Technical 302 won't idle below 2000 RPM, thoughts on what to look for?

But not all 5.0's are HO, there were some in Crown Vics that were roller cam and old 302 firing order. Believe me, I had to do some research before I found that out. I thought all roller cam motors were HO, but apparently not.
Haven't heard that about the Summit carbs, but it's entirely possible. This is my second one, first one was flawless, bolt on and go. Everybodies quality seems to suck anymore.

That was my first thoughts before a vacuum leak was suggested, I'm still leaning that way myself. My next step will be take the carb off and see if I can blow air through the passages that I see. And I may just whip up a couple of gaskets for that 4 to 2 bbl adapter and try that Rochester.

Can't stay out there too long in this heat wave we're having right now, I work on it about a hour and then cool off for 4....
Thanks for sticking with me on this. It's been a few years since my last EFI to carb conversion, and I've slept since then.

 

Did you spray around the base again to make sure the leak is good now?
Always retrace your steps if in doubt,,,see if you can recreate what happened before.

Before,,,you stalled the engine 3 times by spraying the same spot on the base.
That cannot be a coincidence!
Check your work!

Is the intake new as well? ,,,, I have seen the carb area not perfectly flat as well.
If it is the intake flange,,,,,no gaskets will help it completely.
Don’t start looking everywhere else first,,,,make sure the flange and gasket area are not a problem.
It can’t be a coincidence!,,,,check that off your list,,,and then look elsewhere.
Otherwise,,,you will just throw money at it.

Ask me how I know!!!

I always forget my basic rules when working on my stuff.
When I can calm down and sleep on it,,,it always go back to basic knowledge.
Then when I realize what it is,,,,I want to kick my own butt for not thinking it through.
Don’t give up!

Tommy

 

Good advice Tommy. The intake is a used Performer 289. I did straightedge the manifold base before I put it on. The spacer I took off wasn't sealing on the drivers side edge, so I used another, thinner one that I had with two new paper gaskets. Maybe I need some of those thicker soft gaskets? I did not check carb base for flatness, never occured to me since it is new outta the box, but after what big bird said, It's possible its not flat.

You're right, I get frustrated too easily anymore, especially with new parts. After a nights sleep, it will look different tomorrow. And I will probably kick my own ass for overlooking something in front of my nose!

 

My only other thought would be a fuel pressure regulator. I fought a OT car for a month until I realized the pump was forcing fuel past the needle and seat. Put a cheap Autozone regulator on it and it ran like a scalded ape.


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No no no!! Extensive testing hath shewn Cereal box has the necessary makeup for a superior, long lasting gasket with optimum sealing properties and modulus of elasticity.

 

Coat both sides with silver spray pain, and allow to dry first.

 

OK, put my Rochester 2bbl on, getting the same results. Looking now toward the HEI. Is it even possible that it could work above 2000 rpm, but be dead below that? I thought they either worked or didn't? Could be the module bad I guess.....
May try my points distributor again. Can't be much worse.

 

Check your timing, too much spark advance will do that.

 

Yup. Time it by butt-feel, not with a light.

 

At 2000RPM........can you choke it down by putting your hand over the carb or............does it speed up? It still sounds like a vacuum leak to me. If it checks out then do this: Rev it up to about 3000 or so and clamp your hand over the top of the carb and ALMOST let it choke down...then take your hand off and let it catch up and then clamp your hand over it again. It pulls a HUGE vacuum in the carb and will/should/maybe suck any trash out of the internal passages.
6sally6
PS......This^^^ is why Edelbrock carbs are so good. They are sooo S I M P L E to work on.

 

I agree with the post above. Place your hand over the top of the carb, block any vacuum lines first. Usually the idle will smooth out and increase. Is yours set high to keep it running? Regardless it should do something with the 6sally6 test.

 

I would say a large vacuum leak take it apart study gaskets look for place it doesn't seal.

 

Did you try and run a long, fine toothed flat file across the carb mounting surface on the intake to check for a low spot? I know it may sound like a long shot, but it is possible. There might be a spot just big enough for a regular gasket not to seal good enough. A few passes with a file might level the mounting surface enough to seal everything up. Might be worth a shot... At least it won't cost much...

 

Man , seems if it was in the HEI the timing would be so far off that it would buck when trying to start the engine . You have changed the carb and still the same issue , it’s pretty tuff to end up with 2 carbs doing the same thing . I have never had an intake gasket vac . leak on a 302 Ford . I surely thing it could happen , but I just have never had one . Remove the dist cap . twist the rotor and release , determine if it snaps back . This will answer if advance is frozen up .

 

Didn't get a chance to fool with it today. I'm going to try the old worn points distributor again, it just seems like it's loosing fire when it cuts off like that. It cuts off, and as it spins down it spits raw gas out the carb. If it was still firing, it would spit a fireball if it spit back.

I haven't put a light on it yet, not much use checking it at 2000 rpm. Set it to get it running, turned distributor both ways until it sped up or slowed down, then split the difference, backed off that until it didn't kick back on starting, so I feel pretty sure it's not advanced too much.

I think somebody said most carb problems were actually ignition related. I may have been barking up the wrong tree, time will tell I guess.

 

Put the light on a spark plug wire. Let it come under 2000 and watch the light. You will see if spark is going away.

 

Hadn't thought of that, thanks!

 

thinking on the newer 302s there an egr port on the back of the head in the bolt hole were the alternater would bolt in

 

Are you running this style HEI ? Mine likes 12-14 degrees advance.

 

Emission plugs installed in the back of the heads?

 

Screw in plugs blocking those ports. They are on the exhaust anyway, you'd have an exhaust leak if they were open.

 

No, I didn't have room for the large cap, using the small cap, module mounts on the outside of the base.

 

I run a lot of these motors and make sure the intake gaskets are for that motor. The earlier ones are not the same...ask me how I know. Can you try running the carb without the spacer to rule that out? Just a suggestion.

 

I changed the spacer to another one I had. With new gaskets, that seemed to stop the vacuum leak at the carb base. And I changed carbs, too, put on a 4-2 adapter and have a 2bbl Rochester on it for test purposes now, it had the same results as far as going dead. That is what lead me to the ignition. Hope to get some time on it today if the heat will hold off enough. Air was so muggy yesterday it was like you were wearing it.

Oh yeah, intake gasket was for the later engine. It hasn't slipped, visually verified that. Can see a bit of the gasket at both ends of intake.

 

I would suggest putting a points distributor in just for test purposes but that would require a steel geared one and also adding a coil. I've had problems with some aftermarket HEI distributors so now I mostly run Duraspark ones from a 85 mustang GT. Also run that distributor with an HEI module.

 

Follow up and fix:

On the suggestion of a friend, I changed the coil to one that had been on a Duraspark with EFI. Fired right up, after setting the timing down a little, settled into a 950 or so idle, purrs like a kitten! Starts at the touch of the key.

But all is not well in whoville....

Transmission has reverse, but no drive. I filled it up before I got it cranked, didn't want to start it up dry, overfilled it and it leaked out the dipstick O ring. So, with it running, I put my last gallon in, it's still not up to add on the stick, hoping when I put some more fluid in it will take drive then. Talked to a transmission shop this morning, he said since it had been sitting so long, the seals may have dried out, they may soften back up and they may not. Hope they do, he quoted me $900 to rebuild it, with a new converter. Ain't got that to spare right now.

Anyways, thanks to all that made suggestions. If I learned anything, it was to make sure parts match, because apparently a points coil is different than a HEI is.
Now y'all can begin the I told you so's and flames, I deserve them!

 

Glad you got that part of it figured out. It's a good day when you can play with cars and get problems fixed.

 

$900.00 is cheap. Hope it is not needed.

Ben