help!!running bad when hot!!!

[str_motorsport]

hi, i got a problem with my R that is really making me crazy!!basically the car runs fine, but after about 30 min of driving, especially on low boost and revs, the car start to run bad, and it seems it don't want to rev ,it has very slow throttle rsponse until it reaches full boost.....but the EGT temps goes high even for a short acceleration...
i tried everything...
new plugs, plug wires,dizzy,dizzy cover, fuel pump,ecu, maf,relais,trhottle sensor....everything!!!
changed the fuel pump power supply also....
the only thing that i have not tried is the det sensor and the cas and coil ...but there is any fault code on the ecu....
i start thinking i will never solve the problem...
ever had a similar experience?
please help me if you can
thanks
David

 

[Innovate Performance]

Check you Engine temp sensor as it may be reading a higher temp than the engine is really running at.
This would cause it to run lean and give you high EGT temps.
Remember the gauge and the ECU use different sensors.

Hope this helps or solves you problem

 

[str_motorsport]

i replaced the water temp sensor too a while ago...
iy may be defective again...
i really don't know what to do!!
injectors are also new, new fuel filter....
could it be a faulty det sensor?

 

[str_motorsport]

i will also replace the coil with a msd one ...do you think it will help?

 

[Innovate Performance]

If you are getting high EGT temps then i would say you are running lean. It could be worth checking you lambda cause it may be due to the ecu,

Have you got any ajustable engine management on the car.

Also check you MAF is reading right, and if you can check you intake air temp cause this effects the fuel map.

 

[str_motorsport]

the o2 sensor is new too!!!maf voltage is ok, i datalogged it and is ok.
air temp should be ok, i got a front mount now , but i got the same problem with the old top mount.

i got a chipped ecu.
i run on my own map,
i do my maps with wideband o2 sensor, knocking monitor, and egt gauge.

i don't know why the problem arrives only when hot, after 30min fo driving....!!

 

[str_motorsport]

i also had a problem with the power to fuel pump....after driving for a while the voltage droppet to 10v....
and i found that the connector under the dash, near the fuses, was a bit corroded, so as i got the battery in the boot, i put another relais for the pump,with new power wires and added a ground wire.now i got a nice voltage, but the proble is still there.
or i got a faulty fuel pump(a walbro 255 hp), or one of the connector on the tank is faulty, or the wires for the punp in the tank when hot start to cause the problem....but i tested them and there is no resistance on the wires...i start going crazy!!!

 

[Innovate Performance]

air temp should be ok, i got a front mount now , but i got the same problem with the old top mount.

i don't know why the problem arrives only when hot, after 30min fo driving....!!

I would check that the air temp sensor is reading correctly once the car is warm. Cause you cant accept the should be ok factor :!:

You may find the temp sensor does not read the temp correctly once it goes past a certain temp.

I have had this happen to me but with a coolant sensor.
I used the should be ok cause it was new idea and it wasted about 4 hours of my time.

 

[antgtir]

If there is a Nissan garage near by then i would take it there and get the car plugged into the comp and see what that says, it may lead you straight to the cause of the problem, you never know you may get lucky.

Ant.

 

[str_motorsport]

where is the air temp sensor?never heard of it before...can you explain where it is located?
thanks
David

 

[Innovate Performance]

May be part of the AFM i will find out

 

[Olly]

Can you get the Nissan dealer to datalog it on there consult diagnostic machine when this happens. And whats the Nissan lambda voltage on full throttle? 8)

 

[Innovate Performance]

Sorry going a bit mad the system on the GTiR does not use air temp for the fueling so it doees not measure it.

You have checked you 02 sensor, but is it switching all the time:?:, or does it stop switching when the problem happens.

Have you checked your fuel pressure. Just cause the pump is new that does not mean the fuel pressure is right.

You may be maxing out you fuel regulator which would cause this problem.

 

[str_motorsport]

the o2 sensor seems to work ok on my car.
fuel pressure is good on my car.i got a fse power boost valve and in car fuel pressure gauge to monitor pressure and it is fine.

 

[str_motorsport]

just got the same problem!!!!my R runs bad when hot!!!it seems to run leaner than usual, and the EGT temps rises in few seconds!!!
what could it be??the fuel pressure is 3,5 bar at idle like always....
could it be the pump??

 

[Innovate Performance]

This could be caused due to the actual map the ecu is running. Have you tried ajusting it.

 

[str_motorsport]

the map in the ecu is ok...i used it for months and never had a problem.
it is something related to fuel supply, but only when really hot!!!!it could be the pump that is faulty and after a while it losses its performace...

 

[Dooie Pop Pop]

still sounds like voltage drop to the pump or maybe the o2 sensor.

have you tried fitting the new coil yet? iv had ignition problems on other cars once the engines hot. usually a lead :roll: