Top End Miss

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this may sound stupid but sounds like the pickup coil took a dump or its set to close just a thought
 
jimjimjimmy said:
this may sound stupid but sounds like the pickup coil took a dump or its set to close just a thought
Click to expand...

well it was doing this before i put in the electronic dizzy and MSD box

but

i didn't know it could be set to close... i always here about how you file them down even so you can get it really close...

and the pickup either has an ohm reading or not right?
 
OK, IF I understand what you did and what happened.......................please correct me if I'm wrong.


The fact that running a direct line from the battery to the regulator "cured" the problem indicates that you DO have voltage drop in the ignition harness. Visualize in your mind the path (stock wiring)

Battery -- fuse link -- bulkhead connector -- ammeter circuit -- ignition switch connector -- through the switch -- back out the switch connector on dark blue "run" line -- back out the bulkhead connector -- to the ignition system, the regulator "I" terminal, and the alternator field on 70/ later isolated field systems.


ALSO in this mix is the alternator output line which goes

alternator -- bulkhead connector -- other side of ammeter -- through ammeter -- and thus "tees" into the harness section mentioned formerly.

ANY bad connection or drop in this area can cause this surge. In rare cases, surge can be caused by what amounts to R.F. interference from something like a high power ignition system, which can produce noise on the 12V buss and interfere.

But.....I'm betting on a bad connection. IF you cannot resolve a possible bad connection in the bulkhead, or the igntion switch/ switch connector, I'd get a good heavy relay and install in the engine bay

Feed one contact with power off the starter relay stud, and the output contact feeds the ignition system, regulator, and alternator field.

Your "blue run" wire will now go to the coil of the relay, and the other coil can get grounded.

Also, instead of grounding the relay coil directly, you can ALSO run the ground side coil back inside the car to a toggle switch hidden somewhere, and create an anti theft device.

If, for example, you use a Bosch relay, here:

30 -power coming in from starter relay battery stud

87 new "run" output feeds power out to ignition, alternator field, regulator "I" terminal

86 hook your old blue "run" wire here to energize relay with key in run

85 ground this, or run to a hidden toggle to ground for anti theft

RelayWiringGuide.jpg


Another way, if you are planning on running electric fans, fuel pumps, other heavy draws, is to use a "continuous duty solenoid" like this:

These look sort of like a starter solenoid and ARE NOT. You can NOT use a starter solenoid, which are designed only for "intermittent" use, not "continuous" use. Any "good" parts store should have 'em.

In this case, one big stud hooks to the big battery stud on the start relay

The other large stud is the power output in "run" goes to regulator, ignition system

One small stud goes to old blue "run" wire

Other small stud is grounded, or as with Bosch, run to hidden "anti theft" switch.

41fqx8iEc6L._SL500_AA300_.jpg
 
67Dart273 said:
OK, IF I understand what you did and what happened.......................please correct me if I'm wrong.


The fact that running a direct line from the battery to the regulator "cured" the problem indicates that you DO have voltage drop in the ignition harness. Visualize in your mind the path (stock wiring)

Battery -- fuse link -- bulkhead connector -- ammeter circuit -- ignition switch connector -- through the switch -- back out the switch connector on dark blue "run" line -- back out the bulkhead connector -- to the ignition system, the regulator "I" terminal, and the alternator field on 70/ later isolated field systems.

well remember i just "fixed my last no charge issue with running a wire from the alt to starter relay stud... there is no fuseable link as the bulkhead is bypassed (alt lead in and out only)


ANY bad connection or drop in this area can cause this surge. In rare cases, surge can be caused by what amounts to R.F. interference from something like a high power ignition system, which can produce noise on the 12V buss and interfere.

only have a MSD street fire box so i dont think its that
Click to expand...
 
ok so i started cutting all the tap off the harness to follow the blue/white wire from the ballast resistor to the bulk head and then on the other side... so i cut the wire on the inside and ran a lead out directly to the resistor plug and now it wont crank... lol...

also found the wire that broke from the alt to the amp gauge...
 
If it won't crank you "broke" the yellow going to the start relay, most likely. Sounds like you have numerous problems with the harness/ bulkhead connector.

Must be frustrating....................
 
67Dart273 said:
If it won't crank you "broke" the yellow going to the start relay, most likely. Sounds like you have numerous problems with the harness/ bulkhead connector.

Must be frustrating....................
Click to expand...



yea the Previous owner had cut and spliced a bunch of stuff... i pulled at least 15ft of wire out of it with tape on both ends lol... it really needs a new harness but i dont want to get into the dart yet... i need to get my AWB done first...

i'll just have to keep working thru it... but if it helps acts like its in a gear... resistor bypass kicks in but no crank
 
Originally Posted by SpeedThrills
Have you checked fuel volume yet?
Moper added:
I'd also second this. Get a clean 5gal bucket, mark it into 5ths, and flow the pump thru the fuel log into the bucket. Use a stopwatch to see how many seconds it takes to pump 1 gal.

This is from one of your other threads on this problem. (You're all over the place.) I can only guess that you do not understand the theory of FUEL VOLUME VS. FUEL PRESSURE. I don't want to hear about this pump or that regulator. TEST FOR FUEL VOLUME!!! TEST! DON'T BOLT ON MORE PUMPS, TEST!!!!!!!!!!!!!!!!!!!!! DID I MENTION TO TEST?????????? WHY ASK FOR HELP IF YOU'RE GOING TO IGNORE IT????!!!!!!!!! YOU COULD PUT THAT HOLLEY BLACK PUMP ON AND STILL HAVE INSUFFICIENT VOLUME! BUT YOU"LL NEVER KNOW BECAUSE YOU WON"T TEST!!!!!!!! TEST IT BEFORE YOU PUT THE BLACK PUMP ON.
Dam it, dude, we're trying to help, and you IGNORE a very critical and basic test that will give you valuable data!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:violent1::violent1::violent1::violent1::violent1::violent1::violent1:
 
SpeedThrills said:
Originally Posted by SpeedThrills
Have you checked fuel volume yet?
Moper added:
I'd also second this. Get a clean 5gal bucket, mark it into 5ths, and flow the pump thru the fuel log into the bucket. Use a stopwatch to see how many seconds it takes to pump 1 gal.

This is from one of your other threads on this problem. (You're all over the place.) I can only guess that you do not understand the theory of FUEL VOLUME VS. FUEL PRESSURE. I don't want to hear about this pump or that regulator. TEST FOR FUEL VOLUME!!! TEST! DON'T BOLT ON MORE PUMPS, TEST!!!!!!!!!!!!!!!!!!!!! DID I MENTION TO TEST?????????? WHY ASK FOR HELP IF YOU'RE GOING TO IGNORE IT????!!!!!!!!! YOU COULD PUT THAT HOLLEY BLACK PUMP ON AND STILL HAVE INSUFFICIENT VOLUME! BUT YOU"LL NEVER KNOW BECAUSE YOU WON"T TEST!!!!!!!! TEST IT BEFORE YOU PUT THE BLACK PUMP ON.
Dam it, dude, we're trying to help, and you IGNORE a very critical and basic test that will give you valuable data!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:violent1::violent1::violent1::violent1::violent1::violent1::violent1:
Click to expand...


ok i shall test it...

also i fixed the yellow wire so its running again... but bypassing the bulkhead from the blue/white did not fix the voltage surge... so whats next the ign switch??
 
kidintheyard said:
i doubt that you really need a holley black pump,i have a blue on my 13.1 340 and its never ran out of fuel on the motor and im sure the 750 mite be over board to....but thats just my two cents
Click to expand...

a slant racer back east just picked up over a tenth and a half and besides... im sure my 60ft will be much better with the vac secondaries... and all the V8 guys say that the 600 is overboard lol...
 
Thanks for not taking my rant personally. I've been reading all of these posts and it's been killin' me!
 
SpeedThrills said:
Thanks for not taking my rant personally. I've been reading all of these posts and it's been killin' me!
Click to expand...

lol im rhick skinned... and as you say it should be sooner on the diag check list...

my only question is with the car stationary vs moving alot of things change, extra force on the fuel in order to get it up the tube... how do you test for that?
 
Put this on it.

[ame]http://blp.com/pdf/BIG-BO-FLYER.pdf[/ame]
 
805moparkid said:
lol im rhick skinned... and as you say it should be sooner on the diag check list...

my only question is with the car stationary vs moving alot of things change, extra force on the fuel in order to get it up the tube... how do you test for that?
Click to expand...
That's why volume is important. If you have enough volume at the right pressure, at idle, you'll have enough under acceleration.
I really don't know how to explain this, but I'll try. I'd bet a plumber would know of a good source for theory.
This all presumes no needle, seat, etc. restrictions:
Say you have 3/8 fuel line and 7 psi at idle. Now you change the fuel line to 1/2 and touch nothing else. The fuel pressure would theoretically be lower under load. Now you raise the fuel pressure to 7 psi (under load). More volume as a result. If you just raise the pressure, you'll still have about the same flow. It's restricted by the tubing diameter.
If you have a restriction in your say, 3/8 line, the fuel pressure may still be at 7 psi, but there will be less volume.
If everybody on the street opened their faucets at the same time, but the pipe in the street wasn't large enough in diameter to supply them, all the pressure in the world won't push enough water to the faucets.
I never tried to explain this, it's tough!
If you can put enough gas in the bucket at idle (whatever the amount and time is, I'm not sure), you'll have enough flow under acceleration, and the pressure won't drop off as much because you have plenty of flow.
HELP!
 
805moparkid said:
but

i didn't know it could be set to close... i always here about how you file them down even so you can get it really close...
Click to expand...


Yes, it is possible to have the gap too small.

On my previous race car I changed the msd pickup and went to a digital 6 ignition at the same time and it developed a miss at around 5700 rpm and my tach being triggered off of the box would sometimes trigger the shift light at the wrong time. I thought the msd dig 6 box was bad and sent it back to msd. They found nothing wrong with it but did send me a new one anyway and I still had the problem. I made ground and power wiring changes but nothing helped. One day someone told me to turn the rev limiter off on the dig 6 and the car ran fine so I was still blaming the box again. Anyway it turned out that when I setup the pickup gap to .003" it was too close. I changed it to .025" and all my problems went away.
One thing you have to make sure is when you tighten down the msd pickup you don't over tighten it and crack it because it will cause a miss too. AND the magnet has to be oriented right.
 
I'm late to a really long thread and i need to go and read it in depth. But 35yrs ago i chased this very same problem and replacing the rocker shafts, arms and spacing them properly took a 340 from 5500 to 7000+

Im sure this was mentioned early, but if i find any ideas to add after reading i'll post'em.
 
kman521 said:
Yes, it is possible to have the gap too small.

On my previous race car I changed the msd pickup and went to a digital 6 ignition at the same time and it developed a miss at around 5700 rpm and my tach being triggered off of the box would sometimes trigger the shift light at the wrong time. I thought the msd dig 6 box was bad and sent it back to msd. They found nothing wrong with it but did send me a new one anyway and I still had the problem. I made ground and power wiring changes but nothing helped. One day someone told me to turn the rev limiter off on the dig 6 and the car ran fine so I was still blaming the box again. Anyway it turned out that when I setup the pickup gap to .003" it was too close. I changed it to .025" and all my problems went away.
One thing you have to make sure is when you tighten down the msd pickup you don't over tighten it and crack it because it will cause a miss too. AND the magnet has to be oriented right.
Click to expand...

hmm... i think i have mine set at .008" (stock recurved mopar electronic dizzy), i will open it up and see what happens...

OldmanRick said:
I'm late to a really long thread and i need to go and read it in depth. But 35yrs ago i chased this very same problem and replacing the rocker shafts, arms and spacing them properly took a 340 from 5500 to 7000+

Im sure this was mentioned early, but if i find any ideas to add after reading i'll post'em.
Click to expand...

well when i had the head redone due to a stuck valve i spent the time and shimmed all the rockers so they had a little side free play and were centered over the tips... also i went thru about 4 sets of rockers and picked the tightest ones... and i mean tight as minimal slop...
 
For some reason, when I saw you mentioned MSD, I was thinking it was a whole system. If you have a stock style distributor, pull the cap, and pull the rotor/center shaft side to side. My brand new MP distributor had a ton of slop, and the reluctor wheel would contact the pickup at about 5,000 rpms. Dead short, bad miss. Sound familiar? Swapped in an MSD distributor, problem solved. If that is the issue, tighter bushings will fix the stock distributor.
 
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