Hey gang,

My QJet is tuned up to the nth degree. The choke is all set properly and once the engine is warm it runs flawlessly.

But when the temp gets down around the freezing mark the car stalls when I first start it in the morning. To keep it running I have to pump the pedal several times.

It has done this for more than a year now. EVERYTHING on the exterior of the carb is PERFECT--we've gone over it with a fine tooth comb!

We also checked all the vacuum lines and the maniflod gaskets, there are NO leaks.

It gets 19 miles to the gallon around town on my 305 so it does not need rebuilding. That was done fresh about 2 years back.

Does anyone have any idea what the problem might be?

 

You're still running the Qjet?

 

What, you don't believe me?

 

Mine was like that. I richened up the choke adjustment a little and moved up the high-idle a bit. That helped alot.

 

We've done that several times now, to no avail

It is like it just runs out of gas. But we've changed the fuel pump and that's not it. Once it gets running it works OK, but it takes anywhere from one to three tries before it settles down and runs

 

Does it stumble when given some throttle while cold? and have you done any mods to it that may lean the mixture (like exhaust)?

 

Yes, it simply will stall if you throw it in gear and try to drive before it is warmed up a bit. This is characteristic of all QJets.

I have headers and 3" exhaust, as well as ported and polished heads and a Performer intake. But there is NOTHING computerized about my car. It is Canadian and doesn't have any of those computer driven carburetor parts or ignition parts.

If it is 70* outside chances are it will start and run just fine. But get down around 40* and it is a whole different ball game

 

Assuming that your choke is working correctly and is just unable to richen the mixture enough:

If it is non-ccc you may want to richen your primaries. You can go with smaller rods during the winter and swap them back when it warms up (or you may find increased performance from them always). See what you've got and go one or two sizes up. Check some junkyards.

You can also relocate the rod that connects to the fuel pump lever slightly closer to the carb. Some older q-jets had two holes for it to fit, the closer hole increases the leverage on the pump which provides a stronger shot as the throttle is opened. I drilled a second hole in mine and it eliminated the cold running stumble I had. I go back to normal position in the spring. Course I live in SC and we consider it cold when it gets below 50.

 

The pump rod is already in the hole closest to the carb ...

 

If you've done all you can with the choke you can look at your primaries next. If you've made all those mods and haven't changed anything, it's probably due. You could be running lean all the time and only notice it when cold (have you been looking at your plugs?). I would recommend getting hands on an air-fuel meter or get a shop to check it since you don't have an O2 sensor. Or you can find some parts from a junkyard q-jet already sitting on a 350 and trial and error it.

When you installed new exhaust/intake you probably also removed the butterfly valve (EFE) in the passenger y which used to route exhaust gas back through the intake manifold to aid cold weather warm up. Another reason your choke has to work harder now. (I'm assuming the canadian model had this).

This could be all off-base, but you say your choke and everything else is working perfectly.

 

Thanks naf! No, your comments are helpfull. I think it must be as you suggest, the primary rods need to be richened. (The 305 is putting out twice the hp it did as an LG4.) That is the only thing left to do, as far as I can tell

And you are right, the passenger side exhaust thingy is long gone now. Apeiron also axed the EGR a long time ago ...

If anyone else has any other ideas please come forward.

 

Oh yeah, so it's all my fault now. :P and you wonder why I'm going back to BC instead of Calgary.

 

EDIT: nm

 

My Q-jet is doing the EXACT same thing as your's Sitting bull.I was going to post but you went and did it for me.Like you,i've got everything adjusted as well as possible and once it gets past the initial start and furious pedal- pumping for about 30 seconds,the fast idle will keep it running while it's warming up.I've had the top off twice now to check float level and visually inspect everything and wondered about the rods and jets,but the jets are 77's and the metering rods are 52's('k' i believe)i thought were big enough,may i ask what your running for rods and jets?I have been using a Holley on this engine for awhile,so there have been some changes to the exhaust and intake since i've used this carb.I've got afew jets and rods but don't know if i can come up with an effective combo or not.I've got a set of 72 ,and 73 jets along with a set of 43k and 50 straight taper metering rods.Would any of these help the situation?Maybe the 50 rods?Except for the cold start, this carb works great.

 

How have you got the timing on that thing set up?

 

On the primaries I don't even know what the jets and rods are. Whatever came standard on a Canadian LG4 in 1986 I guess. You would have to talk to someone who is familiar with QJets and I'm not exactly the person you need. lol

What you do want is a thinner set of rods than what you have. I'm supposing that one step richer (thinner) on the rods would probably put mine in the right area.

Chris, you talking to me about timing?

 

If it runs fine when warm, the only possibility left is that the choke isn't actually set and/or working properly.

Well, I suppose there's one other possibility - the infamous "q-jet well plugs". When the car sits, the gas leaks out of the fuel bowl through the main metering circuit well plugs on the bottom of the carb. The gas then sits in the intake manifold plenum, so when you first start it, it has that gas to burn. But then when that's used up, the fuel bowl isn't full yet, so it dies. You crank it over and pump the accelerator, the fuel pump refills the fuel bowl and it finally starts running.

You indicated it's fine when the weather is warm, but this only happens when it gets cold out. I don't have any explanation for that, unless there is some thermal expansion/contraction differences that are taking it over the edge - but that's pretty far out there. It may just be more capable of running with a leaner mixture (fuel bowl level lower) when the weather is warm.

 

Yup

 

I don't even know. I think it is about 8* advanced. I just turned it till it pinged and then nudged it back a touch till it stopped pinging.

Tim, we did plug those leaky spots inside the carb with JB Weld, so that shouldn't be a problems.

 

Is it a stock curve, or are you running one of the Crane kits? I don't remember. And is your vacuum advance ported or full-time?

 

Hmm, you're really holding my feet to the fire here ...

As far as I can remember it has a Crane vacuum advance kit, which comprises an adjustable vacuum can and a selection of springs. I've used the medium weight springs and turned the can nine turns out from the bottom using the supplied allen wrench. This provides a pretty lively ignition curve and is basically the stock advice Crane issues with the kits.

It is not taken to the max, however, as everyone I had working on it said the lightest springs will just cause trouble with the idle. It idles very well right now and comes on very nicely as you step on it, with no pinging.

I don't know if the vacuum can is ported full time or not. It is pretty much the way it was from the factory.

Of course if you bothered to come down to Cowtown from Deadmonton you could drive it yourself and satify your curiosity on the matter

 

Movers are picking up my stuff here on the 12th. The plan right now is I'll be driving to Calgary that night and staying there, going west on the 13th.

 

Well, give me a call on the 12th then.

247-5076
56 Citadel Manor NW

 

Hey guys. I'm still following and waiting to see what the solution was. The timing should be an easy one to test. Be sure to post when you've gotten somewhere. Good luck.

 

Sitting Bull: This problem is so basic I'm suprised nobody jumped on it yet.

The stalling you're experiencing just after starting the car is nothing but plan old CARB ICEING.

When a liquid (gasoline) vapourizes, it absorbs heat as it changes state. (liquid to gas) when it absorbs heat the water in the air (humidity) freezes causing a buildup of ice on the edges of the closed throttle blades. The ice buildup stops all airflow into the carb and the engine stalls.

The ice melts quickly and you can restart it
but it will stall again unless you open the throttle or the engine has heated up enough to prevent the iceing.

You'll notice this every year at this time of year (late fall) when the temp is right about 40*F (in Calgary) Once winter sets in and the Oil Co.'s switch to "winter gas" the problem will go away. (methanol in the gas)
You can add a few cans of gas line antifreeze yourself to eliminate/ reduce this carb icing problem.

Try switching to Sunoco gasoline. It has Ethanol already mixed in.

 

That sounds good but I don't know if it's the case. It might be but we get all kinds of temps throughout the year and this is still happening when winter gas is available. So I dunno ... It's a year round problem in that respect.

No such thing as Sunoco in Cowtown. And we ain't got much humidity either at 3500 ft.

 

Just checked your weather for tommorrow morning. Looks ideal for carb icing.

Low temp and high humidity

http://www.theweathernetwork.com/wea...s/CAAB0049.htm

One of the available brands of gasoline in Calgary will be Ethanol blended (10%)
I think its Husky out west there. Give it a try next fillup. Let me know if it helps.