I have an issue I posted about before. In wet weather when I get my RPMs above about 3,000 or so, the vehicle sometimes feels like it loses power momentarily. It's violent enough to jerk me in drivers seat. I've even had this problem after visiting a car wash on a dry day. I was told it was probably the tires slipping due to their old age. I replaced the tires to new Continental Extreme Contact DWs. The new tires are awesome, but they didn't solve the problem. I was informed it couldn't be the clutch getting wet because there is no way for water to really get into the housing, even if it weren't bolted down quite tight enough.

The issue has been so bad that during one of its fits, I've hit the clutch and the engine has stalled. It is an '05 enthusiast. It has the an aem cold air intake (needs to be cleaned). It also has the axle clicking issue in the rear axles, but I have been told by the guys at Nissan that it shouldn't affect performance so much as it's just annoying, but I also never mentioned my issue rainy day issues to the Nissan mechanics. I should also point out that last summer during a rain I was watching the RPMs while going up a hill. The vehicle jerked as it sometimes does AND I saw the RPMs spike slightly. I really feel like somewhere in the drivetrain something is messed up when it gets wet, BUT I AM NO MECHANIC BY ANY MEANS. It has less than 35,000 miles.

I remedied this situation today by driving in a high gear (keeping it under 3,000 RPM and 6th gear at 55 mph), but I feel like I have to accelerate ridiculously slowly in order to prevent this slipping/power loss situation. Also I'm not really looking for it, but I've never seen the SLIP light come on. That doesn't mean it's not coming on, but I feel like I would have seen it by now.

It runs awesome in dry weather. I've also considered an electrical issue. I just don't know. I have a feeling if I take it to a mechanic, they are just going to say "yeah, we didn't find anything." I'm typing this really quickly at work, so if you need more details please ask.

 

Probably a dumb question but are your front fender liners and undertray installed? The driver's side to be exact.

 

I'm assuming you are talking about the plastic surrounding the intake filter. Yes, all that plastic is intact. Could it still be an issue with water getting to the filter?

 

Not if the plastics are doing their job.

 

It must be an electrical issue. Moisture is getting in somewhere where it shouldn't and affecting engine power.

Your statement: (“The issue has been so bad that during one of its fits, I've hit the clutch and the engine has stalled.”) supports the electrical shorting theory.

--Spike

 

Where would you begin your search? Assuming it is an electrical issue. Or is this something I need to see a mechanic for?

 

Check the rubber seal on where the engine harness goes into the car to the ecm. Make sure its a nice tight fit.

 

Excuse my ignorance.. where would I find said harness?

 

I'm not sure you answered the question. I believe you were being asked if the fender lines and the undertray are installed on your car. The fender lines are inside your wheel wells and the undertray is under your engine. Are those items installed?

 

Ok.. first off I. There is a plastic skid/splash shield under the motor. There is also plastic completely surrounding tire.

I was just looking at the cold air intake. There are two metal pipes with a central plastic piece in which 5 wires are coming out (I am sure you all are all familiar with this). In my not very learned, nor mechanically inclined opinion, I believe those 5 wires lead to an oxygen sensor. They are striped and of different colors. I just noticed that there is yellow paint rubber off from the inside of the hood onto the tape surrounding the 5 wires. Further more the tape material the protects the wires appears to be compromised AND some of the insulation has been worn off at least two wires, probably 3. It's very small wear, but I can definitely see shiny metal through the insulation. Now I don't see how they would be physically coming into contact with water, but is it conceivable that the moisture in the air on a rainy day is causing problems with this wiring and furthermore with air/fuel mixing? I'm assuming I need a new set of wires for this unit and I need to loosen the clamps and twist the plastic piece such that the wires do not contact the hood when it is closed. What are your thoughts?

What is this item referred to by Nissan and how much does it cost?

 

I took pictures, but don't know how to post them. It looks like, from the top, the second, possibly fourth, and definitely fifth wire are worn through.

 

Sounds like your explaining the maf sensor wires.

 

Do you think exposed "MAF sensor" wires could lead to the issues I've been having?

 

Jon,

The problem you are describing sounds like you could have an exhaust leak somewhere, and water could be getting in on "wet" days. It would have to be a pretty extreme leak to be causing the level of problems you're describing.

The issue you've mentioned reminds me of a similar problem I had on my Z shortly after I had the Bassani Catback system installed on my 2006 350.

The Y-PIPE flanges that mated up with my CATs were not welded quite right, so they didn't mate flush with the CATs. Even though the leak was very minor, during the rainy season, any large puddles I hit on the freeway got water in my catback(luckily it's stainless). The exhaust note would change dramatically and yes I noticed a loss of power immediately. It only lasted for a second or two since the exhaust gases would blast out what small amount of water got in. Shortly after I confirmed my theory (inspected the Y-PIPE to CAT link), I had the flanges ground down a little and re-bolted with new seals. The problem has never come back since.

If you have any type of water blockage in your exhaust, the back pressure from higher RPMs could be stalling/killing your motor and power. I believe this is the root cause of your problem. It might not be the exact same leak location as mine, but it really sounds like your exhaust isn't breathing correctly.

Do you have an aftermarket exhaust system? Are you aware of any pre-existing exhaust leaks?
-Icer

 

The exhaust on my 350z is the stock exhaust. As far as I know, there are no exhaust leaks, but I haven't looked into this issue. It certainly doesn't sound like it is leaking, but I really do not 100% know. I think I'm going to get some liquid tape at Ace Hardware tomorrow and carefully try reinsulating those wires on the MAF sensor. I'll look into the exhaust situation as well. Especially if my MAF sensor "repair" does not remedy the situation. Thanks for the idea though!

 

Also, exposed wires going to your MAF (mass airflow sensor) is ALL BAD. Get yourself some electrical tape and bind up each individual wire that has compromised shielding, heat shrink tubing would be even better if you're comfortable with removing the individual wires from the plug and putting them back in. Then I would go back and wind up the entire bundle for added protection. Your MAF wiring should NOT be rubbing against stuff under your hood. This is a critical component for proper engine functionality. If you did have some type of short or problem with your MAF, your ECU would be throwing a code and your check engine light would be on.

 

Got off from work this morning. Had heavy rain here in VA all night. RPMs were spiking between 200 and 2000 after starting the engine. Played with MAF wires which caused noticeable fluctuations in the motor. Tried to leave work and the motor quit on me twice. Let it warm up and then it did "ok," but there was still a lot of moisture in the air and the roads were still wet. I think I found my problem that's been haunting me for over a year and getting worse. Appreciate all of the input. I'll rotate the MAF sensor assembly so the wires don't get caught under the hood and reinsulate the wires then wrap them in electrical tape. Would you guys advise removing the negative battery terminal for such a small task?

 

I think I would remove the negative battery terminal. It would be very easy to short out something while you are wrapping the wires.

 

OP, I have an 06 enthusiast ZR with the Nismo CAI as well. My Z was experiencing the SAME EXACT issue you have described. I thought water/moisture was being sucked through the CAI, but this cannot happen as there is a membrane in the tube which will NOT allow water pass through and cause hydrolock. 1st thing I did was clean my MAF and to be safe, I hooked up a OBDII scanner to see if any codes had been overlooked/thrown even though no indication had lit up on the dash (SES or CEL lights). My Cam Sensors were both failing and I had them replaced. Never had ANY issue since (approx 2 years ago). Might be worth checking out your local Advanced Auto Parts or O'Reilly's where they can hook up the scanner and check it for you for free

Also, ABSOLUTELY unhook your battery before performing ANY work to your electrical system! Leave it unhooked overnight too if you can so the ECU will reset/relearn your mods, however minor they may be.

 

Check to see if your relay box got wet. Its in the compartment with the battery. Mine got wet once during heavy rain and everything started running like s*** after that.