My Jap '91 Auto TT seems to have lost all power below 3500 revs, then it takes off.

I can put my foot down and it just bogs down until the revs slowly rise to 3500.

At first it felt like the car was just taking longer and longer to warm up but it seems pretty permanent now.

Sometimes after a long fast drive low end power comes back.

Could I have a duff turbo or a pressure leak?

How do the twin turbos work?

Any ideas chaps?

 

have you checked the ECU for errors, try checking all of the connections to the O2's, temp sensor, CAS, MAS.

Trev.

Try cleaning the throttle bodies... may help..... and will do no harm,,,,

 

egardz

Simple -

 

100Shot N20

3.2 Overbore - happy days

 

Serously Check the ECU for errors - Then Check the timing.

 

Z ya

Nico 91TT

 

Sounds like your O2 sensors are dying. When they go bad they start running rich, causing the car to bog down at low revs.

I don't know if its related but on one of the US Z forums a while back someone had a similar problem and it turned out to be the fuel needed changing. His car was sluggish low down but ran better higher up the range.

 

However I don't think he mentioned it improving low down after a long hard drive.

I can't get the ECU checked without some big bills so I'll have to try any other easy fixes first...

Is there something that changes at 3500 RPM as there is such a difference in power when the revs get there that the wheels sometimes suddenly spin!

 

Is there something that changes at 3500 RPM as there is such a difference in power when the revs get there that the wheels sometimes suddenly spin!

 

Is there something that changes at 3500 RPM as there is such a difference in power when the revs get there that the wheels sometimes suddenly spin!

 

Is there something that changes at 3500 RPM as there is such a difference in power when the revs get there that the wheels sometimes suddenly spin!

 

Is there something that changes at 3500 RPM as there is such a difference in power when the revs get there that the wheels sometimes suddenly spin!

 

I can't get the ECU checked without some big bills so I'll have to try any other easy fixes first...

Deja vu anybody??

 

Andy

 

[This message has been edited by andyduff (edited 08-06-2001).]

here's how to do the ECU-check yourself: http://www.ttzd.com/tech/diagnostic/diagnostic.html

 

3500rpm is when the turbo's start to do their work

 

-Eric

 

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

http://300zx-twinturbo.com

So....

 

for the diagnostics, OF COURSE, you can do it yourself....in less than 10 seconds !!!

http://www.twinturbo.net/ttnetfaq/FAQpages/ECUdiagnostics.html

 

At 3500, the ECU activates the NVCS (Nissan Variable Cam System).....it's like a V-Tec....but was made & tuned long before Honda got the idea to market their V-Tec stickers

 

Henri (who had 3 CRX, and LOVES the V-Tec)

Delving into the memory banks from things that Pete at SE has told me (and he also mentioned this at the open day), it is at around 3,500 rpm that some Zs (and I think it's Jap spec ones but not UK) come out of closed loop lambda sensor control.

 

If this is the case for your car, it could be one or two dodgy lambda sensors - and I'm fairly sure that the ECU diagnostic checks lambda sensors. However, it could be that they are giving a reading but it's just wrong so don't give up on this idea if the diagnostic is clear.

 

If it IS this problem then the reason that it suddenly picks up is that at 3,500 rpm the car stops calculating fuelling from the lambda sensors and moves over to using the fuelling map programmed into the ECU.

 

Dave

 

I'll test the ECU over the weekend.

For some reason I was thinking I had to use a Consult unit even though I have read how to do it yourself in the past... der!

Went for a fast drive tonight and it definately improved after the car got really hot. That Lambda sensor idea sounds good.