440 wont start when hot.

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sbh126

sbh126

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Well I have been trying to tune my freshly rebuilt 440 and for some reason I cant get it to fire when I shut it off once I have it up to temperature. It will crank all day long just wont fire. What are some things that could cause this.

Another problem I have been having is that my engine will rev up just fine in neutral but as soon as I try to drive the car it is very weak and wants to die. What could cause this?

I'm hoping these are both tuning problems. I dont have much experience with tuning carbs/figuring out timing but I'd like to learn rather than give up and pay someone else to do it. Any suggestions?
 
Sounds like fuel delivery problems, check your fuel pressure at the carb. Just my opinion.

Bill S.
 
Tell us what you've done to the car because there isn't enough to go on to tell you where to start.

What have you added or changed? Fuel systems, ignition, etc.
 
Check to make sure you are getting fuel when it is hot. You could be getting a vapor lock in the fuel line. Also check to make sure you have spark, no spark is a sign that your coil could be going bad when the car is hot. Also if you have Electronic ignition, the ECU could be going bad, this is also a sign of a bad ECU when it is hot.
 
I have a fuel pressure gauge and noticed sometimes while the motor is running it is at 0 psi. ??? I thought I just had a bad gauge since the motor was still running. Would this be a sign of vaporlock?



I replaced the metal fuel line in the engine bay for a cleaner look. It's in the same spot as before the only differience is that I have schumacher headers that run very close to the line. I put a large fuel filter back by the tank and a smaller one just after the mechanical fuel pump. I just tested the ballast resistor and it was good. I replaced the distributor with an Autozone one. Temporary fix until I can replace my 440 source one that didn't work. New wires and plugs. It does have an older dist cap on it. I just replaced the ecu with an Autozone one. One thing I should mention is that the new one has 5 prongs and the original only had 4. But the 318 I had in it before was running with the 4 prong ecu. I'm not entirely sure what that last prong is for. I believe the coil I have on is a used one but not original. I cant remember where I got it from now. But I do have a brand new coil for just such an occasion that I'll try out.
 
Sounds like you already found the problem. fuel line close to the headrrs and 0 pressure . sounds like vapor lock to me.
 
sbh126 said:
I have a fuel pressure gauge and noticed sometimes while the motor is running it is at 0 psi. ??? I thought I just had a bad gauge since the motor was still running. Would this be a sign of vaporlock?
Click to expand...

Yes this could be vapor lock as 68dodge stated.

sbh126 said:
I replaced the metal fuel line in the engine bay for a cleaner look. It's in the same spot as before the only differience is that I have schumacher headers that run very close to the line. I put a large fuel filter back by the tank and a smaller one just after the mechanical fuel pump.
Click to expand...

Why two filters? If you are running the stock 5/16 fuel line to a mechanical pump you do not need a filter between the tank and pump. I would remove the filter back by the tank and buy some heat shield to cover your fuel line in all areas that are near the exhaust, headers and engine. Summit sells what you need: http://www.summitracing.com/parts/THE-14005/ They also sell this in 12ft piece: http://www.summitracing.com/parts/THE-14006/

Also, make sure your fuel line is not kinked or blocked.
 
Is your coil mounted vertically on the firewall or horizontally on your intake? If it's horizontal, the oil inside can't do its job and the coil will get hot.

Had the exact same problem on my 440 shop truck and learned about the coil position from a tech at MSD. Tried relocating it vertically to the firewall and haven't had a problem since. Good luck!
 
Sounds like vapor lock to me. I had a 440 tnt Newport that had the same problem. I would remove the extra filter and shield the fuel line in the engine compartment.
 
Sounds like vapor lock to me, insulate the fuel line and if it still has some problems try using some type of insulating spacer between the carb and intake. My old 383 had the same problem, but the fuel line was out of the way, so I put what looked like about a 1/4 thick gasket(insulator) I had laying around (I don't even know where it came from) between the carb and the intake and the problem was gone. The wrong type gas cap will do that also.
I've also had an intake mounted coil that was going bad do the same thing, starts ands runs fine when cold, but once it warms up it starts running very rough and then dies and won't start until it has cooled off. Then it runs fine again.
 
I routed the fuel line to go through passenger side wheel well. Should be plenty far enough from the headers now. I also went ahead and replaced the coil and moved it to the inner fender so I could mount it vertically. When I tested the new coil it was at 1.6 ohms. When testing the old coil it was all over the place, jumped around from 2 to 40 ohms. I couldn't get a solid reading. So maybe this is the problem. I wont know till tomorrow. It's a little late to start a 440 with open headers right now. But I'll be sure to post an update soon.
 
OH COME ON SBH!! nothing like a little LATE EVENING NEIGHBORHOOD SHAKEUP!!!!!! LOL :mrgreen: :mrgreen: :mrgreen:
 
Hello, we started out as a fuel problem and now we mixed in ignition.

What carb?
I've seen this many times before. Hot engine, shut it off and quickly remove the top off the air cleaner. Do you see "fog" coming off the choke tower? If you do then the bowls are boiling off or draining out the idle circuit holes into the manifold.

Need carb info to elaborate more.
 
MVRCorp said:
Hello, we started out as a fuel problem and now we mixed in ignition.

What carb?
I've seen this many times before. Hot engine, shut it off and quickly remove the top off the air cleaner. Do you see "fog" coming off the choke tower? If you do then the bowls are boiling off or draining out the idle circuit holes into the manifold.

Need carb info to elaborate more.
Click to expand...

It's a holley 4160 750. What would be the fix if this was my problem? I'll check this when I fire up.
 
I always follow a simple process of elimination. If it ran before and it won't start I go back to basics. 2 things that are required, fuel and fire. Eliminate 1. If I have a situation like that I will hit it with some "starting fluid" (ether). If it acts like it wants to start it's a fuel problem, If it just cranks it's an ignition problem.
 
Well I drove my Duster to get an alignment today. When I got to the alignment place I was at 190 degrees snd still had 8 lbs of fuel. double what I had before. But when I got home I decided to double check the gaugen again and it was back to zero. So its better than it was but not quite there yet. Should I invest is a fluid cooler and run my fuel through it? or would that help?
 
If you have the ORANGE box I will put my money on that. I have had the same trouble with every one I have had .thay are junk....Artie ( open the hood let it cool off and it will start)
 
Have you insulated your fuel line to carb yet?Any hardware store carry,s the pipe insulation foam and zip ties.It works.:read2:
 
I haven't insulated it yet. I guess I was hoping moving it off the headers would be enough. I'm about to make a summitracing order so I'll go ahead and get some.

Orange box? What exactly are you refering to?

I dont know what my timing is set at yet. I just put it where it would run. I can either get it to run good but kicks back during startup or starts up easy and runs like hell. (and not in a good way) lol. I have it set right in the middle. What is a good number to have my initial set at?
 
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