Starting/Running Problem

[Kyle.70.C10]

Ok so i just picked up a 70 C10 last week and its having some problems starting/running...Some insight, its a 350, has new fuel pump, fuel filter, plugs, wires, cap and rotor, and edelbrock 1406 carb, and a high rise wiend intake. Ok so heres the deal, if i jump into the pickup and go to fire it up after sitting for awhile it'll pop right off and run really good, but after driving it then parking it for a few minutes to an hour i'll go back out to fire it up and it'll pop off and run then if you dont romp on it it'll die then will not start up again at all no matter how much you crank on it...not even shooting starting fluid down the carb...yesterday i probably cranked on it for 20 minutes on and off till the battery died without it firing a single time...so i left the pickup over night and came back the next afternoon and it fired right up and ran perfectly fine, but driving down the road at a steady cruise it wanted to kinda cut out and when i stopped it wanted to die, but if you give it WOT it runs like a beast....got home let it sit for about 2 hours, go back out to start it, it fires up then dies and will not start again.....this is starting to piss me off...if anyone has any idea what could be causing this i'd surely like some insight. Thanks a lot.

[71K20chevy]

Sounds like a carb or timing problem...

[jd7]

you need to check for spark, at least then you will know which direction your heading

[GMCJOE]

I agree, when that happens pull a plug wire and hold it close to the plug and see if spark jumps when cranking. Other than that, it sounds like you might have some settlements in the carb causing issues. http://www.edelbrock.com/automotive_...ech_vids.shtml

[geezer#99]

Fuel pressure too high!
Probably flooding a bit!

[ole dollor]

i would check the fire first, see if its firing when it not starting, may be some wiring problems inside the dist. if its hei ign...the module may be the problem or it's wiring, then if its ok....look for fuel problems...fuel psi.carb leaking inside, choke stuck...float level to high. or no fuel at all....

[Kyle.70.C10]

Ok i'll check for spark next time it happens...and i drove it again today, it started perfect drove it around town and as soon as the engine started warming up it started dieing on me...and now its kind of dawning on me that it only starts dieing when it gets warm, runs perfect when you first start it and its cool...Im assuming that'd be in timing right?

[ole dollor]

don't think you have a timing problem, if it starts ok then at least the timing is close...if the timing was to fast then it would kick back on the starter and drag the battery down kinda like a weak battery....if it's spinning the motor over ok then look elsewhere . i have seen several hei dist. when the vacuum moves the wires they cut out or stop making connection...broke wires that make contact when cold....warm...can be a real pain to locate some times....

[GMCJOE]

Are you running HEI? I am assuming that you are. Sometimes the coil under the cap of the distributor can fail after it gets hot and won't produce enough electricity to fire the engine. You need to narrow it down to whether or not it is electrical or fuel.

Before you fire it up when it is cold, pull the number 1 plug wire (doesn't matter which end). Then hold near the plug or cap where you pulled it, you should get a blue arc. When it fails to start, do the same. If you get a good blue arc of electricity, its not at your distributor/coil. But if there is none, or it is weak and yellowed arc you may have found your problem.

If you are running points, your coil might be failing after it gets hot.

If none of these are the issue, go to your fuel system and start trouble shooting it.

As long as you are getting spark when it fail's, you should be able to eliminate the electrical side of the issue and move on to the fuel system.

[geezer#99]

Next time you drive it and it dies look in the carb.
If you see or smell raw fuel it's flooding.
Even a little bit will cause it to die. Look for vapours first too.
Carry a small flashlight in the golvebox. Easier to see in there that way.

[cdowns]

what type fuel pump?/edelbrock carbs are very senistive to pressure

sounds to me like the thing is floodind out and needs the plugs to dryout to refire

[cdowns]

what type fuel pump?/edelbrock carbs are very senistive to pressure

sounds to me like the thing is flooding out and needs the plugs to dryout to refire// check the smell of your oil

[gearys 5600]

Sounds to me like the coil or module.

[GMCJOE]

Originally Posted by gearys 5600

Sounds to me like the coil or module.

Agreed

[Kyle.70.C10]

It wouldn't start again so i checked for spark and sure enough it had no spark...so i replaced the distributor with one i knew was good and took it for a ride and sure enough its fixed then i lost a u-joint...fixed that, now my tranny wont shift into second...if its not one thing its another...But anyway thanks for all the help.

[GMCJOE]

Damn the luck! At least one thing is fixed. These trucks always keep a person busy.

[ole dollor]

if your trans, is a th350 or th400 check the vacuum line from the back by the dist. to the trans ....it may have fallen off when you changed the dist.out good luck...

[GMCJOE]

That vacuum line should run off the carb, the vacuum port on the driver side of the carb to the vacuum control module on the passenger side of the transmission. Hope it's an easy fix like that.

[Kyle.70.C10]

The line is running into the back of the carb as it was before i ever worked on anything...and it did work after i switched the dist. just stopped shifting after i replaced the u-joint.

[kq4pc]

Got to add my 2 cents,check and make sure the vaccum line is still on modulator valve at tranny. Thanks Bobby

[Kyle.70.C10]

It is...i took the line completely off and made sure it was clean and not plugged and still no luck.

[ole dollor]

if the line is o k and the hoses dont have any cracks...just replace the modulator , it may have give up the ghost....

[oldblue1968chevy]

Run the HEI to full manifold vacumn (driver side port of carb)

Fuel pressure should not exceep 6psi 5.5 is ideal

Floats should be set to spec (And carb tank filter etc should be clean working)

What is your base timing or any of the timing set to?

Need:
Timing light
fuel pressure guage
Edelbrock fuel pump/fuel pressure regulator (edelbrock pump pre set to 5.5psi) OR A holle other type of carb thats not as sensitive to fuel psi

Get your timing/fuel pressure and report back