I hate my car! It's been faulty more than it hasn't! Now the bloody heater is leaking too!

 

Took my car to Nissan, they connected it to a consult & here are the results:

At 2950rpm

Mas air/fl 1.83v

coolant temp 74deg

o2 lhs 0.08v

02 rhs 0.03v

m/r f/c mnt lean

m/r f/c mnt-r lean

------------

Failed on Mixture test:

rpm 2137rpm

mass air/fl 1.5v

coolant temp 80degC

inj pulse-l 2mS

inj pulse-R 2mS

O2-l max 0.06v

o2-l min 0.06v

02-l count 0

02-r max 0.04v

o2-r min 0.03v

o2-r count 0

a/f alpha-l 122%

a/f alpha-r 121%

power balance test OK as was everything else!

 

Since this I've replaced the O2 sensor on the l.h.s & I know that the r.h.s sensor is OK cos I checked it with a voltmeter.

Funny thing is, I detected more than 30mV, I got about 130mV when I checked the sensor, so I'm beginning to wonder if the ECU has gone west. Also checked O2 sensor volts at ECU cct board & was 130mV & varied depending on how much throttle I gave it!

It's almost as if the ecu isn't recognising the signals from the o2 sensors!

Help!!!

I can see that I'm gonna have to pay Andy a visit in Preston pretty soon.

 

 

[This message has been edited by shaunmac (edited 07-02-2002).]

 

 

A thought.. Have you checked the voltages at the fuel pump?

 

Should be 6-7v at idle, 8v off idle, and 12v on boost (from memory).. You want the blue/red whire (pump -ve) and white/purple wire (pump +ve)..

 

130mv seems very low? I thought O2 senors were supposed to hover around 0.5v (1v being rich, 0v being lean, essentially)..?

This is what I've checked so far:

 

Fuel pump voltage, OK

Fuel pressure 40psi to 50psi depending on load, OK

spark plugs, coils, PTU OK

O2 sensors both OK

Temp sensor OK

ECU comes up with 55, OK

Fuel temp sensor OK

Throttle pos sensor OK

Air flow sensor reads 1.2v at idle

 

If I unplug the MAF then the engine runs as smooth as a babys bum but that's because the ECU estimates the correct mixture, but when I plug it back in it runs like s***!

 

It smells like a buggered ECU to me.

 

[This message has been edited by shaunmac (edited 07-02-2002).]

If it's any consolation, I am having similar problems (but nobody replies to my threads, sob sob.. )..

 

Is there anyone nearby you can borrow an ECU off? (Timmy/Andy etc)..

I hope they did the consulttest while driving, otherwise the test was/is pretty useless to troubleshoot your problem.

(I presume your hesitation-problem occurs when the engine is under load)

 

if it was done while driving your MAF is reading too low..should be between 2.5 and 3.3 volt (~3000RPM).

 

about the voltage of the O2's: also this can best be done while driving..you can then clearly see whether the range of the O2's is ok.

if this was the case, then the maximum-reading of the O2's is far too low as well..

 

if the car was under no load the values are fine..but useless to help to solve your problem

 

-Eric

 

[This message has been edited by lymon (edited 07-02-2002).]

The guy did do the test while driving the car! So I guess that there's something missing from the feedback loop & according to the results, it looks like the O2 sensor readings. Now that either means the O2 sensors themselves or the ECU!

personally I think there's something wrong with your MAF...or the voltage to your MAF may be too low (in this case it can be a wiring-problem or the ECU)

if the MAF sends out a voltage that's too low, the ECU isn't supplying enough fuel and the car is running too lean (hence the low O2-sensor readings)

 

maybe it's an idea to borrow a MAF from another Z to further troubleshoot ?

(BTW: the MAF of both the NA and TT are the same)

 

-Eric