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Discussion Starter #1
Hey guys. My 389 has been on the fritz. Maybe u guys have an insight or similar experience. Sorry in advance for long write up but..
Here's my set up;
65 bonneville factory rebuilt 389 with edelbrock 650 carb. Installed pertronix 3 about 4 yrs ago. 400 trans. Last time I timed it was set around 12 and ran perfectly. Car has ran great and started great for the past 5 years with no issues.
So, I only get the car out on the weekends or every other weekend. Took if for a drive a month ago, all normal, exit freeway and Come to stoplight. Car starts to have a rough idle and is going from idling good to rough bogging idle. I lightly brake stand it to feed it a little fuel and bogging stops and runs fine. Kinda still Boggs at idle before I get home. Just kept on the gas to keep Rpms up.
A week later, same story.
Last week: start car, cruse down to get coffee down the street and runs fine. Go to leave, start car and bogging rough idle starts. I start driving away and motor starts pinging the whole way home. Along with rough running and barely staying running. Never stalled though.
Plugs look good, light brownish. Normal color. Car wasn't and hasn't been running rich. Inside cap and rotor very very clean. Figured it may have been the vacuum advance. Looked original. Replaced it and vacuum advance was bad after the suck test. Started car and still had rough idle.
When I checked the timing i noticed on the timing light, that when the car would hesitate or kinda "miss" the light flashing wouldn't be consistent flashing. It fluctuated with the miss. Which leads me to think its the pertronix module because when the car suddenly idles good, the flashing is consistent like it should be. But then idles rough again. I put the car in gear and it would run worse or stall. But isn't hard to start.
Now there's no manifold vacuum port on this intake. Vacuum advance line came from (as long as I've had the car) the carb port on passenger side. Since it ran bad after changing the va, I read that the proper side for VA is the driver side port. Switched them and tried adjusting timing and no difference in idle roughness.
For kicks I put a new fuel pump in because I noticed fuel was very little in filter and figured maybe it was starved too. No change.
I apologize for the long write up but trying to eliminate possibilities and narrow it down.
Could bad vacuum advance cause the rough idle at first and mess up the pertronix? I'm at the basic frustrated point of a lost weekend day/money spent/no progress point, so any info would help.
Thanks guys!
 

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Johnny, you have done some investigating already,....of course rough idle can be many things and petronix can't be ruled out, yet...

a miss will cause your timing light to do that as well..

but it sounds like you might have a cylinder missing, rough idle, worse under load. this can be caused by electrical or fuel air....

first electrical, by looking for a plug or plug wire missing by shorting to ground, use a misfire pen, a spark tester or watch it in dark, ....to see if stray spark is apparent. Bad plugs, bad plug wire can cause a miss.

fuel air on a carburated car can be affected by a vacumn leak near an intake runner...that causes one cylinder to miss because too much air....sometimes does not happen until car heats up, and leak gets worse from say expansion of metal. check around intake manifold gasket for vac leak listen, feel...

at the back they get worse a temp fix is a dab or RTV sealant over the leak, let it set up....then retry...if so replace the gasket

try a different petronix or points if that does not work...

Pinging by the way can be too much timing, if you dial it back 2 to 4 degrees it may eliminate that. Also you need to know if that vac can is pulling full manifol vac...which means at idle...or just ported vac...which is only when throttle is opened...can't tell by looking...just pull the hose off at carb and see ifit is pulling vac at idle or not.....so you know, because it effects timing depending on the vac can.

also make sure distributor springs and weights are moving freely and not stuck advanced, causing a miss and pinging....

also make sure your distributor is down tight....

if nothing helps there make sure your choke is or fast idle screw is not sticking and causing an overly rich condition once fully warmed up''''

like it runs good initially ...then gets rough

PCV systems cause rough idles too make sure it is not clogged and all hoses are good...just keep investigating!

You will get it....pulling for Ya!:banghead::banghead:
 

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Discussion Starter #3
Thanks la mans guy. I'm making a list of stuff to eliminate. Thank u for all the info. I'm going to start with putting points back in and then investigate vacuum.
Thanks again!
 

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Johnny one thing I like to do is find out is it an individual cylinder miss....

or related to a whole engine operation that effects all cylinders?

Points check is a good start...and since you have been around the plug wires and dizzy make sure your plug wire routing and firing sequence are correct...also your wires to the coil are tight.

one way to find a cylinder miss is to use an insulated pliers, not metal don't get shocked,....and pull a plug wire while running if the engine runs rougher that cylinder was firing...if no change than you have a miss there...

I like the misfire pens and spark testers just easier....but this could be a plug gapped too much or not enough..

when I put in a crane module like a petronix I had to open the plug gap to .45....as the factory 35 i think it was was good with points but not the petronix...did not run as good...so a simple plug gap can cause a misfire, and under load....

let us know and lots of guys on here with great knowledge...(not Me)

they will chime in and help.....:thumbsup::thumbsup:
 

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As simple as this sounds, the gas itself could be adding to your problem if you are using the ethanol laced gas. You really are not driving it much and while it sits, the ethanol picks up water and over time, you could build up a little. I use the Stabil 360 additive you can pick up a Walmart. It can help your engine run smoother and break down the water.

Do the usual checks as already mentioned as this is sometimes the only way to narrow it down by knowing what it isn't. I am leaning towards an electrical issue. Did you replace the factory resistor ignition wire to the coil with a 12-volt sourced wire?
 

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Discussion Starter #6
Lamans- good point about the plug gap. Think mine were at .35 when I put them in. But never had a problem. It was hard to keep track of the miss because it would happen then run fine. But Thanks again la mans guy.
Jim- good suggestion on the stabl. I'll look into that. And I don't know about that wire because I got the car with an igniter 2 already in it. Since I just bought the car I swapped out for the new pertronix 3. That was about 5 years ago. And never had a problem with the motor til last week.
I have since removed the pertronix and sending them into the company to test out. I have parts to put points, condenser, ballast etc back in but realized I have no mounting screws. The new ones didn't come with it and the pertronix ones are not usable for points. So I'm at a stand still for now. Until I hear back from pertronix.
I'll keep u guys updates asap. And thank u for all the great advice
 

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Discussion Starter #7
Got a little update.
I said before the car came with an ignitor 2 set up. And I put an ignitor 3 in it shortly after I purchased it. Well, I would only assume it was done right because the car ran great. And after installing the ignitor 3 I've had no troubles for years. Well I guess the wire to the coil is the original resistance wire which is not a full 12v while running. And the tech at pertronix said my symptoms were due to not enough Volts to coil. After testing volts it was very low. My battery isn't 100% but enough to start the car. But that's what I'm going for right now. I mailed in the module and coil to pertronix to be tested anyway. And will either have to install their power relay or rewire for a solid 12v to coil while running.
After all this I'll let ya know if that's what ails me
Thanks again guys!!
 

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You will get it. Johnny, ..but if it ran great for 3 years, on the coil wire that you had installed....why would that now be the culprit?

If module was not running because it needed more volts as Petronius says, than either it malfunctioned internally, as you suspected or...your alternator or wiring is not delivering adequate voltage....like a loose belt or bad alternator.

Don't know what about Petronius but my crane module leaves in place the original ballast resistor wire as designed, same as the points. I discussed that with Crane Tech, and it works fine, but Petronix may be different.

Anyway, you are on it and I agree with Pontiac Jim that it was a good place to examine that resistor wire since the module is not the points....

Let us know what you find....:thumbsup:
 

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Discussion Starter #9
I wondered the same thing about why would it be acting up now, the guy said that it can run but eventually the module will start having little issues. And since I really don't drive the car long distances and only once, maybe twice a month he said it wouldn't act up right away. Either way I'm having it tested and will put it all back together with the proper 12v wire to the coil, and Hope that's it
 

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Discussion Starter #10
Do you guys know if I can run a jumper on the ign switch from the START post to the RUN post? I read that you can in order to give the coil 12v while running. Then add a non resistance wire from the RUN post to the coil. Apparently people say it can be done but should it be done? Will a constant 12v thru the RUN post eventually burn out the switch?
 

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Not quite sure what that will do....on those original harnesses their is a ballast resistor that drops the voltage down to 8.5 or something to the coil....

So I think the thing to do is use the original harness as designed with points....

Or say a crane module which requires no change there...

Or do what Petronix advises which may include something else in the wiring...

Not saying what you want to do can't be done..you.just don't want to mess up the proper voltage delivery to the coil and module....

Generally all the wiring can handle 12 volts or more and does from the alternator...up to 15.2 if you have a temperature regulated alternator, but at least 14.2 volts even on a stock one
 

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Discussion Starter #12
Gotcha. Thank u. Pertronix make a power relay that hooks up direct to battery and the resistance wire and is supposed to eliminate the need for rewiring that resistance wire. It just looks kinda ugly having a relay in the engine compartment. If indeed this is what I need to do to fix the problem then I will. Seems simple enough. Was just considering other avenues. Hope to hear fro pertronix today or tomorrow about testing my coil and module. Then hope to get it back together this weekend.
Thanks again for the info, will update asap!!
 

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I wondered the same thing about why would it be acting up now, the guy said that it can run but eventually the module will start having little issues. And since I really don't drive the car long distances and only once, maybe twice a month he said it wouldn't act up right away. Either way I'm having it tested and will put it all back together with the proper 12v wire to the coil, and Hope that's it

I did the conversion and also hooked up the factory resistor wire knowing I needed 12V (just didn't want to cut it or tape it off) and then I added a 12V hot wire from the battery, through the firewall, to a switch under my dash, and back to the coil. If I forgot to flip the 12V switch, the engine ran on the resistor wire, but not as good or smooth. I would flip the 12V switch on, noticeable improvement.

My battery would run down, which I believe was a not so good voltage regulator that worked, but did not allow the alternator to fully charge the battery so the battery would run down in volts, but not go dead. Again, I knew when my battery was getting low because it didn't have the "pep" a fully charged battery seemed to give my engine. I would simply put my battery on the charger and get it fully charged. Car ran strong again. I did not drive my car much either, so I tolerated it.

That said, the Pertronix will run on the factory resistor wired ignition, but not like 12V will do. Your battery running down coupled with the factory resistor wire was probably making the Pertronix work marginal and causing the engine not to run very smooth, like my experience.

I am sure there is a number of good ways to hook up the 12V power wire, but you want to be able to disconnect the power when the key is off. I used the switch under the dash, but wires showing were the least of my concerns with the way the car appeared in general - which was more like a rat rod. :thumbsup:
 

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Reading all this, as I have many, many times on other forums makes me feel very fortunate for having left the stock, dead reliable ignition systems of my two GTO's alone for the past 34 years or so. Life is tough enough, without putting sticks in your own spokes.
 

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Discussion Starter #15
Pontiacjim- pertronix now has a power relay that does what u pretty much wired up. Only thru a relay so it doesn't drain ur battery and activates thru your factory resistance wire.

Geetee- I've had about as much good luck with points as much as I've had bad luck. I've never had a single problem with pertronix in any of my cars, which is why I always run them. Got sick of changing points on the side of the road after so many years. Until this set of pertronix, but it's not the module itself I assume. But its my fault because I didn't check the past owners work of installing(or wiring) it properly, I just assumed since it had an ignitor 2 and it ran great it was fine. And ran great after I installed the ignitor 3.
Lesson learned I guess.
 

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Johnnie, you must be a young whippersnapper. I have never, ever changed points on the side of the road on any of my cars in the past 39 years of driving. I guess it's because I maintain my cars (change the points every 15,000 miles). I HAVE helped out a fellow GTO driver who was stranded on the freeway with a worn out rubbing block on his points....I simply adjusted his dwell screw, and he was on his way. (I scolded him for lack of maintenance!). Most of my friends, many of them racers, run HEI or upgraded ignition systems for simplicity and lack of maintenance perspectives. To each his own, and no worries. Diversity in this hobby makes it more fun. Now, off to fill up my fountain pen.......
 

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Discussion Starter #17
Hello gents, just heard back from pertronix and they stated I had a power transistor failure in the module. And good on pertronix they sent me a brand new module and coil to replace. I'm hoping to get it out back together this weekend and retime the car and see how it does. If all goes swimmingly, I'll be back to mid life crisis crusing in no time! Haha
I'll update how the car does this weekend.
Thank u again for thoughts and info !
 

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Discussion Starter #18
Almost out of the woods..
So pertronix sent me a new module and coil. Said there was a transistor failure in the module. I ordered their power relay and got everything installed.
Now the kit comes with a diode to install inline on the #4 wire going to the alternator regulator on the firewall. On my regulator there wasn't a wire going to 4, but to #3 and another
to F (I believe).
I installed the diode inline on 3.
The car started and ran great. Once it kicked down I checked the timing and set it to around 12. But once it kicked down I heard a chirping from I think the alternator. The gauge needle was bouncing with the chirp. And it was a consistent chirp.
Is this due to the diode being on the 3 wire? What would cause this?
But the car seems to run fine.
 

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I can't help with the diode or wiring, I would call Pertronix to make sure it is right.

The gauge should not be jumping like that - in my opinion. An the chirping almost sounds like a bad bearing in the Alt. It may be coincidental, but your Alt may be going bad, which is making the chirping, with is causing the jumping gauge. You may have had a couple things going bad at the same time and now that you got one problem fixed, the other has shown itself.

Take the Alt to be tested to make sure it isn't on its way out.
 
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