Tachometer RPM issue after installing tune and CAI

[LordBritish]

Recently I installed a JLT CAI Series 3 along with a Bama Race Tune in my Automatic 05 GT (PCM code BKT2).

It all went well except that my tachometer is not showing the correct RPMs. On Idle, the tachometer is showing 0 RPMs which is obviously incorrect. It might be under reporting RPMs by about 1000 which is why at idle it shows up as 0 RPMs.

Here's a video of me starting and reving my car:
https://www.youtube.com/watch?v=-mE9T6Mtwz4

Notice how the needle goes down to zero RPM !!

I'm thinking this might be a tune issue. I wouldn't think the JLT CAI kit itself could cause the RPM reporting issue.

I tried reverting the tune to stock to see if the problem would go away but I wasn't able to start the car properly since the air/fuel mixture was all wrong with the JLT CAI still installed - it just stalled on start up. I'd have to put back the stock airbox in order to test this fully which is a complete PITA.

What do you folks think is causing this RPM reporting issue?

And can it cause other issues such as shift point problems ?

TIA.

 

[Wes06]

Maybe stepper motor went out at a bad time?

 

[LordBritish]

Maybe stepper motor went out at a bad time?

I would think a bad stepper motor would cause the tachometer to not work at all but clearly mine is working as you can see from my video, it's just not reporting the RPMs correctly (at least at idle).

I'll only really know when I revert the car to stock (tune and airbox). If the problem goes away after doing that then the only culprits or either the tune or the CAI kit itself. How can a CAI kit cause tachometer issues?

My speedometer is working correctly, no problems with that. Only issue is the tachometer.

 

[Wes06]

na, our stepper motors act retarded sometimes, they "work" but show odd levels of fuel/rpm/speed etc.

Try stock tune and air/box, if it fixes itself its something odd in the tune and ask for a revision

 

[NickD87]

I would flash back to stock again and then pull the battery to reset everything (car should run with different intake)
otherwise I would load one of the other tune bama gave you, either there is something wrong with the tune, the way it was loaded on the device or when transferred to the car

I have had weird issues before and simply reloading the tune has often worked, try loading the other tune and request new ones from AM if it works

 

[JeremyH]

People still use bama tunes?

 

[LordBritish]

People still use bama tunes?

Some do. If this happens to be their fault (unproven), they had better fix it. We'll see soon.

 

[fdjizm]

People still use bama tunes?

My bama tune is still running hard

 

[deebo05]

looks like a stepper motor issue. It should not cause a shifting issue.

when mine went out the tach would hit 8k cruising 65-70 in 6th keep going and never thump the limiter.

never seen a tune cause that, but stranger things happen with these things everyday.

 

[Dino Dino Bambino]

What do you folks think is causing this RPM reporting issue?

Stepper motor.

 

[LordBritish]

Stepper motor.

How do you fix a stepper motor?

 

[stkjock]

Search...

http://s197forum.com/forum/showthread.php?t=28571&highlight=Tach+stepper+motor

Just sayin......

 

[LordBritish]

Search...

http://s197forum.com/forum/showthread.php?t=28571&highlight=Tach+stepper+motor

Just sayin......

Oh man, that looks hard.

If it turns out to be a stepper motor issue, I'll just live with it. After all, incorrect RPMs are not a huge issue for automatic transmission drivers.

 

[Wes06]

You can do it yourself. Or if you have a spare car people on eBay will repair for you.

Or go to the dealer and get bent over. Lol

So have you not tried returning stock tune to see what that does?

 

[LordBritish]

So have you not tried returning stock tune to see what that does?

Not yet. I tried with my JLT CAI Kit installed but it stalled out. I'll try putting a plastic bag over part of the cone filter to restrict airflow which might make it closer to stock and then it might trick the car into starting. We'll see.

 

[JUSTA3V]

Really, it takes what 20 minutes to re-install the factory CAI and that's too much for you to see if it fixes your issue?

A plastic bag?

I say just live with it. It can't be bothering you that bad.

 

[06silverbullet]

Really, it takes what 20 minutes to re-install the factory CAI and that's too much for you to see if it fixes your issue?

A plastic bag?

I say just live with it. It can't be bothering you that bad.

20 takes 5 minutes...

i must say had a friend use bama... i will definitely not use their tunes.

 

[Dino Dino Bambino]

20 takes 5 minutes...

i must say had a friend use Obama... i will definitely not use their tunes.

I definitely wouldn't use Trump tunes either. . Brenspeed FTW.
As for reinstalling the stock intake, yeah, it's a 5-minute job.

 

[RJdude3]

My bama tune is still running hard

+1 to that!

 

[LordBritish]

Well I reverted the tune to stock however the tachometer issue remains.

So I guess my stepper motor for the tach needle is flaking out.

Bummer

I'll live with it for now since I'm afraid of trying to fix it myself. I'll probably break it if I try to fix it myself.