Thread: O2 Induction manifold / N1 TB Problems!

Hey guys, I recently installed a lowport O2 induction manifold and N1 throttle body on my 98 Sentra SE. I'm having some troubles that I hope someone could help me to address.

First off, If you don't know, the 98+ are plagued with emissions crap. I removed all vac lines and sensors that were connected to the 98 manifold. The car runs and idles pretty well, but if I depress the clutch above 2200k or so the rpm's will drop and it will die. I have to keep it in gear as I slow down until I get to about 2k, to keep it from dieing.

The next thing, I wanted to check/set my timing. I was following the the steps, warming up the engine, revving 3 times to 3k, then i'm supposed to unplug the tps, but the n1 tb only has one plug on it. I don't have the other plug plugged into anything. Once I unplug the only plug on the n1 tb, the car dies in about 10 seconds. So I can't really set my timing, is there any other way to set it? Am I doing something wrong?

If anyone can shed some light on these problems, I would greatly appreciate it. Thanks

might wanna check for vacuum leaks using a bit of carb cleaner to pin point with car on... might also consider puttin the oem TPS sensor.

Bud, follow JWT's directions for removing the EGR crap, yes?

If so, then you should have the same type of vacuum lines running as you would see on a highport motor. 95~97 core ECU doesn't see most of the sensors that exist on a 98+ lowport motor.

When you do your raindance (Just rev to 4K, let it fall to idle x3), unplug the only plug on the TB, and immediately start adjusting your base idle to prevent the car from dying. Get it to sit where you want, then adjust your base timing. Once done, just plug back in the TPS.

I second the vacuum leak issue with your car trying to die off when depressing the clutch over 2.2krpm. I ended up replacing all vacuum lines with silicone hoses and it has helped quite a bit. Now I need to replace the IM gaskets.

Get a pressure tester and test for vacuum leaks. I almost am sure you have one. Install this as far away from the TB as you can (ie in place of the filter if you can manage it)

Something like this or a home-made one works great too.

I have one of those from silicone intakes, and I tossed it on today, and I def have a vac leak. The problem now is, I can't locate it. Anyone have any tips to find these? I can hear it, it's loud. I reach around, can't feel any air, I can just tell it's coming from the rear of the engine bay on the driver side somewhere.

yes hi, again with the car on.. spray bit of carb cleanr around intake manifold or an area where you think its leaking.. if its leakin the idle will go up as the carb cleaner is sucked it.. dont worry nothing will happen to motor because of carb cleaner


i bet its the intake manifold gasket... when not torqued down properly it will cause a lil leak.. but please test it first

it seems like i found most all of the leaks. It started out as a very large leak, now i can still hear one, and i'm trying to find that, but it is very small. What I don't get is the problem has not changed at all, it's gotten no better at all.

I tried putting back on the absolute pressure sensor, i just t'ed it into another vac line.


That made my start up easier, before I had to punch the throttle a few times before it would idle, now i can start it like normal.

I'm also curious about the iacv air regulator

currently not hooked up. I've seen it hooked up in someone's pic.


Could this be causing my problems? Do I need it? if so, does anyone know how exactly it's hooked up, I can't really tell how it is hooked up from the pic.

Someone help me

one goes to vaccuum off manifold i believe other goes to vacuum on intake but not to sure...

You can delete the air regulator, but you need to have the throttle propped partially open to compensate. The air regulator just bypasses the throttle plate (one side goes on the IM and one side goes on the cold piping) so the ecu can feed air to the motor at idle without actually opening the throttle.

I tried cracking my throttle plate yesterday as well, I was thinking that could have been my problem. When I would go to clutch it would close stalling my engine. But even with it cracked and a high idle due to it, 1500 or so, it still dies in any gear if I go to clutch above 2200k