rb problem...........

[duffspec]

I seem to have a problem with my rb20 powered 240. On start up the car will idle fine until I step on the brakes or turn on the headlights or turn on anything that demands a significant source of power, as i step on the brake pedal to engage first gear the tach will pin it self to redline and the temperature gauge will also pin it self to hot. During this time the car struggles to stay alive and the only way to keep it from dying on me is if I release the brake pedal or turn off anything that draws power for example: headlights, radio, heater fan etc.

These are few things i have checked:

ecu for codesvoltage of the battery pre start and during idle (12v and 13.1-13.3)fusescleaned battery terminals and ensured that they were secure

I really don't know what other options to look for at this moment and any guidance or information would be greatly appreciated.

thank you

[pat1]

your alternator isn't putting out enough juice. It should be around 13.5-14.5. What's your battery voltage at 2k rpm? What's your battery voltage when the engine is running with the lights on and the heater running? Check your grounds.

[duffspec]

thanks pat1...I will check it out the grounds and the voltage tomorrow and get back to you on that. The symptoms i described, is that normally what happens when the alternator is on it's last legs?

[gonshik007]

pat1 is right check that and check for a loose connections somewhere or corrosion check the main harness connection too. also it wouldn't hurt to check for vacuums leaks (just bc when you press the brake pedal it has that effect)!

[gonshik007]

thanks pat1...I will check it out the grounds and the voltage tomorrow and get back to you on that. The symptoms i described, is that normally what happens when the alternator is on it's last legs?

When the alternator was dyeing on me on my 300zx the battery light would come on and then once it didn't work at all my headlights got dim stereo shot off and so on.

But since its running such low voltage that really much could be your problem!

[mott6904]

I would bet on a connection issues. If the alternator is really putting out 13.1 at idle than that is not your problem.

[pat1]

I would bet on a connection issues. If the alternator is really putting out 13.1 at idle than that is not your problem.

If the alternator output is at 13.1 at idle with no other load on the system and if you add a load (ie lights, heater,a/c or anyother load the voltage will go down. There is the problem.

Check the battery voltage @ idle and @ 2k rpm It chould be 13.5-14.5.

The voltage regulator adjust the voltage output of the alternator. It does this by montioring the voltage . Remember the 2 small wires that go into the alternator? Those wires go to the following 1 the alt light( Field )and the other one goes into the regulator and that wire is the supplys the regulator with the voltage. And the the regulator adjust the voltage to the load of the system. So it the voltage is at 12.8 volts the regulator will adjust the voltage to keep up with the load. @ 13.5-14.5

But I would check the wiring and load test the alternator.