no cruising for this Z. all or nothing.

https://www.youtube.com/watch?v=ZI-y7QG2qag

Z still running like crap. i dunno WTF is going on.

this vid is of lowest boost setting, showing what happens when i try to cruise and maintain a steady speed.

when i accel, the car feels and sounds fine.. under boost the wideband is smack in the green @11 where it should be,
when i decel it skips around the yellow, no issues felt or heard mechanically..

but then when i go to feather in the throttle to maintain speed.. the car 'bucks' as the wideband pegs off 19+. there is also a horrendous clanking from the rear end. i dont know if the two are related..or one is causing the other..

Hell mine is doing the same thing in the rear end, i am convinced its the diff bushings being worn out on a 175,000 mile chassy and a 60k motor and tranny and somewhere between 500 and 600 horsepower to the wheels worth of upgrades. I actually figured out thats what was causing mine to do that at the Triangle Z show when i mentioned it to another Z32 owner and before i could finish he said thats what it was. I got the energy suspensions kit to fix it and am planning on doing it this week. Mine has the same symptoms though but the motor on mine is misfiring probably becuase of clogged pcv valves i plan on also fixing this week. Maybe you have already looked this way but if not i am almost 100% sure thats what it is hope this helps

nawp..

my motor is freshly rebuilt, same with tranny.

already have bushing kit installed.

Tony suggested MAF sensor the other day when we met up and you decided to sleep in..

i'd like to try that.. but i kind of doubt it when it happens only when trying to maintain speed.

Brandon can i borrow your sensor for an hour?

As for the plennum reid.. im in no rush to take that ^&#%!@ off sorry. if it was an easy as a filter swap we'd have it done already but... i am so pinched for time these dayas :-/

its cool man, ahh well i wish i had a clue, sorry my idea didnt help, makes me wonder what else is wrong with my car that i havnt weeded out yet... ahh the frustration

could it possibly be a intake issue?. stumbling when around a cruising rpm range...i'm just grabbing at straws here.

have you moded any of the air/fuel system lately??? that sounds like the usual idle problems from a air fuel upgrade w/ out a computer flash. or even if your ecu was flashed to get more performance and the battery died and lost the flash tune on the ecu. theres a couple ideas. if you could get an other vid during day time that might help.

i do hear some trans or rear noise in the vid but thats the motor problem causing the bucking. what fuel adjustments do you have on your car?


does it stall out when you cluth it after a hard pull or high rpm?



it may also be somthing as stupid as a tempermental plug or coil or even a loose ground.


what has been moded in the last couple months

evil zx(t) wrote:

does it stall out when you cluth it after a hard pull or high rpm?

it may also be somthing as stupid as a tempermental plug or coil or even a loose ground.


what has been moded in the last couple months

YES not all the time.. but sometimes ill ride the gear to a stop to prevent it. or blip the throttle a bit in neutral or with the cluth in. after it happens usually.. i have the clutch in and am still rolling. So i put it in the proper gear, then pop the clutch to start it back up.

nothing 'new' has been done recently, except for a reinstall of the motor and changing out IC's

latest Dyno was when i last rode it hard. On Q16 race gas at full boost, i was about 150HP short of my best pull.

power climbs until about 4900 RPM when HP levels out and Tq begins to drop.

were any of the wire harness plugs switched? (plugged into the wrong spot)? was it tuned while on the dyno? it sounds like the ecu isn't set for your fuel system. do you have larger injectors or factory ones.


OR.....


is your vacume at the same neg psi as it was before? you may have a vacume/boost leak and a large one to make it act this way


im not exact on the numbers but you can get the idea


-30 psi vacume........ +15 psi boost = normal

-20 psi vacume........ +15 psi boost = leak


the reason the boost didn't change is because the turbo/boost controller is compensating for the loss.

translation....

you are actually boosting 25 psi at the turbo but loosing 10 psi between turbo and motor.


you can tell through vacume because there isn't a part compensating to make up the pressure


the reason its bucking is the computer is reading so much air at the intake sensor and perfect at the o2 sensor and not to mention a couple others are reading some confusing numbers also. thus confusing the hell out of the ecu and bucking and stalling.


this leak may be a hose, coupler, intake gasket, throtle body gasket, well you get the idea. was anything removed and or tweaked wen removing or instaling.


there is a couple ideas to think about hope they work for you. let me know if you have any luck

I cant help you figure it out but just for your info (really dont think it matters) but mine was also stalling out after hard acceleration if i just push in the clutch and let the rpms fall. Its almost as thought the momentum is lost so quickly (i thought due to lighter parts) that it killed itself. I also used the same method to restart it by poping the clutch. Thought that this data fact might help somehow, just fyi lol

I will watch it later on when I get off work and see if I can work up a conclushion on whats going on.

would a Nissan datascan help?

how when where?

idk if anyone has figured out anything but i heard of a similar problem with a nissan 200sx the remedy on that car were the throttle body sensors tps and ............ the other one i cant remember at the moment or even a loose wire/clip on that.



hope that helps!!!

Idle controll valve is 1 TPS is the 2, Mine did it too after blow off were installed. But mainly Its TPS

HMMM if that is the culprit what is the best way to adjust it, or does it need to be replaced?

Your output voltage should be 4.5v on the TPS at full open throttle. if you have a boost controller you should be able to check it in the censore section.

huh??

i have an old profecII with no display. what do you mean check sensor section?

Oh ok well out put voltage on the TPS at full throttle should be 4.5v, Do you have a Consolt or a Zscan? On my AVC-R i have a section were i can check my sensors. When you check it and notice that you have to clock the tps way to much that means its mostly out. There is a line on the top screw area if you go way pass it its bad!!!

man i wish i had cool stuff to monitor my engine more. add it to my wishlist and MAYBE i can make the thing run right. My TPS is about parallel with the throttle body, should i just adjust it slightly and how should i go about doing that? Or rather what signs should i look for and when should i be looking for the signs? like should it be throttled up or just ideling for example? Sorry so confusing, just one of the many things i have not fooled with yet on my Z.

yeah tell me about it reid..

i just found out tonight thanks to tony that my TPS sensor was tilted to the max (clockwise?) i didnt even realize the thing was adjustable like that. When i last disconnected it to scrub out rust, i didnt even notice. i just thought the thing mounted and that was that

well.. it sure affects things as we played with it..

I am currently trying to install and get nissan data scan to work with my PC and Z..

but THEN...

what would i be looking for?!?!

Here you go!!


http://www.twinturbo.net/nissan/300zx/forums/technical/view/960871/How-to-test-and-adjust-your-TPS-switch-amp-sensor.html

god im a newb ita gunna take me a bagillion years to get this ohms and other voltage things figured out but by god im gunna do it!

thanks Rom! ahhh links w/pix are sooo nice

fairladyaffair wrote:

god im a newb ita gunna take me a bagillion years to get this ohms and other voltage things figured out but by god im gunna do it!

I's not hard at all so just place pins in the white and black wires I belive then hook a meter to it make sure your ignition is on, open the throttle all the way and look at your meter. to change it rotate the TPS back and forth.

nismo300zr2 wrote:

thanks Rom! ahhh links w/pix are sooo nice

Not a problem Happy to help.