Help: '67 HiPo starts, but won't hold idle below 1500

mmi · Jun 6, 2009

Please help :

I have a 67 with a recently rebuilt 289 - near HiPo specs:

4 bbl Holley 650 Street Avenger carb
Ford HiPo highrise intake
Crane mechanical lifter cam
Decked and ported HiPo heads
Balanced and Blueprinted
Pertronix in the distributor and rev limiter unit

The story:

Car ran great until last summer, then battery boiled over - acid everywhere

#@&*!

so I cleaned out everything and car has been sitting for 9 months..

I replaced

>New Alternator with Chrome 60A unit
>Put on gold '67 HiPo look underdrive alternator pulley (and belts might be tigher now - too tight?)
>New starter solenoid
>New Flame-thrower epoxy coil
>New spark plug wires
>New optima battery
>New in-line gas filter
>Drained and refilled radiator

(also replaced cowl brace, montecarlo bar, and other non-engine items, etc.)

So today is the big start-up day with everything replaced...

Starter turns engine over strong

After several tries, it finally fires up ..seems to need heavier application of gas pedal

I run it for several minutes with my foot holding it between 1500 - 2000 rpms

Pump it up to 3000 rpms, sounds strong

...but as soon as my foot comes off, engine abrubtly dies - no idle at all

spray carb with choke cleaner, and retry - same result over and over

the engine used to idle smoothly, now it won't hold idle

Thoughts??? (help)

zookeeper · Jun 6, 2009

If the car sat for an extended time, the carb is likely in need of a thorough cleaning, and I don't mean shooting it with cleaner or any miracle cleaner that comes in a bottle. It needs to be disassembled and cleaned, paying special attention to all the passages in the metering block. Use a good cleaner (I use Brake-Kleen) and compressed air and I'd bet that it runs like new. My wife's Corvette needs this attention every spring, and it has the same symptoms you described.

mmi · Jun 6, 2009

hmmm,

The carb looks awfully clean, and it only had about 3k miles on it before I stopped running it last Fall...?

jlangholzj · Jun 6, 2009

still if it has been sitting for 9 months, it might need to be cleaned.

just because it "looks" clean doesn't mean that there's not varnish thats formed somewhere in the idle circuit thats keeping it from running right.

just pull it appart and give it a good clean and it should fire up okay!

blown65 · Jun 6, 2009

Might have a vacuum leak also, will go lean at idle.

mmi · Jun 6, 2009

If I'm heavy with my foot as I turn the ignition, it fires and roars after a few turns ...keeping my foot half-way, it runs at 1600+ or so rpms

...but if I back my foot off even a little, the tach just drops to zero and she's done (sometimes without even a sputter) and if the rpms start to drop, I usually can't save it with more gas from my foot.

Where would I look for the vacuum leak?

10secgoal · Jun 6, 2009

Does sound lean. But would guess it's the carb also. Easier to see than a vacuum leak appearing just from sitting.

mmi · Jun 6, 2009

10secgoal said:
Does sound lean. But would guess it's the carb also. Easier to see than a vacuum leak appearing just from sitting.

The only thing I did re: Vacuum was disconnect the rubber vacuum tube from the distributor (if that's what you're talking about) briefly when I replaced the distributor cap and plug wires

...seems like the votes are pointing to the carb

zookeeper · Jun 6, 2009

Trust me on this one, carbed cars that sit all winter and today's gas create the EXACT problem you're describing. The gas absorbs so much water, it has completey rusted the accel pump spring in my wife's Corvette as well as ruined all the rubber in as little as 4 months. Since you say yours has sat since last fall, I'd bet money on it.

Platonic Solid · Jun 6, 2009

Did you use a good fuel stabilizer before storing it? And I don't mean "Sta-bil" (that stuff is crap). I haven't had any carb clogging problems in any of the cars or the bike since using "Star Tron" (get the Diesel one - it's the same as the Gas one but twice as strong). It's about $20 for 16oz., but worth every penny.

mmi · Jun 6, 2009

Platonic Solid said:
Did you use a good fuel stabilizer before storing it? And I don't mean "Sta-bil" (that stuff is crap). I haven't had any carb clogging problems in any of the cars or the bike since using "Star Tron" (get the Diesel one - it's the same as the Gas one but twice as strong). It's about $20 for 16oz., but worth every penny.

No I didn't put anything special in the gas ...I wasn't planning on storing it ...it was just a rebuild project that went on months and months longer than I thought it would.

Beyond cleaning the carb, should I put anything in the gas now? Should I also squirt the carb cleaner down the gas line toward the fuel pump?

jlangholzj · Jun 6, 2009

mmi said:
No I didn't put anything special in the gas ...I wasn't planning on storing it ...it was just a rebuild project that went on months and months longer than I thought it would.

Beyond cleaning the carb, should I put anything in the gas now? Should I also squirt the carb cleaner down the gas line toward the fuel pump?

no

its just that after sitting the intricacies in the carburetor have become clogged...nothing more. If you don't already, I'd suggest an in-line filter to eliminate anything comming from your tank.

but you shouldn't have to add anything to the gas once you clean the carb nor should you have to squirt anything down the fuel line. Like suggested, if your going to store it for extended periods put a fuel stabilizer in, also it helps if you have a full tank...and i mean FULL FULL. that way water cannot condense and form in the tank.

just clean out the carb and she'll be ready for summer driving

D.Hearne · Jun 7, 2009

Not sure if it's your problem, but all the E-core coils I've seen so far aren't corect for a Pertronix unit. And if the gas you had put in it last year had any amount of alcohol in it, that's not good either. Straight, quality, name brand gas will do fine over a winter, but not anything with alcohol in it.

mmi · Jun 7, 2009

D.Hearne said:
Not sure if it's your problem, but all the E-core coils I've seen so far aren't corect for a Pertronix unit. And if the gas you had put in it last year had any amount of alcohol in it, that's not good either. Straight, quality, name brand gas will do fine over a winter, but not anything with alcohol in it.

Well, good catch. I do have the wrong coil. I have the Flame-Thrower II epoxy version, which is 45K volt and 0.6 OHM. Pertronix says the regular Flame-Thrower epoxy 40K volt with 1.5 OHM, will work with regular/original Pertronix Ignitors, which is what is under my distributor cap.

Don't know what that has done to my rough running situation, but it can't help.

Now for the other carb news. I didn't take the bowls with the floats off (cuz I don't have a rebuild kit on hand), but I removed the screws and spray/filled them with carb cleaner. Basically flooded the carb with carb cleaner and then turned it upside down to drain it. I put it back on, but now I have a gas leak from the chrome gas tube fitting and maybe also from under the accelerator pump. The carb was pretty new, so I hope I didn't mess it up, when the real issue might have been the coil...

zookeeper · Jun 7, 2009

You've got to be kidding. Squirting carb cleaner into the screw holes does absolutely nothing. That's why I suggested REMOVING the carb from the car, DISASSEMBLING the metering blocks, then BLOWING compressed air through the various passages to REMOVE the offending trash that is screwing up your idle. Next time you feel like wasting time, just wax the car. It won't help your idle either, but it will make the car look better, so at least you'll accomplish something.

mmi · Jun 7, 2009

zookeeper said:
You've got to be kidding. Squirting carb cleaner into the screw holes does absolutely nothing. That's why I suggested REMOVING the carb from the car, DISASSEMBLING the metering blocks, then BLOWING compressed air through the various passages to REMOVE the offending trash that is screwing up your idle. Next time you feel like wasting time, just wax the car. It won't help your idle either, but it will make the car look better, so at least you'll accomplish something.

First, I'm concerned it may be the ignition, as the post above pointed out, so I'm putting the old correct coil back on for now, to see if that improves how the car runs. But the new gas leak may now be the bigger problem...

Regardless, of whether this (new) carb is clean yet (as you seem sure it is not), I now have a gas leak (dripping from the primary chrome fitting) after removing it.

I removed the bolts from the the bowls, and gas drained out, so filling those holes with carb cleaner may not have done much good, but it didn't hurt either. I haven't rebuilt a carb before, and reluctant to, given that this one is only a couple of years old. When I pulled on the bowls after the bolts were removed, they didn't seem to want to come off, so I stopped cuz I would only be addng to the problem if I tore the blue gasket.

As for time, going slow for a day wastes nothing, after working on a car for 10 months. Always open to constructive 'how-to' suggestions.

mmi · Jun 7, 2009

Update:

It does NOT appear to have been a problem with the carb. It was the wrong coil. The car now idles fine with the correct coil back installed.

There is still the gas leak coming from the brass lock nut fitting to the primary bowl (the chrome gas fitting goes into this brass piece). Any suggestions on how to cure the leak?

mtlman22 · Jun 7, 2009

ahh. you beat me to it! i sounded just like an ignition problem, ive been down that road with the Petronix stuff before. as for what Zookeeper is saying it is a very good idea to completely take the carb apart and do just like he says..many people think ill buy a can of carb cleaner and spray the Carb and thats good, wrong! you will just be giving CRC or whoever more $$ for nothing

mmi · Jun 7, 2009

mtlman22 said:
ahh. you beat me to it! i sounded just like an ignition problem, ive been down that road with the Petronix stuff before. as for what Zookeeper is saying it is a very good idea to completely take the carb apart and do just like he says..many people think ill buy a can of carb cleaner and spray the Carb and thats good, wrong! you will just be giving CRC or whoever more $$ for nothing

My only issue now is a gas leak from the chrome gas line into the primary bowl...

Just unscrew it? Unscrew the chrome fitting first? or leave the chrome fitting alone and uncrew the larger brass fitting that goes into the bowl? Does it require thread-lock or something to reseal everything??

mtlman22 · Jun 7, 2009

is the line and carb Orig or somewhat new?? if its old you might bight off more than you can chew. if its new i would undo it at the fitting unless you see otherwise there might be an o-ring of some sort in the fitting or something im ot sure because i dont know what you have

Help: '67 HiPo starts, but won't hold idle below 1500

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