Throttle body does not open

[mustardfj40]

Hi guys, I'm chasing a problem with starting, it cranks and idles for a second then dies.

While doing the troubleshooting I looked at throttle body and noticed that with ignition on and gas pedal is pressed, the throttle plate does not open, it should be opened correct? My truck is an 98 so it has the cable pulled accelerator pedal position sensor .

I followed the FSM throttle trouble shoot and see that the throttle control motor clutch resistance is at 7.2 ohms, the the FSM spec is 4.2-5.2 Ohms (so this is out of spec). The throttle position sensor is measured at in spec as in the FSM. The accelerator pedal position sensor is measured to be in spec.

Can you share more troubleshooting tip on this?

Thanks.

 

[leveeguy]

Im pretty sure your year has to be manually operated.

Post in thread 'Cleaning Throttle Body'

Dec 11, 2018

If your throttle body is controlled by cable 98-02 USA; you can open butterfly by hand.
If throttle body controlled by wire (electronic) 03-07 USA; turn IG switch to on and depress gas peddle to open butterfly.

BG, CRC and others sell a spray can of cleaner for this. I've also used Sea Foam lubricant to wipe clean throttle body.

A note: One mud member years ago put out a warning to avoid getting solvent through wall of throttle body where axle of butterfly penetrates. Where his was on a 98-99 which was reported to have some issues with throttle body. He felt the solvent may have enter...

• 2001LC

• 

 

[mustardfj40]

Im pretty sure your year has to be manually operated.

Post in thread 'Cleaning Throttle Body'

Dec 11, 2018

If your throttle body is controlled by cable 98-02 USA; you can open butterfly by hand.
If throttle body controlled by wire (electronic) 03-07 USA; turn IG switch to on and depress gas peddle to open butterfly.

BG, CRC and others sell a spray can of cleaner for this. I've also used Sea Foam lubricant to wipe clean throttle body.

A note: One mud member years ago put out a warning to avoid getting solvent through wall of throttle body where axle of butterfly penetrates. Where his was on a 98-99 which was reported to have some issues with throttle body. He felt the solvent may have enter...

• 2001LC

• 

Thank you. It’s good to know the butterfly flap won’t open when ignition is on and gas pedal is pressed on my 1998 (unlike the later years), I was concerned my throttle body is bad

 

[CJF]

Wait: If it has a throttle cable, then shouldn't the throttle plate absolutely be opening when the gas pedal is pressed?

(I'm an 80's guy, so maybe I'm missing something??)

 

[mustardfj40]

Wait: If it has a throttle cable, then shouldn't the throttle plate absolutely be opening when the gas pedal is pressed?

(I'm an 80's guy, so maybe I'm missing something??)

That was what I thought originally but the cable moves the sensor which returns the feedback to the ECM and the ECM sends signals to the motor to open throttle butterfly plate. It’s confusing as heck since I thought the butterfly plate should be opened idle

 

[CJF]

That was what I thought originally but the cable moves the sensor which returns the feedback to the ECM and the ECM sends signals to the motor to open throttle butterfly plate. It’s confusing as heck since I thought the butterfly plate should be opened idle

Ah; ok. Thanks and good luck.