engine popping at wot

[drewdude92]

my truck runs perfectly starting and taking off but. there are three problems i have had 1. when taking off at normal pressure on the gas pedal right when it shifts into 3rd gear it stutters. 2. crusin down the highway at about 65-70 sometimes it will stall a lil bit and pop. 3. when you are crusin at about 55 and give it wot it makes horrible popping!! i just put a new 600 cfm edelbrock carb on it and idk what else to do?

[Wrenchbender Ret]

First check the plugs & wires. It's quite possible you may have a worn camshaft lobe. Pull the valve covers & crank the engine over. Look for a valve thats not opening as much as the others.

[Jtrux]

Does it backfire out the carb or exhaust?

[Longhorn Man]

Lets not jump to big problems here.
How long since you've replaced spark plugs, wires, cap and rotor?
And do you have HEI or the old points ignition system?

[drewdude92]

Originally Posted by Jtrux

Does it backfire out the carb or exhaust?

out of the carb

[drewdude92]

Originally Posted by Longhorn Man

Lets not jump to big problems here.
How long since you've replaced spark plugs, wires, cap and rotor?
And do you have HEI or the old points ignition system?

i replaced the plugs and wires not but a few months ago when i put my new carb and intake and all on.
i have HEI

[drewdude92]

Originally Posted by Wrenchbender Ret

First check the plugs & wires. It's quite possible you may have a worn camshaft lobe. Pull the valve covers & crank the engine over. Look for a valve thats not opening as much as the others.

ok thanks will oil go everywhere? will i only have to do it on one side or both?

[Stocker]

Originally Posted by Wrenchbender Ret

It's quite possible you may have a worn camshaft lobe. Pull the valve covers & crank the engine over. Look for a valve thats not opening as much as the others.

I had this happen once, on my wife's '68 327 Camaro. Some of these had (or developed) oiling problems to the front cam lobes.

[LONGHAIR]

Since you just installed a new intake, I would look for vacuum leaks first, along with all of the ignition related parts that Longhornman suggested. If, after all of that, you still have this problem....the flat cam is the next thing.

Some will say that it can be done with the engine still in the truck...simple cam swap. IMHO however it is not that simple. All of the junk that wore off of the cam and the bottom of the lifter went through the entire oiling system. I will overwhelm the filter and cause it to by-pass. That puts metal particles in/on everthing inside the block. Besides, stripping the entire block is the only way to safely remove the lifter. It needs to go out the bottom of the bore because there is usually a big burr around the bottom of the lifter body.

[drewdude92]

Originally Posted by LONGHAIR

Since you just installed a new intake, I would look for vacuum leaks first, along with all of the ignition related parts that Longhornman suggested. If, after all of that, you still have this problem....the flat cam is the next thing.

Some will say that it can be done with the engine still in the truck...simple cam swap. IMHO however it is not that simple. All of the junk that wore off of the cam and the bottom of the lifter went through the entire oiling system. I will overwhelm the filter and cause it to by-pass. That puts metal particles in/on everthing inside the block. Besides, stripping the entire block is the only way to safely remove the lifter. It needs to go out the bottom of the bore because there is usually a big burr around the bottom of the lifter body.

i shouldnt be a vacuum leak because it did all of the popping before i had put the new intake on so...i guess ill replace all my ignition stuff...im sure that will be cheap

hmm a flat cam? that would suck i hope that isnt the problem but if it is ill just rebuild my whole motor

[Bus Ted Knuckle]

Sounds like ti might be running a little lean to me, Im with the check for a vacum leak crowd.

[Jtrux]

Lean, crappy fuel filter, accelerator pump malfunction (maybe), intake valve stuck open (improperly adjusted rocker arms, it would also spit raw fuel out the carb if this was happening), vacuum leak ( make sure your carb is bolted down well and the gasket isn't torn or anything like that cuz you don't want air being sucked imbetween the carb and intake).

Some of these you can rule out automatically like accelerator pump for instance.

Now that i'm reading your original post again, are you sure it's not pinging you're hearing or predetination.


Retard the timing a bit and see if it still does it or run some better gas. It seems that when you put a load on it, it's worse. Maybe i'm on to something, who knows.

[drewdude92]

yeah im thinkin it is running too lean that is what some people told me.
I dont know what your talking about pre detination? im lost on that one lol
its like its backfiring out of the air cleaner really fast whenever i rev it up under the hood and ive tried setting my timing all over the place and no matter where i would put it it would still do the poppping

[Jtrux]

Originally Posted by drewdude92

yeah im thinkin it is running too lean that is what some people told me.
I dont know what your talking about pre detination? im lost on that one lol
its like its backfiring out of the air cleaner really fast whenever i rev it up under the hood and ive tried setting my timing all over the place and no matter where i would put it it would still do the poppping

EDIT: I'm just gonna rewrite my whole post, i'm getting confusing.

Two things may be occuring, detonation or preignition.

Detonation occurs after the initial ingiton induced by the spark plug. Too much advance and/or low octane fuel may be culprits here along with many other things to think about. You will hear the engine ping or knock when this occurs.

Preigniton occurs before the spark plug ignites the fuel mixture usually at the botttom of the compression stroke, it's typically undetectable as far as sound goes.

If you're hearing anything it's more than likely detonating, try running better gas or retarding the timing.

[ChevyC102007]

Mines starting to do this too, especially taking off and when I shift to 3rd. I just replaced the cap rotor and plugs (HEI Ignition). Put on a new choke thermostat, havent checked the timing lately, adjusted the valves last time I changed Valve cover gaskets. Checked for Vaccum leaks (used carb cleaner and sprayed around the vaccum fittings). I had a tapping coming from the driver side of the motor when I first got it and can still hear it sometimes.

[drewdude92]

alright ima try the better gas first i have always just used the lower octane fuel ima try a tank or so of 91 then if that doesnt work ill try to mess around with my timing a lil bit what do you think it should be set at?

[drewdude92]

Originally Posted by ChevyC102007

Mines starting to do this too, especially taking off and when I shift to 3rd. I just replaced the cap rotor and plugs (HEI Ignition). Put on a new choke thermostat, havent checked the timing lately, adjusted the valves last time I changed Valve cover gaskets. Checked for Vaccum leaks (used carb cleaner and sprayed around the vaccum fittings). I had a tapping coming from the driver side of the motor when I first got it and can still hear it sometimes.

yeah mine didnt do it before i put my edelbrock on...but my quadrajet was bogging really bad when i would take off and starting was hard so i guess i traded those problems to the ones i have now lol

[Sinister]

I had this problem after getting my engine pressure washed. It was an ignition problem. I ended up swapping to an HEI.

[bryanw1968]

What do your plugs look like? If it is the carb or a vacuum leak the plugs will tell you what you need to know. It is possible that you have a bad cam load however I would think that you would experience popping at any RPM if that were the problem. Is there smoke at any point?

[drewdude92]

i havent looked at my plugs yet i guess i should. Yes there is smoke right whenever i start it up most of the times but that is just my valve seals

[justcuz]

You developed this problem after you installed the intake and carb right?
Go back to sqaure one, crank the engine around to number 1TDC make sure your timing is right on the money. In other words rotor pointing at number 1 on the cap. If you put the dizzy in one tooth off all this stuff will happen.
After you do that and set the timing, plug in the vacuum advance and run the engine up from 1000rpm's to 2500 or so and hold it. Make sure the timing marks stay steady. If not your timing chain is whipping and causing your timing to go to crap. Next check plugs, then wires to make absolutely sure they are on the right plug and that they are on good with no corrosion at the ends at the cap or plugs. (I clean my engines with a hose occasionally and this is a big culprit for misfires if you do not use dialectric grease on the ends). Your valve seals may be leaking enough to foul the plugs and cause these misfires too. If the igniton timing and chain check out then go for vacuum leaks or carb trouble. Frankly I like quadajets and would not put anything else on a small block (except fuel injection). Chevy makes better intakes than most aftermarket stuff and you can find about 4 different intakes at junkyards from low rise to high rise for a 350 that are cast iron and work great. Hopes this helps.

[Jtrux]

Originally Posted by drewdude92

i shouldnt be a vacuum leak because it did all of the popping before i had put the new intake on so...i guess ill replace all my ignition stuff...im sure that will be cheap

hmm a flat cam? that would suck i hope that isnt the problem but if it is ill just rebuild my whole motor

Originally Posted by justcuz

You developed this problem after you installed the intake and carb right?
Go back to sqaure one, crank the engine around to number 1TDC make sure your timing is right on the money. In other words rotor pointing at number 1 on the cap. If you put the dizzy in one tooth off all this stuff will happen.
After you do that and set the timing, plug in the vacuum advance and run the engine up from 1000rpm's to 2500 or so and hold it. Make sure the timing marks stay steady. If not your timing chain is whipping and causing your timing to go to crap. Next check plugs, then wires to make absolutely sure they are on the right plug and that they are on good with no corrosion at the ends at the cap or plugs. (I clean my engines with a hose occasionally and this is a big culprit for misfires if you do not use dialectric grease on the ends). Your valve seals may be leaking enough to foul the plugs and cause these misfires too. If the igniton timing and chain check out then go for vacuum leaks or carb trouble. Frankly I like quadajets and would not put anything else on a small block (except fuel injection). Chevy makes better intakes than most aftermarket stuff and you can find about 4 different intakes at junkyards from low rise to high rise for a 350 that are cast iron and work great. Hopes this helps.

It did it before he installed them too.

[drewdude92]

no it started the popping right when i installed the carburetor. i had my new carb on for about a month before i did my whole intake installation. but ill check my timing some more this week im gonna take it to a guy that actually knows what he is doing for sure so hopefully he can fix me up! lol

[ChevLoRay]

Which 600 Edelbrock did you install? There's manual choke and there's electric choke models.

My truck had a manual choke and it was jetted for performance (according to Edelbrock). It ran rich and would gas-foul plugs, from time to time. Invariably, at some inopportune time, it would foul one and when it did, the popping started.

Check your plugs, if you haven't already done so.

[drewdude92]

it is the electric choke model. From what ive heard from people that model always runs lean?