More Petronix Problems

Hey guys,



Got my new petronix today and took the day off to install them... The car runs good how ever when put it into drive the idle goes way down and the motor barely runs..yet when in nuetral or park it idles at 1100.. Im domb founded on this please hellp thanks..



wes

Seems to be a common occurence that the timing and possibly even the carb settings need to be set back up after you install a pertronix. Not really the pertronix fault, just a function of changing the timing controller.

Is there supposed to be that much of a gap between idle and and when i put it into gear. Got my dwell meter Rpm gauge meter thing out.. says its idleing in nuetral or park at 1,150 Rpm when i put it into Drive or Reverse it drops to 475 Rpm... If i increase the idle in gear then in therory wont it turn up idle on park or neutral... As for my timing i rotated the distributor to where the engine idles the faastest like pony carburetors said to do. they clam time lights dont work on our sixes. Another issue i noticed about my car is my vacume readings, she is only pulling 12 bls of vacume, Pony said and petronix said i should be at atleast 20-25. I dont know what to do i am so pissed and angry at it im ready to sell it off to the farmer down the street, lol. All my problems started arrising when my petronix went out and i replaced it with the same one i pulled out, however the one i replaced it with is not fried. HOpe you guys can help me out getting my bird on the road again. Thanks a bunch



wes

Is the pertronix the II or the pertronix I??. If it is the pertronix II take that piece of junk off you engine & put on the pertronix I or go to the duraspark ignition.
Read all my posts on the pertronix II. This product should be recalled before it kills someone with its poor idle & stalling at idle.
Make sure you have a full 12 volts to the coil, thats means by passing the resistor in the primary wire to the + side of the coil.
see www.pertronix.com for their trouble shooting link. The only thing they should have said is to replace the II unit with the I.
I loathe manufactures of products that produce junk like the pertronix II
william

You need to make sure the cam for the high speed idle is able to move down freely. This is the cam that allows higher idle speeds when the choke is engaged. It comes into contact with an idle screw on a lever between the choke and the carb body.
Make sure your timing is set with the vacuum disconnected from the distributor. Set the idle in gear, using the setting for warm idle.

Wes, if the problems started with the ignition change, that is your culprit. If you make an ignition change the spark still fires at the same instant as you have your initial timing set. I have experienced this condition myself with the installation of the pertronix II & have had correspondence with many others using this product. Put the stock point system back in or put the #I system & i bet your problem is resolved.
Don't listen to others who claim you have to tune the engine to match the junk pertronix II system. william

hey GOT FORD, i feel like i can actually help now...my pertronix was doing the same thing when i installed it, it would run pretty good on idle,. but as soon as it was dropped into gear, it would get real rough and stall out half the time...so i took advantage of the weather today, and checked my timing, it turns out my timing was off...not by 3 or 4 degrees, but by OVER TWENTY degrees...i finally got my distributer loose and moved it almost an inch clockwise before my timing marks were wher ei wanted them...i shut off the car,and started it back up, and it started up like it was brand new..so take a look at yuour timing, it could be all you need to do. (and thanks to everyone else for helping me get through my pertronix dilemna)

Sean

My understanding of the difference between the Petronix I and II is that the system will shut off if the ignition is left on without the engine running - to keep from burning up the petronix module (problem with the Petronix I). Also: "Compared to the original Ignitor develops an average 3 times more available energy between 3000 and 5000 RPM and nearly doubles available plug voltage." That is from their website: http://pertronix.com/

My timing went 20 degrees more advanced after installing the Pertronix II. I have mine set now to 14 degrees initial timing (static timing) with my vacuum hooked into the carb (not the manifold) and it works great. In neutral it idles @ 800 and in drive it idles @ 500. I can't believe it idles that low - smooth too. I love it.

And yes, I've checked the 12V @ the module. 12V @ idle and it dips down to and levels off at ~8.5 - 9 V @ 2500 rpm

Tuning an engine is an iterative process between timing and carburetion. You change one thing or part of one thing and you need to tweek everything all over again for best performance. No big deal - this makes sense.

Good luck with your endevors

ski

Ski, you must be one very lucky person to get a decent pertronix II.
Maybe i have conversed with the other 99 people who have had problems with this module.
With 14 degrees initial advance, & with 22 to 24 degrees mechanical would give you the perfered 36-38 degrees advance under full throtle conditions. The vacuum advance would give you additional advance under part throttle condition for decent fuel mileage.
Just out of interest what year distributor do you have, i see you have a 68 engine which uses the type of advance i just mentioned. Do you also have the 68 carburetor??
I'm just trying to get to the root of this pertronix problem.
Any additional information would be helpful.
Believe me i'm not trying to bash pertronix, because the pertronix I is a great product.
All i can say many owners who installed the II have gone back to the I or duraspark including me. :idea: william

I have a Pertronix Ignitor II installed and my 66 Falcon runs fine. I did have to raise my idle a little from where it was intially, but it is still pretty low.

I would be most worried about accepting advice from someone that tells you that, "A timing light will not work on your car." If that is really something they said then you need to find someone else to give you advice. Put a timing light on your car, disconnect the vacuum from the distributor and plug the line, and see where your idle is set to. That might be part of your problem.

-Dan in Atlanta

William - Don't know why you had so much trouble with the PII. I am not one of those who has a problem with it. As a matter of fact, mine fixed a poor idle problem. I find your generalization interesting.

Steve

I have a Pertronix II with a Flamethrower coil and stock-look Pertronix plug wires. The setup works great.
I hooked the red wire to a switched 12 volt source under the dash. The idle speed jumped dramatically when it was not in gear. When I put it in gear it would die. I read a couple of strings on this forum and got a couple of great hints.
I tried the vaccuum guage timing thing recommended by Pony and it worked okay. I put the vaccuum guage on the manifold tap, not the carb and I was drawing just enough vaccuum to get in the green zone, about 17 lbs, but the engine would knock and overheat under load constantly. It turns out that a lean mix can cause overheating.
I got a decent dwell tach and worked on the timing with a real electronic guage and readout. I haven't used a light yet, although I do plan to re-calibrate the balancer some day.
I disconnected the vaccuum advance to the distributor, put the car in drive and turned the distributor until it reached the recommended advance setting. I had to advance the static timing so far ahead that the vaccuum advance can touched the block. I re-inserted the distibutor one notch back (also called 're-stabbing' the distributor). When I finally got the idle on the money - with the vaccuum advance disconnected - I had to fiddle with the fuel/air mix, backing it out to richen somewhat. Once I did that, I had to adjust the idle again. Got it right and re-set the fuel/air mix for max vaccuum. Now it runs great with lots of pep and much improved fuel economy. Now I get 2 lbs more vaccuum than before.
I also had a cold idle problem with my Pony 1100 and that required some fiddling to get the choke pull-off to work properly since it sat on the high side of the cam. That also affected the idle in Park and Neutral. This cold adjustment is kind of hard to do in southern California. You can do a cold start adjustment once a day for about 3 minutes tops. Normally you generally don't even need a choke herebouts. You just nurse the foot feed after it starts.
Use a dwell tach and adjust the idle in drive. Get the fuel air mix on the numbers with a vaccuum guage. Check the timing again with the vaccuum guage and the dwell tach. Repeat as often as neccessary until you achieve Zooom.

I have a '71 distributor - so I have both of the mechanical and single vacuum advance. I also have an autolite 1100 set up for an auto transmission (antistall dashpot) without a spark advance valve - just an open port.

I set the initial timing to 14 degrees (with the vac line off @ the carburetor). At idle, there is no vacuum at the ported source on the carburetor. This proves that I didn't need to pull my vacuum line to set my initial timing - but in good form, I did. The vacuum quickly jumps up to ~ 20" when the throttle is opened giving an additional 7-10 degrees of timing advance. The mechanical picks up as expected and brings the total advance up to ~ 38-40 degrees close to 3000 rpm. As the rpm increases, the vacuum at the carb tapers off and at 3000 rpm. So, at and above 3000 rpm, I have just the mechanical and initial timing advance.

I gave approximate numbers since I scribbled it all down in my book in the garage - pulling it all from memory at the moment. I followed several of the threads in this forum and tought myself how this timing thing really works. I went whole hog and plotted the following:
- vacuum at the carb vs rpm
- vacuum at the manifold vs rpm
- advance vs vacuum (while the car was at idle so mechanical wouldn't play a role - used a vac pump connected to the distributor)
- mechanical advance vs rpm (while the vacuum line was disconnected so I could see when the mechanical picked up and how much it gave)
- advance vs rpm (with everything connected - to see how the mechanical and vac added together to get to the total timing - and to see if there was a mechanical limit with in the distributor limiting the total timing)

I plotted the vac adv data every 1" of vacuum and the rpm data every 500 rpm - just to get a feel for how everything was working - mainly to see when each component kicked in and how much it contributed. I didn't adjust the vacuum diaphram, nor did I change springs within the mechanical adv plate. I just wanted to prove to myself how the 40 year old piece of technology worked. Works fine - as designed. There are a lot of opinions out on the web as to how to time a car - some are performance oriented, some are economy oriented, and some are hearsay oriented. I'm happy that I figured mine out.

Also - there is the carb. Once I tweeked with the initial timing, I went back and tweeked the carb settings. Then, back to the timing. Then, back to the carb...unitl I was happy or found no change in one with a change in the other.

If anyone wants the actual timing data - let me know and I'll dig them up.

Oh, the entering element here was converting to the pertronix II from a point style. I added the flame thrower II coil and opened my spark plug gap to .050 - I left it there. I'm sure this helped smooth things out since there is significanlty more energy going to the plugs. Could I go with a bigger gap? Maybe, but this seemed like a good number - alot more than stock.

ski

Always eliminate tuning as an issue. It might surprise you. Number one rule when you have a problem with your car, retune it to eliminate it as the source of problems. It has saved me lots of money tuning the car when I thought I had other problems.

Slade

Ski,
We are told to check the vaccum at the manifold not the vacuum advance port on the carb when tuning.I'm curious as to what kind of difference you got comparing the vaccuum at the carb and at the manifold at same RPM points.

Vacuum at the manifold and at the carb port are the same except when the throttle is shut. When the throttle is shut, the carb port is effectively separated from the manifold. That is why you find no vacuum at the carb during idle conditions (unless your idle setting is high and your throttle plate is opened more than it should be). I recall having to set the throttle plate to ~ 1/8" open from the throttle bore when I was rebuilding it - but for simplicity, let's just say that the throttle is shut at idle. As soon as you open up the throttle, the vacuum at the carb port will go to what the vacuum at the manifold is. This is when you get your vacuum advance to kick in - when you are accelerating from low rpm.

There has been the big question out there (on the threads in this forum) as to where to hook in the vacuum line for the distributor - carb port or manifold? The way my car is set up - I have the distributor connected to the carb port so I get the additional advance when I accelerate and when I'm cruising. This set up works good for me. If I was to have the vac line connected to the manifold, I would have the additional advance from the vac advance canister all of the time, so I might as well just bump up my initial advance to whatever the vac advance canister gives me and get rid of the vac advance all together - just go with straight initial and mech advance. My understanding of the vac advance is that it bridges the gap between idling conditions and when the mechanical advance begins to pick up - and mine tested out to do just that. Here are the numbers from my fiddling around:

Vacuum (Vacuum/advance): 0"/0 degrees, 5"/0 degrees, 8"/1, 9"/3, 10"/4.5, 11"/6, 12"/8.5, 13"/ 10 degrees - 10 degrees is the most my canister would put out.

Mechanical (rpm/advance): 1000/0 degrees, 1200/3 degrees, 1500/6, 1800/8, 1900/10, 2100/12 degrees - 12 degrees is the most my mechanical advance gave me.

Initial: 17 degrees @ 800 rpm (no mech or vac advance contributing)

Sorry, previously I said my initial timing was @ 14 degrees, but I have since set it to 17.

Total timing (rpm/advance): 1000/17 degrees, 1500/25 degrees, 2000/37, 2200/43 degrees - this is with the mech and vac adding into the initial. Now, the numbers don't quite add up - geeking out and interpolating between the above points to add initial + vac + mech at a set rpm. My disclaimer is I don't truely know the exact slope / peak of the vac curve and mech curve - and how they interact together completely when under load - BUT (Behold the Underlying Truth) those are the numbers that I measured. By the way, an adjustable timing light is great.

I tried the tuning by vacuum method and I couldn't get it to work. The vacuum on my manifold did not change a bit while adjusting the carb or while adjusting the timing - 16" is all I got.

Ludwig,
Here is a plot I found when trying to figure this all out. The left axis is vacuum in inches and the right axis is throttle position in percent full travel. The bottom is time. I have no idea of what car this is from, but it clearly shows the relationship between carb port vac and manifold vac. Mind you, that some carbs (the early ones I believe) have a spark control valve at the carb which reduces the vacuum at the carb (i.e. it will only be 25% of manifold vacuum) so a more sensitive vac canister can be used on the distributor. My carb does not have that.

http://www.carbdford.com/tech/portedvsmanifoldvacuum.htm

Does this help?

ski

If I was to have the vac line connected to the manifold, I would have the additional advance from the vac advance canister all of the time, so I might as well just bump up my initial advance to whatever the vac advance canister gives me and get rid of the vac advance all together - just go with straight initial and mech advance.

Click to expand...

This is an intresting subject. 2 small disagreements, when I had my inial at 16 I would get occasional kick-back when starting, using manifold vacuum allows me to have 32 at idle which my car seems to like and allows me to run less initial. Also using either vacuum increases advance when cruising giving morer power and economy without pinging under load.

ski4evr":m4u02hdc said:

This is when you get your vacuum advance to kick in - when you are accelerating from low rpm.

Not if you open the throttle very much. It takes a while for the rpm to build up enough vacuum to matter much at WOT.


If I was to have the vac line connected to the manifold, I would have the additional advance from the vac advance canister all of the time, so I might as well just bump up my initial advance to whatever the vac advance canister gives me and get rid of the vac advance all together - just go with straight initial and mech advance. My understanding of the vac advance is that it bridges the gap between idling conditions and when the mechanical advance begins to pick up - and mine tested out to do just that. Here are the numbers from my fiddling around:
ski

Click to expand...

The purpose of the vacuum advance in conjunction with centrifugal is to provide additional advance for improved economy. If you "just bump" the initial advance up that far and "just go with straight initial and mech advance" it will be too advanced at high rpm unless you do some serious re-curving of the advance mechanism.
You are correct in using the carb port for distributor vacuum, although many folks do use manifold vacuum with some sucess. With the manifold vacuum applied the engine idles faster so you have to close the butterfly more to compensate. This also allows the engine to idle cooler, not a bad plan for hot climates. I use the ported vacuum on my truck as I want it to warm up quicker and burn cleaner, which is partly why the ported vacuum was developed in the first place.
Joe

Ski,
As your graph shows, at anything above 30% throttle position, the engine vacuum falls sharply. So during those periods of more than 30% throttle position, there is very little if any contribution from vacuum advance whether it its connected to ported or manifold source. Keep in mind that engine speed and engine vacuum readings obtained in the driveway are not indicative the readings you would see on the road where a load would act to reduce engine spped, and you would have your foot into the throttle in order to maintain speed.
Doug

Very valid points. The "driveway test" is not what's happening when it's being driven. I've thought about getting a vacuum line long enough to run through the A/C hole in my firewall so I can see what vacuum at the carb does while driving and then what manifold vacuum does while driving - to get a better understanding of what is really happening. The only thing keeping me from doing it - my car runs pretty good now. But, this thread has got me wondering again.

Thanks for the outside observations. Without inputs from forums like this, we could probably all go on tangents and we'd all think the way we went was right. I'll run the vacuum line into the car and get some actual numbers.