Advice Needed - Check Engine Light

[davidv10]

I bought my Zed about 2 years ago now. I will say its an import, but not sure that will make any difference.

 

I bought the car already decatted and with an aftermarket exhaust system. The check engine light never made an appearance throughout the whole time, even with me changing the catback section a couple of times throughout that period.

But now the engine check light has decided to make an appearance and the code the garage read was O2 sensor in bank 1 (i think thats what they said). Which is the sensor for the cats i believe/i was told. The garage said thats because there are no sensors giving a current as its decatted, so it will always cause the light to come on. But its been decatted for 2 years without having the light come on.

Does anyone have an ideas as to why it would start coming on with nothing changing..? Or how I can get it to go and stay away?

The only thing the garage advised was thatwhen i told them  i started using Premium Unleaded a week or so before the light came on, and they said it could be this as it can happen with Japanese sports cars especially imports..? So i emptied the tank and refilled with normal BP unleaded and had the light reset a couple of days after. But within a day or so it came back on.

Any ideas or advice on how to get the light to stay away will be greatly appreciated!

I have got my hands on a stock Y-pipe and will get some stock cats if I have to, but they arent cheap so would rather just get rid of the light.

Thanks in advance!

Edited May 4, 2018 by davidv10

[longsh07]

Hi David,

 

First off, all UK cars should be run on premium fuel (97 octane or above) all the time to avoid knock. Given Japanese imports are used to running on even higher grades you should certainly stick to the premium stuff!

 

Don't suppose the garage mentioned which sensor it was as there are four, one pre-cat, one post cat, then the same on the other side (bank) of the engine.

The code (if you have it) will refer to one of the four sensors, like so 'bank x, sensor x'. It should also say rich or lean condition I believe which will help diagnose the issue.

 

As for why it would suddenly come on, it could be the fuel is cleaning out a lot of crap from the engine/exhaust but I'm not expert so take that with a pinch of salt.

 

And for getting it to stay off, has the car been remapped? If its the post-cat sensors, then these can be switched off (ignored) during the mapping process to solve this. Otherwise, you could try fitting O2 sensor spacers as these can help to fool the system into thinking its fine.

 

HTH  

Edited May 4, 2018 by longsh07

[veeg33]

When you said no sensor, did previous owner removed the O2 sensor completely? If so, i would check the connector for the 02 sensor. I might be wrong but suspect the previous owner replaced the sensor with a dummy connector with a resistor across it to cheat the system thinking there is a sensor, the resistor is now faulty hence your zed is giving you an engine code now.

[MDMetal]

3 hours ago, veeg33 said:

When you said no sensor, did previous owner removed the O2 sensor completely? If so, i would check the connector for the 02 sensor. I might be wrong but suspect the previous owner replaced the sensor with a dummy connector with a resistor across it to cheat the system thinking there is a sensor, the resistor is now faulty hence your zed is giving you an engine code now.

Hello! Wasn't aware of this. What resistance is usually needed? I'm sick of staring at my CEL with my Berk HFC's!

[davidv10]

Thanks for all the information guys! I dont know the exact code im afraid. I may try and get a code reader to find out.

 

Unfortunately i dont know exactly what was done when the system was fitted, as im the second owner since it was done. But i believe its had the uprev map done.

 

How much/how easy to fit are these O2 sensor spacers/dummy resistors?

 

Ill have a look for some Youtube videos as well.

 

Also, do you know of any good garages Near Norwich that would be able to fit this sort of thing? As its a bit niche and not all garages would want to do it.

[veeg33]

On ‎04‎/‎05‎/‎2018 at 16:52, MDMetal said:

Hello! Wasn't aware of this. What resistance is usually needed? I'm sick of staring at my CEL with my Berk HFC's!

Some info here --> https://my350z.com/forum/engine-drivetrain-and-forced-induction-diy/524603-o2-sensor-simulators-complete-guide.html

[PPod]

I've got a faulty sensor and been running the z with engine light on for about 3 years  no problems and passes mot each time. 

[Ekona]

It won’t from May 20th onwards, that’s a specific fail now. 

 

Also with the light on permanently you've no idea if you've got other faults...

[MDMetal]

I hate having the light on all the time it makes me think there's a constant issue when there clearly isn't! 

[MDMetal]

ugh really? Mines always on and whenever I've asked before Everyone just says up rev it which I didn't want to do just because I've got HFC's. I guess I'll try replacing the sensor or building the dummy circuit.