Bogs at WOT

[Flashback]

So I have been trying to get the 305 in my 86 C10 running well these past couple days. The first problem was that the engine bogged at more than 1/2 pedal. At first I figured that the double pumper on it was too much, so I switched it out for an Edelbrock 1406. Still had same problem but more pronounced, I assume because of less fuel being dumped in. I changed the plugs and cleaned all the contacts under the cap. Nope. However the plugs that came out all looked fairly new and were golden brown, except 2 of them. The one from cyl # 8 was black, sooty, and had a little buildup on it. This engine has all the emissions equip. and EGR removed. The one from cyl # 5 looks barely used. I unplugged that wire and the engine runs worse tho. I set base timing @ 4 degrees advanced, it was way off. It runs great now except it still bogs at wot and sounds like its sucking air though the carb. Vacuum reading drops to zero when this happens. I looked down the carb at the jets and they just drip the fuel as well, so I figure fuel pump isn't making enough pressure. So I get one and replace it. Nope still the same, except no ticking noise now.  So I am out of ideas, my only other thought is vacuum leak, maybe around the #5? I'm lost now, I need an experts help.

[Flashback]

Update, I retuned the carb, it runs great now, but it still misses/dies out at WOT.

[eventhorizon66]

Have you inspected the entire length of your fuel line, checking for kinks?

[Captkaos]

When you crack the throttle open you are going to go to zero on the vacuum...

You need to set base timing to about 10 and work your way from there.  4 is way to low.  Disconnect the vacuum advance when setting it.

Are you testing WOT with it parked or in drive?  You still have the same Edelbrock carb?

[VileZambonie]

Have you inspected the entire length of your fuel line, checking for kinks?

This

Advance your timing. Hook the vacuum advance directly to the full vacuum port on the carb. Set the total timing around 36°

If the vacuum gauge stays at zero when you mash gas check for a plugged exhaust.

[Flashback]

Well that seems like a lot of timing, 4 degrees is stock base timing. Its something to try tho

Could the exhaust size be causing a restriction? I measured it today and its 1-7/8" OD piping, that seems way to small even for a stock V8, I think my Honda's stock piping was that size. lol.

[VileZambonie]

....

[Irish_Alley]

your pipe is OK the only problem it could be there is a clogged cat, they will rob you allot of power and once they warm up you ain't going no were. but AS VILE SAID check your fuel lines and filter. when you said ticking noise you mean under a load or at idle

[Flashback]

Well update, I have been towing with this thing and everything. Still have this problem, seems as if a cylinder is missing. And when I pulled the plugs, the #5 cylinder looks like its barely been fired. Seems thats where my problem is at. Cap is good, plug wires are dirty but seem good, plugs are all gapped correctly.

[78 Chevyrado]

If you have a timing light, alternate hooking it up to each plug wire while the engines running.  if it flashes, that wire is good, if it doesn't that plug wire is bad.

Does it bog at WOT and then go on after a couple of seconds?  if so it's the throttle pump on the drivers side front, adjust it.  It also may have to big of jets in it.  stock they are setup for a 350.  Get some wd-40 or carb cleaner and check for vaccum leaks.

As far as the plug wires, if they test bad, they're bad;  if they test good, they still may be bad.  Check for cracked spark plugs.  Again, even if it looks good, it may be bad if it's cracked inside the hex.

[VileZambonie]

Did you do this?

Have you inspected the entire length of your fuel line, checking for kinks?


This

Advance your timing. Hook the vacuum advance directly to the full vacuum port on the carb. Set the total timing around 36°

If the vacuum gauge stays at zero when you mash gas check for a plugged exhaust.

[Josh454]

Is this the same truck that is overheating?

[Flashback]

Yes this is the same truck. I did set my timing to 10 degrees at idle. I cleared out the cat, otherwise the only restriction is the tiny piping. Can't remember if the vacuum goes to zero when i mash it. I can always check another day.

[84ramcharger]

I had this problem a few times on other brands 

Like said in a previous post it was a kinked fuel line and the other time it was an issue with the carb gasket .

also what intake are you using ?

[Josh454]

I would sure go after the overheating concern before trying to diagnose any driveability concerns.  The fact that you have a plug that looks washed out compared to the rest doesn't sound so good...