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350 still fouling plugs

adamforsythe

adamforsythe

1/2 ton status
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Ok I changed the dizzy, plugs, wires, carb 3 times, adjusted everything. Should I put a hotter plug in???? Please help. The truck runs fine for about 3 days of starting it and running it for like 1/2 hour then shutting it off. Well I just took it out I know my plugs where fouling but I needed GAS. So I went and got gas then went home. I ate dinner then I got back into the truck to take it back to the shop for the night. Well on the way (1 1/2 - 2 min drive) The engine started to miss fire and loose power I stuck it in N and gave it some gas so it could come out of it and it did. I put it back in gear and it did the same thing in tell it died. I pushed it out of the road. My step-dad came with the dodge to tow me. I tried starting the truck and it fired seemed to run fine. Then I put it in gear and it sh!t the bed. So we towed it back to the shop. The engine is a 330-380HP 350 with a edelbrock 600 cfm carb, Newer edelbrock intake, headers, 2.5" exaust. Tayler custom wires, A NEW HEI dizzy.
Thanks
Adam
 
As long as the engine isn't burning alot of oil the problem will be in the carb. Is your timing set correctly?

A hotter plug may help but that is a bandaid fix more then a fix. What brand plugs are you running?

Harley
 
The Engine burns no oil. My timing is pretty close to being top dead. I changed the carb 4 times in the last 5 months.
I am running I believe I have autolites in my truck. Trust me I have ran all brands this year with the same results.
Thanks
Adam
Hossbaby50 said:
As long as the engine isn't burning alot of oil the problem will be in the carb. Is your timing set correctly?

A hotter plug may help but that is a bandaid fix more then a fix. What brand plugs are you running?

Harley
Click to expand...
 
adamforsythe said:
The Engine burns no oil. My timing is pretty close to being top dead. I changed the carb 4 times in the last 5 months.
I am running I believe I have autolites in my truck. Trust me I have ran all brands this year with the same results.
Thanks
Adam
Click to expand...

What's your fuel pressure look like?
 
adamforsythe said:
i'm not sure. should i check it????
Click to expand...

Yeah... if you're fouling plugs that means you're not burning all the gas. That means either not enough spark or too much gas.
 
I will check that tomarrow.
Thanks
Adam
jonrpick said:
Yeah... if you're fouling plugs that means you're not burning all the gas. That means either not enough spark or too much gas.
Click to expand...
 
Put your timing out to about 6-8* and replace those autolites and see what it does. Also tune the jets in the carb.

Harley
 
Ok I will try....what is the best way to tune the jets????? what should I do to tune them??????
Thanks
ADam

Hossbaby50 said:
Put your timing out to about 6-8* and replace those autolites and see what it does. Also tune the jets in the carb.

Harley
Click to expand...
 
adamforsythe said:
Ok I will try....what is the best way to tune the jets????? what should I do to tune them??????
Thanks
ADam
Click to expand...
On the Edelbrock...If it's a Performer, it's probably a model 1405 or 1406. If so, it's the same carb as the old Carter AFB. You pull the top of the carb off and there's a couple of needle/piston assemblies sitting on springs. You lift those out, and when you look down in the hole, you'll see a little brass plug with a hole in the center of it. That's the jet. The only thing you can do is drill them out (not recommended) or buy new ones (very cheap).

Just get the Edelbrock carb calibration kit, part # 1480.

Here's a link: http://store.summitracing.com/partdetail.asp?part=EDL-1480&view=16383&N=700+115

Your carb manual will have a chart detailing how the various combos of jets, springs and needles will affect the fuel/air mix. A vacuum gauge will be useful in tuning if you go this route.

Now, having said all that, if you got the carb new, and it hasn't been rejetted or anything, it should be just about right for the engine you have, if not a little on the small side.

Edit: do make sure that the calibration kit is for your model of carb. But before dropping another dime on parts, find out your fuel pressure, and as was suggested, get a good idea of where your ignition timing is sitting. Make sure your vacuum advance module is working too.
 
Also like mentioned before check your fuel pressure. That could be a big contributing factor. Carbs like 4-6psi I believe normally.

Harley
 
Hello,
I have this carb http://store.summitracing.com/egnsearch.asp?Ntt=edelbrock+600+cfm&N=700+115+400065&Ntk=KeywordSearch
It is a month old.
I will check fuel pressure and everything elts again. Before I start playing around with jets. Did chevy change anything on there 350s from '85 to '86 that would need different spark plugs?
Thanks
Adam

jonrpick said:
On the Edelbrock...If it's a Performer, it's probably a model 1405 or 1406. If so, it's the same carb as the old Carter AFB. You pull the top of the carb off and there's a couple of needle/piston assemblies sitting on springs. You lift those out, and when you look down in the hole, you'll see a little brass plug with a hole in the center of it. That's the jet. The only thing you can do is drill them out (not recommended) or buy new ones (very cheap).

Just get the Edelbrock carb calibration kit, part # 1480.

Here's a link: http://store.summitracing.com/partdetail.asp?part=EDL-1480&view=16383&N=700+115

Your carb manual will have a chart detailing how the various combos of jets, springs and needles will affect the fuel/air mix. A vacuum gauge will be useful in tuning if you go this route.

Now, having said all that, if you got the carb new, and it hasn't been rejetted or anything, it should be just about right for the engine you have, if not a little on the small side.

Edit: do make sure that the calibration kit is for your model of carb. But before dropping another dime on parts, find out your fuel pressure, and as was suggested, get a good idea of where your ignition timing is sitting. Make sure your vacuum advance module is working too.
Click to expand...
 
Did you ever disable the EST in the distributor? 85 had EST (electronic spark timing) and 86 had EST and a CCC (computer controlled carb). If you didn't dissable the EST when you replaced the carb that could be part of you problem.

Some of your dizzy parts may need to be changed to dissable the EST and you will need to disconnect the computer.

The EST computer is behind your glovebox.

Harley
 
I doubt this is it but I had similar experiences with a Holly that kept blowing power valves. This was years ago before they had a bypass drilled into them. Could the samething be causing this? Hmm,
doh.gif
I guess since once you swap plugs all is good again so I guess not- never mind. I'll just watch this thread.
pop2.gif
 
These engines are way more tolerant to carbs being off a bit than they are to having poorly set timing. If it is the carb, I'd bet it has more to do with the float being set wrong than it does the jets being the wrong size.

I'd be willing to bet the problem is with your ignition system. Get a timing light, set the timing correctly for your cam, and make sure you tighten the clamp down good when you're done adjusting.
 
It's gonna be timing...

TDC? heck, stock should be 6 to 8... And if it's as hotrodded as his numbers imply, it's gonna want a fair amount more than that...
 
Check the fuel pressure Edelbrocks don't like more than about 5.5 lbs of fuel pressure. Check the timing, TDC is way wrong for your specs.
George
 
I check with the guy that does all the work to my truck when I don't want to. He said it could be a weak spark cause buy a low votage number going into the dizzy. Can I check that some how?
Thanks
Adam
 
Yeah, you can check the voltage going to the dizzy with a multimeter. That can be a problem if your wiring or connectors are in bad shape. I'd definitely check the timing though. Also, it doesn't matter how many times you change your carb. Each carb has to be tuned to the motor after installation. New or not, gotta tune it if you really want it to run right.
 
Ok so I checked the fuel pressure and I am at 7-8PSI. I checked my plugs and they are not fouling at least number 4 is not fouling. But it seems like the engine starves for fuel after I really get on it. I am still getting black smoke when I get on it.
Thanks
Adam
 
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