Limp Stillen Supercharger dtc p1239

Z4fun

Sorry, that's incorrect. I have one and they are 6 wires and work fine with my Z , not sure if the quality is better then stillen but we'll see how long they hold up. From the amazon pic its hard to see the wires but if u count the holes in the connector u can see 6. I tried to post a pic but it wouldn't upload

I believe its a heat issue with the wires and going to wrap them in a thermal sleeve as some suggested.

cgr406

I've been having this same issue and it's really affecting my enjoyment of the car. It's happened to me probably 7 or 8 times this summer / fall. Seems to be increasing in frequency. It's to the point where I'm uncomfortable driving the car in heavy traffic b/c I never know when it's going to go limp. I've emailed Stillen about this, but of course, I've not heard back from them. I just ordered the Michigan Motorsports cable, so I'll see if that helps / fixes it. Thanks @Z4fun for finding & posting that!

__________________
TopGunZ Rotrex SC / CJM RFS / 1300 / Ecutek / Dynosty / F.I. TP & CBE / Z1 / Swift / SPL / Whiteline / Hotchkis / Michelin SP4

Z4fun

I would of bought Topgunz cables since he is selling them for $20, if I knew before. Awesome guy, definitely support him !

My issue was the same it ran fine for about 1 year , then started acting up once in a while then more and more often. Cables shouldn't react like that unless there's an external force acting on them to lower the life span like (heat , tention, ice, ect) I feel changing the cable is a bandaid if we don't fix the underlying issue.

I have the car with my mechanic and we are gonna try to find a way to resolve it permanently, if we can reroute them somehow, or if not insulate the hell out of them I will send some pics when we figure it out.

cgr406

I checked w/ Aaron a while back & the replacement cables that he has are the same ones (Stillen Gen II) that came w/ the full SC kit that I bought from him. So, I'm wanting to try something different. I will also try wrapping / insulating the new cable.

__________________
TopGunZ Rotrex SC / CJM RFS / 1300 / Ecutek / Dynosty / F.I. TP & CBE / Z1 / Swift / SPL / Whiteline / Hotchkis / Michelin SP4

Z4fun

Oh ok , makes sense. Plz post pics of ur fix , im sure all of us would like to see how it came out when ur done.

Z4fun

Hey guys , after some testing and research we concluded the cause is 100% heat. since the wire is being heated its increasing the resistance causing and interruption in the signal throwing the tb off and causing it to go into limp mode.

My mechanic said he tested the wire cold then warmed up the car and tested again and saw a dramatic rise of resistance in the cable. The two options we had is to insulate with a sleeve or try to reroute the wire. Since I am adding a vented hood, we decided to go with the sleeve. (attached pic)


In doing more research this is actually a well known fact in thermal electrical engineering here is the definition for Heat resistance.

Heat Resistance

Heating a metal conductor makes it more difficult for electricity to flow through it.

In metal conductors, electrical current flows due to the exchange of electrons between atoms. As electrons move through a metal conductor, some collide with atoms, other electrons or impurities. These collisions cause resistance and generate heat. Heating the metal conductor causes atoms to vibrate more, which in turn makes it more difficult for the electrons to flow, increasing resistance.

https://nationalmaglab.org/education...eat-resistance

Attached Images

1.jpg (535.3 KB, 39 views)

WhiskeyHotel

Yes, the actual equation is R=Rref(1+a(T-Tref)) and the temp coef (a) of Cu is +0.000393 per degree centigrade. That means the effect is pretty small at the lengths and temps you would experience under your car's hood. (That Bunsen burner temp in your example link is ~1700 degrees C!)

Example: 100 feet of 20 gauge wire with resistance of 1.015 ohms at 20° C (room temp). If the temperature of the wire goes up 10°C, the resistance will change by 0.0399 ohms (10 degrees * 0.00393 per degree * 1.015 ohms = 0.0399 ohms).

The wire resistance will now be 1.015 ohms + 0.0399 ohms = 1.0549 ohms.

In my opinion, that wouldn't be enough change to account for the large increase in resistance your mechanic is seeing. (I think - I don't know what the increase was. I also don't know how the resistance was measured nor do I know which of the conductors he measured and there are grounds, power, and sensor signals going to the throttle body. You can see that I am shooting from the hip here.) My electrical engineering spider sense is tingling at this point. There could be something else going on - connector pins heating up and losing continuity - something. I hope the proposed solution works - but I am a bit skeptical at this point. Let us know how it goes.