Codes 33 & 34, Fixed & Reset ECU 2 times and still having probs!!

[delinquentracer]

I recently took out my timing chain guides on my 95 obdII s14.I pulled the top and right side guides.

Since the distributor had to be pulled to do this, We had to reset timing.We put the car at TDC, put the distributor in correctly, and my friend set timing for me while I was taking care of something else.He also said that he advanced it 1-2 degrees, just to see if there was any power gain.

The car ran fine for I wanna say...15-20 miles, and then the check engine light came on. But even with the check engine light on, the car still ran perfectly fine.

I checked the codes by the light on the back of the ecu.I pulled codes 33 & 34. Which are front 02 sensor and Knock sensor.

I figured that the timing must have not been set right and thus I checked the timing, and it was off by 5 degrees. I thought maybe that the ECU felt knock and threw itself into a safe mode of some sort and knocked timing down.I then reset timing and the ECU.

Then yesterday, I was driving normal.. the car was running fine, and the Check engine light came on. I figured it was the same thing again.. So i checked the codes and it was 33 & 34 again.

I then checked the timing and it was @ 15 Degrees again.

So I then set timing the CORRECT way.I let the motor warm up, Turned off the car, Disconnected the TPS, Turned the car on, Set idle to 700rpm by turning the idle air screw on the back of the intake manifold.Then I set timing to 20 degrees, and tightened down the distributor.Reconnected the TPS.

I figured it was fine.Then tonight on the way home @ 3:30 am on a cold *** night, the check engine light came on again. I have no doubt that its the same thing again.

Each time this has happened, I havent heard any pinging/detonation.(although that doesnt mean its not happening)

-SO now I ask for anyones help in trying to figure out why this is happening??!?!

I figure that maybe the Front 02 sensor circuit code came on because if the eng. detonated, the exhaust gas got a lot hotter, and maybe the 02 sensor didnt like the hotter EGT's.-ANY THOUGHTS ON THIS?

Im dam sure that I followed the correct directions on how to set timing.- Is it possible for the Distributor to not be tightened down enough and the distributor to slip, causing timing to advance, and causing knock??? (kinda not likely)

I have no other thoughts on why its happening. But I want/need to fix it in case something is really wrong.. I dont want to screw up my car by driving it if something is really wrong.

Thanks for anyones help!!!!

[delinquentracer]

anyone?

[Alch]

I know this doesn't answer your question, but i've got a check engine light coming on as well .I'm getting a check engine light, but i haven't been able to get my ecm out. I removed the kick panel and unscrewed the bolts that holds it in place, but i just can't get it out. Also, i imagine i have to remove the mounting bracket to get to the mode selection screw and LED's, right?

I drive a 95 240sx.

[ricebike]

original poster: goto here or have mod move this thread...

zerothread?id=131961

alch: did u check the http://www.240sx.org click on FAQS and it'll have procedures to read the ecm trouble codes. heck there's even an online free FSM floating around for your engine...

[Alch]

Sorry about high jacking the thread:

I have an ecm, i know how to read the codes. My problem comes from being unable to physically pull out my ecm and get to the diagnostic mode screw. I've been making a plan all night on how to do it. There appears to be a little piece of my dash that's holding it in place and very difficult to work out of the way. We'll see.

[Alch]

bump

[ricebike]

i dunno if late-model 95's are OBDII compliant (do u see a connector near the steering wheel-knee plate area?)

if so, bite the bullet & let autozone scan the ecm w/out u pulling out the unit.

other than that, othes will chime in eventually... <bump>

[delinquentracer]

i figured it out a couple days ago.. just havent been able to get on here and post.

The problem was that the ECU wasnt reset properly the first time.

Those having probs pulling out the ECU. its not hard.. 1 plastic screw holding on the kick panel and then 2 screws holding on the ECU, you also have to pop off the plastic thing holding the wiring harness to the ECU. then you can turn it around and see the LED and diagnostics screw.

- I finally read the 240sx.org FAQ again and realized that I didnt reset it properly.In order to read the codes you take a flathead screwdriver, spin the diagnostics screw clockwise all the way till it stops.. hold for 2 seconds and turn it counter clockwise again till it stops. ( all with the key in the on position).

This puts the car in mode 2.the LED will start blinking the code(s).

In order to clear the ECU properly, you have to then turn the screw again clockwise all the way, hold for 2 secs.. turn it the oposite way again. This puts the car in mode 1 again. To clear the codes. Put the ECU in Diagnostics mode 2 again and then back to 1, then back to Mode 2.. Youll get a code 55, all clear.Then you can switch back to mode 1 and start the car.

IF this is confusing, Go read the 240sx.org FAQ on it.

Good luck

[ricebike]