up4speed

Thanks again for the kind words. I just wanted to log in to tell you that I haven't been on the forums lately. I sold the car recently because I am in the process of selling 2 of my "toys" to buy one better toy, lol. If you are handy, I wouldn't be afraid to work on these cars. Some things are very tight in the engine compartment, but other than that, they are easy. I'm glad I was able to help, that was my whole intent so people can follow my troubleshooting process. Enjoy your car, and drive it in good health! Regards, Chris

good idea u4s. I'll try both with ohm meter. Would really like it working for a pending 2 day work out at the track! Don't worry, it seems like it's going to get hot enough on the track to trigger the fan anyway! ;) All kidding aside, I don't blame you, I would also want it working properly.

I assume that you checked the fuse? It seems like it's working like it supposed to if the fuse was pulled. Check the fuse with an ohm meter, sometimes they are burnt and look normal.

Dave, I forgot it was intermittent. Good job finding and fixing it!

Look in your fuse box. Look at fuse #5A. If it is missing or blown, the cars fan will come on only when the engine gets hot. If the fuse is in there and good, it will turn on when the car is started.I haven't figured out why some cars have the fuse and some don't, but it seems that the different cars from different areas are set up differently. My best guess is that maybe if the car is from a colder area, the fuse is pulled. I would imagine if the car sat parked and snow got packed in the fan preventing it from spinning, that could be a bad thing. Those cars are probably set up to warm up and melt the snow, then spin the fan. Not sure, but that's my best educated guess. I will check the fuses. The engine lid light also is sporadic in operation. The light is a whole other issue. That is most likely one of a few things. I would start with the bulb and check that it's not on it's way out (maybe even change it just to be sure. Sometimes a bulb won't look bad when it actually is. It's cheap insurance). I would also make sure that the wiring harness is plugged in tightly (It's the same harness for the fan, spoiler and light), it's plugged in on the passenger side on the inside of the right rear fender. If it's not either of those, It may be a flaky switch (I think it's incorporated in the lock mechanism, but not sure because I didn't look). Please let us know how you make out. Here is the result of the light. The double wire was sliced through clean about 1" from the connector. Why? No frickin idea. stripped the wires back and put a wire connector between each - works like a charm... Now back to the fan issue. That's great news that it's something simple! Now I wonder why it's cut? Is it possible that the light was staying on and the prior owner just cut it (instead of fixing it properly) so it didn't kill the battery?

You are correct, it is confusing. I wonder if the engine compartment temp sensor is bad and the fan is defaulting to "on" causing the symptoms that you are seeing? In other words the computer is giving the message that it's defective, but to you it looks normal since the fan is on. Does your fan stay running as soon as your engine is shut down? If I remember correctly, the fan will go off, then a few minutes later as the engine compartment heats up, the fan will come on. Does your fan stay on even if the engine is not fully hot, then shut down?

Look in your fuse box. Look at fuse #5A. If it is missing or blown, the cars fan will come on only when the engine gets hot. If the fuse is in there and good, it will turn on when the car is started.I haven't figured out why some cars have the fuse and some don't, but it seems that the different cars from different areas are set up differently. My best guess is that maybe if the car is from a colder area, the fuse is pulled. I would imagine if the car sat parked and snow got packed in the fan preventing it from spinning, that could be a bad thing. Those cars are probably set up to warm up and melt the snow, then spin the fan. Not sure, but that's my best educated guess. I will check the fuses. The engine lid light also is sporadic in operation. The light is a whole other issue. That is most likely one of a few things. I would start with the bulb and check that it's not on it's way out (maybe even change it just to be sure. Sometimes a bulb won't look bad when it actually is. It's cheap insurance). I would also make sure that the wiring harness is plugged in tightly (It's the same harness for the fan, spoiler and light), it's plugged in on the passenger side on the inside of the right rear fender. If it's not either of those, It may be a flaky switch (I think it's incorporated in the lock mechanism, but not sure because I didn't look). Please let us know how you make out.

I strongly doubt that your Infiniti or Mercedes have better brakes compared to the 996. Be course you feel that you need to push the pedal harder for it to brake is just becourse the brake amplifier is adjusted in a different way on the 996. If you wanna compare brake systems with each other, take the cars on a track and see how they handle when they get pushed to the limit. I think Porsche adjusts their brake and throttle like that on purpose so they are easier to modulate. If the throttle and brake are too touchy, it adds abruptness to the persons driving (very bad for track). I noticed that the brakes are very strong, but need a very deliberate push to make them work hard. Same goes for the throttle, it feels slow reacting, and has a long travel compared to my other cars. With the throttle and brake adjusted that way, I find my driving smoother when pushing it to the limit. Some cars I've driven in the past have obviously adjusted the throttle in a way that a slight touch makes the car lurch forward, therefore making the car feel fast and hyperactive. While this makes the car feel faster than it is, it makes it touchy and harder to drive at the limit. My Ferrari is like that. It is actually slower than my Turbo, but with the incredible screaming sound and the touchy throttle, it feels way faster under part throttle acceleration. The Turbo feels very docile like a Toyota when driven gently. I think the German engineers are all about making the better "tool for the job".

My brakes seem to behave as the OP's do. I have a TON of brake dust right away, so I'm assuming that I have standard pads.

Mine feels the same way. I changed the fluid recently also using a power bleeder and no change in feel. The pedal definitely feels like it needs a good amount of initial pressure. The brakes are strong, but they don't feel like they are too strong unless I push down with more pressure than I would expect to.

Look in your fuse box. Look at fuse #5A. If it is missing or blown, the cars fan will come on only when the engine gets hot. If the fuse is in there and good, it will turn on when the car is started. I haven't figured out why some cars have the fuse and some don't, but it seems that the different cars from different areas are set up differently. My best guess is that maybe if the car is from a colder area, the fuse is pulled. I would imagine if the car sat parked and snow got packed in the fan preventing it from spinning, that could be a bad thing. Those cars are probably set up to warm up and melt the snow, then spin the fan. Not sure, but that's my best educated guess.

I have an UMW performance tune on my car (I bought it that way) and during troubleshooting a cold start issue I was having, I went back to stock tune. I can not believe how much slower the car is when stock! The only mod to my car is the UMW tune, and it is a NIGHT and DAY difference in torque and power. I would have never imagined that it would even be possible to make that much of a difference with just a tune. In all fairness, I don't have experience with turbo cars, and it is probably easier to squeeze power out of a turbo rather than a normally aspirated engine. The car goes from being quick to a car that feels really fast! If you are on the fence about it and not sure if it is worth the money, I'm telling you that it definitely IS! Not only is the tune great, but Kevin is also very knowledgeable and willing to help out another enthusiast. It is obvious that he has a passion for what he does and I have to say that I'm very appreciative of the help that he gave me in the past few weeks with troubleshooting my car. By the way, I couldn't even leave the stock tune on my car for more than a mile or two. It felt so bad/slow that I pulled over and reinstalled the UMW performance tune just to drive home, lol

It's all back together. I have to admit, it is a very easy job. If you are handy and are considering doing the plugs and coils by yourself, don't be afraid. There is nothing hard about it. It definitely takes a long time the first time, but it's not hard. As far as the results of my work, it's hard to be 100% sure until I get a little more time with it. As of now, I felt like it idles smoother overall, but it still does that whole dip in the RPM's after 3 seconds, then hunts a little for the idle (visible on the tach, not enough to hear anything). Even though it does the same routine that it used to, it feels smoother during that time. I feel like it went from feeling abnormal to something that generally feels normal. I also haven't heard that rattle sound under engine load that sounded like detonation. I tried giving heavy throttle several times and it just pulls very hard and smooth and doesn't make that noise. I'll have to assume it's fixed unless I hear it again. It also hasn't done that slight surging either. I'm guessing that the rattling noise was caused by loose spark plugs, and the surging was caused by the leaking v-pipe. Since I did the spark plugs, coils, O2 sensors, MAP sensor, MAF sensor and I still have that dip in RPM's when started cold, I'm going to have to assume that it's a normal characteristic. Especially since it runs great and idles rock solid when warmed up. If something changes, I will post back, but I will assume that everything is fixed for now. I want to also thank everyone that chipped in to help me with diagnosing and fixing my car. I appreciate all the time you guys took out to help me! I also wanted to give a special thanks to Kevin from Ultimate Motorwerks (UMW). He went above and beyond to help me out and his troubleshooting is always spot on, which is truly amazing when the car is thousands of miles away from him!! Speaking of Kevin at UMW, I have an UMW performance tune on my car and during this whole troubleshooting episode, I went back to stock tune. I can not believe how much slower the car is when stock! The only mod to my car was his tune, and it is a NIGHT and DAY difference in torque and power. I would have never imagined that it would even be possible to make that difference. In all fairness, I don't have experience with turbo cars, and I guess it is probably easier to squeeze power out of a turbo rather than a normally aspirated engine. I'm so impressed with the tune that I'm going to start a new thread letting people know how I feel about it.

The only way I could see the climate control affecting the idle is if the compressor is sticking and dragging. Or when it cycled on, he noticed his idle change slightly, which is normal. In my case, it was off when having the issues. I should have it back together later today or tomorrow and I'll report the outcome.

I decided to change the coils also. After hearing all the facts and speaking with Kevin at UMW, I decided to replace them since all of the labor is already done. They are the original 996 coils that are bound to eventually fail, so the 997 updated coils sounded like a good idea. I should have it all together by the end of this week (hopefully). I'm anxious to see the result. I will definitely update with the results. Keeping fingers crossed