Author Topic: Carb and fuel issue question  (Read 15087 times)

Offline 46binder

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Carb and fuel issue question
« on: January 29, 2014, 09:34:44 am »
Hello, 1984 K30, 350 goodwrench engine, quadrajet I just rebuilt.  Haven't had good luck, not able to test drive it yet.  To top it off, was negative 17 below, 37 below with the windchill yesterday.  New float, electric choke, pulloff during rebuild.  Then I had to replace the tank selector valve.  It starts, I try to get it to warm up, and before the choke opens, it starts to stumble and die.  Then I squirt some gas into it, still nothing, barely tries to fire.  I try to pump the accelerator by hand, and I don't see any gas squirting in the carb.  New filter, I unhooked the fuel line and turn engine over, and its pumping.  Its been too cold out to do anything, but It starts, stumbles, dies, won't start, but next day it will start right back up again and do it all over.  I thought it could be bad fuel and a clog, but with it starting again after sitting, it sounds like it floods, but I don't smell like there's a bunch of gas, and like I said, I didn't see it squirt gas when I tried the accelerator.  I'm going to remove the filter, put in a clear plastic inline one, try again.  I have to check fuel pressure, see if it starts to drop off before it stumbles, but it a new pump.  I also thought of blowing out the lines, thought there might be a clog in the pickup tube in the tank.  I need to get this running so I can drive again, but the weather hasn't been helping my ambition.  At this point, I don't even know if the electric choke is opening yet.

Offline Boone83K10

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Re: Carb and fuel issue question
« Reply #1 on: January 29, 2014, 10:33:19 am »
Sounds like you have two issues. Follow this in order.

First, the choke. Check that you are getting 12V to it in IGN ON only (when you switch the key on to crank). If you are then proceed to checking that the choke flips open slightly when you start to crank. It should open anywhere from 1/8 to 1/4 inch. This is the vacuum pulloff. If not, crank the engine and open it some manually by hand. If it continues to run good then you need to adjust the vacuum pulloff, which isn't opening/not opening enough and is choking the engine out. You can bend the linkage from the dash pot to adjust. Do not try to fix by adjusting the choke spring.. that won't work as that only changes the duration the choke is on.

Second, the fuel. When you pump the gas you are squirting gas in from the accelerator pump circuit. Once cranked, your carb pulls from the idle circuit. If you do not get any squirt/at idle, you could have a bad accelerator diaphragm or you have created a vacuum in the fuel system somewhere. Take the gas cap off both tanks, crank the engine. If it runs good then you have a vacuum in the fuel system somewhere. Did you hook up the return lines correctly on the selector valve? Is a rubber line collapsing? Are the vapor lines hooked up from both tanks? What shape is your vapor canister in? If all that check out ok, you could have a bad needle/seat in the fuel bowl or a sunk float.
1966 Mercury Comet - Built 429 (First Car/Show Car)
1983 Chevrolet K10 - Built 350 (Winter Toy)
1992 Chevrolet Lumina Euro (Sold @ 265,000 miles)
2003 Ford Escape 4x4 - Mac Perf. Intake/Exhaust (Wifes' DD)
2007 Mercury Milan - Steeda Tuned (Summer Toy)

Offline 46binder

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Re: Carb and fuel issue question
« Reply #2 on: January 29, 2014, 03:42:34 pm »
I had checked the 12 volt to the choke prior, and yes I have 12 volt at the wire.  Choke is closed when not running, and when first started, about 1/8" gap.  Have not seen the choke light turn off yet, replaced the oil pressure sensor, now that works.  Have not seen the choke open completely yet either, but temps have been below freezing. 

You brought up vacuum in fuel system, that sounds possible, PO removed any charcoal cannister, and checked old photos of carb before rebuild, large vacuum ort that went to it was left open and I had put a plug on it.  Course I couldn't run it now, battery is dead, belt to alternator tore off.  Will be able to fix it this weekend and try.  Here are some pics of the truck, and carb vacuum lines.

Offline 46binder

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Re: Carb and fuel issue question
« Reply #3 on: January 29, 2014, 04:14:38 pm »
Forget it, cant post pic, says its too large.  I tried.
 
« Last Edit: January 29, 2014, 04:28:09 pm by 46binder »

Offline Boone83K10

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Re: Carb and fuel issue question
« Reply #4 on: January 29, 2014, 06:12:45 pm »
Post the pics to image host like imageshack or something. , or post to Facebook and hotlink from there.

 

1966 Mercury Comet - Built 429 (First Car/Show Car)
1983 Chevrolet K10 - Built 350 (Winter Toy)
1992 Chevrolet Lumina Euro (Sold @ 265,000 miles)
2003 Ford Escape 4x4 - Mac Perf. Intake/Exhaust (Wifes' DD)
2007 Mercury Milan - Steeda Tuned (Summer Toy)

Offline Boone83K10

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Re: Carb and fuel issue question
« Reply #5 on: January 29, 2014, 06:14:32 pm »
On the driver side of the radiator, right next to the frame, there should be a metal line. Is there a rubber hose from that to something? Is it capped?

 

1966 Mercury Comet - Built 429 (First Car/Show Car)
1983 Chevrolet K10 - Built 350 (Winter Toy)
1992 Chevrolet Lumina Euro (Sold @ 265,000 miles)
2003 Ford Escape 4x4 - Mac Perf. Intake/Exhaust (Wifes' DD)
2007 Mercury Milan - Steeda Tuned (Summer Toy)

Offline 46binder

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Re: Carb and fuel issue question
« Reply #6 on: January 29, 2014, 08:04:38 pm »
My son had to show me how to upload the pics. 

Yes, there is a tube coming out by the frame by the steering box, not plugged, nothing hooked to it.
« Last Edit: February 01, 2014, 04:12:01 pm by 46binder »

Offline 46binder

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Re: Carb and fuel issue question
« Reply #7 on: January 29, 2014, 08:07:37 pm »
truck

Offline 46binder

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Re: Carb and fuel issue question
« Reply #8 on: January 29, 2014, 08:09:56 pm »
carb

Offline Irish_Alley

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Re: Carb and fuel issue question
« Reply #9 on: January 29, 2014, 11:32:55 pm »
if you can after it warms up and the choke opens then it stalls put your hand over where the choke is and suffocate it and get your boy to turn it over. see if it will start.
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Boone83K10

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Re: Carb and fuel issue question
« Reply #10 on: January 30, 2014, 08:06:29 am »
You should run a rubber hose from that metal line up to the carb. Preferably use ported vacuum so you aren't introducing gas vapor during idle. Also it looks like you have a lot of vacuum leaks, although maybe you just took them off.

1- I assume that the air tube (the metal tube on rear passenger valve cover) no longer hooks into the air cleaner? You should get a breather cap to replace it.
2- I see you still have the cruise check valve but you no longer have the servo. You should cap the line that is open going to the firewall that is just laying there.
3- is your choke properly grounded?
1966 Mercury Comet - Built 429 (First Car/Show Car)
1983 Chevrolet K10 - Built 350 (Winter Toy)
1992 Chevrolet Lumina Euro (Sold @ 265,000 miles)
2003 Ford Escape 4x4 - Mac Perf. Intake/Exhaust (Wifes' DD)
2007 Mercury Milan - Steeda Tuned (Summer Toy)

Offline 46binder

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Re: Carb and fuel issue question
« Reply #11 on: February 01, 2014, 03:49:54 pm »
Another 4" of snow last night, still had some flurries but in between shoveling took some more pics.  The air tube does hook to the stock air cleaner, along with a smaller vacuum line going to the top middle rear port of the carb.  I did remove the cruise, but lines going up the firewall connect to a vacuum switch on top passenger side, and the other goes to some 'ball' cannister, gas recovery?  I have pics of both.  Large port on front top of carb was open when I bought it.  I capped it, but when I removed it some gas came out of it. 

Pic 1 shows front of carb with 4 vacuum ports.  Lower left is capped, top left is capped, lower right goes to dizzy, top large is capped. lower large middle goes to drivers side valve cover.

Pic 2 shows lower small port going to pulloff, top middle not currently hooked up but goes to air cleaner, hard line goes to one way valve that I hope isn't backwards and to brake booster.  Then theres a tree off the manifold, goes to pic 3 and 4, and I believe a vacuum switch for the trans.  Maybe previous pics will show some of that. 

I hope I got the lines right? 
« Last Edit: February 01, 2014, 03:59:29 pm by 46binder »

Offline 46binder

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Re: Carb and fuel issue question
« Reply #12 on: February 02, 2014, 02:54:00 pm »
This is really turning into a big turd, and is about to be tossed out.  Won't start at all now, don't know what is wrong now.  It turns over, I added a clear fuel filter before the carb and I can see fuel pumping, of course now it leaks where the line goes threads into the carb.  No EGR, but where it was is a plate that looks factory, with two brass or copper tubes, one sticks out.  Are these open holes into the manifold?  Doesn't look at all like the EGR blockoff plates I've seen before.  Cruise check valve, is that the white one?  It goes to the ball shaped vacuum canister and the other vacuum switch it the pics#3 and #4.  Any help before I throw in the towel?

Online bd

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Re: Carb and fuel issue question
« Reply #13 on: February 02, 2014, 11:43:49 pm »
This is really turning south, and is about to be tossed out.  Won't start at all now, don't know what is wrong now.  It turns over, I added a clear fuel filter before the carb and I can see fuel pumping, of course now it leaks where the line goes threads into the carb.  No EGR, but where it was is a plate that looks factory, with two brass or copper tubes, one sticks out.  Are these open holes into the manifold?  Doesn't look at all like the EGR blockoff plates I've seen before.  Cruise check valve, is that the white one?  It goes to the ball shaped vacuum canister and the other vacuum switch it the pics#3 and #4.  Any help before I throw in the towel?

Walk away for a couple of days and let the dust settle and your blood pressure return to normal.

Seal the fuel line nut with Teflon tape.  The tape won't seal the threads, but will allow the nut to tighten more effectively by lubricating it.  And, use a 6-point 5/8" tubing (flare) wrench or you'll have even more problems to solve due to a crushed tubing nut. 

In addition, that steel vacuum line off the back of the carburetor that connects to the brake vacuum reservoir should be replaced next Summer, since it's crushed.  But, don't worry about it until the weather warms.

The "EGR block-off plate" is actually the hot air choke stove.  The tube just makes a u-turn in the exhaust cross-over passage.

Exactly what is it you want to know about the check valve?
Rich
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Offline 46binder

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Re: Carb and fuel issue question
« Reply #14 on: February 03, 2014, 09:14:50 am »
Thanks, its getting a little frustrating here.  Below zero again when I woke up, and my lower back is sore from almost slipping on the compacted snow all around the truck yesterday.  No ambition to work on it, but this was supposed to be a winter beater for now, and its not on the road yet.  It was running before, only thing I did was added a filter before the one in the carb, removed that one, and air cleaner is off.   There was a vacuum 'tree' right behind the carb, split off between the items posted in pics#3 and#4, and I plugged it, and a new line and valve for the brake booster.   I do need to know the routing for the vacuum cannister, trans switch by the brake booster, and the other vacuum switch in the pic.  Can I just connect them all?  And where should the one way valves go?  I need to go charge the battery, and see if it will fire again after sitting.  Then I think I will go work on my IH Scout, that might be on the road sooner.