Thread: Mis-Fireing out of Carberator

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I have a 1985 Pontiac Bonneville with the original Motor in it. It has the 5.0L 305 V8 with the original Rochester Quad-Jet Four Barrell. The motor just hit 100,000 miles. I am the second owner.
I have owned it for about 2 years. Motor has never been tampered with, either has the Carburator. All I did since I have gotten it is given it a tune up and put the hyper-tech chip in it about a year ago just for better gas milage. It's been driven daily back and fourth to work since I've bought it. But my work is about 25 miles away so everyday I got it over 60 mph. 6 months ago I quit driving it to work and had my wife start driving it daily to her work which is only 2 miles away there and back so the car hasn't seen 50 mph in the last 6 months. Now just last week it started popping from the carberator. It only does it when you goose it. Now I have talked to 6 different mechanics and 4 of them say its the timing and 2 of them say it needs a CAM job. Yesturday I went out and bought the Distributor Wrench and loosened the distributor a little bit, I turned it a tad to left aand still got popping, turned it to the right about an inch,still popping,another inch to the right still popping, and another inch to the right and still popping, so then I turned it back to the origianl position and re-tighting the distributor bolt. So I guess I ruled out the timing being the problem. Now what I need to know from you guys, does it need a "CAM JOB"????? Help Me cause I don't feel like dumping $500.00 right now.

Well even if you goose it in Park, Drive or nuetral, it does that popping sound from the Carb.

At this point, I'd be thinkin' about finding another motor. Look in the Jacksonville paper in the "Parts & Equipment" section of the want ads and search for someone parting out a GM product that's been wrecked or partially burned (interior or rear of car) with a 305 or 350 motor. I suspect you could buy a good running motor for $250 or less. Rent a cherry picker from the rental yard and enlist a buddy to help. You could change the motor out in a weekend easily, particularly if you chose a motor from the same year and make as your car and didn't have to cobble up fuel lines and such.

if you were closer I could get you a 305 that just needs some cleaning and a tune up for 125

if its a pop its a cam. one of the exhaust lobes is wore down on the cam so bad it want open the exhaust valve and thats exhaust you are hearing coming back up through the carb. because it cant get out of the tailpipe. i vote cam.

Could the dist have a carbon runner causing misfire? When did you tune it up last? How many miles since? Has the dist gotten wet? These are some things I would look for before replacing the engine or cam or anything. Check to make sure it is not an ignition problem first.

Just my opinion.

jramshu, dont take this the wrong way now but, i agree we didnt cover all of the bases and i guess no body should take anything for granted on here, but i would and everybody else on here would to,if they tell someone it might be the cam, he would know to pull the valve cover and check it first before he tore the motor down. he probably didn't know anything about a flat cam, but it don't cost anything to look.(pull a valve cover) the steps he should take is check comp., check for flat cam, if he don't see anything wrong then spend the money for a tune up, but with the miles and a pop in a SBC i would think the cam would be the first thing to check. he don't know what a carbon track is either so in this case looks like the best thing would be to go to the worse first and back out of it and don't spend any money until you know for sure. i hope you take this as a discussion and not a cut. its 90% cam and 10% cap, but he will spend the 100.00 for cap and wires hoping that's what it is, when all he need to do is check the cam first.

That's fine, no hard feelings here. I am not disagreeing with yall. I just thought I would throw that in there. MAutozoner2 don't spend money just because of my opinion.

[QUOTE]Originally posted by jramshu
That's fine, no hard feelings here. I am not disagreeing with yall. I just thought I would throw that in there. MAutozoner2 don't spend money just because of my opinion. [/QUOTE


good we gave him something to think about anyhow.

I even stayed on the main topic this time..........

I agree with all of you. A friend already told me to pull the valve covers to see if one of the valves is sticking. I guess it wouldn't hurt to do a Cam job on that motor. Another friend of mine had the same 305 in his Monte Carlo and put a mild cam in his and said it was the best thing he ever did to that motor. He said it opened that motor up WIDE OPEN. I got a mechanic thats honest that will do a CAM job for $350.00. that includes Cam, timing chain, & lifters.

keep in mind you still got 100,000 mi on the rest of the motor.

good point, but at the moment I am trying to sell the damn thing because the wife is bitching about no AC and the gas prices are not helping and it just started making this damn noise with the for sale signs on it!

thats when it happens.

There is a guy coming over to buy it, well he wants to anyways. He seen me cruisin in it today but didn't hear that sound cause I wasn't gooseing it, so he might not even test drive it. If he does test drive it and questions the poppin noise, I'll just tell him it needs a carb rebiuld cause he doesn't know shit about motors.