I am running a 76 caddy quad on my 70 455. Having trouble with the choke. I replaced the old electric choke with a new Jet one. I pump the gas and the choke goes to the high speed. I start it and it runs (kind of stumbling) for about 10 seconds and it dies. If I re-pump the gas it will drop to the second step and not start. I took off the choke pull-off and put vaccum to it and I adjusted the opening of the butterfly down a bit (that was what I am told should be done in this instance). It seems to be the same. I try restarting without pumping gas and nothing. And after the failed attempt to start, I have to prop the butterfly open a bit to get it to start. Once it starts I let the choke close then after it runs for a few seconds, it is good with the high speed and then kickdown. I think I may have to give a bit more spring to the choke, does this seem to be logical? I forgot to mention that the carb has been mod'd with the help from Cliff's book. Thanks, sorry for the novel. John
I have an idea that may help you, I do all my electric chokes this way. I run the hot wire to the choke THROUGH an oil pressure switch. That way the choke doesn't get juice until the engine starts. The part number for the switch is; http://www.autozone.com/autozone/pa...e-Switch/_/N-8znc6?itemIdentifier=123802_0_0_ PS98 at autozone, I think the Standard number is PS64. The sending unit has 3 terminals the center one is for the oil light, the other 2 are a switch that comes on when the engine builds oil pressure, this delays the choke heater a little bit. If this doesn't give you what you need you could put the hot wire for the choke on a toggle switch, then you can delay it as long as you like. With the choke staying on longer, due to lack of juice, and a correctly adjusted choke pull off, maybe your engine will get running good before the choke kicks off. Just a thought. Mike
I just went through this on my car. Here is the procedure for setting up the choke. It takes about 15 minutes and is well worth the effort. http://www.autozone.com/autozone/re...uide/E4ME/Rochester-M4ME/_/P-0900c152801c8553 You can also check out my thread here in the mixing shop "Which Q-Jet is right for me"? as it covers your questions.
I think mine is doing the same thing that yours is doing. I have set all adjustment and tried different coil positions and different pull off positions. On mine when you first start it cold you have to keep you foot on the gas right when it starts or it will flood. Mines on a 454 in the tow truck. Its like the pull off can't act fast enough to give it air right when it starts. After that it's fine. The other thing that sucks on the electric choke is you go somewhere and when you come back out to start it you don't hit the gas or the choke will set. Then after you accelerate the choke comes on again till it heats up electrically to shut off again. I thought about putting the heater hose against the housing to keep it warm like on the 307 Olds motor.
Add a ground wire to the choke housing so it will get hot faster. If you do not add the ground wire the choke seeks ground through the choke linkage which is a poor ground. It also sounds like your primary choke pull off is not set right or your electric choke is set too tight.
The choke pull-off and fast idle speed adjustment on the highest step on the cam are the key players here, not the choke itself. The choke should be set when the engine is dead cold, dialed in counterclockwise till it just closes the flap completely, then about 10 degrees or so further, or put the mark on the choke in the center of the "range" of marks on your housing, IF you are using the correct choke coil and it is marked. That is going to be your base setting. On start-up, the throttle is depressed once or twice, which allows the choke to close the flap, and provides some fuel from the accl pump to get the engine to fire. Once it fires up, the choke pull-off unloads the choke slightly so that it stays running, not too rich so it chugs, or so lean that it dies out. This adjustment is the KEY to success here. The fast idle speed is also a player, typically about 1200-1400rpm's at initial start-up is fine. Those later carburetors have an adjustment screw right on the pull-off that controls the angle of the choke flap. You have to work quickly on initial start-up to find the flap angle that the engine likes. If you have an open crossover in the intake, it's going to heat the parts quickly, so you basically only get one shot at this per cold start-up. The choke coil itself (there are many part numbers) should go from fully closed to fully open in about 3 minutes. To make it stay in longer it will need to be turned a few degrees counterclockwise. Keep in mind here that there are many different electric choke coils, some being sold aren't even for Q-jets, but still fit the housing. If it doesn't "clock" with the terminal down, and doesn't unload like it should, it's probably for something else. The part we sell has been researched and fully tested to work like it's supposed to. We have next to zero issues with them, even in long term service......Cliff http://www.cliffshighperformance.com/parts.html#a
I played with it some more and I got it to work. I gave it a little more high speed idle. It is about 1650 RPM's. It starts and goes just fine. Is that acceptable or is it just masking the problem? I also opened the vaccum break a little. There is a bigger gap there after start-up than I am used to seeing. I start it and wait 15 seconds and kick it down to the middle step, seems to work. Thanks for all you advise.
As related to this topic, we sell the correct electric choke for the q-jet. I took every single part number still avaiable and tested each one of them, to find the one that "clocks" correctly, and works the best. We have next to zero issues with them, and to date the only ones that were returned is when the installer put a gasket between the choke and the housing (no ground)....DUH!.......Cliff
Cliff. Will this electric choke be for the 350 or 455 quadrajet? Also will it mount directly to the carb or to the intake?
The E-choke kit that we sell is to replace an existing carburetor mounted E-choke, or "hot air" choke. Our kit includes the choke, clips, screws, and the OEM style electric connector. There are a few divorced E-choke conversions available, but we don't sell them here.....Cliff
>>Thanks for letting me know Cliff. I'm running an aftermarket non electric choke at the moment but picked up a '76 Buick quadrajet carb with the electric choke for a future rebuild.
