Rpm hanging above 5,500 video inside

[slackinoff]

Help me figure out what is causing this....recently changed the alternator because it self destructed, and cleaned the TB. Since doing these, it will sometimes act normally above 5,500. (Before, it did this all the time) Clutch in or out, still or driving make no difference. Completely random it seems.

2008 Bullitt. Bama tuned (they tried to change the throttle decay to minimse it....not really a fix)

https://youtu.be/1vcA8l5ki0c

Thanks,

RM

Oh and the only mods besides the bama tune is an off road x pipe.

As you can see, it only hangs if I go over about 5,500 rpm.....can you imagine how frigging hard it is to shift like this?! I just don't do it and it pisses me off to have to short shift by 1,000 rpm.

RM

 

[eighty6gt]

lito

 

[slackinoff]

lito

Good suggestion. After work today, it only "hung" with the clutch engaged (out). Which is good, because now it doesn't mess with shifts as bad above 5,500.

RM

 

[Phil1098]

It may be a function of you cleaning the TB, the one on my daughters car acted this way for a bit after I cleaned it. It did settle down after a few days, but I was already on Rock Auto checking prices figuring I had screwed it up.

 

[slackinoff]

Ok yea that might be it. PCM is still learning how to function after being cleaned. I like this idea, all it involves is just me driving it to fix it. The TB had some pretty substantial build up.

RM

 

[CJ-]

That amount of hang is very close to how fast the stock tune will drop RPMS, if anything i would say its hanging ever so slightly due to having to relearn the base idle... have you tried disconnecting the negative terminal and running a jumper wire from the negative cable to the "Still connected" Positive cable? Doing so will make your ECU/PCM forget the idle values that it had learned prior to your TB cleaning.

If you havent done this, Do it and leave the neg terminal disconnected with a jumper wire leading to the pos battery post for about 15 minutes. Once thats done, Turn the ignition on but dont start the engine, Wait for all the dash chimes to stop and then slowly and smoothly press the throttle pedal down and then slowly release it all within a 5 second time period, that'll tell the ECU PCM 0-100 open range and then start the engine and let it idle for 15-18 minutes for it to relearn base idle.

Make sure your radio, AC and lights are off while you do this so the drop in voltage wont interfere with the relearn process.

Also, After the engine has idled for up to 15 minutes, drive around the city for about another 15 minutes without any ac or radio, then after 15 min of driving go ahead and turn on your ac and radio so the engine can relearn idle under load with the ac and other components active. After that all should be well.