View Full Version : What vacum lines are needed for a q-jet to run?
06-08-2010, 01:13 PM
Kind of a weird question but I have a qjet on my engine and have a bad idle once its warmed up. when the engine is cool its idles fine but once its warmed up it will shake a coffee cup off the dash,lol. It seems also to waist a lot o fuel while idling. When I press the pedal it clears fine and operates fine , the only problems seems to be at idle. I was going to try and pull the vacuum lines that are not necessary , vehicle has about 30 vac um lines with tons of stock emissions crap, so I can by pass all that stuff and maybe tell if its the carb or something in the emissions system thats causing the problem. 84 c-10 350/350. Thanks
06-08-2010, 03:21 PM
you need the vac. for the dist. if it has a vac. adv. dist. you need one for the trans, mod. if the trans is a th400 or th350, you need one to power brakes if you have vac. power brake booster, you need one to the pcv in the valve cover, the rest are basically for emissions. One to a charcoal can, the rest to various things.
If that doesn't work you might want to see if the plugs are fouled like black or white from being lean, maybe a tune up, or even a heat insulator gasket or carb rebuild.
We had the same truck basically an 84 c10 with a 305 and th350 trans. and unhooked all the vac. stuff, removed the air pump and plugged the manifolds with bolts. You're only gonna need the power brake, big one, pcv, middle sized, and a vac. line to the dist. and transmission modulator, however sometimes the mod is in the intake itself and so could the dist.
Most of the ones I seen the power brake went to the back of the carb, pcv to the front both are in the middle of the carb, vac. adv. dist. to the front either ds or ps, and vac. mod. in the intake.
06-08-2010, 09:14 PM
Thanks for the reply. I have done a tune up on engine , everything but (I have tuned the carb) dist have been checked . One thing that I need to do that would answer a lot of questions is to do a compression test but since It does not waste oil, no smoke , plugs looking clean I have not done it. I do know that this is one of the worst vehicles I have seen as far as the emmisions crap. I have replaced all the lines with new rubber lines but there has got to be 30 lines on this thing. I wanted to keep it "bone" stock ,just because , but thats being a real pain in the rear. I am still going to cap off whats not really needed to make the engine run and see what happens.
06-08-2010, 09:34 PM
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.
SEO by vBSEO