power loss

[Tylah]

hi all, im having a massive loss of power in my zd30 di 2000 model, i don t have any engine lights on or fault codes, i have replaced my fuel filter, MAF sensor, air filter an a few other things that ive herd it might be my turbo is still running fine but driving along im having to over work my motor just to get it up to speed come to a hill it drops speed an i have to drop to at least 3rd just to get it up, doesnt blow any smoke whatsoever runs fine idles fine and starts fine does anyone have any insights of what i might be dealing with 

[Rumcajs]

G'day,

I'd check if turbo actuator is functioning as this sounds like you have no boost. since the actuator is vacuum controlled, the most common culprit is either split hose or leaking vacuum canister/reservoir.

When engine idles the actuator lever/rod should move fully up against its stopper (do not attempt to adjust!)

Regards

Edited January 8, 2021 by Rumcajs

[zd owner]

I am also experiencing the exact same symtoms on my DI, im a mechanic and im stumped on this one. Ive checked the actuator it operates as expected. Ive cleaned MAF, sensor bypassed the solenoid, ive got a boost controller and wound that all the way up it can achieve and hold 25 PSI so I thought its more likely to be fuel related. Swapped the fuel filter and still nothing. It even has a new (second hand) fuel pump on it that installed a couple months back. No codes nothing. Somwbody who knows these engines better than me please help!!

[Rumcajs]

On 4/6/2024 at 1:50 PM, zd owner said:

I am also experiencing the exact same symtoms on my DI, im a mechanic and im stumped on this one. Ive checked the actuator it operates as expected. Ive cleaned MAF, sensor bypassed the solenoid, ive got a boost controller and wound that all the way up it can achieve and hold 25 PSI so I thought its more likely to be fuel related. Swapped the fuel filter and still nothing. It even has a new (second hand) fuel pump on it that installed a couple months back. No codes nothing. Somwbody who knows these engines better than me please help!!

if you've got boost controller setup to 25 psi, but is the engine actually achieving that? I doubt. What other modifications have you got? Nissan is know to limit or limp if MAF signals are incorrect without any codes. Have you tried new/another MAF sensor?  Just cleaning it doesn't mean jack. The main problem is that if MAF sensor reports incorrect air flow rate but within specs there will be no errors just lack of power.  Engine ECU uses MAF sensor to do all its calculation, MAP or turbo pressure sensor is there only for safety limp overide or something like that.

I recommend to read/record MAF voltages during a drive to see what values you're getting under loads. While it is not easy to correlate, anything bellow 2.5 V once accelerator is pushed indicates possibly incorrect reading especially if you are unable to achieve max values up to 4 V, however again if "no fuel no boost no air no fuel" no power catch apply so you must ensure/eliminate each scenario.

If you have portable computer with MS software you could obtain ECUTalk USB to Nissan Consult/OBD interface and use ECUTalk software to view /log related data. 

Also ensure if it is manual transmission that neutral switch is working correctly, use warm up switch when cold to increase RPM when idlin in N and once you move g/lever to a gear position RPM should cut to normal idle.

Regards