next time it happens to me, i'm going to disconnect the brake light switch & see what happens. oh wait... that's futile.....:confused:

the problem is becoming more frequent for me. i will either adjust the brake light switch or change that rubber stopper for a stiffer object

I wonder if anything can be done with a tune to disable this brake check sensor, etc...

i believe disabling ETC via uprev might do just that. except you'd lose features like SRM etc

ok so the issue became so frequent and random that i deemed the car unsafe to drive. i ended up doing a dodgy fix to keep me going until i have more time to investigate it further.
the fix is simply a paperclip jammed into the harness side connector, simulating the brake pedal at rest position (ie. closed circuit).

works a treat and it's a cheap troubleshooting trick for anyone suspecting a faulty/incorrectly adjusted brake pedal sensor

If you've concluded that the switch is faulty, get it replaced. What I wanted to do in the past was rig up an LED to indicate switch status and eventually to a datalogger to plot the switch state to see if it's intermittent.

thing is, i've tested the switch itself and it seems to be fine on the bench hooked up to a multimeter so i'm thinking it's an adjustment issue.

for the LED indicator thing, since the switch is normally open when the brake pedal is pressed then it would be simple to wire a lamp so the lamp comes on when pedal is at rest

this did not fix my issue unfortunately, I disabled ETC once again until I can think of something else to try

so the joy brought by the paperclip trick was short lived. on long drives, the problem eventually resurfaces but this still tells me i am on the right track to solving this issue.

i removed the paperclip and refitted the cruise control brake switch and also the brake light switch. i read further into the issue in the FSM and there's a section that basically states the cruise control switch must be depressed first, which then switches on the brake light switch circuit. Sounds bizarre and far too complex for a simple system to be honest. But anyway, with that in mind i set out to adjust the two switches so the cruise switch trips first. Remember that this is a normally open switch (open circuit when not depressed).

i took it for a drive last night and the f**king issue came up again!!

my mind is now focussed on the soft plastic grommets/button pad things on the brake pedal which press on the switches' plungers. since it's winter here (a much colder winter than last) i usually have the heater on max with the air directed at my face and feet.

I'd like to also mention here that my heater never felt effective. It was either super hot or luke warm... until i recently did the throttle body coolant bypass mod (complete removal of all associated rubber hoses) which seemed to restore function to the temperature modulation function.

My new theory is that the heater aimed at my feet is heating up the plastic grommets to the point where they become pliable enough to allow the switches' plungers to deform the grommet and create a false pedal-depressed situation. Extreme view, but i'm losing my head over this issue

That's why I added a shimmy.

time to put the thinking cap on..

i want a more permanent solution

If the switch is still operational you can loosen the nut holding the switch and try to lower it. Otherwise, you can add a shimmy. You can also replace the grommet with something a little thicker. Lastly, bypass it altogether, but there are risks.

the paperclip was the bypass :) it works but the ECU eventually figures something is sus and kills the party. it's a good get you home trick though and it might work for those who want to light up the rears/do standing launches in their 7AT.

risk IMO for this trick is minimal unless the driver uses cruise control frequently.

i'll look into a nylon object but we'll see how my hunt goes. thanks again mate.
are you still getting the lag randomly these days or have you completely cured it?

after much f**king around, i conclude that neither of my brake switches are faulty.

I finally decided to follow the crank and cam angle sensor route today, pulled out the crank angle sensor (absolute bitch because the bolt is not visible, side of the gearbox is sharp/coarse and it's right near the cat). Done the resistance tests and it is defective as per the FSM.

Pin 1 (+) to 2 (-) : 1.117k ohm
Pin 1 (+) to 3 (-) : infinity ohm
Pin 2 (+) to 3 (-) : infinity ohm

All readings should be anything but zero or infinity ohms. I always thought with resistance checks, polarity of the test leads should not matter. If i connect the test leads in reverse, all readings show the sensor is ok so be sure to check the polarity of your test leads when doing these checks.

For kicks, i also checked both cam sensors. Both failed for the same reasons....

Looks like it's a dealer visit for this one. Still no codes either....

interesting, I'll try to check these this week as well

the crank angle sensor is very annoying to get to. i have small hands and at this rate i will be referred to a psychiatrist from all the scratches and cuts on the back of my hands! there's not much room to work in.

cam sensors are really easy - at the front of the engine. you can do the checks without removal but the engine should be cold because the service manual specifies @ 25*c

:icon18: Yeah, that crank sensor is a Bee0tch to get to. I can't imagine removing it w/the OEM cats installed.

Did you reflash the ECU back to the OEM ROM and see if the problem persists:confused:

still running the tuned throttle tables. i dont think uprev is the cause because the problem only seems to appear when the engine gets up to operating temp. it's still a variable which i will explore when i get my car back.

i got my car back from the dealer.
i had a list lf warranty issues to fix:
- boot doesnt release on first press (new hatch springs fitted)
- boot struts provide little assistance at upper half of travel (new struts fitted)
- ac/volume controls are jittery (control panel backordered from japan)
- clutch fluid disappearing (slave cyl replaced)
- severe lag when at operating temp...

i took the tech for a test drive when i picked up the car. they blamed my stillen intakes but i argued. they said the cam and crank sensors are fine even though i pointed them to the exact page in the service manual.

the fault did occur during the test drive. tech tried to mask it by demonstrating that it 'is normal' by driving aggressively (launching at 2500-3000+ rpm and keeping revs above mid range). i pointed this out that the car shouldnt have to be driven like that all the time. he took the car into the workshop and brought it back out for me to drive home and monitor its progress.

i have to say, whatever happened in the workshop prior to me taking the car home seems to have cured it. i cant seem to make it happen. i've crawled home thru traffic a few times, driven it hard and gently. so far so good. rpm still sags to 500rpm at idle sometimes.

as for the slave cyl, my clutch feels better than the day i picked up the car 2nd hand with 15000km on the clock! pedal is heavier but has more feel. gearshifts are really smooth. 1st to 2nd no longer clunks. rev match is pretty much flawless.

let's see how she goes :)

Good for you juld0zer! I should be taking mine in sometime the following week, things at work have been hectic but hopefully i can get Monday off.

Be prepared for the clutch master cylinder to need replacing if they didn't do it at the same time as the CSC...

looks like my joy was short lived. it was inevitable that the issue would eventually resurface but now it is more difficult to reproduce and it will occur in unpredictable circumstances. before i took it in, it would happen pretty much within 25mins of casual driving from the first start of the day.

so far i've had it happen mainly after driving for about 35mins or more, or whenever the coolant temp stays above 90*c for a while. but there was one time during a 1.5 non stop drive including heavy traffic crawling where the lag did not occur at all!! so that occurrence certainly makes my temperature related theory a bit muddy.

i was due for an oil change today. changed the oil to Valvoline 5w30 MST with the same model mobil 1 filter (108). Prior, i was running Nulon 5w40. viscosity is important for the VVT solenoid function so if Nissan designed the engine for 5w30 worldwide, i will run 5w30 until the issue is sorted (got lots of 0w40 and 5w40 at home)

i still have warranty til september. clutch feeling like it did before i had the csc changed now :( sighhhhhh

I have been told that the issues that you are having are throttle body related. I am having the same problems and thought that it was temp related but it has done it when cool also. I went so far as taking all timing out of my tune for the vvel to see if it was to aggressive. We have started like I said thinking its the Throttle bodies having an issue. Let me know what you think. THese issues didnt occur until I put the ported intake plenum and a grounding kit on then retuned. It has to be related to one of those issues.

Did they replace the CMC when they did the CSC? If not, that sounds like your problem.

master cyl and clutch disc components were not replaced. but wouldnt a dud master feel sloppy when i first got the car back also? rather than re-emerge after a few weeks?

Mike,
Pedro and his mate suggested the throttle bodies were at fault. i followed that lead with no success, but i knocked over a different problem in doing so. I had an idle which needed a good dose of Viagra :p basically at the lights it would flop to 500rpm, rumble a bit then come up to normal. It wasnt 'rough' but it wasnt normal. On inspection i found what is in my opinion only minor carbon buildup. However, after cleaning (including removal from the engine and cleaning on a bench and actuating the flaps by hand) i realised how much carbon there actually was. There may not have been a lot but it was built up around critical areas, such as the edges of the butterfly plate and near where the butterfly plate rests on the walls of the throat. Because of this, i concluded it was carbon buildup around the idle/rest position of the butterfly causing an erratic idle due to carbon creating a sticky/tacky surface which catches the butterfly ever so slightly.

Both throttle bodies were not equally soiled. I cant remember which throttle body was the most soiled. I might also conclude at this point that the throttle rest relearn probably only considers bank 1's position and it tries to command the other throttle to be the same position at idle and so forth.

End result of cleaning the throttle bodies is a smooth idle but still lagging randomly. Give me a week and i'll report back with something else that im experimenting with. Ive become superstitious with this car.

I tried grounding the throttles to no avail also. that was just with a small wire bolted using one of the four allen bolts.

hang in there mate :) i've been battling this for over half a year now

Sorry to hear youre still having issue Juld0zer :shakes head:

However, its good to see you have not given up on this yet! After all this time, Nissan should just give you a new Z :stirthepot:

problem is, it's very hot here in Australia (and it's only just spring!). we are seeing 38 degrees celsius ambients already. Because of the high ambients, it's getting harder to tell if it is actually the super-lag or just high IAT and high under hood temps causing knock to come on earlier, resulting in timing being pulled. I'd say it does feel more like a timing retarded sort of lag though

Not necessarily... The CMC might have still been OK when the CSC was replaced, thus giving you the feeling of a repaired clutch system. However, the CMC is just as old as the original CSC was, and they are both fairly prone to failure. That's why the guys at Z1 and ZSpeed recommend replacing the CMC if you're replacing the CSC. I wouldn't be at all surprised if the CMC finally crapped out a few weeks after the CSC replacement - it certainly wouldn't be the first time its happened to someone on this forum. One guy was on the side of the road bleeding his clutch for over an hour with a buddy before determining that his CMC had failed, and that was just a week after he had the CSC replaced.

Also, the CSC failure will basically strand you - when it goes, it is typically sudden and complete failure. The CMC failure is usually a seal that might not fail completely when it starts to go. The pedal with a failing CMC may still be operable but will be pretty mushy. If this is what you are feeling, it's a pretty good indicator that your CMC is done. Luckily, the CMC is a much easier job (pretty cheap to pay someone and pretty easy to DIY).

Was reading the thread-
 

Been a couple years I suppose since people have been on this thread.

Just curious and would like input from others about possible issue I am facing. I've owned the Z since the beginning, and this issue just came about.

Z (manual) drives like a champ up until the oil temps reach around 220-230. I live in LA and majority of the time is stop-go traffic.

As soon as the lights turn green, I get this hesitation from the Z between 0.8-3K RPM. It's most definitely hesitating/lag, if you're an enthusiast, you would know how your car responds to your driving, but in this case the car hesitates to accelerate. Once it reaches past 3.2-3.5K RPM, as if nothing has happened. It's a strange sensation.

I've read up on oil pressure for VVEL, brake switch, etc. was wondering if any of you would have further insight. No error codes, ECU was reset. I'd truly appreciate any insight if you have experienced the issue or know the cause and solution to this issue I am facing. Cheers

Sounds like stock throttle lag ... get a tune :twocents:

Get an oil cooler to begin with. Mine was a 2011 model with the factory oil/water heat exchanger and even in our hot Aussie summers it rarely went over 100*c in normal driving

Sounds like the car is doing what it was designed to do - when temps get hot, the ECM starts pulling timing to protect the engine. A good oil cooler will help.

I thought timing wasn't pulled until 250ish temps? Plus thought it was weird that he only notices it at lower RPMs ... if heat related it should still be pulling timing at higher RPMs.

Not that an oil cooler is a bad idea by any means. It just sounded to me like normal stock throttle lag, although heat soak on this car is a bitch and probably guilty as well.

If his oil temp is is in the 225 range, IAT is probably high. Especially when sitting at a stop light - IAT is going to rise if stopped for more than a few seconds. My guess is that the problem would not be as bad if only stopped for a second or two (eg, stop sign with no cross traffic).

IIRC, timing is pulled across the range of RPM, but risk of pinging if greater at lower RPM so timing advance is reduced more.

Yeah. Probably a combination of both.

Thanks guys. Getting more insight. To break it down a bit further, the car feels as if it slips/hesitates between 0.8-3.2K RPM. I suppose an analogy is like your dog is on a leash and the you've got a grasp of your dog who wants to run free.

The catch is, I've already installed a oil cooler from 2 years back. Usually keeps my temps between 180-220 depending on how hot it is outside and how lead-footed I am. LA traffic definitely contributes to higher oil temps.

Do you guys still think it could be related to IAT, oil cooler or oil temp related? Heat soak is definitely a factor, but the problem only comes around when the Z reaches the 220-230F mark.

If it were the brake switch would it occur at any oil temp?
Could also be throttle response at that specific oil temp?

I'll have to see if the problem returns after like a quick stop on the side of the road or re-cranking. Further comments are appreciated, cheers guys.

Get an OBD monitor and watch IAT. I'm betting it goes high when you stop moving and the nannies kick in. Your oil temp is not high, just elevated enough to indicate warm ambient temps.

Hi all. I have exactly the same issue as as juld0zer has. My car is a completely stock 2009 model with a manual transmission. This issue only surfaces if my oil temperature gauge shows above 90 Celsius or 194 Fahrenheit. Does anyone have a solution for this issue?

HELP! Severe acceleration lag
 

I think it's IAT as I had been monitoring my air intake temps. It would spike when sitting at a red light, heat soak has to be it. I seem to have issues when I get to 190-200. Very bad lag on low rpm take offs.


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[QUOTE=tjlazer;3607284]I think it's IAT as I had been monitoring my air intake temps. It would spike when sitting at a red light, heat soak has to be it. I seem to have issues when I get to 190-200. Very bad lag on low rpm fake offs




Please excuse my ignorance. I'm guessing IAT is Intake Air Temperature. From my experience even if it's very hot outside with temperatures past 40 Celcius / 104 Fahrenheit as long as my oil temperature shows under 90 Celsius / 194 Fahrenheit it won't lag at all.

Could this mean that under heavy heat soak/ high under hood temperatures our engines are getting pre ignition/pinging and the knock sensors are retarding the ignition therefore we are losing low end power?

Did you find a solution for this issue?