Emergency- Qjet bog

[freemonty]

Afternoon ladies and gents,

I got a bit of an emergency. I've got to drive from Chicago to fort Wayne tomorrow in my 71 C10. Just yesterday it started bogging under throttle AND just randomly during cruising. It's a stock 350 with Qjet. I've read a bunch on the Qjets secondary air valve needing adjustment but what's confusing me is that itll bog when I mash the throttle and then every 20min or so I'll just be cruising at speed and without any acceleration it'll just bog off and on for a few seconds.

I figured itd be just one or the other. Im really looking for a quick fix if possible and then when I get home I can pull the thing apart if I need to.

I have limited tools with me since I'm here for the holidays.

Happy new years, and thanks for the help!

R
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[trac209]

Could be a number of things. Fuel filter should be your first check. Did you get some strange gas recently? Could be some water in fuel. I would add a fuel system dryer a new filter,check secondary's operation and lube linkages. Good luck
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[Wrenchbender Ret]

There is a small fuel filter in the carb were the fuel inlet line goes in. If it is pluged up it will cause this. It could be the pri. metering rods stuck. If you stick a screwdriver down the vent tube with the engine off you should be able to push down on the holder & spring back up. I dought it is the sec. air valves. They only function under heavy throttle.

[Ol Blue K20]

I vote on the fuel filter

[Stocker]

I agree with possible fuel filter or fuel contamination... might also be a failing fuel pump.

[freemonty]

Thanks guys, I'll try the filter. I replaced it a few thousand miles ago but it can't hurt anyway. Hopefully I have a wrench big enough, I remember it takes a pretty large one to get off the fuel line.

I'll throw some water remover in the tank and see what happens.
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[Ol Blue K20]

1" and 5/8" wrenches, Good Luck

[Coley]

I agree with the fuel filter....that is in keeping with this kind of carb behavior.
I would avoid 'mashing' or 'flooring' the vehicle on your trip home if possible. If something else is marginal in/on the carb then this kind of throttling will probably send it over the edge. ie: 'dont' push it' until you are better set to deal with the consequences.
I would make sure I had a good flashlight for the trip back and just some basic tools...enough to take the top air horn off....including a small punch pin to move the linkage pivot pin out of the way. As well, make sure you have a tool for all the attachment/adjustments points on the carb including the fuel inlet....this shouldn't take too much.
That way, if you do need to peek in the top of the carb you will be able to do it quickly and easily.
Check/change the filter and taps its contents out on a table...you might be surprised what comes out.
Make sure you don't run the gas tank below 1/4 if you can help it.
good luck
Coley

[freemonty]

New filter is in and Heet is in. Old filter wasn't too bad, not nearly as clogged with junk as the last time I pulled it out.

It didn't run too bad on the way to the auto parts store which reminded me that it only really happens when the truck is warmed up.

I noticed something else interesting when I was cleaning the carb up with some carb cleaner. When I sprayed it into the secondaries it started to drip out from the drivers side right from the secondary shaft. It actually pooled up on the manifold. Is that dangerous?

I will of course baby it when I head home but it happens even when I'm just cruising at low rpm. We'll see!
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[Wrenchbender Ret]

It will be normal for the carb spray to puddle up & leak out the shaft. The secondary throttles seal tightly. There is no fuel going to them untill they open which is about 3/4 throttle.

[freemonty]

I made it!

That's the good news. I babied her the whole way, kept it under 60mph and did not have a single issue the whole 4hrs.

Now here's the bad new: this morning I was driving to work and started getting the bogging on the interstate, it got progressively worse until I was about to pull into the parking lot and then the truck just completely died. The electrical was still working, I had flashers and the radio, but THERE WAS NO IGNITION. The truck wouldn't even turn over.

About 20min later I tried the ignition again and BAM! started right up. It's sitting in my work parking lot now.

So.... now it seems that the problem was never the carb at all. It's got to be electrical right? It almost seems like the bogging is the engine actually cutting out completely. Why would it lose the starter? If there's a bad connection, where would it be that it would cause me to lose ignition?

I hate electrical.....

[hyatt]

Check alternator output If battery voltage gets too low engine will bog from lack of hot spark A good battery will sometimes recover enough charge to start after setting a while thus the restart after sitting

[71GeneralMotorsCorp]

yeah, try the alternator or external voltage regulator. The voltage regulator is on the core support on the drivers side. My 71 had that problem with stalling and not starting then randomly starting again. If your alternator is going bad it won't push enough amps through the system so the distributor won't get enough amps to push all the cylinders. strange, I know. I went through so many parts like a new carb, distributor, battery, etc. just trying to save you some money and time.

[freemonty]

Sounds like a good place to start with the alternator. Fortunately I keep a multimeter in the truck. I'll check the output on alternator and regulator and likely check continuity on my grounds as well.

Thanks, wish me luck. Of course this would happen on the coldest day of the winter....

[freemonty]

Alrighty, so my multimeter was dead and I took it to Autozone and everything checked out per their tests though I don't know if they checked the regulator. I will get some new batteries for my meter and check that.

The truck drove fine to and from there. I'm starting to suspect a bad connection or bad ground. When I get home I will clean the battery posts and check connections.

[freemonty]

Well, this is embarassing........

I debated not telling you guys this, but in case someone was genuinely interested in how things worked out for me, I think it'd be best to share and maybe someone can learn from my mistakes.

TURNS OUT MY TRUCK STILL HAS POINTS!

I was under the impression that it'd be converted. The points were going bad and that was the cause of the bogging. Yesterday it died on the way home and I had to have a friend tow me a couple miles home. Also, I'm guessing the reason that the ignition didn't turn over that one time was because I had left it in drive.....Oy...

Anyway, I'm taking this opportunity to put it an HEI system. Thanks for all the help guys.

[Ol Blue K20]

Oh well it's just a reminder of what we all forget "it's probably something simple" I know I have done it multiple times. Glad you found it

[alsriv2]

I am glad you were able to find the problem. I had problems with an old GMC I had where the condenser in the distributor kept getting fried. I have no idea what was causing that failure but while driving that truck in Phoenix for a couple of years, I learned to keep a supply of condensers in the glove box along with the tools needed to swap it out.

[no moa]

Been there, done that. (Left truck in gear) that moment that makes you go "duh" glad you got it figured out.
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[Shyguy]

Glad you figured out the problem. Electrical problems sure can cause a person a lot of problems.

Points work great, but do require attention from time to time.

I have chased more than my share of electrical gremlins over the years.