Quote:
Originally Posted by consultIII
can you get a scanner and view live data. Hard to know with out information. If you can get one; here is what to do.
view iac counts and fuel trim.
sounds like a fueling issue not spark....why...doesn't happen cold in open loop (engine not using o2 data and idle speed is higher).
Also a/c engagement will demand a higher iac opening position.
View fuel trim...nissans read as 100% as ideal (at least with factory consultII scan tool)...readings more than +/- 10% indicate a fuel control issue possibly relate to maf (you stated you installed a K&N filter...nissan maf sensors are very sensitive to contamination...they don't have a burn off circuit...if you installed a wet filter (oiled) the oil has contaiminated the maf. Aftermarket air filters are bad as they don't filter fine enough. Never put anything but a factory air cleaner in a Nissan. Otherwise will wreck the maf which is a $400 part (in Canada are cheaper in USA). Open the air filter and wipe your finger across the mesh screen before the maf. If you can wipe off residue the maf is dirty...you can try maf cleaner spray but it may not recover.
check for vacuum leaks...view trim at idle if no good rev engine to 2000rpn and keep it there and see if fuel trim comes back in spec if yes you have a vacuum leak. locate leak by spraying around intake with brake cleaner...when idle changes you have located the leak...inspect the air snorkel for cracks or leaks that occur before the maf
If trim ok check iac counts... should be within 5 - 50 counts
let me know what you find
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K, I bought an obd2 interface for my laptop and hooked it up and I drove for about 10 mins and recorded live data.
My Long trim Fuel is pretty much all the time at between -20 and -25 or around there except under very hard acceleration when it increases to almost positive levels.
The Short trim is mostly negative and it only goes positive under hard acceleration.
I will check for vacuum leaks and I will check the MAF.
Another weird symptom here. Once the engine is warm, in P or N I cannot accelerate anywhere between 1500rpm/5000rpm. If I only accelerate a little (lets say trying to aim for about 2000 rpm) the rpm jumps up and down fast between 1500 rpm and 1800 rpm. I accelerate further, still the same jumping up and down of the rpm in the same range. I go further down with the pedal and then the rpm jumps to over 4000 and then within half a second it falls down to the same range 1500-1800 and it keeps on bouncing up and down. It is really frustrating right now...
Here is the video I recorded:
http://www.youtube.com/watch?v=BRA8YSTYe5I
Also, the MAF readings seemed to go along with my accelerator (more pedal more gals of airflow per minute) so maybe my MAF is not bad...
And also my exhaust smells like when a vehicle it just started, even if I just drove it for 30 mins, so I think its running rich.
I still have to analyze more the data I recorded on my laptop through the OBD.
Still no check engine light on. Any ideas?