K5, new fuel pump, still won't start

[nebraskasurf]

Here's the story...72 K5 typically runs great. 350, Edelbrock 600 about 4 years old. Replaced fuel filter 3 mos ago. Got gas 3 days ago (Ethanol blend and yes...i know i shouldn't be running that gas) from a Cenex. 40 miles down the road, I get on it and engine starts coughing, sputtering and loses power big time. it seemed as if it was through it's spat and it continues to do it until today. I added Seafoam to the old tank of ethanol blend, ran it to less than an 1/8th of a tank, then added some HEET (red bottle) and filled up the tank with 91 Octane. THAT didn't do the trick either. Figured it had to be the fuel pump. Put new Holley fuel pump on it this morning, truck fired right up, took it out to jump on it and it finally died. I can't get it started, period. Tried the ether trick and nothing. It turns over, but just won't fire off. I can see gas spraying in the carb, smells like gas and the fuel filter is a Mr. Gasket clear gas filter and it appears clean as a whistle. It does seem like some fuel has leaked thru the gasket between the intake and the carb and besides that, I've replace all the vacuum plugs. From everything I'm reading it's telling me that it could be electrical if even a bit of ether spray in the carb gets me nowhere. Where the hell do I start and that STILL doesn't explain why this engine was sputtering at high revving RPM's on the street...
could the float(s) be stuck because I've heard that as an excuse as well. It's killing me to have a little snow on the ground and this truck is stuck indoors....

[Deep C 915]

Have you recently replaced the gas cap by any chance? (Not a joke)

[nebraskasurf]

i have NOT...you serious about that, Clark?

[Deep C 915]

Yes, I had replaced my gas cap with one that was not venting properly and every time I opened the cap I heard pressure sucking sound so I ran with cap partially on and my K5 stopped hesitating and sputtering. I guess there was a vacuum or pressure build up which effected my fuel pressure. When you remove the gas cap do you hear any sucking /relieving sound.

[Deep C 915]

You said that you have fire...?

[nebraskasurf]

i haven't checked the sound with the cap off...nor have i checked to see if there's a spark.

[nebraskasurf]

it sounds like it's just waiting for the initial punch from some gas. just cranks and cranks and cranks and usually would fire up, but now...just over and over and over and over...but never fires up.

[Deep C 915]

Pour a little gas in carb and rule out fire...? So since you put the new fuel pump has your problem has worsened.

[kSStamp0182]

the cap wouldnt matter if its not even trying with spray in the carb. i dont know a whole lot about carbs, but id check your spark. remember the basics, fuel, air & fire.

[Critter]

Originally Posted by Deep C 915

You said that you have fire...?

That's what I was thinking, don't rule out a possible HEI/points problem (don't know what you have).

[nebraskasurf]

i did the gas in the carb. did some starter spray, too. there's definitely gas going into the carb because i actually watched it spray. as soon as i put the new fuel pump on, it fired right up, i drove it two miles and then jumped hard on it to make sure that fuel pump resolved the initial problem and the same damn thing happened...lots of coughing, sputtering and then it died and did NOT want to start. had to tow it home.

[nebraskasurf]

soooo, if i got this right, the next step here is to see if there's a spark. since it's just me solo-ing this fix, what's the best way to check to make sure there's a spark? and yes...big red HEI distributor cap ...not the old skool cap.

[Deep C 915]

I'd have to lean towards Critter's thought on a possible HEI/points problem. Timing could be off.

[kSStamp0182]

it could possibly a vacuum advance problem as well.

[Critter]

First thing I would do is unplug the main connector from the drivers side of the HEI. With the key in the "on" position use a test light or DC meter and see if that wire has 12V. If it does, I would reconnect everything, pull a plug, and see if you can get it to spark outside the engine as you turn the engine over. Kinda hard to do by yourself but you can get creative and make it work. If the HEI wire DOES NOT have 12V then you have problems in your wiring/fuse block/ignition switch, etc. If the wire has the voltage but the plugs are not firing the you have an HEI problem most likley. They have a couple different components inside that can go bad without any warning.

[nebraskasurf]

well, i guess i have my work cut out for me tomorrow...if it also matters, i was recently hearing a little bit of squealing coming from the belts in the last 24 hours. so the timing thing is starting to sound more and more favorable.

[Deep C 915]

Keep us updated...

[Critter]

I wouldn't bet on the timing issue. Even if the distributor clamp worked its way loose and the distributor turned around a quarter turn you would still be popping and backfiring when you turn the engine over. It sounds like you are getting either NO fuel or NO spark (pouring gas/ether into the carb should bypass the no fuel problem). Either way, good luck and let us know what you find.

[nebraskasurf]

thanks guys...never used the assistance of a post before, but damn....i'm thoroughly impressed. thanks again.

[dubds10]

I posted over at Stovebolt forums, but I second the cap and rotor and electrical. It's easy enough to check them. Mine were toast in my S10 and it was acting up the same as your truck. Then I started it the other day, and it was a HARD start. Sounded like something exploded, ran for about 2min then died. Just wouldn't start up after that. I did a tuneup - oil change, filter, plugs, wires, cap, rotor and it runs great now. I've never had a rotor and cap go on me before so I didn't realized how bad that alone could make your engine act.

[old man jimmy]

easy way I check for spark is to just pull an easy to get to plug wire off the plug, put a phillips in it and hold it about 1/4 to 1/2 in. from any grounded metal while someone cranks the starter. Just make sure you're not touching the screwdriver blade.

[nebraskasurf]

Truck fired this am...t'was the batt lead next to the tach lead on the distributor...not connected. :/ still doesn't explain the rough idle or coughing and sputtering at high RPMs though. That could be a timing issue, correct?
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[Boneyard]

Try checking your vacuum advance and vacuum line. Generally the distributor vacuum line goes to the timed (pass side of carburetor) port.

[Critter]

Originally Posted by nebraskasurf

Truck fired this am...t'was the batt lead next to the tach lead on the distributor...not connected. :/ still doesn't explain the rough idle or coughing and sputtering at high RPMs though. That could be a timing issue, correct?
Posted via Mobile Device

It could explain why it was doing it before, connector was just barely touching at the HEI and was arcing across to somewhat fire here and there. Is it still coughing and sputtering? If it's still doing it then I would look to make sure vacuum line are still attached, timing didn't get thrown out of wack, etc.

[bigbadchev72]

I would bet good money that your spark plugs are fuel fouled now with all the cranking you have been doing and all that gas going into your motor and not being burned off.

I personally run only AC delco plugs in mine and have had great results. Dont waste your time on the autolite crap.