intermitent CEL?

[albertgunit101]

i was driving yesterday and my check engine light went on. but i was heading to school and i figure i am so close at the parking lot and that is where i will diagnose it. but the light went out after less than a minute. it would have been ok to me but that is the second time it did that. first is when i was driving in the freeway. the Check Engine Light went on again and i was just about to exit but before i get to slow down and stop it went off already.

im getting bothered coz i want to know what is going on. but i cannot do anything until i catch that CEL on again.
sounds so weird. has any of you guys ever experience this? i hope its just a
02 sensor.

[Sylvan]

Might be an EGR code. Maybe you need to clean it out. You can still read the code, it should be stored in the computer.

[albertgunit101]

yeah youre right. possibly. so what do i need to do. if i clip te1 and e1 even w/o the CEL will it give me the code?

[albertgunit101]

if the egr is dirty will it affect the MPG? coz lately my car has been eating so much gas.

[Ben]

Originally Posted by albertgunit101

yeah youre right. possibly. so what do i need to do. if i clip te1 and e1 even w/o the CEL will it give me the code?

Yep.

Originally Posted by albertgunit101

if the egr is dirty will it affect the MPG? coz lately my car has been eating so much gas.

In theory, everything that causes a CEL (except a speed sensor or something like that) will effect gas mileage.

[albertgunit101]

ok. ill check it out.

[albertgunit101]

so i went to my car and diagnose it. it gave me code 21 which is the O2 sensor. this sucks coz i just changed it when i put my headers in. i guess toyota does not like it when you put aftermarket parts. coz i just put headers on my friend's celica which also have 5sfe. and the cel went on his car too. but it was fine before the headers. so he have to change the O2 sensor too.

thank you again ben and sylvan. so now i know that you can diagnose it even w/o the CEL light on.

[David_K]

What header and where'd you put it?

Did you use the EMS/XS/SSAC header?

If so then use the second o2 port farthur down the line. The first one gets all carboned up sometimes.

[albertgunit101]

how can i use the other lower one? my car came originally here in illinois. i only have one o2 sensor. and its the one that requires two bolts.

[albertgunit101]

the O2 sensor for the lower one is a 1 wire O2 sensor. while the top part is a 2 wire O2 sensor. is there a 2 wire O2 sensor for the lower one?

[albertgunit101]

i found some 2 wire oxygen sensor for the lower one. can i rewire that for the top 02 sensor? and i have a long tubes ebay headers.

[albertgunit101]

i just found out that the 2 wire sensor i found for the lower o2 sensor have a black and white wire. but the upper part of the o2 sensor have blue and white. can i rewire white to white and black to blue?

[Ben]

You need to find out what each wire is for (heater circuit, sensor element) and match it to the connector. On the instructions for the new sensor, does it specify which wire is for what?

If the white wire on the engine harness is for the heater circuit (not sure if it really is), match that for the heater circuit wire on the sensor.

[albertgunit101]

disregard my previous postings about having two wires. i just found out it only have one black wire. i was arguing with the person who is helping me out at autozone. she insist that i should have 2 oxygen sensor one after and before. but i told her that when i bought my car it only came with one. and that is the before catalytic. and she argues that someone rig out the second o2 sensor the one after the cat. but i inspected the stock exhaust before i put the headers and it does not have a bung for a second o2 sensor. so it clearly means i only have 1 oxygen sensor. and i told her that my old 92 civic cx also have one o2 sensor. and that is right at the cat. and my civic was bone stock coz the last owner is a 42 year old guy who does not care about modifications and he only drives it to and from work coz he lives far from his work and the civic gets up to atleast more than 35 MPG.

sorry for the long post. but i bought a universal o2 sensor with one wire and im going to put that on the second bung the lower one. hopefully this will end my CEL, fingers cross. im getting the o2 sensor on tuesday.

[albertgunit101]

i just finished relocating the o2 sensor to the loewr one. it runs the same which is good. i thought it would change a bit coz it was on the lower section meaning it will burn gas a bit late or something. ill see what will happen.