1996 Gtst Manual Fuel/idle Problems

[Kirbz101]

Hey everyone one I know I need to go see a mechanic but was wondering could anyone shed some light on my problems

My car has done a tad over 88,000 ks

2 problems not sure if there related

1st : my car seems to idle very weird the car ideals at about 1100 on a cold start up after a few minutes I drops down which I believe is normal problem is once the car warms up it idles very low and bounces between 550 to 800 and the car seems bumpy/splutery when sitting there!

2nd : my fuel consumption is crazy!! I am lucky to get 200ks to a tank most of the time 180ks my tank takes 50 liters and cost about $88 always premium you I drive a little reckless sometimes but not completely thrashing the car and I consistently get these ks only

Any I for would be greatly appreciated and if anyone know any good skyline mechanics in the northern suburbs of Melbourne (mill park, thomastown, heidelberg,Epping) please let me know thanks again

Jeff

[Dose Pipe Sutututu]

O2, change it.

To see if it's faulty, unplug it. Car should idle better (if using the stock ECU)

[89CAL]

Do you have a vent to atmosphere BOV? If so that would explain both problems

Otherwise as above, check 02 sensor.

Also check for any vac leaks etc

[blind_elk]

Highly doubt it will have anything to do with the O2 sensor. Melbourne suburban driving is predominantly stop / start, accelerate / decelerate; not conducive to the ECU paying any attention to the voltages coming off the O2 sensor. If you want to check the health of the O2 sensor, try getting on the Hume and CRUISE up to Albury, then check fuel economy.

Low &/or erratic idle will usually be associated with a dirty AAC valve. Additionally:

- get injectors cleaned

- check fuel pressure at the rail.

The biggest cause of poor fuel economy is the lump of lead attached to the end of the right leg. FWIW, the RB25DET in my R32 regularly gets 400k+ to a tank, in Melbourne suburban driving (includes "a little reckless sometimes").

May I offer a spot of advice here - it is not necessary to hit boost through every gear change when you have a RB25DET. The engine has more than sufficient torque to get even the whale that is the R33 up and boogeying without the use of boost.

[Kirbz101]

I've had the o2 sensor changed today ($110 from bursons) and read a instructional post on cleaning the AAC might give that a go on Monday cheers

[Kirbz101]

Ok so been through another tank of petrol didn't work any other ideas??

[Dose Pipe Sutututu]

Unplug your TPS and set your idle flat on 650rpm, check your base timing, will need to be at 15 BTDC then replug in TPS.

See how that goes, then if you have a multimeter, check your coolant temp sensor.

Mine was faulty and my car would idle at 12:1 AFR, changed it and bamm back to stoich.

The ECU might always think the car is cold and dump in more fuel