Engine management Light

[Kaveney]

Hope some one can point me in the right direction .

 

I have had some HFC and a Y pipe and an Uprev fitted weeks ago and on Saturday the engine management light came on so I did the peddle dance and cleared this but today after 80 miles its back on again .

 

I have a OBD2 reader so will check tonight but is this going to be the O2 sensor and will i need some spacers .

 

The car runs fine pulls well just to note .

 

Thank

 

Alan

[Tricky-Ricky]

Cat monitor light should have been turned of permanently if its had an up-rev remap, check back with whoever did the remap.

[Keyser]

Cat monitor light should have been turned of permanently if its had an up-rev remap, check back with whoever did the remap.

 

What he said - spacers should do the job as well though

[Rock_Steady]

I put on spacers and I haven't had a up-rev yet and the light is out. Got my spacers from Clark motorsport.

Edited November 26, 2014 by Rock_Steady

[KyleR]

As Ricky said, I was under the impression that during UpRev the EML light for 02 sensors is permanently switched off, but I'm hearing quite a few people recently having tunes and then getting lights.

[Kaveney]

Ok the code is a P1273 so not what I was thinking .

 

Any thoughts .

 

This has only come on after the HFC , Y pipe and Uprev .

 

Alan

[bytespc]

http://engine-codes.com/p1273_nissan.html

 

There you go some light reading

[Kaveney]

So could be lots of things .

 

Ok I will have a look for any leeks but the car still runs very well ?

 

Alan

[Stutopia]

I saw that after uprev, it was down to a crack on the weld on the cats leaking gas. Defo go back to whoever did the uprev and get it looked into.

 

General question, the link a couple of posts up refers to "lean shift" for this code but wouldn't an exhaust leak cause it to run rich?

[Tricky-Ricky]

I saw that after uprev, it was down to a crack on the weld on the cats leaking gas. Defo go back to whoever did the uprev and get it looked into.

 

General question, the link a couple of posts up refers to "lean shift" for this code but wouldn't an exhaust leak cause it to run rich?

 

Exhaust leak before the lambda will result in the lambda reporting a rich mix due to more un burned oxygen being read, but the CEL code will be because the ECU has gone over compensation limits. and cannot compensate fueling.

[Kaveney]

It seems to come back on after 80 miles or so after a reset .

 

Would this not point to something other like the O2 sensor ?

 

Alan

[Tricky-Ricky]

It seems to come back on after 80 miles or so after a reset .

 

Would this not point to something other like the O2 sensor ?

 

Alan

 

Depends which bank, only the front O2 sensors are used for closed loop fueling adjustments, the rears are just for cat condition monitoring unless the is a problem with the front bank and or other conditions, but generally you can actually run without the rear set with no problems.

[Stutopia]

It seems to come back on after 80 miles or so after a reset .

 

Would this not point to something other like the O2 sensor ?

 

Alan

 

Depends which bank, only the front O2 sensors are used for closed loop fueling adjustments, the rears are just for cat condition monitoring unless the is a problem with the front bank and or other conditions, but generally you can actually run without the rear set with no problems.

 

Thanks for the informative answer Tricky.

 

With regard to closed loop feeling adjustments, does these adjustments operate in the same way pre and post uprev?

[Tricky-Ricky]

It seems to come back on after 80 miles or so after a reset .

 

Would this not point to something other like the O2 sensor ?

 

Alan

 

Depends which bank, only the front O2 sensors are used for closed loop fueling adjustments, the rears are just for cat condition monitoring unless the is a problem with the front bank and or other conditions, but generally you can actually run without the rear set with no problems.

 

Thanks for the informative answer Tricky.

 

With regard to closed loop feeling adjustments, does these adjustments operate in the same way pre and post uprev?

 

Yes but the fueling tables base figures are altered, to give better power.

[Kaveney]

If the problem was a leek would this just not throw up the engine light straight away as when the fault is cleared the light seems to come back on after 80 miles or so ?

 

Also the car drives fine and the MPG is normial so would this not rull out a fault O2 sensor

 

Alan

[Tricky-Ricky]

It could be that there is a fault with the primary O2 sensor and because of this the ECU is trying to read the cat sensor, but because this is in a high flow cat its throwing the fault code.

The default for a faulty O2 sensor is to run the fueling slightly rich, but not by much with an N/A engine so its unlikely that you would notice a big difference, is yours a UK or JDM car?

[Kaveney]

2005 UK car

[Kaveney]

UP rev was done at Abbey along with the Cobra HFC and Y pipe

[Sam Mcgoo]

Your fault light is suggesting a lean condition as read by bank 1 sensor 1 (front sensor drivers side).

The reason its taking 80 miles to come back on after a reset is most likely that the ecu is able to compensate for any fueling errors using the Fuel Trims. But once it reaches its maximum adjustment it will throw the light on as it can no longer compensate.

 

You say you have an OBDII reader. Plug it in and get some more information BEFORE you reset it. Look at the real time data display and look at the short and long term fuel trims. , I suspect that LTFT bank1 and LTFT bank2 will be quite different values.

 

Let us know what you see.

 

Also, - DO NOT drive your car hard until you have got to the bottom of this. If your car IS running lean on one bank you could do some serious damage if driven hard.

[Tricky-Ricky]

The ECU would have reached adjustment trim limits way before 80 mls if the main lambda is out of adjustment the ECU starts to try and read the cat sensor to determine if its a sensor problem or something else.

[Sam Mcgoo]

The ECU would have reached adjustment trim limits way before 80 mls if the main lambda is out of adjustment the ECU starts to try and read the cat sensor to determine if its a sensor problem or something else.

 

Depends how far out of calibration/dirty the sensor is - however, I'm not saying the sensor is at fault I think the sensor may be fine, and something else may be causing the lean reading in bank 1. Vacuum leak, exhaust leak, injector issue etc...

 

It could have been a problem that was there before the mods and Uprev and the ECU could compensate for it, but after tuning (which usually means running the car a little leaner in order to gain more power) the fuel can't be trimmed enough.

Or it could be a new fault such as that listed above.

 

The fact is these can be very difficult faults to trace without more information, equipment, tuning ,dyno etc and from home your limited to what you can do.

 

Regarding the 80 miles, I've had a few issues on the zed over the years with fueling and I have had a similar thing happen. Mine had a lean spot in the map that would only materialise approx 60 miles after reflashing the ECU due to the ecu being able to compensate for a while before it had run out of adjustment.

 

You have two main choices 1. Contact the tuner and ask his opinion /advise on the matter. 2. do a few checks yourself to try and find it yourself.

 

If I was you this is what I would do -

 

1. Read the fuel trims with your OBDII reader and see what it tells you. eg - if Bank1 is +ve **% and Bank 2 is -ve **% (you would expect them to be roughly the same or at least both +ve or both -ve. Make a note of what ever you get.

 

2. Get under the car and swap your two front sensors over (they are in the downpipe before the CATs) - so fit drivers side to passenger side and vise verse. While your there look for any exhaust leaks and deal with them accordingly.

 

3. Reset your ECU and go for a drive. It may need to be 80miles again for the EML to illuminate, or you could just keep an eye on your fuel trims to see if its heading in the same direction. If you get the fault back, but its on Bank 2 this time, then the Sensor is probably your issue. Get a new one and try again. If the fault remains on Bank 1, then there is another issue.

 

4. Look for Vacuum leaks around all pipes, joints,hoses, plennum etc. A good way to do it, is to remove your intake and block the pipe (air tight). remove a vacume hose from the plenumm and using a pump/airline/tyre inflator pressurise the plennum to 5-10psi and see if it holds. Go round all joints, connections hoses and gaskets with some soapy water and brush it on looking for bubbles. If you find any, fix them.

 

Start with the above and let us know what you find regarding the fuel trims in stage one.

 

Good luck.

 

Edit - I'm not pretending to be an expert but over the years have gained some experiance and I have managed to sort my own similar issues in this manner.

Edited December 1, 2014 by Sam Mcgoo

[Tricky-Ricky]

Vacuum leaks will effect both cylinder banks,unless its from plenum to intake interface, and so would result in both lambdas reading lean and needing to compensate, you will also notice that the fuel trim will actually vary a fair bit between banks 1 and 2, IE you would quite often see + and - on each bank at the same time, not by much but still not exactly as you would expect.

I had mine on live monitor and data log via ECU Data-scan, and I also had a couple of wide bands fitted to mine and was surprised at the differences.

Exhaust leaks will make the lambda read a rich mixture for that bank, and so the ECU will chuck in extra fuel, it could be a dirty injector, but as I said before its just as likely to be the main or secondary lambda issue.

 

Swapping the primary lambdas is a good idea, but they are a pain to get at and usually difficult to remove, but just monitoring their behavior should tell you if they are OK, as they usually fail by sticking at voltage so will read lean to force the ECU to run rich for safety.

[Kaveney]

Ok I will have a look at the few points .

 

OBD2 reader is just a code reader so no live data .

 

Also the light now comes on every 3-4 miles and at low RPM small throttle and each time it has been cold ie 5-6 deg .

 

Wold this point more at the O2 sensor .

 

Also I thought the code was for the Passenger side ?

 

Alan

[Mark@Abbey m/s]

It is a closed loop DTC , it is a front sensor so you cant run spacers on the front sensor.

 

It will not harm your car at all because once the car is in open loop it will not use the front lambda sensor readings

 

the code is a LEAN shift , it means the ECU has read a AFR figure that is outside a parameter for a certain amount of time.

[Mark@Abbey m/s]

The ECU would have reached adjustment trim limits way before 80 mls if the main lambda is out of adjustment the ECU starts to try and read the cat sensor to determine if its a sensor problem or something else.

 

if the car was at its maximum trim level is will flash the DTC light to say that there is a serious issue and should put the car into Limp, as the car just illuminates the DTC is minor warning issue.