My Z is still bogging down below 3500 RPM.

I cleaned the throttle bodies last night and have noticed a big improvement overall - much smoother and more free revving, but the problem is still there.

I haven't had chance to do an ECU diag yet but some of you guys said it could be the O2 or lambda sensors.

How much are these and what's involved in fitting them if they have gone?

I'll start preparing the bank account for another shock...

 

I think the O2 sensors are 50 quid each from Courtesy Nissan (shipped and Tax inc) They are from what i hear a bastard to fit - altho i haven't tried the job or heard of anyone trying it on a car with Downpipes and not PreCats.

 

They are located straight after the Turbos on each side.

 

Do a ECU diag before buying them tho as a failure will show up on there.

 

Mr A. Duff is doin this Job when i get round to ordering them for him so im sure he will give ya a better idea what is involved then.

 

Z ya

 

Nico 91TT

it sure is a nasty job....have some bandage ready !

 

There is a small tool available (I think they also sell it at courtesy) that makes the removal of the lambda's a lot easier.

... If I only knew that before ....

 

-Eric

The ecu diagnosis will only show a sensor in complete failure (open or short circuit). The sensor may have gone in that it doesn't sense but may not show as a fault code on the ecu. The only ecu diagnostic check is to put it into mode 2 and count the flashes every 10 seconds (I think!) then do the same for the sensor on the other side. Here's the link for the procedure:-

http://www.ttzd.com/tech/diagnostictech.html

 

Hope it helps,

 

Andy

what about the lamda sensor?

you guys only answered half the question. JEEZ MAn!!!

Same thing Warren.... Doh!!!

 

Andy

o2-sensor = lambda-sensor

Chris, got another theroy, but first has the car been laid up for any amount of time, say a couple of weeks or more, Smithy

Smithy, put me out of my misery..... I'm intruiged

 

Andy

LOL

I thought the O2 and Lambda sensors were different things too. Doh again.

If people just called them exhaust gas sensors then it would be a bit clearer I suppose.

When I visited Ian at Hiteq he did a Consult test for me and said the O2 sensor was giving some odd readings but they went away after a few seconds. He said they were probably OK at the time but a few weeks later I started getting this problem.

Sometimes you can floor the throttle and the car just slowly creeps between 1500 and 3000 rpm then takes off and wheelspins at 3500 as the variable valve system/Turbo's come in.

 

No, the car is in daily use Smithy.

Smithy,

 

Thinking about it I did go away for a weeks holiday but can't remember if the problem had already shown before that...

What's the theory Sherlock?

The reason a lambda sensor is an O2 sensor!

 

They're both correct terms. The sensor basically measures unburnt fuel/oxygen passing through the exhaust system to determine the correct mixture for the engine. Oxygen in the exhaust = too lean (not enough fuel for the volume of air, so not all the air is used). Fuel in the exhaust = too rich (too much fuel to be burnt so the excess passes into the exhaust).

Now, Lambda is the term used for the air/fuel ratio. Therefore, it is the sensor that is either measuring perfect mixture, or it is measuring how much unburnt oxygen (O2) in the exhaust.

 

Go on, correct me if you dare...

 

CheerZ,

 

Andy

 

It's important to run the check with the engine warm.

 

Although I didn't do it myself, I watched it being done on my car. The passenger side was the most awkward but was easier with the battery removed.

 

Hope this helps.

 

Dave

 

Hello Mate,

 

I've just replaced the nearside O2 sensor and I found a tool that is pretty good at doing it, it only cost me a fiver.It's a 22mm crows foot I used it with an angled drive a couple of extension bars and it came off a treat.Hope this helps,

 

Mark H