90 Ka24e Smog failed stock car

[Trixzim]

Hello,

I went to get my 1990 240sx ka24e smogged today and I failed. Does anyone have an Idea what is causing this?

Failed with this info:
Idle speed CO was 6.13% (Greater that 1.20%)
Idle speed HC Was 683 (Greater than 220 Parts per million)

Do you think my coolant temperature sensor is bad? (Replaced 10/12/22didn't help with OEM sensor)
Or do u think it has to do with thermostat, water pump, and fuel pressure regulator?

This is a picture of my stock engine bay:


Few Things I noticed with my Car:
-Plugs are wet and seemed to be cover in gas. Running rich (You can smell it)

Old plugs

-When I tap the gas and let go, the idle drops and kind of bogs
-The engine seems to be running hot but the gauge is showing about a quarter

Things I replaced:
Engine temp sensor
O2 Sensor (NTK 02 sensor)
New OEM Dizzy and rotor
New spark plugs and wires ( NGK wires and NGK Iridium plugs )
New Air filter
New fuel filter
Timing was check and its a 15 B.T.D.C




Thanks,

[relaxamigo]

Your car is running rich, hence the high Hc content.

Tips to bring the A/F mixture back to OEM spec:
- new OEM coolant temp sensor
- check ignition timing and set to OEM spec
- check fuel pressure
- replace fuel pressure regulator
- check injectors for leaks (rubber O-rings go bad)

To address cooling issue:
- wire a good water temp gauge and diagnose from there. stock unit sucks, you don't even know what temp your car is at

To pass your emissions test:

- "check" all the things in the first list on my post
- inspect catalytic converter (if this is clogged/fucked, it won't clean your emissions) you can replace with a universal for less than $50, but you'll need to weld

[Trixzim]

What fuel pressure regulator would you recommend?

Will the auto zone one work ? GP Sorensen Fuel Pressure Regulator 800-171

Originally Posted by relaxamigo

Your car is running rich, hence the high Hc content.

Tips to bring the A/F mixture back to OEM spec:
- new OEM coolant temp sensor
- check ignition timing and set to OEM spec
- check fuel pressure
- replace fuel pressure regulator
- check injectors for leaks (rubber O-rings go bad)

To address cooling issue:
- wire a good water temp gauge and diagnose from there. stock unit sucks, you don't even know what temp your car is at

To pass your emissions test:

- "check" all the things in the first list on my post
- inspect catalytic converter (if this is clogged/fucked, it won't clean your emissions) you can replace with a universal for less than $50, but you'll need to weld

[ZenkiKid]

Originally Posted by relaxamigo

you can replace it with a universal for less than $50, but you'll need to weld

Not in California. CA "compliant" ones are at least $200.

[Trixzim]

Originally Posted by relaxamigo

Your car is running rich, hence the high Hc content.

Tips to bring the A/F mixture back to OEM spec:
- new OEM coolant temp sensor
- check ignition timing and set to OEM spec
- check fuel pressure
- replace fuel pressure regulator
- check injectors for leaks (rubber O-rings go bad)

To address cooling issue:
- wire a good water temp gauge and diagnose from there. stock unit sucks, you don't even know what temp your car is at

To pass your emissions test:

- "check" all the things in the first list on my post
- inspect catalytic converter (if this is clogged/fucked, it won't clean your emissions) you can replace with a universal for less than $50, but you'll need to weld

Originally Posted by brndck

did you replace the sensor for the gauge or the sensor for the ecu?
there are two sensors, next to each other.
one feeds signal to the ecu, and the other is just for the gauge on the instrument cluster.

Okay, I figured out whats going on but I don't understand whats happening. Please help me understand.

I make sure the car is running at operating temperature. Then I set my timing to 15 B.T.D.C with the TPS unplugged both connectors unplugged (unplugged it with car off). I turn off the car and plug the TPS back in. I start the car and check the timing again and its retarded to 10 degrees. It loses 5 degrees of timing some how and dumps more fuel?? limp mode??????? The only way I can get the timing to go back to normal is loosen the TPS and adjust the volt up and then back to where it was at .50. Then the timing is back at 15 degrees and the cars runs well, but once I turn off the car it does the same thing again where it runs at 10degrees in a limp mode.

I also replaced the TPS with a new one and does the same thing. Anyone have any ideas?

[brndck]

also, a fresh oil change right before your smog check can be the difference between a pass and a fail.

[Trixzim]

Originally Posted by brndck

also, a fresh oil change right before your smog check can be the difference between a pass and a fail.

New oil, New spark plugs, New dizzy, New rotor, checked time, new air filter, new fuel filter, new o2 sensor, new temp sensor now.

I think I'm going to replace the MAF now, fuel cap, replace the o-rings on injectors and have them cleaned. Then maybe get a new fuel regulator. I'm going to take off my cat and check it out too.

[rat240]

You can check the egr ports on the intake manifold there hex caps each runner has one plug

[PoorMans180SX]

So the 25 year rule doesn't apply to state smog eh? I didn't know that.

[mav1178]

Originally Posted by PoorMans180SX

So the 25 year rule doesn't apply to state smog eh? I didn't know that.

25 year rule never applied to any state smog, it is (and always was) a federal rule.

[brndck]

Originally Posted by Trixzim

Do you think my coolant temperature sensor is bad? (Replaced 10/12/22didn't help with OEM sensor)
Things I replaced:
Engine temp sensor

Thanks,

did you replace the sensor for the gauge or the sensor for the ecu?
there are two sensors, next to each other.
one feeds signal to the ecu, and the other is just for the gauge on the instrument cluster.

[Trixzim]

Originally Posted by brndck

did you replace the sensor for the gauge or the sensor for the ecu?
there are two sensors, next to each other.
one feeds signal to the ecu, and the other is just for the gauge on the instrument cluster.

Sensor for ECU and tested to make sure it works.

[AKADriver]

Some states have their own separate "25 year rule." We do in Virginia, separate from antique registration which also becomes available at 25 years. (Antique registration just gets me a tax/fee break in exchange for keeping mileage under 2500/yr.)