I had to finally succumb and buy them as well but it did eliminate my throttle positioning issue.


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I shared this in another P1239 thread, but I figured I would share this here since this is apparently the main and well-linked thread

I have a 2007 HR 350z now at about 60K mileage. Three years ago (Summer 2016), I had a local shop install the a Stillen/Vortech supercharger. I have some non-HP supporting mods in the engine, hi-flow cats, and a motordyne exhaust. I wanted a conservative tune since this my daily driver and only car, I have about 400 rwhp and 315 tq. Performance wise I'm very happy with it, and I don't abuse the car. Fun highway driving only.

However, I have had multiple problems with the kit.

Problem 1: Bad Throttle cables
A few months after I bought it, Stillen came out with upgraded Throttle Body Extension cables but deigned not to mass inform their customers. These cables were improved to have a much thicker gauge since the original ones were crimping. Crimping may, and in my case did, cause the engine to not turn on, or go into 'limp mode'. We had to buy the new upgraded cables for $140 and install them. Still, this required a tow and a few days down time. All sets bought post winter 2016 will have these new cables

Problem 2: Heat/EMI problems
Maybe about 6-12 months after that, it happened again. Was driving just fine, the next morning for work, car turns on, then heavily lurches, dashboard is now a xmas tree. I get it towed to same shop, the check engine light is a P1239 code. This is a very famous code for this error, its all over google and Z forums. After conducting forum research, the 'new' cables Stillen provided still are susceptible to heat and electrical interference, so a heat/EMI sleeve was placed over the cables.

Problem 3: Now ******* what?
This morning (May 14 2019), the car went into limp mode again. Jesus ****ing christ what now? After several attempted restarts all fail, I call a tow. An hour later, the second the tow gets here, I start up car just fine and it seems perfect, like nothing is wrong albeit with check engine light. It's in the shop now, they are looking at it.

So overall, I'm kinda not that happy with Stillen. The performance is great, but this is my only car, so I care more about reliability. Something is seriously wrong with their electrical division, but its the same problem now 3 ****ing times over the past few years.

I started this thread. I had a guy run a stop sign & T-bone me Nov. 2018 totalling the Z with 190k miles on it. Only issue I ever had was this p1239 code & limp. Stillen uses a Bosch recirc. valve. I replaced that valve with a turbosmart dual port BOV. Once I dialed the BOV in, I had far fewer issues with the p1239. When I would tighten up the BOV I would get the codes again. When I ran it loose, I had far fewer problems. I read once where Stillen runs the TS BOV on thier red SC car .... ps. when it goes limp, sometimes it will take 10-20 restarts before it will take throttle in neutral. Hit the start button & immeadiately start pumping the gas pedal, if it is limp, turn it off & try again until it revs properly, then get back on the road. My car never 'stranded' me .... just super anoying & made you NEVER want to have a passenger with you. I can almost promise you, if you run an adjustable BOV & it is adjusted too tight, you will be going limp like crazy. The Bosch recirc. valve from the kit will also go limp. I will say that all the cable/foil wrap/heat shielding never cured the problem as well as the Turbosmart dual-port BOV set at the loosest setting where idle vacuum would barely shut the piston. On boost the valve would shut fully from boost pressure, so no worries there. ALSO, NISSAN is to BLAME for the car going LIMP, not Stillen. This car should throw the code & engine light ONLY. Not sure why Nissan decides to KILL the car.

I just got the car back from the local performance shop. They did not have kind words to say about Stillen. I'm pretty sure I heard 'shitastic' used several times about this singular cable. The crux of the issue is that the supplied throttlebody cables, even the 'improved' ones aren't great. My car has failed a few times due to this problem, with the only silver lining is that it wasnt failing for any other reason. Just this one part.

You see Gentlemen, we are a community of modders. OEM is treated as a dirty word synonymous with 'bottom dollar' and 'crap'. While this view is not incorrect, it is incomplete. A part simply being created in the aftermarket does not guarantee that it will be better than the OEM it wants to replace. And this leads us to their solution: Permanently remove all of the Stillen harnesses and use OEM instead.

On the surface, both Stillen and OEM are the same with (i think?) 6 cables. The issue with Stillen is that even with the known workaround heat/EMI sleeve, only 1 cable is being insulated. With OEM, 4 cables are insulated. And I must note that in the 10 years I've owned my 350z, not once did I ever experience an electrical issue.

So now with the OEM harness in (labor+material cost = $192, very reasonable), my car starts fine. Of course, it started fine with the normal, upgraded, and sleeve cables too, so really only time will tell. As for how to get these OEM cables, they happened to have some on hand, so sorry I can't provide a part number or link for you.

Something for you all to consider.


Update: 2 weeks later, and running good with OEM cables. No issues experienced.

So I have been fighting the p0300 and p1239 code since I ever installed the kit(2 years ago). I have an 07 HR nismo and last night the p1239 came back. I even have the update stillen cables. Was this ever resolved? I'm going crazy... still can't figure it out.

I never had a single problem with the z when it was N/A. Low miles and ran like a champ. Installed the charger, and gremlins. I get the p0300 only when it's cold out.... which is strange. the p1239 comes out of no-where. Last time I got this was last year.

I added extra shields at the filters,
Boost leak/ Vacuum leak tested,
installed a catch can
replaced spark plugs
re-tuned countless times for idle.

Thanks

Are you still using the stillen cables? Even with the heat shield, only 1 of the cables is insulated. Meanwhile, the OEM cables, 4 out of the 6 are. Trying switching to those

Edit: For the p0300 code, funny enough I did get one of those in the extreme (Polar Vortex) cold. My car started and drove fine btw, just that check engine light on. The shop said it was because they gapped the spark plugs closer than they could have to protect against premature ignition which can ruin the engine. They said the code would go away 1) In warmer weather or 2) After a few minutes of highway driving.

They were correct on both accounts. I've only see it just that once.

Edit 2: For what its worth, i have stock GTR spark plugs in my 350z (HR)

You may want to get some Viagra cables. Limp mode should be solved then.

:icon17:

I'm aware of 3 stillen cables. One to extend the TB harness, and the 2 MAFs. Which ones are you saying to switch?

I'm using OE 370z spark plugs on standard gap... They are +1 colder for my HR. I have not had any issues with them when driving hard. Just idle with the p0300 and this p1239.

I have a turbo smart bypass I'll install and try to screw around with... Heard it's tough to get it right


Thanks for the info.

I believe I am just going to make my own cables with proper shielded wire. Actual connectors seem to be 15 each. Shielded wire is cheap... Probably be under 100 and properly done.

I suspect extending the driver's side TB across the front engine is causing induced EMI... Same thing with extending the MAFs. Just a pain in the *** dealing with this.

On another note. For us 07/08 HR's, I did notice a couple months back that one of my throttle body TPS adjustment screws was touching the hood when it was closed... Saw red paint on the screw. I was getting a different p code for this... I trimmed a bit more from the hood and it hasn't showed up since. Sucks that we have to hack the hood to fit this for 350z HR's. My poor nismo

If possible, replace all of them with OEM. I'm not sure about the MAF, but most def replace the TB harness.

As for spark plugs, they installed oem GTR in my 350z (HR)

How do I get an OEM extension harness?

**edit**
Are you talking about getting OEM wire and just cutting the OEM harness and extending it?

You are asking questions that I can't answer, since my shop did the work and not me. Perhaps look in the Technical Service Manual in the Electrical section? Look for all SKUs that are wires that go over the entirety of the top of the engine.

Also, I will take a picture tomorrow of my engine bay and show you.

Awesome! Thanks. Pretty sure this will help ALOT of frustrating SC'ed Z's on this forum. I F****** hate this Stillen kit with absolute passion. Close to taking a $h1t in it and sending it to stillen's front door ;-)

Truth be told, this one singular part aside, the stillen SC kit has been perfect and 100% reliable