I need help verifying a strange sound occurring with my 2003 Lightning (10K miles) when accelerating with the engine partially warmed up.

The truck runs fine, but when cold I hear a “fluttering” noise when she shifts from 1-2 and 2-3. She pulls fine and there is no stumble. After the engine is up to temperature I don’t hear the noise.

Ford tells me it is the “waste gate”, and not to worry. But I’m familiar with a waste gate on a turbo, not with a supercharger.
Has anyone else experienced this or can confirm what Ford has told me.

Thanks for any feedback,
Buck

 

usual ford talking out there *** is what it seems like to me.......


we dont have wastegates. is this sound at WOT shifting?

 

What they might be talking about is the boost limiting or bypass valve at the back of the supercharger. It is controlled by a black diaphram valve on the driver's side rear of the blower. Disconnect and plug the pink line and the black line going to it and see if the noise goes away. Better yet, do the boost bypass routine.

Go to http://www.rpmoutlet.com/boost%20bypass.htm

Easy fix and easy to swap back to stock if desired.

 

Sounds like it could be torque reduction. I'm pretty sure that it doesn't change based upon coolant temp though. Do a search on torque reduction and you should be able to find more info to see if it sounds like what you are experiencing.

-Nate

 

thats why i asked if it was shifting at WOT.

see i can be civilized.

 

Is your truck stock?

It does sound like the torque reduction feature. EVERY new Lightning owner has heard/wondered about that. But its been such a long time ago that mine was stock, I forgot what it sounded like

 

Thanks folks for the ideas.....

The noise occurs at mid throttle and only just as the tranny shifts from 1-2 and 2-3 when not up to full temp.

The truck has a superchips 1715 program loaded which I unloaded and the noise was still present.

I did installed the RPM boost-by pass with no change. With the by-pass installed the supercharger just sounded louder.

The odd thing is after driving 5-10 miles and she is warm there is no fluttering sound. Just the normal fast shift between gears.
Even when I hear the noise the truck runs great. Pulls hard and shifts fine. I'm just puzzled about it.

Thanks to everyone for your thoughts.
One of my buddies also suggestion something about a torque reduction when the pcm was still in open loop.

 

Could it be the idler pulley bearings going bad?

 

If it was me, I would put a socket on my sparkplugs to elimanate that possibility

 

I second that

then

Buy long tubes and a bassani and you will not be able to hear it anymore

 

My truck does the same thing when cold Mine is a 00. I have been told that it is something in the egr. Others have reported the same problem but I havent found the sollution. I thought it was maybe chip related.

 

Thanks again folks...
Although I have no loss of power or other noises I'll still give the plugs a extra twist. (Maybe look into bigger speakers!!!)

BDAZSVT.....Odd that you mention the EGR valve. The first time I went to Ford, the service manager mentioned something about the EGR valve sticking or fluttering when cold. I'll investigate a little more..
Thanks again,
Buck

 

I had a similar issue which I posted a while back (thought it was detonation). My truck would have a rattle noise when cold, at part throttle and when changing gear. I tried speeding up the idle RPM, adding octane booster and even changing gas stations, but no luck. I then took off the supercharger belt and ran the truck without and the noise disapeared. I put the belt back on on and the noise did not reapear for at least 2 or 3 days of use. Anyway I decided that the belt was either stretched and/or worn, so I changed it for a belt which is 0.5 inch less than stock size. and the problem went away and that was 2 weeks ago. You would not believe how happy I was. Anyway just my input and hope it helps.



01 Silver Lightning
2.8" Upper Pulley
Predator Pulley Tune
Twin Flowmasters
K & N
372 RWHP 452RWTQ@ 90F Ambient

 

Lightnin_truck....Thanks for the info.
What brand belt did you use & p/n. How much pain is it to replace?

THanks again,
Buck

 

Mine has had 2 new belts and still does it. One stock and one whan I put on the 4lber.???