EAT chip threw o2 code... (A bit waffly)

[e34.535i.sport]

Hey - As we all know I put an EAT chip in a few months back and I was pleased with the results at first and people told me it would get better as time went on... I'm sure 'normally' this is the case but instead my car began to run badly and it lost performance rather than gain. The idle got worse and worse and it lacked a lot of power. I didn't suspect the chip at all as it was so gradual and it worked fine at first so I checked all other options...

When my good (and only :D) friend Whiskychaser kindly offered to let me use his code reading software it showed that the car had threw an 02 code and I posted a thread, you might remember. The funny thing is - my car is non-CAT and doesn't have an o2 sensor! (No vacuum leaks etc!). We erased the stored code.

Now, under recommendation I changed the chip out to see if that was the cause of the poor running due to the numbers not being the same as on the DME case... I checked, and they are exactly the same. However, after changing the chip back to the original the car felt much better and still does a while on- much more power, much smoother idle.

So as a controlled test we got the car back on the code reader and no code with the original chip in (as I excpected due to the car running really well).

Question is - Why would the chip do this? Are these chips built for US cars - i.e with CAT/02 sensor so when it doesn't get a reading from mine it throws it into open loop or something? I did buy it from a US member on the board as he sold his car... I've PM'd and emailed MarkD at his website but haven't had a response yet so I thought I'd post.

I'm hoping Mark will get back to me and have a suitable chip I can exchange it for or something as people do rave over them and see really good results...

[Ferret]

MarkD should have the records as to exactly what that chip is (assuming it's one of his :) ) yours was manufactured two years before cats became a legal requirement in this country... it could have been at a time where bmw were flip-flopping between installing them and not.

It might be worth checking to see if there's any O2 sensor wiring been cut back/hiding under the car to see if someones done a professional de-cat on the vehicle. There seems to be a lot of that happening around the uk - people decatting bimmers with the far fetched hope that it'll increase performance.

I recently worked on a 540i/6 that had been professionally de-catted - however the owner could get away with it because the vehicle was LPG converted - ran with an almost perfect emissions score as well. (Was just prone to trying to blow your face off when coming on-idle after high RPMS, anti-blowback valves for the win.)

What you should do I suppose is take your proof of ownership into a bmw dealer and ask if it was born with a cat or not, that'll mop that one right up. It's just then a case of figuring out what the chip is that you've got.

Even if the ECU numbers match, yours could have been slightly adjusted for no O2 or something like that.

Cheers,
Andy

[e34.535i.sport]

MarkD should have the records as to exactly what that chip is (assuming it's one of his :) ) yours was manufactured two years before cats became a legal requirement in this country... it could have been at a time where bmw were flip-flopping between installing them and not.

It might be worth checking to see if there's any O2 sensor wiring been cut back/hiding under the car to see if someones done a professional de-cat on the vehicle. There seems to be a lot of that happening around the uk - people decatting bimmers with the far fetched hope that it'll increase performance.

I recently worked on a 540i/6 that had been professionally de-catted - however the owner could get away with it because the vehicle was LPG converted - ran with an almost perfect emissions score as well. (Was just prone to trying to blow your face off when coming on-idle after high RPMS, anti-blowback valves for the win.)

What you should do I suppose is take your proof of ownership into a bmw dealer and ask if it was born with a cat or not, that'll mop that one right up. It's just then a case of figuring out what the chip is that you've got.

Even if the ECU numbers match, yours could have been slightly adjusted for no O2 or something like that.

Cheers,
Andy


I'm hoping it is one of his!!!

Mine isn't converted to LPG it's just normal petrol injection and the emissions scores are exemplary! The full exhaust system looks almost new and is OE - maybe fitted by BMW themselves? I can't find anything in the way of wires for the sensor and I've searched thoroughly, but I will check with the dealer to be sure. It has passed an emissions test with flying colours in my ownership too which is a good indicator.

I'm kind of glad mine hasn't got CAT/o2 as they're costly when they go wrong.

It's a good point you make on the ECU numbers, I wonder if Mark will be able to/willing to just adjust the chip to suit?

[leicesterboy15]

I'm sure that for pre-1993 cars a cat was an option, but it reduced power and cost extra so very few people fitted them, if you get a list of the options fitted to your car from the dealer it should show up either way. After 1993 as ferret says they were compulsory.

[The Bigfella]

I'm hoping Mark will get back to me and have a suitable chip I can exchange it for or something as people do rave over them and see really good results...

Good luck - I've been waiting for over two years to get two working chips from him

[632 Regal]

Haha!
Good luck - I've been waiting for over two years to get two working chips from him

[e34.535i.sport]

Good luck - I've been waiting for over two years to get two working chips from him

Hmmm that's not good, I was keeping hold of it to see if he'll fix the problem - otherwise I may as well sell it to someone who can get the full benefits from it. I'll hang on to see if he get's back to me but I won't hold my breath cheers!