![]() |
![]() |
#1 |
Registered User
Join Date: Feb 2010
Location: San Antonio, TX
Posts: 117
|
Q-Jet frustration
In my 72 K20....I have sent the Q-Jet off to be rebuilt by the 'Best Guys In Town' .....three times now
![]() ![]() It seems to run dry if it sets overnight...you have to crank it over a while and pump the gas before it decides that it has enough fuel to start. Once you get it hot, you have to hold the pedal all the way to the floor to get it to start again. When driving down the highway, it gives up at random times, but will restart after it sits for about 5 minutes. It will die randomly when idling at a light. The high idle will 'stick' at times, it just takes a tap of the pedal to get it back to normal. I am about to jerk that dang gas burner out and stick a Cummins 5.9 in over that damn Q-jet.....I don't have the time or $$$ to do a Cummins swap right now and the motor is plenty strong.....any ideas what to do with the carb before I lose what's left of my sanity? oh, and last time I took the whole truck to the carb shop....on the way home, it backfired (rapid fire- bang bang bang bang!) ...so badly a carload of bangers drove off of the highway into the grass....now, that was really dang funny, but it was freakin' irritating at the same... time |
![]() |
![]() |
![]() |
#2 |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
|
Re: Q-Jet frustration
first thing that comes to mind is the well plugs. Were they sealed properly?
(slide 24 of this site: http://www.gmcws.org/Tech/quadrajet/...iles/frame.htm Also, the needle valve may not be seating properly and allowing fuel to drain. There's other possibilities but can't think of them right now. |
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Jun 2010
Location: Upland Ca
Posts: 4,143
|
Re: Q-Jet frustration
What does "best guys in town" mean? By the results it sounds like hack jobs. Many of these so called carb rebuilders don't understand q-jets. Did you get a warranty?
Posted via Mobile Device
__________________
1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703 |
![]() |
![]() |
![]() |
#4 |
Registered User
Join Date: Feb 2010
Location: San Antonio, TX
Posts: 117
|
Re: Q-Jet frustration
Yup, it has been back 3 times...still doesn't work for crap.....maybe 'best guys in town' is short for -> only people who work on these old cars anymore...I have lost faith in them (they have asked me to bring the truck back again, but I am not wasting another day waiting for them to get it right).
|
![]() |
![]() |
![]() |
#5 |
Who's got steelies?
![]() Join Date: Feb 2006
Location: Morrison, Oklahoma
Posts: 1,026
|
Re: Q-Jet frustration
Sounds like leaky plugs under the float bowl, not an uncommon problem on older Q-jets.
These carbs aren't that hard to work on. See the link in my Signature. Get the book by Cliff Ruggles and rebuild it yourself. Like my Dad always says, if you want to drive old cars, you'd better learn to work on them. ![]()
__________________
![]() ![]() ![]() ![]() ![]() ![]() How to add a trip odometer to your 67-72 stock speedometer How to rebuild your Q-Jet My Truck Page My Youtube Channel |
![]() |
![]() |
![]() |
#6 |
Registered User
Join Date: Sep 2000
Location: Gold Bar, WA
Posts: 1,216
|
Re: Q-Jet frustration
THe high idle could be from the choke not being adjusted or assembled right. I am in that situation with mine right now (mine is an electric choke tho). I don't think I've assembled something right or cleaned it up good enough and the fast idle cam sticks. I've pretty much diasbled the choke until I have time to work on it again.
If you have the time and determination, try working on it yourself. There is an overload of information out there.
__________________
My Projects: 1960 GMC 1/2ton with 305 V6 (daily driver) 1963 Chevy 1/2ton 2wd...converting to 4x4 1967 Suburban 1/2ton 2wd My Girlfriends Projects 1985 Chevy Suburban 3/4ton 4x4 with 6.2L diesel, 4" lift, converted to TH-400, Warn Premium manual hubs, & Wildcat 315/75/R16 tires. (daily driver) 1978 Camaro Type LT with a Marine 350 & vortec heads, Rochester Carb, & roller cam 1978 Camaro Z28 |
![]() |
![]() |
![]() |
#7 |
Registered User
Join Date: Feb 2010
Location: Hartselle, Al.
Posts: 466
|
Re: Q-Jet frustration
It sounds to me like how mine was before the rebuild.
PM me and I will give you contact info of a guy here that does a fantastic job rebuilding them. Believe me, I hated Q's until I had one built by someone who really knows what they are doing. Steven
__________________
“Life is and will ever remain an equation incapable of solution, but it contains certain known factors.” - Nikola Tesla Matt. 6:27 "Who of you by worrying can add a single hour to his life?” http://www.67-72chevytrucks.com/vboa...=507266&page=2 |
![]() |
![]() |
![]() |
#8 | |
Registered User
Join Date: May 2011
Location: Northern Calif.
Posts: 3,700
|
Re: Q-Jet frustration
Quote:
|
|
![]() |
![]() |
![]() |
#9 |
Registered User
Join Date: May 2004
Location: Topeka, Ks
Posts: 2,293
|
Re: Q-Jet frustration
Pretty common to put the clip that holds the inlet needle to the float on wrong, that will cause the dying issues you are seeing and could cause fuel to drain back. It MUST be installed correctly.
Jeff
__________________
I'm not a pessimist, I'm just optimistic that bad things are going to happen. 1971 Cheyenne Super K10 - tilt, cruise, air, am/fm, tow hooks, factory buckets! 1986 Jeep J10 pickup, - 5.3L Vortec with 4L60e and NP241. |
![]() |
![]() |
![]() |
#10 | |
Registered User
![]() Join Date: Nov 2010
Location: Venus Texas
Posts: 217
|
Re: Q-Jet frustration
Quote:
|
|
![]() |
![]() |
![]() |
#11 |
Sierra Grande Club
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
|
Re: Q-Jet frustration
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe. ![]() |
![]() |
![]() |
![]() |
#12 |
Registered User
Join Date: Feb 2012
Location: JBLM, WA
Posts: 153
|
Re: Q-Jet frustration
Yup yup, get the book and do it yourself. A q-jet was the first carb I ever rebuilt, with the book, I had it up and going the next day (over night cleaning), not a single problem - OTHER THAN - look at the picture posted by chipflyer. I once thought it didn't matter
![]() But if nothing else, whoever did your carb slapped on a gasket kit and that was all I bet. I'm sure he's their 'go to' guy because he's the only one who knows SOMETHING about rebuilding carbs. There's hard parts (not found in your gasket kit) that should be replaced on a 30 year old truck, throttle shaft bushings and such. Don't give up on that Q-jet. If you found someone to rebuild it who knew what they were doing, you'd love that carb forever.
__________________
68 GMC C2500 - 305 V6 - 4spd |
![]() |
![]() |
![]() |
#13 |
2WD Jimmy
![]() Join Date: Mar 2005
Location: Davis County, Utah
Posts: 2,564
|
Re: Q-Jet frustration
The quadrajet is a wonderful carb... IF its rebuilt correctly. The 'best' guys in town didnt know what they were doing. If the plugs are not sealed (which they obviously were not) and if the control shafts arent properly resized (which they probably were not),... then you will Never be able to get it adjusted correctly.. never.
Send it to "The Carb Shop" in California... they specialize in that carb. Or someone else who actually knows how to properly truly rebuild a quadrajet. cleaning and putting in a "kit" is Not a rebuild... trust me on this one. |
![]() |
![]() |
![]() |
#14 |
Registered User
Join Date: Feb 2010
Location: San Antonio, TX
Posts: 117
|
Re: Q-Jet frustration
Thanks guys for all the help.
When I lived in Houston, I had a guy that was nearly 100 years old, and he could REALLY build any old carb up and do it right. He passed away a few years ago and his son gave up the business....I guess the hunt is on for someone who can drill and bush the body and make it run like a top....I just know that there is more to it than a simple clip out of place....if I had more free time, I would probably pull it apart and tinker with it, but I'm not 17 and unemployed anymore, so it needs to get done right the first time around. Thanks again guys! |
![]() |
![]() |
![]() |
#15 |
Registered User
Join Date: Sep 2011
Location: Ark City, Kansas
Posts: 3,339
|
Re: Q-Jet frustration
The clip is there for a purpose, to keep the needle from sticking to the seat in prolonged non use. THe clip can be easily installed incorredtly. I've always used the clip, w/o problems. The clip CAN be left out, I've left it out on the last couple I've built, no big deal.
www.cliffshighperformance.com is the answer man, Sean Murphy is good also....don't give up |
![]() |
![]() |
![]() |
#16 |
Registered User
Join Date: Feb 2012
Location: JBLM, WA
Posts: 153
|
Re: Q-Jet frustration
And if they're backed up. try http://www.sparkyscarbs.com/ he's the man too. Think he mainly does muscle cars, but it shouldn't matter.
__________________
68 GMC C2500 - 305 V6 - 4spd |
![]() |
![]() |
![]() |
#17 |
Registered User
Join Date: Sep 2011
Location: Ark City, Kansas
Posts: 3,339
|
Re: Q-Jet frustration
I can tell you that Cliff IS backed up, WAY up. He's been only taking names for a waiting list (YES, he's THAT GOOD). He can sell you the parts and his book, and help over the phone, but sometines it takes a while for him to get back to you...
I've herd nothing but good things about Sean Murphy also, but am not as familiar w/ him... |
![]() |
![]() |
![]() |
#18 |
Registered User
Join Date: Jun 2010
Location: San Diego Co.
Posts: 1,167
|
Re: Q-Jet frustration
I support all positive statements about how good these carbs are if done right.
Also that Cliff Ruggles is "The Man". Got his book, parts, and a primary shaft/bushing job from him, and did the rebuild myself. Couldn't be happier with the results. I believe I left out the aformentioned clip as well. I had never done a carb rebuild before. Just take your time, and don't rush it...it'll come out fine. |
![]() |
![]() |
![]() |
#19 |
Registered User
Join Date: Dec 2009
Location: edmonton ab
Posts: 73
|
Re: Q-Jet frustration
make sure your ignition isnt contributing to your problems, kinda sounds like you may be loosing spark or something in the ignition. i love q jets but most dont understand them
__________________
formerly cooter |
![]() |
![]() |
![]() |
#20 | |
DND Trucks
![]() Join Date: Dec 1999
Location: NW Indiana
Posts: 2,383
|
![]() Quote:
![]() |
|
![]() |
![]() |
![]() |
#21 |
Registered User
Join Date: Feb 2010
Location: San Antonio, TX
Posts: 117
|
Re: Q-Jet frustration
Well....I had a little free time to look things over....I took the air cleaner off and sure enough she was getting plenty of gas....so....off to the dark side of electrical I went.....no spark? hmmm, got out the digital multimeter and no juice at the dang coil....started looking and found a slightly melted plug at the rear of the ignition switch....Had the local parts pusher send me a new plug and harness....okay, now I have 12 volts at the coil with the wire loose and not so much once connected, but still no stinking spark...I'm thinking that the Mallory ignition module has bit the dust...I guess that I need to figger a way to test out that dang Mallory Coil too....
anyone want to hold the output stud and tell me how much juice it's giving off? Maybe it's time to ditch the Mallory stuff and go back to GM HEI....I have had those little modules die unexpectedly, but a spare in the glove box has come to my rescue before.....what say the gurus? I just hate a truck that doesn't start....and the new 68 fires every time and the 72 sits there in quiet shame.... |
![]() |
![]() |
![]() |
#22 |
Registered User
Join Date: Sep 2007
Location: Mundelein, IL
Posts: 862
|
Re: Q-Jet frustration
my edlebrock always "drained" gass back and would need a fair amount of pumping anytime it was left sitting. my 402 has an edlebrock Qjet and the little fuel filter has a check valve inside it. Maybe you need a new filter?
I would also vote for the HEI swap, but I'll admit my experience with points is slim to none. Good luck! P.S. what kind of choke setup you got?
__________________
time is inversely proportional to money; that's why it takes me so long 1967 K10 1967 Camaro |
![]() |
![]() |
![]() |
#23 | |
Registered User
Join Date: Feb 2010
Location: San Antonio, TX
Posts: 117
|
Re: Q-Jet frustration
Quote:
|
|
![]() |
![]() |
![]() |
#24 |
Registered User
Join Date: Sep 2007
Location: Mundelein, IL
Posts: 862
|
Re: Q-Jet frustration
just make sure the choke can move freely and opens properly. or once warm wire it open and see if anything changes ( as far as drivability)
__________________
time is inversely proportional to money; that's why it takes me so long 1967 K10 1967 Camaro |
![]() |
![]() |
![]() |
#25 | |
Registered User
Join Date: Feb 2010
Location: San Antonio, TX
Posts: 117
|
Re: Q-Jet frustration
Quote:
![]() I guess that I will be hunting up a good used GM HEI unit and ditch the Mallory crap...plus +++ NOBODY has one in stock here in town....sucks to be broke down and no parts ![]() |
|
![]() |
![]() |
![]() |
Bookmarks |
|
|