A Nissan Sentra Forum banner
1 - 13 of 13 Posts

·
Registered
Joined
·
84 Posts
Discussion Starter · #1 ·
Problem: After this years rebuild/reseal etc. Car was running fine (took it up and down the lot at work a few times did a few pulls up to 1-2psi boost..short distance). No real problems showed up in about an hour of playing around.

Took the car out to storage (vehicles in an unheated garage now)

Came back a few weeks later to start the car up, battery was dead, so I put it on a slow charge (12v 5amp) overnight.

Next morning I start my car, and from the time that it starts until its shut back down again, It idles/revs between ~1500 - ~2750 rpms just up and down without any hesitation.

Conditions:
- Tried Idle Air Volume Learning with Snap-on Solus
- Idle relearn wont take, itll idle and as soon as throttled up, starts again.
- Checked/Cleared DTCs no codes remained or came back
- Replaced TB
- Checked/Replaced Cam and Crank Position Sensors this year
- Checked/Replaced MAF/TB pigtails in hopes of correcting the problem.
- Cleaned MAF
- Traced all TPS related wiring and found nothing wrong.
- Checked all grounds for secureness.
- Reverted AEM FI/c with the bypass harness back to stock settings and still does it.

Ideas:
- Bad IM gasket even though new/torqued properly
- Bad ECU, but no codes?

Im running out of ideas and have NEVER had this problem before in the last 2 winter teardowns.
 

·
Premium Member
Joined
·
11,452 Posts
How are your vacuum and wideband gauges reading at idle? That would eliminate a vac leak.
Seems like everyone is having idle issues these days :thinking:
 

·
Premium Member
Joined
·
11,452 Posts
Rich/lean? So it's only a narrowband gauge? Vac sounds good though.
Are you guys holding the clutch down during the relearn process?
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #8 ·
im codeless, but had an idea to pop off terminals and connect them for an hour or 2 to drain the capacitors in ecm to try and erase the memory and see if itll try and relearn from fresh. last resort :/
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #12 ·
thats my next step, i just feel like im shooting blanks i considered d/c battery and connecting terminals to drain ecu memory and start fresh.
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #13 ·
close if need be.

Found the problem, it was rooted to ECU.
For some reason the old stored data for the idle and tps closed position learning wasnt clearing and was conflicting with new data. After I cleared the old data using a snap on solus, and did the idle relearn everything is running normal, thanks for the help!
 
1 - 13 of 13 Posts
Top