POWER LOSS WHEN WARM!!!!!! 300zx Na 5 speed manual

[nofski]

hey guys im new to the forum and have been searching for a fix since i got my Zed 3 weeks ago... i got the car missing on cyl 3 and quickly put that down to an injector failing so i got myself a spare motor because 300 bucks for a whoel motor was better then 350 for 1 injector... replace the injector and the miss went away ...yay.... i was so excited i took the zed for a skid :o it was amazing UNTIL it hit half way on the temp gague it was boggy and slow after that and just felt like it had no tourque ... i fiddle with things for a couple of hours with no change so i left it... the next day i was on my way to get some vasso to spank the monkey persay and it went hard! UNTIL it hit half on the temp gague again so basically power loss when warm things i have tried....

*new spark plugs
*MAF clean
*02 sensor change
*checked the coolant temp sensors
* cleaned as many of that sensor plugs as i could get to with a good contact cleaner
* checked for error codes on the ecu manually and using DATASCAN 55s all round yay...
*moved the ptu up front even tbough its an S2
*checked timing and set it to factory
a few more things that i cant remember
*new air filters

other things i think it could be
*AAC?
*fuel temp sensor?
*fuel filter?
*fuel presure

i have just about had it with the car its been racking my brain for 3 weeks anfo helpful info is much appreciated ALSO the car is smashing through fuel... uaing about 25 Liter per 100ks.... i dont own BP i cant afford to run that... also the promblem iant as bad when the weather is cold....

sorry about the long read i tried to make it a little interesting haha

cheers...

[solaire]

Sounds like a clogged catalytic converter to me

[Ziggy1621]

Do you have another coolant temp sensor you can change it out to? When you pulled the codes, was it cold or was it at full operating temp?

[nofski]

clogged cat would make it bad when its cold as well wouldnt it?

no i dont have a spare and iv checked codes both when hot and cold

[Metacom]

Go to the online FSM http://www.300zx-twinturbo.com/cgi-bin/manual.cgi

engine fuel & emission control sytem > page 42 > Try following diagnostic procedure 7 (page 77)

I'd check out diag procedures 5, 9, and 11 as well.

[solaire]

I've seen converters not cause issues until the car warms up and it builds up back pressure in the exhaust. Especially if there was a faulty injector dumping fuel. I'm making that judgement assuming you have no codes.. If you have codes chase them first. Don't ignore your coolant temp sensor. I believe there's links here to the OHM readings based on temp. Check it cold and get it to act up and check it warm and see what happens. Also that injector may have fouled out the o2 sensor. The sensors are ignored until the car goes into closed loop if I'm not mistaken. But the fact that it happened after the injector failed would make me lean towards the O2 or cat converters. I'd recommend taking an O2 sensor out and letting it warm up and run it to free up the exhaust but odds are in our cars you'll destroy the sensor trying to get it out.

[nofski]

Update... both 02 sensors are defs working... i checked both cats today not blocked at all fuel temp sensor is working fine, AAC is working fine still got no error codes... did have a leaky injector seal i replaced that seems to be smoother both when hot and warm but power loss is still the same...

[nofski]

when cold and warm sorry *

[solaire]

What are the Coolant temp sensor ohm readings cold vs warm (during power loss issue)

[nofski]

FIXED!!! well sort of fixed haha put it down to the knock sensor... either the sensor is faulty or my egine gas a knock... i bypassed the sensor and it runs fine now now worries

[Ziggy1621]

Glad you figured where the power loss is from, but I wouldn't say "No Worries". If it really has a knock, that is BIG worries