Hard starting 360

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hemisedan

hemisedan

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Just bought this Valiant in December, and even though this isn't the best season to drive a 69 Mopar, it is very difficult to get started.

Even in the warm weather (+45) it took a lot of work to get it to start. Engine is a built 360, J Heads, mild cam (but sounds very aggressive) Weind intake with Edelbrock 650. MSD box ignition, and long headers. Rebuilt 904 torequeflight and a 3:55 surgrip 8 3/4 rear end. I don't know what grind that the cam is, just that I was told that it was a mild Purple Shaft cam. Unknown distributor. Once it does start, it doesn't run badly, but that something isn't right.

What I have thought is that there are problems in the fuel system, or else the ignition, but have been out of the Mopar hobby long enough that I am open to suggestions. Just for now it has me baffled.

And, to me very unmoparite, when I go to start it, there is no indication that it wants to start, just grinds, then all of a sudden it coughs then working the throttle and key it starts. This doesn't feel normal to me. Not like my old Mopars of long ago. So, any help?
 
Classic eddy carb issue.

Check timing
Check carb tuning
Ditch eddy for a Holley based carb
go electric fuel pump

in that order.


And here come the carter carb and mechanical fuel pump lovers in 3.... 2.... 1.....
 
Honestly, if it doesn't want to start, and doesn't seem to run real well when it does run, it's very hard to "chase" down a problem like this over the internet. A lot of folks will tell you how they "like to set up" a car, or what their "preferences" in a build would be, but really, the car should start, idle, and drive well.
  • As stated above, check timing and carb tuning.
  • Also look for a massive vacuum leak.
  • Make sure the MSD is working properly. Seen a lot of times when folks "upgrade" to MSD or other ignition systems, only to have a problem within the system or installation of the system.
 
Make sure you have good spark. Make sure the choke is closing all the way and make sure the float level is correct. Also make sure the accelerator pump is working correctly. Nothing wrong with Holley or Edelbrock carburetors they just have to be set up correctly. Carburetor's can really test your patience at times.
 
make sure the ign coil is not hooked up backwards ,ran into that once, ran great once it started.
 
Put a timing light on it at idle and find out what you have for initial/idle timing.

If it has an aggressive cam, it will want 15+ for idle timing. If it has less, you'll have to adjust the mechanical advance in distributor to hit a safe total number. Can't just bump the idle timing.

Ede carbs are pretty bad for vaporing off fuel after sitting for any length of time. It's not the carb so much as fuel formulations. The bowls may be dry and it takes the fuel pump time to fill them up.
 
Not that this will help, but here’s a couple of pictures.

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If your engine is cold or even lukewarm that choke is way too far open. That's about all I can tell from the picture. Hope that helps you.
 
Go to the back bumper and put your palms over the tailpipes, one on each, covering them completely. Then have an assistant crank the engine. You better not feel any suction there.
Obviously, this goes not work very well with a leaky exhaust system.Tape it up or do what you gotta do. This is the best and fastest test I can think of, and has saved me hundreds of hours of other diagnostic measures.
But if you do have suction back there, you have exhaust valve problems, and that guarantees hard starting.
 
Thanks for the replies, gives me some area to work on. Timing, vacuum leaks, spark and fuel systems, that’ll get us going.
 
First thing that came to my mind was timing. Bill, the other thing you could do is sell that Valiant to me. LOL.....
 
did you modify the dist I see you have no vacuum lines going to it?
 
As teringer says
A cold engine wants plenty of timing, at least 10*to 20* more than after it warms up. It needs this to start the fire early enough , so that the peak cylinder pressure will occur at the right time, to push the piston down hard enough to keep itself running. This is even more important if the choke is not working properly. But if the choke works too good. then the cylinder walls may get the oil washed off, and then the rings will not seal, and then the "suction" from the falling piston goes away, and then it becomes yet harder to start.
A cold engine likes plenty of fresh winter gas, plenty of timing, and a good ring seal. The gas can lay in the bottom of intake, that's ok; it may take two or three pumps from the accelerator-pump to provide enough vaporizing light gas components to initiate running
 
I am absolutely convinced that fuel washing is a lot bigger problem than any of us thought. Look at all these magnums come out of Doge Rams with 200K on them, often never having had the pan, vc or intake off the engine in that time. Many of them still run well at that mileage, don't burn oil, and other than some "weak" valves leaking produce decent power, certainly not perfect. You tear them down and there is VERY little wear. EFI, amoungst other reasons
 
OP............Get right down to basics. "Rig" a spark test gap using a WIRE coil wire. Test the spark USING THE KEY to crank the engine. Should develop an nice not blue spark at least 3/8 and more typically 1/2" long

Before you try and start, take a lamp and look down the carb throats, then work the throttle and check for accelerator pump action. Should be a nice strong spurts of fuel in each barrell

Might be a good time to run a compression check and see what you have there (or leakdown) and this will give you a great opportunity to INSPECT THE SPARK PLUGS for wear, gap, fouling, etc etc
 
Thanks guys, this is just what I have been hoping for. Lots of good ideas here. My thoughts all along is in the ignition/timing and getting spark to the engine. As well in the fuel system. My intentions are to go with a EFI throttle body, but I want to get this running well first, before I start making changes like that.

The distributor: No vacuum line connected? That has concerned me and I was thinking that this just might be part of the problem, but I'll do a plug check and check the timing out and plug in the the vacuum line and see if this does anything for starting. When it does start, it seems run quite well, very well as a matter of fact.

As I stated in the beginning, I just got this car in December, and with the weather situation here in Iowa, I haven't gotten out to really do anything yet. I've driven it a couple of times, first to get air in the tires, then to just see if it would drive right with the new tires and wheels that I put on in January. That was all before the real cold weather and snow hit.

Forgot to mention, I haven't done any modifications to this yet, except the wheels and tires. It is as I bought it in December. The engine was done in 2012 or so, and the body was painted and mostly restored in 2014-15. It was never stated, but I think that the engine wasn't run much during that down time. I've talked with a guy that was aware of this car, it was in northern Kentucky, and he said that I was not an easy car to start when he knew it. He saw it a couple of times before it was painted. He also said that it was a hard running 360 plus.
 
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Vaccum advance has zero to do with starting the engine.

2 things I would do first.
After it sits, pull air cleaner and see if accel pump is squirting fuel into carb. If it does, you have some fuel still in carb.
Find out idle timing.

That's where I would start.
 
Some engines are just different on cold starts. If the accelerator pump is working correctly, some engines take maybe 1 or 2 pumps of fuel before starting and others may take 3 to 5 pumps. And once running, if it starts running richer than at first, it's building up ice on the throttle blades. Turn engine off for a few minutes and let the heat melt off anything and all will be ok after that for engine to start heating up by then. The line going to distributor is only going to matter if it's ported or not for starting and isn't an issue as long as the ignition is strong, timing is in ballpark and the accelerator pump is squirting fuel to richen up initial start as everyone has already mentioned.
 
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