Check engine light. WTF!

[-ToM-]

ok guys, so last couple of days ive been getting these engine light warnings coming up whilst driving along.

After about the 3rd day in a row, i decide to give it a check.

I bridge the 5 and 6 jumper, and whaddaya know, code 12, system pass ok!.

Is there something im not doing right? Basically i got it home, turned it off, grabbed a paper clip, went back to the car, and got code 12.

The only thing thats changed recently is my injectors, but they all seem to be seated properly and no leaks.

any ideas?

[hako]

Pull the engine fuse for 30 secs to reset the ECU and see if the CEL comes on again. I guess you know that when reading codes you get 3 lots of 12 and then whatever errors come up....some people quit when they see a 12.

[Vee-ard]

code 12 will flash 3 times before showing anything else. Try again. If the engine light comes on, it IS recording a fault.

[-ToM-]

Code 45 - Oxygen Sensor Rich (O2)

just had that replaced 3 weeks ago in an expensive service :S

[Vee-ard]

I hope it wasnt expensive purely because you needed the oxy sensor changed, its a 5 minute job, and a $90 part at best.

Its actually easier to change than your oil.

[-ToM-]

oxygen sensor rich wouldnt be the oxygen sensor though would it? it would have something to do with the fuel supply?

[Vee-ard]

an oxygen sensor sits in your exhaust pipe and detects how much oxygen comes out after combustion.

It can give false rich or lean readings based on how crusted up with carbon and crap it is.

If the new oxygen sensor reads rich as well as the old one, then I would start looking into other things, such as checking for leaking injectors or advancing your timing.

[-ToM-]

never had a problem before. As i said, only really started popping up after i changed my VR injectors to VX injectors 3 days ago. I was told they run on the VR engine fine, could they be causing it to run rich?

[Vee-ard]

I always thought that the ECU dialled back larger injectors to suit pre-set flow rates, but this could be causing your rich reading I would guess. Best to wait until someone more educated adds his/her 2 cents.

Larger injectors is never a good idea unless you NEED them, as it does nothing for power at all unless you have the tune to suit.

[-ToM-]

As far as i am aware, they flow the same, but have a different spray pattern. That and they were in better nick

[-ToM-]

had a chat to my mate, and he said the ecu shouldnt be feeding it any more fuel then what the other injectors where. He also said that if they werent fitted properly then there would be leaks, and id say would give a lean reading instead of rich.

1 suggestion was to disconnect the battery and reset the ecu, and see how it goes. Failing that, putting the VR injectors back in and seeing if that stops it running rich.

[Vee-ard]

"had a chat to my mate, and he said the ecu shouldnt be feeding it any more fuel then what the other injectors where"

Thats pretty much what I said. but how do you figure more fuel = leaner mix?

I'd go with your course of action though.

[-ToM-]

"had a chat to my mate, and he said the ecu shouldnt be feeding it any more fuel then what the other injectors where"

Thats pretty much what I said. but how do you figure more fuel = leaner mix?

I'd go with your course of action though.

Sorry i kind of continued on. I was agreeing that the ecu should be setting the flow rate, but then i was implying that if the installation of the injectors where faulty, then there would be leaks and the engine would run lean due to less fuel. correct?

ecu was reset anyway, back to code 12 only. Well see how it goes

[Vee-ard]

a leaking injector means it leaks fuel into the chamber even when not pulsing, so that would be more fuel in the chamber come combustion time?

not leaking as in leaking out externally.

[-ToM-]

i wouldnt think so. The injectors only sit less than a cm into the chamber, and into the fuel rails, and everything in between is dry?

And if it was leaking into the chamber when not pulsing, wouldnt the car be chucking codes almost immediately after startup? usually its been 10-15 minutes into a drive on average.

And wouldnt the fuel pump need to be on for that to happen?

[Vee-ard]

You're missing what I'm saying.

Normal injector = squirt.stop.squirt.stop.
Leaking injector = squirt.drip.squirt.drip

You arent going to see a leak by checking the outside.

[-ToM-]

so how would one test that? i spose just put the VR ones back in and see. Performance differences would be squat anyway

[-ToM-]

Well, seems like the reset might have done it.

let the car idle for 15 minutes, drove it 10 mins to the gym. Let it sit for 1 hour. Drove to the city and around a big loop for 40m including 25, 40, 60 and 80km/h. Car didnt surge or idle rough, or no backfires (wasnt doing it before anyway). Hopefully resetting the ECU has forced it to adjust something thats fixed the issue

[Vee-ard]

Sounds good. Resetting it probably would have gotten it used to the different injectors.

Nice one.

[-ToM-]

Fingers crossed. Time will tell

[-ToM-]

engine light came back on, so the old injectors went back in

[Kurtp]

If it comes back on, see if it turns off if you turn your car off and start it up again.

[-ToM-]

yeah it does. Already tried that. Turn it back on and it was gone. Drive for a bit and then it comes back.

[hako]

Did you check to see what fault codes were logged by the engine light?

[-ToM-]

45 every time. Oxygen sensor rich