Holley carb question

[djs69stang 10]

Holley 4bbl on Edelbrock 289 IM on 302

 

When in neutral and I set the idle to 1100 or 1200 etc., runs fine. When I put it in gear it dies. When it is in neutral and I turn the idle below 1000, it dies.

So, apparently whenever it drops below 1000, it quits.

 

It also runs fine when I hold the accelerator in just a bit while in gear to keep it running.

 

Everything, and I mean everything that I can think of has been checked. I have had the carb off 3x to check gaskets, lines, clearances, etc.

 

Troubleshoot please.

 

djs69stang

[S code 69 13]

It could be your timing or a vacuum leak, causing your vac advance to drop out. have you tried covering the carb to see if it speeds up? my " other " car is a '70 Challenger 440 six pack and it's a constant battle between keeping enough vaccum to hold the advance in at idle so it doesn't die and to high of idle. fords are new to me and mine isn't running yet but is your vac advance hooked to ported or manifold vacuum? if it supposed to be manifold like Mopar and you have it hooked to ported you'll be way retarded at idle.

[djs69stang 10]

Been through all that with the timing. Vacuum advance goes to the carb.

The engine runs fine. It just won't stay running below 1000. I did find a crack in the carb's base plate by the PCV port awhile back but had that welded shut and the body fits flush on the base.

If it is a vacuum leak, (whether it is in the carb or manifold) shouldn't it be "off" no matter when it is running? It "pops" fine, starts fine, warms up fine, runs fine when I am driving, I just cannot let it go below 1000.

[S code 69 13]

I see , I thought this was a new carb installation. you should have a manifold vac and a ported vac port on your carb, most of the time ported is on the passenger side of the base plate. Sounds like a vac leak to me, if you have power brakes the booster cound be shot, have you covered the carb with a rag to see if the engine speeds up? if it does find the leak, if it doesn't I'd advance the timing 5-10 degrees and see if it's better or worse, if it makes a noticable difference then find out why.

[SlimeGold 69 15]

Do you have a big cam? I agree with S code. Put a vac gauge on it and see what kind of reading you get at idle. Adjust idle mixture, timing ect to get the highest reading, then go from there and start looking at the booster or any other vacume operated accesories like A/C, ect. Also I have had problems with aluminum intakes sealing to the heads and causing vac leaks unless you use a good gasket like a printoseal or the like.

[KevinT 10]

I am fighting a similar problem with my car. When I adjust the timing for the highest vacuum, it is way to far advanced and will ping under the slightest load. With the timing retarded so it won't ping, it pulls great when the rpm's are up, but won't idle well at all and will stall very easily. I don't know exactly what the timing is, I can't find the marks on the balancer. I am pulling what's left of my hair out over this, I already replaced the booster, plugs, wires, cap, put in a pertronix to replace the points. Any suggestions?

[SlimeGold 69 15]

Sounds like it may be running lean. Just a guess tho. A good place to start would be to clean the balancer, find the marks and see what's going on with the timing. With any of these problems it's hard to give advice without being there in person to check things out. I agree that it can drive you nuts but don't give up. A vacume guage is not the tell all but it may help rule out a leak for dj.

[jerry69 10]

I'll throw 2 cents in.... I know the subject is Holley...

When I bought my 69 coupe with a 302 it ran the way you describe the problem... It has an Edelbrock 1406 this car would die with any rpms below 1200 rpms. No way to even drive the car. I ended up taking the carb apart to rebuild... there was so much gunk "inside the jets" that I had to keep my foot on the gas above 1200 rpms to keep the car running... After cleaning and rebuilding the carb the carb runs like normal...

Like I said the inside of the carb didn't look bad until I removed the jets and found the junk inside and under them... so when was the time the carb was rebuilt?

[SlimeGold 69 15]

Jerry is right. That could be another very possible problem especialy with a Holley. The least little bit of trash in your carb will give you big problems.

[jerry69 10]

One more thing I might add is where did the carb come from? The reason I mention that is if the carb came from another person and that person lived up above 3000 feet then the normal jets would have been changed.... I know that St Louis is not in the mountains but when I bought my Mustang it was in Phoenix, Az. maybe 500 feet high and lived in Prescott Valley, Az at 5000 feet so I would have to re-jet the carb and lean it out.... This is just another thing I thought of in case the carb was bought somewhere else, check the jet sizes....

 

Jerry69

[69BossMach1 10]

While there could be junk in the jets, the jets realy aren't being used in the idle circuit.

Sounds like the two idle mixture screws are screwed to far in,or your needle and seat aren't properly set.

First set the needle and seat. Get it idling at the lowest RPM you can, and remove the sight plug on the passenger side of the front bowl. Set the needle so the fuel level is just below the hole and BARELY trickles out of the hole. You set this by breaking the flat tip set screw on top of the bowl, and turning the adjusting nut underneath of it to get the needle at the right height, then re tighten the set screw.

Next, turn in the idle mixture screws until they lightly seat, and back them out 1 -1/2 turns, then adjust in or out the same on each side until you find the max RPM. don't back them out more than 2 turns from seated.

 

BTW, what style of holley is this? Vac secondaries? Double Pumper? what CFM vs. CID of motor?

[djs69stang 10]

I see , I thought this was a new carb installation. you should have a manifold vac and a ported vac port on your carb, most of the time ported is on the passenger side of the base plate. Sounds like a vac leak to me, if you have power brakes the booster cound be shot, have you covered the carb with a rag to see if the engine speeds up? if it does find the leak, if it doesn't I'd advance the timing 5-10 degrees and see if it's better or worse, if it makes a noticable difference then find out why.

 

I do have a manifold vac and ported vac port on the carb. I did not try the rag trick but I can tell you that after it is warm when I close down the choke plate it speeds up, too far and it doesn't like that.

[djs69stang 10]

Do you have a big cam? I agree with S code. Put a vac gauge on it and see what kind of reading you get at idle. Adjust idle mixture, timing ect to get the highest reading, then go from there and start looking at the booster or any other vacume operated accesories like A/C, ect. Also I have had problems with aluminum intakes sealing to the heads and causing vac leaks unless you use a good gasket like a printoseal or the like.

 

I don't have a big cam, it is slighlty mild at best. Don't know for sure as I did not put together the motor's interiors.

I did redo the IM last Spring but it ran great all summer. I use to feel confident in the work I did on that item.

[djs69stang 10]

I'll throw 2 cents in.... I know the subject is Holley...

When I bought my 69 coupe with a 302 it ran the way you describe the problem... It has an Edelbrock 1406 this car would die with any rpms below 1200 rpms. No way to even drive the car. I ended up taking the carb apart to rebuild... there was so much gunk "inside the jets" that I had to keep my foot on the gas above 1200 rpms to keep the car running... After cleaning and rebuilding the carb the carb runs like normal...

Like I said the inside of the carb didn't look bad until I removed the jets and found the junk inside and under them... so when was the time the carb was rebuilt?

 

The carb was rebuilt in 2006, only has a few thousand miles at best. In 4 years the car has only 5,000 miles. During the winter every 2-3 weeks I'd run or drive just to keep the gaskets wet. I use only premium, ouch.

[djs69stang 10]

While there could be junk in the jets, the jets realy aren't being used in the idle circuit.

Sounds like the two idle mixture screws are screwed to far in,or your needle and seat aren't properly set.

First set the needle and seat. Get it idling at the lowest RPM you can, and remove the sight plug on the passenger side of the front bowl. Set the needle so the fuel level is just below the hole and BARELY trickles out of the hole. You set this by breaking the flat tip set screw on top of the bowl, and turning the adjusting nut underneath of it to get the needle at the right height, then re tighten the set screw.

Next, turn in the idle mixture screws until they lightly seat, and back them out 1 -1/2 turns, then adjust in or out the same on each side until you find the max RPM. don't back them out more than 2 turns from seated.

 

BTW, what style of holley is this? Vac secondaries? Double Pumper? what CFM vs. CID of motor?

 

Checked all of those and they are good. Like I said in the original post. I have checked everything. The carb is a older 4160, Vac Sec., 4bbl, dual side hung bowls, electric choke, 600 cfm on 302.

[djs69stang 10]

This weekend I went to the World Street Challenge and ran into a friend who has a friend who has a Holley just like mine except it is 650 cfm. I am going to borrow it, I know that 650 is alittle too big for my set up but as you might guess, it should help me narrow down the problem, carb or not the carb? If it runs well, then the problem is the carb. IF it does not run well or change the problem, it could be the existing carb and or a vac. leak somewhere. I have been through all the other vac. components so, if it is not the carb then I am going to suspect my IM has "popped" a hole in the seal I did last Spring. I just gotta get this figured out now because we are finally having dry weather to drop the top and cruise the streets.

[Gazoo 10]

Just my opinion - in the 24 years I have owned my Mach, I had Holley(s) on for the first 12 or so - and constantly fought with them to get it to run properly. I tried a double pumper, a 4160, a 3310 - tried different power valves, different jets, different nozzles, viton needles and seats, fuel pressure regulator, had the baseplate milled to be sure it was flat, had the blades rebushed to be sure they didn't leak, and on and on and on. I even had a special pan that I made to allow me to pull the float bowls off and catch all the gas without spilling on the manifold, I was doing it so often.

 

Then finally, in about '96, I got fed up and bought an Edelbrock 1406 - bolted it on and IT RAN GREAT. I still have that same carb on today, and haven't done a damn thing to it, other that rebuilding it about 3 years ago to clean it out and refresh the gaskets.

 

So, just another perspective. For those of you who have great running Holleys, I salute you. I guess you understand them better than me. But I'll tell you, I'm sure happy with my Edelbrock.

[S code 69 13]

You say choking it when it's warm makes it speed up, again that sounds like a vacuum leak and probably not in the carb though that's possible. your vac advance should be on the manifold vac port if you're running the original style distributor no matter what anyone tells you, and a vac leak will retard your timming only making matters worse at idle.

 

Ported vac advance came in with the smogger engines, there's a great tech article on this matter of ported vs manifold vaccum advance on the FE engine forum. if I knew how to post it here I would, this has been an argued about issue with Mopar guys for years.

[bnickel 10,004]

what do you have your timing set at? with the mild cam i'd set the timing to about 10-12 degrees at idle with the vac advance unplugged. i'll argue the point that the vac adv should be hooked to manifold vac, i wouldn't do it personally because you could get too much advance at idle. it's kind of a personal perference and what the engine likes really, try it both ways and see where it runs best BUT if you do hook it up to manifold vacuum DO NOT set the timing at 10-12 like i said earlier, keep it at the factory spec which should be 6 degrees, you might be able to swing 8 degrees but i wouldn't go any higher than that.

 

to check for a vacuum leak at the intake manifold you can spray all along the sealing surfaces with carb cleaner or if you have a small propane torch you can turn the gas on and run it along the sealing the surfaces, if the idle changes at all then that's where the leak is. BTW, your engine should idle closer to 750-850 with a mild cam if not lower

[S code 69 13]

The whole idea of manifold vac advance it to get more advance at idle and light cruise speeds, your engine likes LOTS of advance in these situations and it won't hurt a thing.

 

Anyone wanting the whole story look up the article by Lars Grimsrud, SVE Auto Restoration, called Timing and Vacuum Advance 101. it's a great read and solved the debate for me, after years of fighting my 440 Six Pack timing I hooked it up correctly and solved all my problems. this is on early non smogger cars with stock distributors of course.

[bnickel 10,004]

true it does help some engines but if you have had your dizzy recurved what you'l get if you do that is a lot of low speed pinging a lot depends on compression ratio too, generaly speaking higher compression motors will not need as much timing as low compression motors at low rpm so it could cause pinging there as well, again depending on initial advance and of course the cam specs and cam timing will also come into play too. it's always worth a try as a tuning aid though, it certainly won't hurt anything to try it

[djs69stang 10]

what do you have your timing set at? with the mild cam i'd set the timing to about 10-12 degrees at idle with the vac advance unplugged. i'll argue the point that the vac adv should be hooked to manifold vac, i wouldn't do it personally because you could get too much advance at idle. it's kind of a personal perference and what the engine likes really, try it both ways and see where it runs best BUT if you do hook it up to manifold vacuum DO NOT set the timing at 10-12 like i said earlier, keep it at the factory spec which should be 6 degrees, you might be able to swing 8 degrees but i wouldn't go any higher than that.

 

to check for a vacuum leak at the intake manifold you can spray all along the sealing surfaces with carb cleaner or if you have a small propane torch you can turn the gas on and run it along the sealing the surfaces, if the idle changes at all then that's where the leak is. BTW, your engine should idle closer to 750-850 with a mild cam if not lower

 

I do have the timing set at 10-12 with the carb ported vacuum. I had not heard of the carb cleaner trick. Maybe I will give that a shot tomorrow (no pun intended). If the leak is on the back of the block, will the cleaner help there? There is no "valley" for it to pool in.

It has run fine prior to this crack I found in the base plate. And after I fixed that it ran fine, once. After the cleaner trick and whatever it determines, I will take it off (if necessary) and check the weld. Hopefully by the weekend I will have the other carb to test.

[djs69stang 10]

Just my opinion - in the 24 years I have owned my Mach, I had Holley(s) on for the first 12 or so - and constantly fought with them to get it to run properly. I tried a double pumper, a 4160, a 3310 - tried different power valves, different jets, different nozzles, viton needles and seats, fuel pressure regulator, had the baseplate milled to be sure it was flat, had the blades rebushed to be sure they didn't leak, and on and on and on. I even had a special pan that I made to allow me to pull the float bowls off and catch all the gas without spilling on the manifold, I was doing it so often.

 

Then finally, in about '96, I got fed up and bought an Edelbrock 1406 - bolted it on and IT RAN GREAT. I still have that same carb on today, and haven't done a damn thing to it, other that rebuilding it about 3 years ago to clean it out and refresh the gaskets.

 

So, just another perspective. For those of you who have great running Holleys, I salute you. I guess you understand them better than me. But I'll tell you, I'm sure happy with my Edelbrock.

 

I have thought about this option also. But there are 2 factors that may effect the use of the Edelbrock. I have a shaker from a 351C, so the height has to be just right for the hood to fit down on the shaker; I know that the correct phenolic spacer is key to the height, I currently use a 1". Two, the Edelbrock has bowls to the sides instead of front/back so I don't know if the shaker base will fit over those bowls.

Sweet ride!!!!!!!!!

[djs69stang 10]

Gazoo, got any more pics of the engine?

[Gazoo 10]

Yes, send me a PM with your regular email and I'll send you some of decent resolution.