PLEASE HELP! 69' Charger 440 auto - can't figure out what's happening

[STIG]

Hey guys,

Thought I may as well come and ask on here as I'm sure there's a Mopar guru who will be able to solve this a lot quicker than us.

At the start of last year we had a bigger cam/lumpier cam installed while it was in the shop, but ever since then we've been having issues. If I remember correctly, at the same time we had an MSD Ignition installed as well (including distributor pack). Recently we changed the MSD coil thinking that might solve the problem, but it's still there. We've even installed two massive electric fans thinking it was a heat issue.

Issue: ever since the cams and MSD have been installed, it'll drive along perfectly fine all day at 180, but after it's at running temp and you come up to a set of traffic lights (or anywhere at slow or crawling pace), the car will start to splutter and completely cut out after a minute or so - we try to start it up again but it'll just turn over and not fire up for about 30 minutes! we've noticed the temperature when sitting creeps quickly to around 200-210 (which isn't very high anyway) and then cuts out. The other day we were idling and as it was just about to cut out on us, the old man floored it, spluttering for a couple more seconds but then as we continued driving without stopping, the car cleared itself and was driving fine again.

I'm not sure if that makes sense, but we'll take anyone's at this stage! very frustrating.

Much appreciated,

Cheers 

[garner7555]

I am no expert,  and I'm very likely wrong, but I'm gonna say that your fuel may be boiling in the carb or in the line.       There are plenty of others on here that truely are experts and I would listen to them over me.  Haha   I broke the ice with the first guess, now lets see where this goes.   

[Cooter]

Type of carb? How old? Rebuilt? Fuel type? Cast iron/aluminum  intake without heat crossover blocked?

[STIG]

Thanks for the inputs already!

We also hazarded a guess at the potential of fuel boiling in the lines! so we'll test that theory soon by wrapping heat resistant tape around the metal lines we have in there.

3x Holley carbs. It's a 440 6-pack. There was some residue/soot build-up in the carbs before we had them completely stripped down/blasted and flew in a brand new carb (the center one) as the middle piece melted whilst on the dyno. Apparently that's rare. Fuel is 98 RON (94 Octane in the States). Motor was very clean when they opened it up last year, so it had been rebuilt recently. I'm not too sure, but probably cast iron being an old 440 big block? not sure about your intake question

[STIG]

It might also be worth noting that the other day for the first time when we were just coming down our street heading home there was a rattle/vibration from the engine bay and a bit of smoke coming out from underneath the motor/transmission area, accompanied with a very loud 'clunking/ticking' noise from the motor which resulted in me opening the hood and pulling the battery terminals off (as turning the car off with the key did nothing and it was still running - very loudly!). Even with the battery terminals disconnected the car was still running until it finally, what I thought, seized and blew up (as it was that loud)... but the next day we went to start it, she runs like normal. Very, very confused as to what's going on.

[Kern Dog]

When the car continues to run after  switching the key off...YOU have a few things going on that may or may not be related. The ignition switch and wiring may be corroded or damaged and not making a good connection. Oddly enough, pulling a battery cable shouldn't cut power to the coli since the alternator is still providing current when the battery is removed.
Anyhow...
I've had vapor lock issues before. They match the symptoms you described: Car starts to sputter and sometimes stalls and will not restart. Vapor Lock is when the fuel gets hot and tirns to a vapor inside the carburetor. The carburetor is designed to mix and meter a liquid, not a vapor or mist. The cure is to keep the fuel in liquid form. To do this, you need to keep the fuel cool.
Do you have an inline fuel pressure guage? You'll need at least 5 psi of fuel pressure at idle with no more than 8 psi total. Some guys in hot climates will devise a fuel system that takes fuel the carb doesn't use and return it to the tank. This keeps fuel from boiling in the lines near the pump and engine because it is not sitting near heat all the time. To do that, you'd need a regulator that bypasses any pressure greater than an amount that you decide.
Another way is to add sheathing to the fuel lines to deflect heat, install an electric fuel pump, reroute the lines away from the exhaust, etc.

[don duick]

I had very similar issue when I installed my MSD. I have the 6AL box, there are 2 red power wires. one heavy wire that connects directly to the battery and the smaller red wire that connects to your blue ignition wire. I assume you have eliminated the resistor and are getting a full 12 volts to the red wire. Well I thought I was getting a full 12 volts but was not. I have connected the small red wire directly to the battery as well and it is now turned on using a relay that is powered by the blue ignition wire.

If this has confused you then simply check you have full 12 volts going to your MSD they don't like anything less than 12 volts. They will play up and turn off and will then work again later.

[justcruisin]

Before you waste to much time replacing parts and doing mods it is a good idea to establish what is going on, most likely it will be either fuel of ignition. When it plays up and wont start pull a plug lead and see if you still have spark. Check if you have fuel coming from your accelerator pump. If it wont start for 30 minutes I wouldn't imagine it will be fuel boiling over and flooding as you should be able to re-start with full throttle, could well be vapor lock as mentioned though.

[six-tee-nine]

I read alot here about phenolic insulating spacers between carb and intake...
They block alot of the heat going from the intake to the carb.
I also guess you have a vapour problem.

The second problem almost sounds like your engine was dieseling (self combusting).... could be on fuel vapour but cannot happen without spark.
Could be on oil. Dont guess that was the case. Then you should have alot of exhaust smoke and excessive blow by...

[moparnation74]

I read alot here about phenolic insulating spacers between carb and intake...
They block alot of the heat going from the intake to the carb.
I also guess you have a vapour problem.

The second problem almost sounds like your engine was dieseling (self combusting).... could be on fuel vapour but cannot happen without spark.
Could be on oil. Dont guess that was the case. Then you should have alot of exhaust smoke and excessive blow by...

Great points 69! 1/4" or bigger spacer will work wonders.  Wrapping fuel lines as well is an added benefit.  As a previous member stated focus on the sputtering/stalling problem and then move on from there.

[STIG]

Hey guys,

Thank you very much for all the suggestions, it's greatly appreciated. All fingers are pointing towards the possibility of vapour lock right now, and as that has never been mentioned to us before, it's a great starting point for where to begin looking!

As soon as we get back from our trip we'll get on top of it and go from there

Cheers 

[mopar0166]

I had a simuliar issue, and I did a ground check to the ign system , then re timed the engine.  also upgraded my charging system.   its happy in the 190s and rarely goes over 200

[polywideblock]

why don't people use "cool cans" anymore          would help with the fuel boiling issue   

                                           http://www.ebay.com/itm/Moroso-65125-Super-Cool-Can-Fuel-Cooler-3-8-NPT-Inlet-Outlet-Blue-/221687199160?pt=Race_Car_Parts&hash=item339d9635b8&vxp=mtr

                                                 

   

[myk]

Cool idea, but the car should be able to run without any sort of 'mods to the ignition or fuel system...

[el dub]

It might also be worth noting that the other day for the first time when we were just coming down our street heading home there was a rattle/vibration from the engine bay and a bit of smoke coming out from underneath the motor/transmission area, accompanied with a very loud 'clunking/ticking' noise from the motor which resulted in me opening the hood and pulling the battery terminals off (as turning the car off with the key did nothing and it was still running - very loudly!). Even with the battery terminals disconnected the car was still running until it finally, what I thought, seized and blew up (as it was that loud)... but the next day we went to start it, she runs like normal. Very, very confused as to what's going on.

I'm no expert but that sounds like the engine is dieseling, caused from hot fuel igniting without spark.

[Jaysick]

Hey buddy, I had the exact same problem on my 383 Charger.  All the heat was boiling the fuel and when I would idle it would sputter and die.  I could wait a few min and crank it (without giving it more gas) and let go and do it again and that would always get it going but I had to get the car moving or it may happen again.
I added a spacer between the carb and intake and moved my fuel lines around so they were a little further away from anything really hot.   This did the trick for me  
They also sell a valley pan gasket that blocks off the heat cross overs on the heads if you feel like getting a lil bit deeper into it.
http://www.summitracing.com/parts/fel-1215/overview/make/chrysler

As a side note I recently had a problem with my Mustang that had similar symptoms.   After the engine got warmed up (15min or so) it would sputter when idling and then die (sometimes while driving at 30-40mph) but in this case I couldnt get it to turn over again on a consistent basis after it would die.  sometimes i had to wait 10 sec sometimes 2 hours...   After a couple days of troubleshooting this I found it was a bad magnetic pickup.