no offense to your friends but "techs" at dealerships are just that, techs. They aren't real mechanics. All they know how to do is throw parts at the problem until it's finally fixed.

With the cams not functioning your car will still put down power. My cams don't work on the first pull but that still yielded over 600hp for me. Your car will run perfectly fine with the cams off and at 0*.

The coolant on the floor can be 2 issues: There is still air in the cooling system or the head gasket is blown. Air in the system is common. it gets trapped behind the thermostat causing the car to overheat and boil over. You can run the car until it's warm then feel the lower radiator hose. If it's still cold the thermostat isn't opening probably due to air behind the t stat. I recommend to use the spill free funnel. It's pretty much the only way to get air out properly on these cars.

Now, due to all the problems you are experiencing i'm leaning more towards a head gasket issue. If the cylinders are leaking compression into the cooling system that would explain the low power.

I didn't see all the stuff that was checked but the first things i would do on this car is a leak down test then a compression test. Leak down will tell if there is something wrong with the valves sealing (bent valve, problem with the seat, ring sealing issue do to improper machining). The compression test will tell you if the cams are functioning properly when the engine is turned over.

Without those being in spec then it's stupid to go any further.

I'm not sure why they think it is the ecu. if the car ran fine on the stock block, nothing was done to damage the ecu (water, etc) and the build block was put in the car there shouldn't be any issue with the ecu.

I know people say the utec burns out coils so after the leakdown and comp test checks out i would put 6 new coils in to see if that does anything.

also, with the o2 sensor. If that was bad it wouldn't run properly in closed loop (vac) but in open loop (WOT pull) the utec or osiris will be a set fuel injection that will not be altered by o2 sensors so bad o2 sensors won't affect open loop. So really that wouldn't be the issue with the low power.

 

i agree 100% and yes you are right. most of the time i feel like a know way more than any tech i encounter, especially when it comes to modding/tunning. I re-did the timing but i still have the same issue, i also have changed injectors thinking that was the reason for the leaning on the dyno but that didnt do anything either. I agree with Binder in that i feel it is a head or head gasket related. im going to bring it somewhere to do a leak down test.

 

just posted this on my350z.com
here is the link to my find there. some people with the same dead spot/loss of power.

http://my350z.com/forum/engine-and-d...from-hell.html

wow. what a story. ive been trying to figure out this same exact problem and came up with NOTHING. Ive literally checked everything accept the 02 sensors being that the problem seems to not be that. Absolutely frustrating. especially with all the money i have in my motor.... completely built and turboed. the flat spot you've been talking about is not imagined as some people has suggested. Ive been trying over and over to get it tuned with various tuners and ECU's and all i can put down is a pitiful 285 WHP with 14 lbs of boost... fuel economy is terrible as well and i occasionally get codes p2a00 along with p0187 but mostly just p2a03 bank one sensor one range performance. Lately however ive been getting p0300 RMM which doesnt make sense because it is out of no where. It almost feels/sounds like the exhaust valves are not opening all the way or something, i notice that the AFRs are erratic sometimes lean and sometimes rich, tuned with Osiris now) there is a deffinate flat spot-sputtery sounding exhaust note and no power. at times it seems like it wants to go... but it dosent. i went to the extent of redoing the timing thinking it was that but does the exact same thing. now im leading towards it actually being the A/F sensors because ive checked everything else. the other few things that it may be as suggested by other is: bad ECU and or bad harness.

 

i am also throwing the p2a03 and p0300 codes and dame dead spot under boost, but my g is also having startin issues as well. im at the same point you are with the car. i changed parts and all but still no solutiin to the problem. hope you find out the cause of the problems cause im clueless on mine. good luck

 

wow. do you have a built motor? what turbo kit? this is a crazy problem... how is it that noone can figure this out!!!! did you change your 02's as well? thats what im doing now. have you changed your computer or harness? i just cant believe how this issue causes all this!

 

no motor isnt built and im running a turbonetics kit and using uprev. car will run fine after first start up, but once the motor warms up it wont start. i have to wait an hour for it to start and thats when the issues come and i get those codes. i gotta wait till this weekend to replace these parts. i was also told to check the cam position sensor. once i get these issues fixed im gonna try and get tuned and maybe ill be able to boost

 

I feel bad for u guys. Problems like this give FI a bad rap.

 

i know what you are saying. i have so many people saying " i hate modifying cars, this always happens" Which is not true... my last cars where heavily modified as well and didn't have a lick of problems. i know soooo many people with boosted/modded cars that don't have any issues either. It seems we've been dealt a raw deal with our situation however, i haven't given up. I am awaiting the arrival of the primary 02 sensors. this is really the last part that I have not swapped out. I hope to God that this solves the problem, If not, there is only one this to do, rip everything apart and start from scratch with a new wiring harness and possibly a new ECU.

 

Got my new af sensors yesterday and I'll be putting them in tomorrow... Hope that's the issue! I'm bit counting on it though...

 

Good luck........ill be praying to the VQ gods for u.

 

good luck to ya. im still fighting my gremlins

 

ok... so i put the sensors in and turned her on. idle seemed to be smoother than before. i let her warm up and checked the AFR's which are on point but varies between 14-15 which is normal. then i decided to rev her a bit. reved up nicely, same as before in neutral. however when i slowly let the RPMs climb its smooth and can go to redline but when i floor it to rev it, it will get caught up around 5500k them it will break though to redline, almost like there is a rev limiter there strange... but may be normal. i dont know. anyone can chime in and let me know?

Now the drive; took here out and immediately noticed it was way to rich. at normal thorttle just to get up to speed, it was hitting 10-12 AFR very rich. i made a u turn and gave it some gas and wow.. broke loose in 1st, 2nd, (didnt do that before) then laid off. Then i decided to do a third gear pull to see how it was at the top where my problem was most noticeable. it started to pull, you can feel it wanting to go! but it didnt... just didnt like it. now, i noticed on my AFR gauge when it was running good, when under boost, the gauge would be around 11.5 at worst-since my problem it starts off with plenty of fuel and as the RPM and load climb it slowly leans...strange.... around 11.5-12, not really off much but, it leans at the top.

overall it seemed like it wanted to go but maybe its the tune? i don't know. it still had the flat sounding exhaust note and not that explosive pull,like a modded turbo car should have....I only tried to pull it once as i didnt want to mess anytihng up or foul my 02s since its so rich. so Im hoping to GOD that a tune will bring her back to life!!!! ill be going to HP logic tomorrow for a tweak. I will post an update when i get done. wish me luck!!!!!!!!!

 

glad that your issues are getting worked out. hope you can make more then 300 hp this time. good luck

 

any update?

 

Perform a leak down test or combustion leak test