[cmpcpro]

Okay, I am at my wits end with this one! I have done everything, and spent hundreds and still can't figure this out!

My cat seems to drive great when its cool, or when it hasn't been driven in a while, but once it's been driven for about 30 minutes or longer it has this bad hesitation when you get on the throtle from a stop.

I took it to Burbank Carb. and they told me it had bad gas in it. So, I ripped the gas tank out, had it dipped in acid, changed the fuel lines, changed the fuel pump (converted to electric) and rebuild the carburator!

Still! It does the same thing! I have also, converted to Electronic Ignition (Pertronix), New plugs, cap, rotor, wires, and replaced all the vaccum lines, and fittings (Besides the vaccum for the A/C).

I have checked the timing, and tried all different settings, I believe stock is 3, so I brought it to 6, then 9, still nothing. I am runing Mobil 91, and never ran anything else, no other brands or anything.

Does anyone have any idea of what this could be? When I noticed the hesitation, I took it to a stop sign and stuffed the pedal just to see what would happen, and then thing sounded like it was gonna die!

Thanks in advance!

Chris

 

[modifiedmark]

How about the coil? I have had them give trouble before. They would work great cold and then mess up warm. mm

 

[sixt9coug]

sounds like either a coil, or possibly a carb problem. when mine wanders around ( its a holley, love the constant adjustments ) it bogs on me. usually its just lean and some turning of the screws brings it back in line. but more than likely it sounds like a coil. i had a problem with one about a year and a half ago. the car would run fine for about 5 minutes, then it would get real rough then die. then it would start right up then die after about 10 seconds. after it cooled it would do the same. run for a few minutes then act up again. check it all out.

 

[cmpcpro]

Yeah, I thought that too, but I replaced the coil also, and it didn't change a thing =(

Chris

 

[modifiedmark]

You didnt say who rebuilt the carb and what type of carb it is. Sounds more like a misadjusted acc pump to me, especially if its a holley.mm

 

[cmpcpro]

Yeah, its a Holley, that was adjusted too.

Thanks

Chris

 

[calcat]

Did you check your fuel filter? Is the choke fully open when warm?

 

[leonbray]

My 69 has a similar problem. Once it warmed up it was getting too much vacuum to distributor and creating too much advance off idle. Only way we found it was to put it on a dyno.

 

[cmpcpro]

Yeah, the fuel filter is brand new also. Both of them are. The choke is bolted down at an open position. I will have to check into the vaccum part. I have the vaccum from the distributor going straight into the carburator. Where Holley themeselves told me to put it.

Thanks for the help guys!

Chris

 

[dark7068]

There are 2 vac. ports on the base of Holley's, try switching between them for a day. See if that does anything. If your mod. valve on the tranny isnt hooked up it will make the car run rough too. Check that line and vac. reading on it.

Rick

 

[Todd]

You may also check the side play in the distributor shaft,as the engine tries to increase speed the worn bushings may change dwell and timing.

 

[cmpcpro]

Hey guys, I just replaced the coil for the second time, this time with an MSD Blaster 2 (I also have the Pertronix Ignitor2) and gapped the plugs to .45, also moved the coil off of the intake and onto the inner fender, and whoa! What a difference. Crisp throttle response (Well for a big pile of metal)!

Thanks for all of your help! I do believe most of it was the coil being on the intake, and once it was getting hot, it was malfunctioning. Dunno for sure though.

Thanks again!

Chris

 

[sixt9coug]

what did you have to do to use the MSD coil?? did you have to run an additional resistor for it?? or did you just slap it on? i have an Accel "Racing" coil in my car, but i know its only listed at 38K volts. personally id like a more powerful one. do you know the specs on the MSD one?? and i really should regap my plugs eh? i still run the stock .035 gap . matter of fact its been over a year and i havent changed the plugs at all. ...... maybe i should take a look.

 

[cmpcpro]

Yeah, I put the resistor on that it came with, they have two versions of the coil, for a dollar more you get the resister. Same coil, just one comes with the resistor. The Blaster 2 has 45k volts. And yeah, I regapped my plugs to .45, excatly what the guys at The Classic Cougar Network did, when they put the Pertronix in. Although they used the Pertronix Flamethrower coil, which is only 40k volts.

Seems to be working great.

Chris

 

[sixt9coug]

how much wa$ it?

 

[cmpcpro]

With tax, 38 bucks at PAW.

Chris

 

[leonbray]

Just curious - is your block earthed back to the firewall?

 

[cmpcpro]

No, bolted on the inner fender.

 

[modifiedmark]

I'm glad you got it fixed!! I have a feeling it was more a bad coil than from the mounting on the intake. Although the inner fender mounting is probably better in the long run. mm

 

[cmpcpro]

Yeah, same here, thank you MM!

Chris