My car rev currently (MY97) keep hunting around, up and down when idling. At around 600 rpm to 800 rpm......going up and droping down constantly. Could this be a faulty Lamda? Can i check the Lamda by just disconnecting it? Recently i just change my injectors ..... alot of fuel went into the manifold...... Could this kill the Landa sensor?? . Usually my A/F ratio is reading on the Apexi turbo timer is at 14.2 now only 12.1 ..... Thanks in advance.

 

It could be a number of things such as MAF, ISCV or Lamda.....Get it on a diagnostic to save buying many expensive sensors

 

Thank you for your reply.
Should i bring to the Subaru dealer? There is reading from the MAF......when i disconnect....no readings......also when i disconnected the MAF plug.....the engine also idle rougher ..... I have check many things........(spent 4 week ends)...driving me nuts now.

 

maf will cause bad "hunting" up and down etc......sounds like it is your lambda sensor ans poss maf starting to play up !

matt

 

Will check it out this week end, thanks guys..... Will update post when prob solve.

 

Hi guys/gals!
Problem not solve yet, i have just replace wit my friend MAF...still...same prob...idle keep going form 600- 800 rpm.... .
1. Could it be a Lamda sensor (oxygen sensor)?? I am having Apexi tt...it's displaying A/F .....initially from 14.1 then drop down to 12.9. Can it be the Lamda sensor is faulty?
2. Could a 550 CC nissan injector causing this?? Original resistance injector is 11.5 Ohm .... nissan injectors is 12 Ohm......

Ahhhhhhhhhhhhhhhhhhh.......dont really know what to do next!!!!
Checked injector and vacumm leaks, fuel pressure. Replaced MAF and reset ECU too....

 

As above , Have you gone for bigger injectors ?? As they will push in more fuel making your Afr change, The stock Ecu can only adjust so much & this could be the cause of the lumpy idle

Dean

 

Hi Andy and everyone!!!
Spot on!!!!!! I just been to the dyno tune place everything is fine........ The car is runing ways to rich therefore having funny idling. I read alot of thread saying 550 CC injectors are idling fine when putting on ....... Well totally WRONG ...... From 380 CC to 550 CC required after market computer to re-adjust the fuel. Otherwise will idle the way i described. Also even after the dyno tune the idle still doing it but very very minor.
Poor me spending 5 weeks to see what's wrong (for nothing). I also learn a couple of things which may come in handy if someone wants to do in the future.
1. To check if the injectors are leaking, put a gauge on the output of the fuel filter ..... run car for 1 min....turn off.....if pressure doesnt drop in 5 min......no leaks.
2. Nissan injectors are fully compatible, as long as they are the same shape, high impedence and should read around 12 Ohm (7-18 Ohm is fine- unconfirm).
3. Most injectors plugs are the same, just the slot to plug in is different. Just go to the wreckers and get the plug and cut the slot.

There is other things as well.....but got to go check out my car on the road now..... Any question can PM me......i will try to help out if i can.