Diagnose me! Wont rev over 2000 rpm

[mindless1]

Hi guys - would appreciate any help on this:
car wont rev over 2000 rpm.   revs smooth to that point, but then begins to feel like it's missing and wont rev any higher.  I took it out for about a 10 minute drive and it seemed that after a while the problem went away and I rev normally.  I tried replicing all the plug wires with new 8mm supression wires, but no help.  It has the electronic ignition conversion.  Do I need to change out the distributor rotor, weights, or entire shabang?  Does this sound like perhaps it's just not advancing the timing?

69 charger 440, .60 over, basically stock performance.  AVS 650 carb, 10-1 flat tops,  727, 323 rear end, stock exhaust manifolds, stock intake, etc

[John_Kunkel]

Welcome to the board.

What is the history of the car, have you had it for a while and this just started or is the car new to you and the past history unknown?

[General_01]

So you are saying that it does this when it is cold, but after it warms up it revs up just fine? Does your choke work?

[mally69]

just a thought from a past experince ,  make 100% sure your timing marks are exaclty where they need to be,, i seen a 440 put together and  that would not go over 2000 rpm and the timing marks were off by one tooth and it was  hard to tell just by looking at it  ( Check the cam with a degree wheel)    just 

[mindless1]

Thanks for the quick responses guys- just got back from another drive and had the same exact experience.  After about 15 minutes (from a dead cold start) of being unable to rev over 2k, it just 'clicked on' and ran normally.  General01 I think you may be onto something with the choke- that makes a lot of sense- though the carb is relatively new in terms of little use, though older in age.  I will investigate the choke first.  What is the best way to confirm the electronic choke is working or not?

John - the history of the car is an interesting one - I've owned the car for about 15 years or so, I bought it and restored it with my dad during high school, and only now have resurrected it from storage and moved it out to Phoenix to be in its rightful home, my garage.  We purchased it as just a rolling body with no motor or transmission, but it is a numbers correct 440 rt. The car had a near ground up restoration since we got it, though much of the suspension was done by a previous owner who gave up and sold it.  We purchased a well maintained '68 New Yorker as a motor-donor, and then had the 440 built by a reputable race shop in Albuquerque, NM.  Nothing outlandish was built into the motor, our goal was the power the car had originally, and much of it is stock spec.  We did move to the electronic ignition as noted before.  Other changes since the charger moved back in with me include a new 727, upgraded torsion bars, a new hi-po carter mech fuel pump, and I finally installed the factory specified vapor separator.  Oh, and I also discovered that some yahoo (namely me when I was 15...) had hooked up the 1/4 inch fuel return line as the supply line, and left the perfectly good 5/16 fuel line unused.  That problem is corrected...  I did recently rebuild the carbeurator, thinking it was part of the problem with why it wasn't getting enough fuel at higher RPMs (see previous problem...fixed now).

To mally's question - I dont have a degree wheel - but I'm thinking if the timing marks were off then it wouldn't likely fix itself after driving it a while.  This is definitely a new problem that popped up on a previously normal running engine.  I'm going to look into the choke and go from there.  Thanks!!

[mally69]

 sorry, that part slipped my mind as a read   

stupidly that was one of my mistakes on one of my first engines 

[General_01]

Not sure how to check an electric choke. I only use carbs with manual chokes. Make sure you have power to the choke first. Then check the choke. I am thinking you would check the resistance with an ohmmeter, but I am not sure what readings you would be looking for. Maybe check the website of your brand of carb to see.

[mindless1]

Well it is not the choke.  I let the car cool off about an hour, restarted it and it was still running normally.  I let it sit another 2 hours, then retried it and it is back to its 2000 rpm sputtering limit.  I confirmed when the car was sputtering that the choke plate is completely open.  Any other ideas?  Distributor?  Coil?

[mally69]

could it maybe be vapor locking

[bordin34]

This is probably not the problem, but is your gas cap venting?

[General_01]

I don't think your choke is working. When the car is cold, the plate should be almost closed so the the engine gets less air and more fuel. As it warms up, the plate will open for more air. Start the car up and manually shut the plate and rev it up at the carb and see if it revs up any better.

[charger Downunder]

Check the fuel line hose between the fuel pump and the factory vapour (filter) canister it may have a sharp bend in it thats restricting the flow of fuel i am in the process of replacing mine with a molded hose.

[mindless1]

Thanks for the ideas.  Tonight I will check it from a dead cold start (and try to take pics to show its state before and after running).  I should note that 'cold start' is a bit of a misnomer, I'm in Phoenix and this time of year we are lucky if it gets below 80' F!

[y3chargerrt]

Is the gas in the tank new? You said you just got it out of storage.Did gas sit in the tank for a long period of time?