Welcome to the Corvette Forums at the Corvette Action Center!

L83 problem. Off idle stumble? What do I look for?

J

jamie1984

Guest
When I floor it off the line, there is a stumble...much like a carb feels then it launches and runs pretty good. It really feels like a carbed car. Has new fuel filter, just changed the spark plugs today. Has K&N in factory airbox and other than that only "mods" are Flowmaster mufflers and the cold air mod.
 
Jamie, like mentioned on the XF Forum, it seems to point to the fuel pressure/weak pump. Did you check your fuel pressure?


:w
-Stefan
 
I agree with all the above.
You might also want to check the hose that run to the MAP sensor for pinches. Restricted air flow will cause a delay in fuel/air mixture calculations.
Check to see if your EGR valve lines are all good, with no cracks as well.
 
First thing I'd do is take "c4c5specialist's" advice. Check the idle TPS setting per the Factory Service Manual. Then check the TB shafts as "geekinavette" suggests.

If you're worried about the fuel pump, then check the fuel pressure per the FSM. If it doesn't meet the specs in the manual, then troubleshoot the system according to the FSM.
 
having same deal with 82CE-usual mechanic just looks at me, and am hunting for a new one! I swear she "hesitates, stumbles. gasps," etc. for just a sec before kickin in. Makes me sweat when I am trying to pull out or jump up the highway ramp.Runs like a bullet once she gets going. All original, but may have to start adding some "new" Am going to save this page for new mech if I can find one! Aside, it has a/c but hate to run it (really drags engine) but here it gets might hot! Any way to force in some cooler outside air through interior vents? There are 2 small vents at windshield base corners but not much comes through.
 
CF motors are rather sensitive to fuel pressure. You need to know where its at before going any further. GM says 9-13 works, set it at 14 and you'll be happy and so will the motor. If that's ok, start with the other items mentioned, set the TPS to as close to .525v as possible, Key ON, motor OFF when you set it. Good luck and post results.:thumb
 
Thanks. Got a guy to call on Monday and am taking this with me. And Hey to Jamie in Houma-I'm in se TX just tween Orange and PA.
 
One more thing just in case you didn't know it. The fuel pressure is adjusted on the rear TB (drivers side). If the GM blocking plate is still installed in the FPR, you must take the tower off, take the FPR off the tower and remove the plate to make it externally adjustable. Just punch the plate out and re-install the reg. While you're there you might as well replace the (red) bladder. Do not mix up the springs if you happen to replace both bladders, they are different in color and tension. Install them back into the correct TB. Measure the FP in-between the TBs.
 

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors

Dealers:

MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Back
Top Bottom