Idle Issues

[redram2007]

Every since I installed my 08 intake manifold, airram tb adapters, f&b 72mm tb, and my custom tunes my idle has been kinda wacky. After the truck has been running and warned up it will sometimes surge when I put it in park or neutral. It also will not idle up on cold startup like it used to, instead it starts out around 650-700 rpm and stays there. I have replaced the IAC valve, TPS sensor, checked for vacuum leaks, rechecked torque of intake manifold and tb mounting bolts, and returned the pcm back to stock. Anyone have any suggestions as to what my next step should be? These parts have been installed for about a year now and I just can't figure it out?

 

[KGBIGCOUNTRY]

Can you get it to idle up with the defroster or a/c on?

 

[redram2007]

I'm pretty sure that doesn't change anything as it has been cold and snowing for the past week and I have been using the defrost. I will check again later to verify.

 

[KGBIGCOUNTRY]

If it does not then check with your CMR tuner to see about him changing your P/N and D a/c/defrost setting. You can verify yourself if you want to look into the quick change settings in the Trinity. Not sure if Dave locks out his files to where you yourself couldnt make the changes. That should be 200-250 above normal setting.

 

[redram2007]

Will do. Now I just wonder why it randomly surges after the engine is at operating temperature?

 

[redram2007]

Well the a/c defrost didn't work. I'm going to go through the trinity and see what I can change. If I can't I will contact David.

 

[KGBIGCOUNTRY]

It should be in the quick settings. I have had mine surge like a pro stock before going from drive to park and the temps were low before. Has happend atleast twice I can think of, racked the gas and it would plane out.

 

[Redtruck-VA]

Being a 4.7 I believe your TPS is adjustable and if not set correctly could affect your idle.

 

[redram2007]

I have tried racking it out before and sometimes it works but most of the time it doesn't. It is really bad if I have been giving it hell.

Not sure how I could adjust it unless I mess with the set screw on the throttle shaft. According to my tuner when at idle it says its at 0%. So I'm not sure if I want to start adjusting that or not.

 

[Redtruck-VA]

I have tried racking it out before and sometimes it works but most of the time it doesn't. It is really bad if I have been giving it hell.

Not sure how I could adjust it unless I mess with the set screw on the throttle shaft. According to my tuner when at idle it says its at 0%. So I'm not sure if I want to start adjusting that or not.

I did a Service Manual check and I didn't see where the TPS is adjustable, in fact it stated the signal output to the PCM is a "learned" value which means to me that all you need to initially do is reboot the PCM and turn on the ignition switch without starting the engine or touching the pedal and wait 10 seconds while the PCM registers the signal value for throttle blade closed position. Turn off the ignition and then start normal.

 

[redram2007]

I did a Service Manual check and I didn't see where the TPS is adjustable, in fact it stated the signal output to the PCM is a "learned" value which means to me that all you need to initially do is reboot the PCM and turn on the ignition switch without starting the engine or touching the pedal and wait 10 seconds while the PCM registers the signal value for throttle blade closed position. Turn off the ignition and then start normal.

I have actually done that a few times, once before new IAC valve and TPS and twice after. All with the same results, problem still there and no CEL.

 

[KGBIGCOUNTRY]

See what pids he can check and try recording them when the truck does it. When it does it does your truck rack between pig rich and dead lean?

 

[redram2007]

See what pids he can check and try recording them when the truck does it. When it does it does your truck rack between pig rich and dead lean?

It does.

 

[KGBIGCOUNTRY]

I think its the computer fighting the tune. When mine has done it I glance at the gauge and the PCM is trying to correct it intsead on the tune keeping it in check. Mine has done that after making a pass.

 

[Redtruck-VA]

This is sounding like the O2s is not reading correctly, reading about O2s it doesn't take much for a narrow band to make the PCM not adjust correctly.

 

[redram2007]

Are you referring to the pre or post cat?

 

[Redtruck-VA]

Are you referring to the pre or post cat?

The one in front of the cat controls the PCM.

 

[redram2007]

Gotcha. I'm at 94k miles so it may be time to change them. I was thinking of going with the NGK sensors bc I have heard Bosch is no good. Is there any others that are good and any to stay away from?

 

[Redtruck-VA]

I would only use OEM sensors.

 

[redram2007]

I bet dodge is proud of these just like most of their parts.