Thread: Strange constant speed issue

Nope, still doing it. Odd thing is while I was doing my oily blowby gasses, I accidentally forgot to reconnect the front o2 sensor. It ran great, until after an hour of driving, just as before, started hesitating. It seemed it didn't do it after 4k. I plugged the o2 sensor in again and it ran exactly the same. Would that be 100% the problem then or am I reading into things?

Also, since I drive an nx, and need the slim o2 sensor, can I purchase a slim o2 sensor aftermarket or does it absolutly have to be a nissan genuine part?

MOAR updates!

I was bumping around the vaccum gallary, when I accidentally bumped the tps sensor harness. The car surged....what the heck? I peeled back the wire sheathing and electrical tape, and sure enough, the black wire was slightly cut - only 2 strands out of about 6 (it is 20 gauge wire after all, small small!) - were still attached. So off to the auto wrecker, snipped a new one (same harness used on any 91+ nissan apparantly! Crimp, heatshrink tubing, a bit of electrical tape, and now my wife took the ride out on a 45 minute drive and back. We'll see if she reports any hesitation now. If so, back on to the o2 sensor - I couldn't find a contininuity point anywhere on the intake manifold, the ssac header, anything! Looks like I'll be running that bosch 4 wire if I plan on getting anywhere with figuring this out.

2.5 hr drive and not a single hesitation! BAM!

Issues though now is a bad rough idle. that's the next 'what the hell is up with my ride' chapter.

Okay. Great that you found the wounded harness. They can be a bear to find..

After fixing the harness, you need to reset the TPS.
- Turn On Ignition to dash xmas tree (dont start car).
- With Throttle Butterfly completely closed: Make sure that the TPS voltage between 0.45 & 0.55V.
- With Throttle @ WOT: Make sure the TPS is at 4.0V exactly (use the Throttle Stop Screw to set it).
- Finally, put car in timing mode and reset your idle & timing. This should correct your idle.

Couple of other Suggestions:
1. Test your 2-wire Temp Sensor to make sure its good.
Unplug the CTS. With harness plug latch pointing up, terminal A is left & B is right.
Power Supply: Turn ON Ignition, Check voltage between terminal B and ground: Approx 5V
Ground Circuit: Turn OFF Ignition, Check voltage between terminal A and engine ground: Continuity should exist
2. If you have a Calum ECU, check to see if the O2 Sensor delete is turned OFF or ON. If OFF, turn it ON and do a test drive.

Your intake mani has 2 grounding screws near the firewall. The engine harness uses those screws to ground all of the sensors (except the O2 sensor). Follow the injector wiring harness down behind the intake mani and it will lead you to the group of grounding wires. They should be grounded to the Intake Mani. If not, you have found your problem. Those grounding screws are your continuity point.

excellent. that's the next step - After reading your writeup with vadium on the o2 sensor, I might have to do that as well, seeing as how the car ran the same with and without the o2 sensor. I have tested through the ecu the o2, and it did blink more than 5 times in 10 seconds, and resistance was 11 (within the 3-1000 ohm resistance compliment) so it seems the o2 sensor is fine, but one can never be too sure I suppose. I will try the cts next.

Thanks for the help thus far.

tps is exactly 4v (was 4.08 before the screw was adjusted) and .48 at closed. CTS was at 748ohms at around 100F, so that checked out ok, with 4.87V at on ignition, and perfect continuity with ignition off.
I did an idle relearn and also measured the voltage with the MAF as reccommended - .755V with ign on, not running - and 1.48 at ign on, running, and warm (150F+). Is that close enough? I know it's supposed to be 1.5, but that's damn close.

We'll see how it runs tomorrow from cold - hopefully ok. If not, I'll have to check out the air regulator valve to see if it stopped working in the interim.

Your sensors appears to be well within specs and the MAF is well within range too.

The Air Regulator will sometimes stick partically open and cause a high idle but not a fluctuating idle.

As for the O2 sensor, Do you have a Calum ECU?? If so, it could be turned off ! ! Check before buying another O2 sensor...

I dont' have a calum ecu - but I ran the ecu nob/flashing check engine light and checked resistance between pins with the car off, both were within spec - how should the car run with it disconnected? because it ran ok (would it just run rich, but the rest of the things such as idle and drivability would be fine?)