MoparFins

Techical Discussions => Tech- - Engine => Topic started by: Brian on June 21, 2011, 11:32:50 AM

Title: Ignition problems??
Post by: Brian on June 21, 2011, 11:32:50 AM
Well I'm a bit stumped on this one and thought I'd post up my issues and see if someone can see something I am not.

This problem has developed, and gotten worse, over the last year or so.....The 440 in the wagon when I first fire it up the problem is not that bad but when it warms up I get a fluctuation of 100-400 RPM in the ignition.  Doesn't seem to matter if I'm accelerating or just cruising, the tach is jumping sporadically.  It doesn't seem to be cyclical in nature, and it's always a RPM drop, not a spike.

I have a Petronix ignitor I in a re-manufactured stock dizzy, with a matching Petronix Flame thrower coil.  I just recently swapped out the old mechanical voltage regulator for the new electronic unit in the original case.  

Here's what I've tried.

- swapped out the flame thrower coil for a stock unit....No change.
- Changed ballast resistors...No change.
- Pulled out the Petronix dizzy and re-installed the original points dizzy...problem got worse!  During warm up it was missing horribly.

Can't think what else it could be.  I also installed new Champion plugs, and Accel 8.8 plug wires, cap and rotor, last fall hoping this might solve the problem.

Thoughts, suggestions?


Title: Ignition problems??
Post by: Brian on June 21, 2011, 12:51:01 PM
Alright I figured out why the points dizzy was running so bad.  I just tossed it in and set the vacuum advance in line where the other dizzy was set...well I was running about 30+ degrees advance!!  

So I set the timing properly with the timing light at about 12 degrees.  The problem is exactly the same as with the petronix dizzy.


Title: Ignition problems??
Post by: Jason Goldsack on June 21, 2011, 01:23:47 PM
Run a direct line to the battery so you can check it from a known source. If you have a ballast in place run it inline to the battery or however the stock is wired.....

Something must be grounding... if it runs better from the battery then you might need to dive into your wiring..



Title: Ignition problems??
Post by: Steve on June 21, 2011, 01:35:04 PM


Could be the box too
Title: Ignition problems??
Post by: Guests on June 21, 2011, 02:08:44 PM
Can you move the shaft on the distributor to close the points or the gap for the Pertronics? You may have an intermediate shaft bushing that is going bad and adjusting the shaft from the bottom of the distributor. You can pull the distributor, pull the oil pump intermediate shaft away from the cam and see how loose that is by rocking back and forth. If it isn't electricity, well, this is the next place to look.  The old Sun Supertach 2000 or whatever engine diagnostic scope could tell you if it is a single location or random by breaking down each cylinder spark and comparing them to each other.
Title: Ignition problems??
Post by: Brian on June 21, 2011, 03:41:19 PM
Well the tach matches the the digital timing light reading.  I'm going to
double check the plugs, and wires for continuity.  Something my
grandfather always told me to do since sometimes you get bum parts
right out of the box.   I can't recall if I did this when i installed
the new plugs and wires.



 When I had the motor apart I installed a new chain at that time and
maybe have 3000 miles on the car since then.  So I doubt it's a chain
issue.  Plus usually with a chain going bad you will see the timing mark
 fluctuate a fair amount when the timing light is on it.



 I am now wondering if it's a fuel delivery problem.  Will change
out the filter and swap the fuel pump and see what happens.  The carb is
 a TQ, and was a reman unit when I go the car going.  Turned out the
reman unit was set up wrong so I had to pull it apart and redo the
entire carb.  So I don't think it's the carb but will tear it down and
re-set all the factory settings.


Title: Ignition problems??
Post by: Brian on June 21, 2011, 04:49:55 PM
I just got back from another drive, and I'm pretty sure it's not a fuel delivery problem.  I've had such problems in the past and the feeling you get from the motor when you have a lack of fuel is kind of like the motor is coughing.  This feels nothing like that.  When I accelerate the car is still smooth but it's like a real quick short and then back to business.  

The shorting is pretty constant though, as soon as the RPM fluctuates and then goes back to normal it's right back to another fluctuation.  But the drop in RPM is never the same, sometimes it's only 100 rpm, then the next will be 300 rpm.

I did notice that under moderate acceleration the RPM seems to fluctuate 200-400 rpm.  Under hard acceleration it seemed like 500 rpm.


Title: Ignition problems??
Post by: Guests on June 21, 2011, 05:37:35 PM
Intermediate bronze bushing on the oil pump distributor drive shaft. As the torque goes up, the gears mesh at a different angle and the Pertronics gap becomes different, and that is why the points distributor was worse, not better.
Title: Ignition problems??
Post by: Steve on June 21, 2011, 07:22:17 PM


He said this is why a TQ rebuild fails in a short time.  I need to order a kit and have Cory rebuild my TQ again.  Or I'll save it and put a large edelbrock on it.  I was going to use this on the Diamond until I got the bugs out of it.
Title: Ignition problems??
Post by: Brian on June 21, 2011, 08:41:01 PM

Quote from: POLARACO


Not sure what your making reference to?  I've rebuilt and set-up dozens of TQ's over the years and never noticed a missing O-ring in the kits.  You do have to spend a lot of time setting up the carb properly, but I've put kits in and run the carbs for years in daily drivers  and never had a problem.

Title: Ignition problems??
Post by: Brian on June 21, 2011, 08:41:43 PM

Quote from: dana44
Intermediate bronze bushing on the oil pump distributor drive shaft. As the torque goes up, the gears mesh at a different angle and the Pertronics gap becomes different, and that is why the points distributor was worse, not better.

Will look into that this coming weekend.  Thanks for the advice!(http://www.moparfins.com/forum/smileys/smiley4.gif)

Title: Ignition problems??
Post by: Steve on June 22, 2011, 07:46:47 AM


Engine speed going up and down like that is either fuel delivery or rich/lean situation in the carb.  Fuel delivery could cause that too.  It's almost like the speed drops until the bowl is filled again
Title: Ignition problems??
Post by: Brian on June 26, 2011, 05:29:36 PM
OK had a couple hours today to work on the car, been sick and still had a bunch of family events to attend.  (http://cbodydrydock.com/e107_images/emoticons/cry.png)



 So the other night I pulled all the plugs and wires and tested them, all came out good. No change.



 Then today I put on 2 new fuel filters, I run one before my fuel pump, and one after.  No change.



 Then I by passed the ignition switch with a hot wire from the battery to the ballast. No change.



 Disconnected the vacuum advance and then the power brake booster. No change



 Re-set the air fuel mixture screws on the carb with my vacuum gauge,
getting just shy of 20 inches of vacuum.  But the vacuum seems to slowly
 build about an extra 1/2 inch and then drops back down..kind of odd?
Again no change.



 I'm going to pick up another rebuild kit for one of my spare TQ's and
rebuild that one.  Then swap it on and see if the problem persists.  I
starting to lean towards fuel delivery.







Title: Ignition problems??
Post by: Guests on June 26, 2011, 06:23:44 PM
Remember, there should be a fuel filter within the carb also, one of those thimble looking bronze colored ones, might be dirty if you are thinking fuel now.
Title: Ignition problems??
Post by: Brian on July 17, 2011, 11:19:59 AM
Well I rebuilt my spare carb and put it on, car ran like crap.  Think
the throttle shaft had WAY too much slop in it, and the carb to intake
gasket wasn't sealing right.  Anyway when I did manage to keep it
running the problem was still there.  So I swapped the original carb
back on and went on vacation.

Now during my 1125 miles drive in
the wagon I began to notice something.  I always drive with my running
lights on, but during holiday time we have a small 12V to 120V power
converter to run the lap top for movies for the kids.  And then when I
had the defrost/Heat on the A/C cycles.  During these big load times the
 jump in the RPM was much larger, 3-400rpm.  I would then shut off
everything and the jump would drop to just over 100rpm.  So I'm thinking
 maybe it is the alternator not putting out enough AMPS?  I'll try
swapping on another one I have laying around.

One thing I want to
 be sure of, when you put a dual field alternator on a single field
system you just need to ground out one of the field plugs...correct?


Title: Ignition problems??
Post by: Brian on July 17, 2011, 11:20:32 AM
Oh and I also installed a new fuel pump as well before we left on vacation, no change.





Title: Ignition problems??
Post by: Guests on July 17, 2011, 11:52:05 AM
Don't ground it out, it has to go to the positive side of the coil or it won't work. Double-verify it is the positive side, I had the same issue with an 82 or 84 Ramcharger, it will not work with it grounding and may actually cause damage. It took me a bit to get it straightened out because all the lean burn stuff, along with all the sensors, were part of this extra wiring for the second field wire, and it won't charge unless it is there. I say get a wiring diagram with the two field wiring because it may actually be the negative side of the coil, so double-check my response with the wiring diagram. The two field wire alternators were only used a couple years.
Title: Ignition problems??
Post by: Steve on July 17, 2011, 12:41:24 PM


I think you can bolt in a 87 to 89 Mitsu alternator in there.  That's a 100 amp.  But, run a 2nd # 6 wire direct to the battery.  You'll have to convert to the electronic regulator.  Better off
Title: Ignition problems??
Post by: Tom Dawson on July 18, 2011, 09:50:55 AM
Have you checked the intake for leaks?, a bad seal on the intake could be sucking air.


Tom



Title: Ignition problems??
Post by: Brian on July 18, 2011, 07:52:09 PM

Quote from: furyman67
Have you checked the intake for leaks?, a bad seal on the intake could be sucking air.


Tom



Gonna try the alternator first, then it's spraying carb cleaner in and around to see if I can find a leak.