My truck is misfiring..help!

[ivorton74]

I'm getting pissed off now. my trucks been running weird for awhile now and im tryn to figure it out. She's misfiring, hesistating, idles erratically and now it even stalls out on me while driving. I changed plugs, points,condenser,fuel filter, fixed the vacuum leak on my carb, checked my coil, adjusted the mixture on my carb and checked the condition of my plug wires. I know that the vacuum advance control on the distributor dont work and my uncle tells me that could be the problem. I'm starting to think that its my fuel pump but im just guessing. It would idle smoothly one minute and erratic the next. anyone know what it could be?? Im getting frustrated!!

[rs72z]

First off the vacuum advance will not cause it to miss. What carb do you have? Have you had it apart and checked for trash or water in it?
Have you checked the distibutor shaft to makes sure it isn't worn and has slack in it?

[ivorton74]

Has the stock quadrajet carb. have not taken it apart and the distributor shaft has no play in it. heres a short vid of it idling...

http://youtu.be/GK0Q0WmO64s

[All Biz]

try getting a fuel pump

[Corts60]

My vote is on the fuel pump as well. They can be erratic when they fail sometimes.

[72lb4x4]

It seems to me that since it runs the pump isn't a problem. I didn't hear anything in the vid.

Maybe open the hood after dark to see if any spark is going where it shouldn't... Cheaper than a fuel pump.

[ivorton74]

Originally Posted by 72lb4x4

It seems to me that since it runs the pump isn't a problem. I didn't hear anything in the vid.

Maybe open the hood after dark to see if any spark is going where it shouldn't... Cheaper than a fuel pump.

yeah i did that and didnt see any spark. listen to the video again...its better if u use headphones then u would hear it better.

[72lb4x4]

Yikes. I was trying to help with the after dark thing. If you want to be a dick, feel free. Ahole!

[INSIDIOUS '86]

Im sure he wasnt trying to be rude in any way but its foolish to try and interpret tone in text, IMO

moving on....

the fuel pump is a 20 dollar fix and it cant hurt to replace it anyways if you have an older one, fuel pumps do act eratic when they die out so it may be worth checking.

also try and get your vac advance working and can you see if you can find out your timing specs? your initial and total please

[72lb4x4]

Sorry

[bikes&bowties]

Were any plugs oily?
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[ivorton74]

@72lb4x4...whoa man why the name calling? I answered ur question politely man. Wasnt tryn to be mean or anything...wow.

anyway@bikesandbowties...there were 2 bad plugs on the right side of the motor( the 2 rear-most ones). They got fouled cuz the carb was running rich and I kept tinkering with the mixture screws tryin to get it running properly. Im new to chevys and am tryn to learn as much as I can. Im gonna try changing out the fuel pump. Its only 20 bucks at NAPA. Plus I think I wanna change my distributor to hei. I hate this point type thats in my truck now. The local junk yard has one for 45 bucks. Sounds like a good deal.

@INSIDIOUS86...Im gonna change that vacuum advance too.Its 14.99 at napa. i'll have to check my emissions label for the timing specs and get me a timing light. Never checked or adjusted timing before so this will be a first for me.

[INSIDIOUS '86]

well changing to hei is always a good idea,

when looking for a used hei find one with as little wear on the gears as possible and on that uses 4 pins on the module inside(little black box)

make sure the wights move ok and arent loose and floppy and make sure the shaft has no side play save money and go heu instead of buying an advance canister

pay no attention to the emissions label for timing specs your initial timing should be around 8-10 degrees without vac advance plugged in, this will make the engine run rough but still run, when you plugg the vac advance in to MANIFOLD vacuum it will run just fine

lets focus on one change at a time though. start with the fuel pump and play with the timing after if there is no change then go hei and if no change still well try a few things on the carb

[ivorton74]

Originally Posted by INSIDIOUS '86

well changing to hei is always a good idea,

when looking for a used hei find one with as little wear on the gears as possible and on that uses 4 pins on the module inside(little black box)

make sure the wights move ok and arent loose and floppy and make sure the shaft has no side play save money and go heu instead of buying an advance canister

pay no attention to the emissions label for timing specs your initial timing should be around 8-10 degrees without vac advance plugged in, this will make the engine run rough but still run, when you plugg the vac advance in to MANIFOLD vacuum it will run just fine

lets focus on one change at a time though. start with the fuel pump and play with the timing after if there is no change then go hei and if no change still well try a few things on the carb

kool...i appreciate the advice man. tomorrow im gonna check the fuel pressure and see how it is. then on monday ill get a new f/p and see how it work then move on from there. About the hei...I've seen some on ebay...there's this one selling for 69.99 with moroso wires. also summit has one for about $100. what do u think about that? im thinkin maybe ill just get a new one and save the trouble.

[bikes&bowties]

Im just saying I've come across misses from oil fouled plugs. Valve seals..
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[INSIDIOUS '86]

cheap man buys it twice,

i would suggest this one, about $100 shipped to your door

http://www.summitracing.com/parts/SUM-850001R/

[rs72z]

Make sure when you change to HEI that you run a new heavier 12+ wire to distributor. Don't want to you have a fire.

[ivorton74]

Originally Posted by INSIDIOUS '86

cheap man buys it twice,

i would suggest this one, about $100 shipped to your door

http://www.summitracing.com/parts/SUM-850001R/

yep that's the one i was talkin about from summit..i have it on my wish list. i really wish i get this engine running good again. I had plans for headers, intake and a cam. its always ran strong until now. cant wait for income tax time.

[i8tokyo]

Originally Posted by ivorton74

yep that's the one i was talkin about from summit..i have it on my wish list. i really wish i get this engine running good again. I had plans for headers, intake and a cam. its always ran strong until now. cant wait for income tax time.

Just a short heads up. Don't let the price fool you. This is the same dizzy that Summit sells. It has a different packaging, but comes off the exact same assembly line. How do I know, because I sell them too and get them from the same place. But I sell them for $89.00. I've been selling aftermarket performance for the past 21 years, and you can't beat these for the price. No, I don't work for Skip White...

http://www.ebay.com/itm/SBC-BBC-CHEV...item56461e9734

[ivorton74]

Originally Posted by i8tokyo

Just a short heads up. Don't let the price fool you. This is the same dizzy that Summit sells. It has a different packaging, but comes off the exact same assembly line. How do I know, because I sell them too and get them from the same place. But I sell them for $89.00. I've been selling aftermarket performance for the past 21 years, and you can't beat these for the price. No, I don't work for Skip White...

http://www.ebay.com/itm/SBC-BBC-CHEV...item56461e9734

i actually have that distributor saved on my watch list.

[INSIDIOUS '86]

look on craigslist and you may be able to find some headers used for under 100 dollars

[ivorton74]

oh yeah..ive been checkin out craigslist too...seen some nice headers for $80 sometime aback. I wanna get some long tube headers. summit also has one for 109 bucks.

[ivorton74]

heres a video of the truck driving. u will need headphones to hear it good. there's some wind noise though..sorry..
http://youtu.be/eeHg6aAeh3o

[Cue-Ball]

I think you need to go through and check all of the basics. Make sure the timing is correct, make sure there are no vacuum leaks, make sure the plug wires are all plugged in all the way, hook up your vacuum advance, etc.

Personally, I'd bet that the fuel pump is not the problem. Your truck will barely idle and as long as there's fuel in the bowls that wouldn't be a problem. Even if you're only pushing 2 psi of fuel pressure, your truck should idle without dying. Doesn't seem like a fuel pressure issue at all to me.

To be honest, it worries me a bit that you say you've already adjusted the carb but don't know how to set timing. Carbs are a hundred times more complex than timing and I wonder if your adjustment made things worse instead of better.

[ivorton74]

Well Ive never really adjusted a carb mixture b4 either. I just learned how to do it last week. I want to leran how adjust timing too but dont ahve a timing light. Im not a professional mechanic but I have some experience working on vehicles. I still have alot to learn which is why Im on here asking for help.