Dead In The Water...Please Help

[slownrusty]

Guys - This car I tell you, its going to drive me to the asylum, well it can't drive, so maybe I have to walk to the asylum.

 

Heres the story. Car has been running great, power out the wazoooo, took it off the road for a few weeks to wire up my EGT gauge, an AEM wideband and an Autometer Water temp gauge. The car is runnling low boost 5psi with all stock Nissan OEM EFI incl. stock 265cc injectors.

 

After I got the gauges wired up and installed, car started right up and revs perfectly, will even rev to red line only if the car is in neutral *only*. As soon as I start driving it and it hits approx. 2,500rpm it falls on its face, as if the spark or fuel disappeared, once the revs drop below 2,500 its fine again and I can toodle along, so long as the rpms are below 2500rpm.

 

So it only dies under load, if I pull over on the side of the road and rev the motor it revs with no issues whatsoever.

 

I think that this all happened when I wired up the gauges is a mere coincidence.

 

This is what I have done so far or checked:

1) Confirmed the fuel pump is working (taped a pressure gauge to my windshield), the guage holds 50psi of pressure when it starts to die.

 

2) Switched out AFMs with a spare one - no difference.

 

3) Switched out the ignition coil with a spare one - no difference.

 

4) Switched out spark plug wires with a spare set - no difference.

 

5) Checked all the intercooler piping, couplings and clamps for leaks

 

5) Checked the Cylinder Head Temp sensor (which only has a few hundred miles on it)

 

6) Cleaned and checked a bunch of Grounds and also sensor plugs

 

7) Switched out the ECU with a spare one - no difference.

 

Do you guys think it could be the distributor? I am grasping for straws. If it might be the Distributor, why would it rev all the way to red line in neutral but not under load?

 

Please help me guys, I am befuddled and very exaspirated.

 

Any suggestions and recommendations welcomed!!!

 

Regards - Yasin

Admin sorry I double posted this thread, please feel free to remove it from the Turbo Supercharger section.

[JMortensen]

Not much of a turbo guy, but I seem to remember a similar problem with a turbo Volvo 740 that ended up being an intake boot that had cracked.

[JSM]

Is it running rich? I'm guaging stock electronics, are all of you water temp sensors good? I was under the distinct impression stock electronics had to have all that hooked up properly to work.

 

Any chance you Autometer WT gauge may be the issue?

[Sparky]

how did you route the wideband cables? They can create a lot of noise and that might just be your problem. I know it seems like a long shot but take the wideband out and see what happens. You can probably just take remove the sensor from the car and then disconnect the power to the brain box.

[slownrusty]

Thanks to all that chimed in!

 

My OE temp gauge and both sensors are still hooked up as I realize that the stock ECU relies on a signal from this sensor for fuel mixture.

 

Sparky's post got me thinking, I went back and removed all the wiring on the gauges I inistalled and sure as $hit the car returned to normal, lots of power no more cutting out at 2500rpm.

 

I think its how I connected the gauges to the 12V switchable source, so I will be re-wiring the gauges today.

 

A learning process!

 

Regards and thanks - Yasin

[Tony D]

Yeah, Sparky had the same thought I had: remove everything you installed and confirm that what you thought was a coincidence, really is...apparently it's not, so you sound like you're on the track now.

 

Good Luck!