Hi guy's,

I will apologize in advance for the long winded post

73 coupe w 92 crate 350. It had a stock intake w/ EGR and Edelbrock Q-Jet model 1901. I just changed the intake to a Edelbrock performer w/o EGR I copped from a friend. Everything came out good. Distributor checked out and was re-installed with new points. I positioned it back to the factory spec so the TAC cable is at the correct angle, and the vacuum advance can is on the outside of ignition shield bracket.

I re-installed the Q-Jet after an external cleanup as it is working good and i see no reason to mess with it att.

Now the real reason for the post. I have always been Holley man, but had gotten out of the hot rod scene for a few years. Since buying the vette and reading lot's on this board, it seems the dominate opinion is that the Q-Jet's provide better economy/performance/driveability. However, I seem to be having some issues with this one, maybe some of you could help:

1. Hot Air Choke...does not engage with the new intake. i move the coil assembly over from the old intake, and adjusted the rod so that it moves and will open and close the choke flap. No luck. The choke never engages. Any ideas would be apperciated.

2. Vacuum ports not working. Iniitally, the Vacuum advance had been connected to a port on the left front of the carb. The EGR was connected to a port on the bottom front right, and the log skinny port extending from the right side of the carb under the choke mechanism was plugged. After installing the new intake, and reinstalling the carb, I reconnected Vacuum advance where it was (left Front), and plugged the rest. Once I got it running, I set the dwell, and initial timing with VA disconnected at 12*. When I reconnected the VA, no advance occured, timing stayed at 12*. I moved the VA hose to the bottom right port, (Formerly EGRport), with the same result, no advance. When holding my finger up to either vacuum port the sucking was very faint. Then I pulled the plug off the right side skinny shaft port, and bingo, it about sucked my finger in. I connected the VA to it, and "viola"...idle speed increased and I had 30* advance.

So, my question is more centered around why the two front vacuum ports may be dead. Secondary question is regarding the choke. The choke was the only thing I really liked about this carb.

Any idea's? Part of me really wants to go order a new Holley, but I think part of that is because i am not confident in tuning the QJet. I am going to read Lars' paper on QJet and see where I get tinkering.

It did come out looking pretty good, and my stock cowl air cleaner fit's just fine. It seems to run ok, but something stills seems like it is holding back a little.



Many obstacle's were overcome reading advise on this board. Thanks to all who contribute. Any idea's on the choke and dead vacuum ports is appreciated.

 

I think your "dead" ports are metered vacuume, that is to say at idle they are very low vac signal because they are above the lip on the throttle plate. For performance the Adv should be connected to manifold vacuume, for fuel economy it should be in metered vac. Egr is not used at Idle only cruise so it was connected to metered.

 

as far as the choke goes, if you can't get it working ,you can buy a bolt on electric choke conversion for about 70 bucks.

 

As Fast Idle mentioned, the electric divorced choke is about your best option. Just about anytime you change intakes on a divorced choke carb you tend to run into this problem, the geometry of the linkage tends to change. I ran into this same problem running from my stock LS-4 intake to a 68 L-36 intake, I had to custom bend a rod to make it work, and it's still not perfect but it gets by without a problem. Carbs Unlimited sells the electric divorced choke conversion if your interested. As six footer mentioned I think those ports are metered/off idle ports.


Pat Kunz

 

Thanks guys, with the VA connected to the constant vacuum source, the car run's much better and times to spec. as for the choke, I'll play with it some. Before I spend any money on choke kit's, I will probably get the Holley w Electric choke and then tear down the QJet and see how I do on a rebuild using Lar's instructions. After that we will have a holley/qjet face off!.

 

If you send me the #s off the Q-Jet I may want to buy it, but only as it is in it's current cond. E-mail me if you are interested.
Later,
Sly

 

I had the same problem. You can use a coat hanger to make a new choke rod. It might need to be bent different etc. Play with it when the car is cold. Bend it so that it pulls the choke closed hard and work out from there. You can start car when cold and let it run for second and see how it works - I also used the beer cooler - AKA fridge- to cool off the thermo spring to make it close fully to get it set. Just play with it and it will come around.

 

Thanks RLS, I will try the coat hanger wire and see what I can get.

Sly, I'll most likley keep the QJet around.

 

Welding rod works good for the choke rod also. I had to bend one up for my setup.