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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: DuckAholic1 on August 23, 2013, 10:32:56 pm
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Hi Everyone, I am in need of your expertise/advice.
I have an 87 c10 with a 5.7 350 TBI. I,m not sure how to explain myself, so please bare with me.
The gas peddle seems to be unusually hard to push. From a stop, When I push down on peddle it seems to stick, then it accelerates rapidly.(kind of jackrabbit like) Also, while traveling at any speed,
Let off, press again to speed up or maintain speed, it sticks.
The things I have tried so far are, clean & lube Throttle return springs on the TBI, and cleaned & lube cables. Any suggestions would be greatly appreciated.
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well i was thinking spring, but disconnect the cable from the tbi. then move each one and see if you feel anything
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Yeah, disconnect the cable and find out which is sticking, the throttle body plate or the cable/pedal assembly.
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it seems to be the throttle cable, but not sure!
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make sure it doesn't have to sharp of a bend or the angle on it isnt to sharp. this will cause it to bind and stick
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The pedal could also be hanging up. Make sure the pedal is not catching on carpeting or floor mat or whatever, up under the dash where you can't see it.
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Make sure no one connected a return spring to it... Or that the spring on the shaft is there.
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Well the peddle is good, the cable is good, it seems to be the plate!!!
Any advice????? :-\
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- If you have cruise control, remove the slotted steel link running between the cruise vacuum actuator and the TBI throttle lever to see if that relieves the binding.
- If removing the link doesn't help, grab the TBI throttle lever and wiggle it fore and aft to determine how much play is in the throttle shaft - more than about 1/32" is excessive and will require "bushing" the TBI base followed by centering the throttle plates in their bores. Replacing the TBI is the alternative.
- In addition, with the engine OFF, look down the throats of the TBI with a bright flashlight and inspect the throttle plates for wear around their circumference, especially where they pass over the throttle shaft. If there are gaps between the plates and the throttle bores, you'll need to replace the TBI assembly.
- Crack the throttle open by hand while you're inspecting the condition of the plates to determine if the plates are jamming in their bores at idle. If that's the problem and you don't notice excessive side-to-side play in the shaft, you may be able to recenter the plates in their bores, set the base idle, and be done. (In spite of what you may hear, there is an adjustment for throttle closing that affects minimum base idle speed).
- As a last resort, remove the TPS from the right side of the throttle body (two screws) to see if it's binding. The TPS is not adjustable on the '87 TBI, so you can remove and reinstall it, or install a new TPS, w/o worry.
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Thanks bd, I'll take a look at it today!!