416 motor, W2 heads, Holley HP950, 15.1 compression, running Sunoco 112. Was having some high rpm cut out issues last week and found that it was a spark plug glazing issue. I changed out the plugs and it ran like mad. BUT, when I checked the plugs after that run, the plugs showed that it was running lean which would explain why my plugs glazed before due to too much heat in the cylinders. The other thing I noticed was that I was getting some black "peppering" on the insulator, which from what I read is the result of detonation. My speculation is that since the car was running lean, cylinder temps were getting hot. Plus with the high compression, I think the fuel was detonating. Or so that's how I am assuming what happened. I'm sure I'll hear your thoughts on that. So right now I'm just running primaries until I get it tuned right. Was running 80's on the front jets and changed to 86's. Changed my spark plug gap to .035 from .038. Checked timing and have it set to 34 total. It may have been 35-36 degrees before. Now it starts, runs, and idles fine just like before. But when I go to drive it, it will cut out beyond 2500 rpm. It just runs like crap. I can't imagine that the 86 jets would make it run like that. The spark plugs are dry with a dark tan color to them. Not wet at all so I don't think I'm flooding it. I am up in arms right now. Any ideas?
Engine Cutting Out! What to check?
- Thread starter clinteg
- Start date
-
I am certainly no expert, does your fuel pump have the capacity to keep up? Power valve maybe? How about fuel pressure?
Just throwing it out there.
Just throwing it out there.
OldmanRick
Well-Known Member
Could you be in the early stages of a coil failure. With 15to1 comp. any weakness would show up pretty quick. This came to mind as you opened the plug gap some and it seems to have gotten worse. Careful not to run too hard on just the primaries as you'll be lean under power no matter what jet you run :smile:.
P.S. Disregard the plug gap comment above, i misred the sentence....oops.
P.S. Disregard the plug gap comment above, i misred the sentence....oops.
Bulldozer
free ice cream sandwiches
i would suspect your ignition box and/or a fuel issue
I actually closed the spark plug gap so it shouldn't have done anything but made a little better spark.
Oh yeah, I guess I should have noted that I am running a 140 GPH Aeromotive electric fuel pump with bypass regulator. Fuel pump pressure never moves under acceleration and stays right at 8 psi. I had accidentally touched the hot side of the coil wire with a socket while it was running and it caused a spark to pop. I was told that would not have done anything, but I'm not so sure. I sure think it's got to be a spark problem.
So just to be clear (and I'm still learning), If I run just primaries, the air/fuel mixture has a certain air/fuel ratio. If I open the secondaries, these will have the same air/fuel ratio if the jets are the same as the primaries, no? The only difference being twice the air and twice the fuel, but same ratio. So how would that run lean if I were just on primaries if the air/fuel ratio is the same whether I'm running primaries or secondaries?
OldmanRick
Well-Known Member
67Dart273
Well-Known Member
Ignition, ignition, ignition.
Suspect everything and anything
I agree with possible coil failure
Carefully examine the cap / rotor and test the coil wire
Check primary voltage to the ignition. WHAT are you running for ignition, by the way?
Substitute something else you may have there for the system you have now.
Suspect everything and anything
I agree with possible coil failure
Carefully examine the cap / rotor and test the coil wire
Check primary voltage to the ignition. WHAT are you running for ignition, by the way?
Substitute something else you may have there for the system you have now.
Just running points setup at the moment. I have a Pertronix Ignitor III to replace the points and a 45,000 volt coil to mate it with. I was trying to get the bugs worked out before I upgraded it all just so I knew the exact problem. Just wierd that it all of a sudden runs bad. I am wondering though if I should upgrade to their street/strip HEI setup instead. I am a little concerned with the Ignitor III handling high rpm's. Their website doesn't really say.
TrailBeast
AKA Mopars4us on Youtube
Get that Pertronics in there and the coil also.
I think 273 (Del) has hit it on the nose.
Sounds like you have a spark blowout, or weak fire at the plugs.
Or maybe just a crap condenser (They do go bad)
I think 273 (Del) has hit it on the nose.
Sounds like you have a spark blowout, or weak fire at the plugs.
Or maybe just a crap condenser (They do go bad)
and also chech the pickup coil in the dist
67Dart273
Well-Known Member
LOL he's running points
It could be as simple as a worn distributor, a weak spring on the points, or just not set correctly AND AS MENTIONED a bad condenser. Points type systems MUST have a good condenser to fire. The condenser (capacitor) does not just keep the points from burning, it also GENERATES the spark along with the coil.
I know. It's how I bought it. I've been trying to go through it and get some things changed the way they should have been done the first time. The fuel system has been updated, added a mini tub with MT 325 tires that will hold it a lot better than the 235's it had, front disk conversion will come later, but for now, I just want to get it running good so I can get it to the track a few times before winter gets here. I've just had hangup after hangup so far. :violent1:
Mad Dart
Nothing to see Here!
I would get rid of the distributor and go with electronic ignition. You have some serious compression, do you have an Ignition Box? I have had good luck with these. 2 Step, NOS, Dial up Rev Limiter instead of chips etc.
http://www.summitracing.com/parts/MSD-6520/
http://www.summitracing.com/parts/MSD-6520/
You beat me to it. As I was reading his original post, I thought "ignition issue" immediately.
Mad Dart
Nothing to see Here!
Yeah, I think it is a combination of both. Need to straighten out the ignition first set the timing correctly then move onto tuning the carb. Doing the opposite order you could chase your tail forever.
KitCarlson
Well-Known Member
Mad Dart
Nothing to see Here!
This may be off topic a bit but I did have an alternator take a chitt inside the unit after some really hard runs with my 410 4 spd. Symptoms of a bad low RPM miss that I could not find. I was under the hood revving the car and the alternator had a dead short in it when I revved it up. Sparks and chitt flying everywhere just over 2500 RPM. Crazy *** miss too. Went to napa and got a new one on warranty. Fixed the ignition problem.
I did just change out the alternator, but it could be a bad unit though. You never know. I think I'm going to run it tonight in the garage with the doors shut and lights out to see if I can see any sparks anywhere. Could be alternator, bad ground somewhere on the ECU maybe? I did read some problems people on here were having with that. I ended up ordering a Pertronix FlameThrower III Billet distributor as shown below. Essentially same as an MSD unit without the external box from what I have read. This unit requires a full 12V so I do know that I need to bypass the ballast resistor at least, but I am unsure yet as to what other electronic parts I will need to remove or modify to make it work. I absolutely hate messing with anything to do with electronics when I don't know all of the components and their functions. So any help in that area will help too
.
Mad Dart
Nothing to see Here!
Your gunna want to run an ignition box also like the one I posted above. They are real simple to install. With as much compression as you have a Multiple spark at low RPM's should do it good.
Lonewolf3165
Living the Dream!
I was agreeing with you up until this post. The condenser doesn't generate the spark. I'ts there to help prevent the points from burning up & for noise suppression. The spark is generated in the coil when the primary field collapses & then transfers energy to the secondary side when the points open & break the primary circuit & the electricity has to find it's way back to ground. The points & condenser are the control side of the ignition, not the high voltage side. A shorted condenser however may prevent the ignition to work.
Having said all that, to the OP I'd suggest checking the voltage while running at the coil primary + terminal & verify that you have good voltage. Repair any troubles you have there. A bad alternator can cause trouble if the voltage is too high or too low. Next check the secondary side for anything that creates higher than normal resistance. Cap, Rotor, Wires & Coil & even plugs that are "new" can have problems.
Well crap. I thought the whole idea behind that pertronix unit was that you didn't need an ignition box because it provides multiple spark and has the rev limiter built in. I'm going to have to call them then and get the scoop.
Mad Dart
Nothing to see Here!
Shoot it might I have never used one. I don't think it has Multi Spark Discharge though. 2 Step etc. I will research them so I know WTH I am talking about.:banghead:
According to what they advertise here http://www.pertronix.com/prod/ig/ignitor3/default.aspx it has the multi-spark function.
After testing some of the voltage to the coil and ballast, everything looks good at key on and idle. But when I rev the engine, I'm getting some crazy readings hitting 30-40 volts at times and the coil was darn hot. Think I'll try a new voltage regulator. Hopefully I haven't fried something else. Been having issues with my tail lights not working and the dome light staying on since day one but I don't know if that has anything to do with it or not.
-
