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mcarbaja · 03-20-2002, 01:03 PM

I have a 64 pontiac 389. The car has 3 problems. I am wondering what it might be so that i can solve this problem. The car has a petronics ignitor instead or points, MSD 6 and regular AC spark plugs i have ACCEL disturbutor cap and rotor . When the i drive the car it drive and respons good. But sometimes it feels like if the engines skiped a beat. Sometimes it just , like turns off then turns back on . when ever it starts to have problems i look at the rpm gauge it goes to zero then jumps back up to more or less were it supposed to be . nothing turnes off in the car everything is on while this happenes. sometimes it happenes and sometime no. I checked the connection and evrything is good. I feel that the ignition is turning off but wonder what can it be . The car also sometimes pings like crazy right after it changes gears , i guess when it is giving straight power. that also happenes sometimes. At idle sometimes i will see the rpm move down a little like if it is misfirring and sometime it will turn off but rare . I checked the cap plugs and wire and it looks good. any help will defently help me a lot

gtoguy1967 · 03-21-2002, 02:02 PM

half inch as i recall my 67 came factory with a ground stap are you sugesting replacing this or just making sure there is one there. Don

Half-Inch Stud · 03-22-2002, 02:13 PM

Don,

Distributor case to block to have any type groundstrap in good condition.

Goatman · 03-20-2002, 05:22 PM

Ed, as I'm sure you know, engines need spark and fuel to run. If Mig says his elctrical is "OK", then its his fuel.

When my mechanical went on my 70' GTO, it did alot of weird things. It would run fine sometimes, then it wouldn't start. Sometimes it would run only when I didn't give it gas (idle) or when I pulled the manual choke out. I once drove the car 15 miles down the highway at night with the car only runnning on the manual choke. Not fun, as you can imagine. Mechanical pumps will go slowly sometimes and their strange habits can make it hard to trace accurately.

[ March 20, 2002: Message edited by: Goatman ]</p>

455HOGT37 · 03-21-2002, 02:31 PM

That tach going to zero clearly indicates a problem on the primary side of the coil, but the "pings like crazy" sounds like a temporary lean condition, and I am sure G-man picked up on that. There may be a bit of both going on here.

Tom Vaught · 03-22-2002, 09:45 PM

Thanks for the additional info, Karl. Don't know
much about ignitions other than how a stock set-
up works. The cam sensor uses a sine wave per our
previous discussion. Tom V.

mcarbaja · 03-20-2002, 05:29 PM

yes 6567GTO your their more or less were their and ed also whith stumble it feels like that its crazy.Goatman i feel that it actualy is electrical. We have that good engine only needs air gas and electricity. if the RPM metter goes to 0 in the spit secound then back up it makes me feel that it electrical. I could on feel that it might be the petronics( it goes in place of the points it uses magnets that spin with the rotor) just what i think i will try to do something todayand post it up

Goatman · 03-21-2002, 03:39 PM

I hate sorting out gremlins! LOL Easy solution, rip everything out and start over with new stuff. Too bad money doesn't grow on trees like it used to.

Blue '66 · 03-22-2002, 09:56 PM

Karl,I know this is off the subject.I just bought
a Ignitor 2 system.My engine is pretty mild.Will I
have trouble recurving the dist using this system?
...Eric

Goatman · 03-20-2002, 05:48 PM

It may be that Mig, but I don't know why you wouldn't think that that split second stumble couldn't be the diaphram inside the pump failing or pumping air instead of fuel.

If all else fails.............

JJake · 03-21-2002, 04:44 PM

Check the wire that went to the points, now to the Petronics sender unit. They sometimes get pushed down and rub against the distributor shaft wearing off the insulation and will ground intermittently. They are easier to find when the ground is permanent, been there.

Goatman · 03-23-2002, 02:42 PM

Anyone know what happened in this particular case??????????

mcarbaja · 03-20-2002, 01:03 PM

I have a 64 pontiac 389. The car has 3 problems. I am wondering what it might be so that i can solve this problem. The car has a petronics ignitor instead or points, MSD 6 and regular AC spark plugs i have ACCEL disturbutor cap and rotor . When the i drive the car it drive and respons good. But sometimes it feels like if the engines skiped a beat. Sometimes it just , like turns off then turns back on . when ever it starts to have problems i look at the rpm gauge it goes to zero then jumps back up to more or less were it supposed to be . nothing turnes off in the car everything is on while this happenes. sometimes it happenes and sometime no. I checked the connection and evrything is good. I feel that the ignition is turning off but wonder what can it be . The car also sometimes pings like crazy right after it changes gears , i guess when it is giving straight power. that also happenes sometimes. At idle sometimes i will see the rpm move down a little like if it is misfirring and sometime it will turn off but rare . I checked the cap plugs and wire and it looks good. any help will defently help me a lot

cpetrice · 03-20-2002, 09:44 PM

I once had a 78 lincoln town car. when driving,it would sometimes just stop completely (I mean the motor) the rest of the car,ie lights,power brakes,etc seemed to work fine,then a few seconds later it would "catch up" and continue on. on some occasions it would idle,while in gear,if I gave it gas,it would not move,would coast to a stop then died. It would restart fine,and go on for another 10-20 miles. I replaced tons of stuff on that car,distributor,carb,sylenoid. damned thing continued to happen. after about $300 in parts,I finally figured out that the fuel filter was getting clogged and would get just enough gas to idle,but when you put on the accelerator,it would do nothing,until enough gas got in to match where I had the pedel pushed too. So,when it started to act up,I would pull over,take out the handy flathead screwdriver,take off the fuel filter,clean it out,and continue on.

Tom Vaught · 03-21-2002, 07:52 PM

Most times an ignition issue, (intermittent) will
cause a misfire, a pop in the exhaust pipe, etc,
the pinging like crazy has all indications of a
lean condition (This is why Goatman and I say it
is fuel). If he puts points back in the ignition
and the problem disappears then it was the after-
market ignition, if it is still there then fuel is all that is left. Tom V.
ps Karl, have you ever heard of a pertronics that
was able to advance timing?

GTO Karl · 03-23-2002, 07:12 PM

Blue 66:

There is nothing inherently wrong with the Ignitor II design theory, although it would not be my approach to improving an ignition through the use of a microcontroller. The only problem as I see it, is setting the curve on a distributor machine. I think you will have to very carefully use your engine, and an advance timing light, or fully marked balancer to check your curve. You will need to build a mechanism that allows you to accurately step your engine through 200 rpm increments to 3600 rpm or so to accurately check the curve(this could be just a longer screw in the throttle adjusting position).

It could be that the effects of this dwell variation are minor and only change the timing a degree or two...but I won't put up my 100odd dollars to find out.

Karl

Goatman · 03-20-2002, 02:45 PM

Replace the fuel pump and filter.

Tom Vaught · 03-20-2002, 10:11 PM

I need to jump in here. Goatman, got to agree
with you on this one for the following reasons:
I had a 79 mustang one time (wife's car). She and
I decided to go to Colorado for a vacation. One
of my "buddies" had borrowed one of my gas cans and later returned it full of gas. Cool, 5 more
gallons of gas for the trip. Fast forward to the
great plains on I-80 west of Lincoln. Car ran great and got great gas mileage for miles and miles. Fact is every tank it got better and better
mileage but every so often it would have a sharp
jerk and then the motor would continue on. I was
wondering what was going on. Then it died. 3/4
tank of gas! Hum! I pull the coil wire and we got spark. I work the gas lever on the carb and we have no fuel out the accelerator pump. I take the fuel line off at the carb (before the gas filter)
and still no fuel. Take off the line before the pump. With 3/4 tank of gas I should see fuel now!
NO Fuel. Dam*! I know what it is, the dam*ed tank
fuel sock. Fortunately, this gas tank was like a GTO and you could see the fuel sending unit and
retaining ring. Knock the ring off, gas all over
everything. Pull the sender out and pull the sock
off and blow through it. ONE PINHOLE BUBBLE of
air. Throw the sock as far as I humanly can and
put the fuel sender back in the tank. Crank the
engine until it starts and drive for the next
86,000 miles with no problems. Tom V.

yournose · 03-21-2002, 11:15 PM

My money is on ignition. Just my .02

mcarbaja · 03-24-2002, 11:33 PM

Well finally I was able to work on the car . I looked at what everybody said and went and did a little of everything. On saturday I disconnected everything . I took of the petronics installed the points and rewired evrything ignition based. I replaced the spark plug wires and cap. I don't feel that was the problem but did it anyways. Changed the grounding on the MSD. took off the male and female connectors and crimp everything back on.I put a grounding wire on the dist. I had problems getting the points to work again so i reconnected and crimp the petronics back on but i cleaned the top on it because looked dirty. I dive the car yesterday and today seemed to be ridding smooth. Don't feel the problem any more. I must have done something right. Now the question i have is how do i adjust the idle mixer screws. when they say 1 3/4 or so on do they mean turn it 1 complete turn around and 3/4 of a turn or what. Now i want to tackel the heating problem takes time to heat up now that i back the timming but still gets up there. Thank u guys for all you input MIGUEL [img]/infopop/emoticons/icon_smile.gif[/img]

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