Chuck33079]

Originally Posted by ANMVQ

Its the HOT start and idle set on the tune. My First issue was mine wouldnt start after it was warm, Too much fuel( hot and cold starts where set the same?)

Yeah, if the hot start settings are dumping in the cold start enrichment, you'll idle like crap. I would hope the OP's tuner would have known that. Oh well, it should be an easy fix. As far as spark plugs, a lot of us are running the OEM GTR plugs with no issues.

[DIGItonium]

No wonder I smell fuel after a couple rough starts. I thought the injectors were leaky and flooding the cylinders. Well, I was hoping GTM would send me an updated tune after giving them my logs. It has been over a year, and I never heard back. I'm still running the out of box tune. This is something I've been dealing with for the past 1.5 years since owning the kit, and I also give it some extra gas so it snaps out of it.

[OFFTOPIC]Ditto on OEM GT-R plugs. I'm thinking about HKS for my next set. BTW, are the gap specs the same as stock? [/OFFTOPIC]

[Chuck33079]

Originally Posted by DIGItonium

No wonder I smell fuel after a couple rough starts. I thought the injectors were leaky and flooding the cylinders. Well, I was hoping GTM would send me an updated tune after giving them my logs. It has been over a year, and I never heard back. I'm still running the out of box tune.

Paul at Baker had to harass him pretty good for my updated tune. When it gets a little cooler I'll just take it to Kosmic and get it dialed in all the way.

Jason and Paul said the HKS plugs weren't better enough than the GTR plugs to warrant the extra cost, but that's all I know about it.

[ANMVQ]

I would get that done sooner than later. You do not want to wash out the cylinders. :/

[Chuck33079]

Originally Posted by ANMVQ

I would get that done sooner than later. You do not want to wash out the cylinders. :/

Me or Digi? I've gotten an updated tune from Sam, i just think there's more left on the table as well as some part throttle stuff that could be better.

[theDreamer]

I am having a similar idel drop issue, getting a full new tune done by Kozmic in Houston tomorrow finally. They are aware of this issue and have told them this is basically 90% what I need fixed.

[Realale]

I just had an issue with my Stillen kit, but not the same. First the engine light came on after running hard for about 5min. Also would always idle with a constant 300-400 RPM swing. I took it back to Stillen to get fixed and it was one of the throttle bodies sticking. So they replaced it under warranty and ran great.

Then I started having a hard time starting the car. It would always start, but take a few cranks to fire up. And then kinda sputter to get going. So I took it back to them and it was a small pin hole in the fuel pump fitting. Keeping it from holding fuel pressure. They replaced the hose and all has been good since.

If you can try to read the code with a reader and then you will know where to start looking. Also you might try to turn the car to the "ON" position for a few seconds without your foot on the clutch. Then turn the car off. Then you can try to start it. Hope you get the issue resolved soon and get your Z back on the road. Keep us posted with the results.

[ANMVQ]

Originally Posted by Realale

I just had an issue with my Stillen kit, but not the same. First the engine light came on after running hard for about 5min. Also would always idle with a constant 300-400 RPM swing. I took it back to Stillen to get fixed and it was one of the throttle bodies sticking. So they replaced it under warranty and ran great.

Then I started having a hard time starting the car. It would always start, but take a few cranks to fire up. And then kinda sputter to get going. So I took it back to them and it was a small pin hole in the fuel pump fitting. Keeping it from holding fuel pressure. They replaced the hose and all has been good since.

If you can try to read the code with a reader and then you will know where to start looking. Also you might try to turn the car to the "ON" position for a few seconds without your foot on the clutch. Then turn the car off. Then you can try to start it. Hope you get the issue resolved soon and get your Z back on the road. Keep us posted with the results.

Glad you cought your fuel issue, They didnt listen to me and motor blew up becasue of that. :/

[Realale]

I'm kinda lucky because if I ever have an issue I can go straight to Stillen and drop off my car. They did the install and gotta take care of it.

[ANMVQ]

Originally Posted by Chuck33079

Me or Digi? I've gotten an updated tune from Sam, i just think there's more left on the table as well as some part throttle stuff that could be better.

Sorry man LOL Digi.

[theDreamer]

I know mine has the idle issue and then will throw a P0174 (bank 2 too lean) and then just idles at 1k.