q-jet throttle lever and accelerator pump delay

Computer controlled what?

Moderators: Super Mod, Moderators

q-jet throttle lever and accelerator pump delay

Postby s10+5 » Wed Feb 07, 2018 1:59 pm

hello, i have a 75 pontiac q-jet on my 350. i rebuilt this carb and it runs fine, idles well, but i see the throttle arm move a good amount before actuating the other arm that moves the accelerator pump lever to move that pump. i thought the throttle should move the pump lever instantly to give it a shot. i have a small bog and believe this is why. am i missing something? any help would be appreciated thanks.
very little compares to firing up a small block or big block Chevy motor for the first time.
1974 K5, 2001 S10 Blazer, 1984 S15
s10+5
I just gutted everything.
 
Posts: 90
Joined: Tue Feb 14, 2017 1:20 pm
Location: Los Angeles, CA

Re: q-jet throttle lever and accelerator pump delay

Postby Rickracer » Wed Feb 07, 2018 4:06 pm

A pic or some video would help immensely, I haven't even SEEN a Q-Jet in a few years, though I've rebuilt dozens over the years... :? :? 8)
Rickracer
ASE Certified Master Automotive Technician (well over 3 decades of experience, :thumbup: )
'93 S10 SB,RC, Comp XR276 Hydraulic Roller, Vortec head 363, 400 + hp, built 700R4, JW 2800 stall lockup converter, 3.73 posi, disc brake, narrowed 8.8 Exploder rear, LS Camaro front discs, Cal-Trac clone traction bars, Best N/A passes to date: 7.76 in the 1/8th, 12.24@109.27 mph in the 1/4, gonna spray it one of these days... :mrgreen:
76 Chevy Vega Drag Car, TWIN TURBO 355, P/G trans w/ brake and JW 4000 stall vert, 4 link back half, narrowed 9", 3.50 gears, 29.5x10.5W ET Drags. Best time9.669 @ 139.79, Latest video: https://www.youtube.com/watch?v=S59riYn ... ata_player
Rickracer
Master Swap Tech
Master Swap Tech
 
Posts: 28989
Joined: Wed Apr 26, 2006 8:02 am
Location: Kissimmee, Fl.

Re: q-jet throttle lever and accelerator pump delay

Postby s10+5 » Wed Feb 07, 2018 8:04 pm

Here is video of the throttle moving but not squirting. Thanks for any help or info.

https://youtu.be/cUVMJUsObSA
very little compares to firing up a small block or big block Chevy motor for the first time.
1974 K5, 2001 S10 Blazer, 1984 S15
s10+5
I just gutted everything.
 
Posts: 90
Joined: Tue Feb 14, 2017 1:20 pm
Location: Los Angeles, CA

Re: q-jet throttle lever and accelerator pump delay

Postby Rickracer » Thu Feb 08, 2018 8:24 am

That would definitely cause a hesitation...I can't tell how that linkage is attached to the throttle shaft by the pic, but that IS the problem, for sure. Can you take that linkage apart and take a pic? :?: :?
Rickracer
ASE Certified Master Automotive Technician (well over 3 decades of experience, :thumbup: )
'93 S10 SB,RC, Comp XR276 Hydraulic Roller, Vortec head 363, 400 + hp, built 700R4, JW 2800 stall lockup converter, 3.73 posi, disc brake, narrowed 8.8 Exploder rear, LS Camaro front discs, Cal-Trac clone traction bars, Best N/A passes to date: 7.76 in the 1/8th, 12.24@109.27 mph in the 1/4, gonna spray it one of these days... :mrgreen:
76 Chevy Vega Drag Car, TWIN TURBO 355, P/G trans w/ brake and JW 4000 stall vert, 4 link back half, narrowed 9", 3.50 gears, 29.5x10.5W ET Drags. Best time9.669 @ 139.79, Latest video: https://www.youtube.com/watch?v=S59riYn ... ata_player
Rickracer
Master Swap Tech
Master Swap Tech
 
Posts: 28989
Joined: Wed Apr 26, 2006 8:02 am
Location: Kissimmee, Fl.

Re: q-jet throttle lever and accelerator pump delay

Postby s10+5 » Thu Feb 08, 2018 9:11 am

Thanks for confirming. Here is a video but it revs when throttle blades open. But it takes a second to engage the pump. I'll post pics as my friend is selling me two for a song. I'm going to swap it out after cleaning them up or rebuilding.

https://youtu.be/VcbH5GagXo4
very little compares to firing up a small block or big block Chevy motor for the first time.
1974 K5, 2001 S10 Blazer, 1984 S15
s10+5
I just gutted everything.
 
Posts: 90
Joined: Tue Feb 14, 2017 1:20 pm
Location: Los Angeles, CA

Re: q-jet throttle lever and accelerator pump delay

Postby lowblazin94 » Thu Feb 08, 2018 9:16 am

If its doing that with no load then I cant imagine how bad it is while driving. Pump should almost be instant
92 S10 Ext cab
385
700r4
User avatar
lowblazin94
TheCowWatcher
 
Posts: 5039
Joined: Wed Jul 20, 2005 8:16 pm
Location: Houston, Tx

Re: q-jet throttle lever and accelerator pump delay

Postby s10+5 » Thu Feb 08, 2018 10:29 am

yeah i can only go if i slowly get it in. no fun. I'm swapping carbs this weekend. thanks guys. ill report back.
very little compares to firing up a small block or big block Chevy motor for the first time.
1974 K5, 2001 S10 Blazer, 1984 S15
s10+5
I just gutted everything.
 
Posts: 90
Joined: Tue Feb 14, 2017 1:20 pm
Location: Los Angeles, CA

Re: q-jet throttle lever and accelerator pump delay

Postby s10+5 » Fri Feb 09, 2018 11:46 pm

My buddy sold me 2 qjets for $20. I took off the air horn of one and cleaned it up a little. Checked the float level. And threw it on.it runs much better! I may put a new carb kit on it later but for now the Jets and rods are clean and the pump was still soft. I may get a ruggles kit later. Thanks for the help.



https://youtu.be/9PTYX81h0w4
very little compares to firing up a small block or big block Chevy motor for the first time.
1974 K5, 2001 S10 Blazer, 1984 S15
s10+5
I just gutted everything.
 
Posts: 90
Joined: Tue Feb 14, 2017 1:20 pm
Location: Los Angeles, CA

Re: q-jet throttle lever and accelerator pump delay

Postby Rickracer » Sun Feb 11, 2018 7:51 am

Happy to try to help, glad you got it going, :thumbup:
Rickracer
ASE Certified Master Automotive Technician (well over 3 decades of experience, :thumbup: )
'93 S10 SB,RC, Comp XR276 Hydraulic Roller, Vortec head 363, 400 + hp, built 700R4, JW 2800 stall lockup converter, 3.73 posi, disc brake, narrowed 8.8 Exploder rear, LS Camaro front discs, Cal-Trac clone traction bars, Best N/A passes to date: 7.76 in the 1/8th, 12.24@109.27 mph in the 1/4, gonna spray it one of these days... :mrgreen:
76 Chevy Vega Drag Car, TWIN TURBO 355, P/G trans w/ brake and JW 4000 stall vert, 4 link back half, narrowed 9", 3.50 gears, 29.5x10.5W ET Drags. Best time9.669 @ 139.79, Latest video: https://www.youtube.com/watch?v=S59riYn ... ata_player
Rickracer
Master Swap Tech
Master Swap Tech
 
Posts: 28989
Joined: Wed Apr 26, 2006 8:02 am
Location: Kissimmee, Fl.

Re: q-jet throttle lever and accelerator pump delay

Postby s10+5 » Tue Feb 20, 2018 3:29 pm

Rickracer...what do you think about ru nning a power piston spring rated at 14inches? I'm getting about 15 max on the intake manifold. ive read that you run a spring 2 inches lower than what you are pulling. any thoughts, thanks man.
very little compares to firing up a small block or big block Chevy motor for the first time.
1974 K5, 2001 S10 Blazer, 1984 S15
s10+5
I just gutted everything.
 
Posts: 90
Joined: Tue Feb 14, 2017 1:20 pm
Location: Los Angeles, CA


Return to Carburetion

Who is online

Users browsing this forum: No registered users and 1 guest