Engine woes

[suki243]

So, school's finally over, and now i want to get the stang back in running condition.

A month ago i got my stang back from the painter and it was running sloppily, i gave it to him in perfect running order. w.e. he did a pretty crappy job in general, not going back to him.

So, at low rpms the whole engine shakes violently. At 800 Rpm and then at 1000 its fine then at 1200 it starts shaking again violently. At higher rpms it doesn't shake, or it shakes but so fast you can't really tell i guess
The firing order is correct,
It happens in neutral and in drive, so its not the tranny.

Any ideas? could it be a timing jump?

 

[wild70stang]

do you know how long the car sat for? If you leave a vehicle equipped with a carburetor sitting for a long period of time, the jets get gummed up. This happened to my Carter Carb several times. One time my car was parked for 2 months because all the main brake components fell apart. When I put everything back together and started the car it ran like crap. After cleaning the hell out of the carburetor it ran just fine. Also go to an auto store and pick up some fuel cleaner that you dump into the gas tank to clean out the rest of the fuel system.

 

[matt0matic]

x2

Also if a simple cleaning of the carb doesn’t help pull a valve cover and check the valve train geometry. And while you’re at it check the timing to rule out that as a culprit.

 

[suki243]

it sat for about 2 weeks, the carb was just rebuilt last year, i try to make an effort to start the car every week. but i've been neglecting it lately.

I don't have a timing light =\ but as soon as my parents come back i'm takin it to the mechanic to get it checked out.

 

[rbohm]

you might retorque the intake using the proper inside out pattern. also check the fuel pump for proper output. it should fill a 16oz soda can fairly quickly.

 

[suki243]

So i gave up and took it to my mechanic he found out that one of the points burned out. probably when the painter was working on the car, turned the key all the way to the left and it wouldn't come out, then just put it to the right without starting it... not the first time it 'd happen i've seen him do it on other cars.

 

[iskwezm]

So i gave up and took it to my mechanic he found out that one of the points burned out. probably when the painter was working on the car, turned the key all the way to the left and it wouldn't come out, then just put it to the right without starting it... not the first time it 'd happen i've seen him do it on other cars.

That can also happen if you listen to the stereo with the key in the "on" position.

 

[suki243]

eh, i spoke too soon. I took the car out to run some errands. every once in a while the car would sound like its about to die, that sound thats in the movies where it sounds like something is rattling under the hood, its like a knocking rattle kinda noise. it'd go away at higher rpms. but idling was bad.

Btw: gauges said everythign was fine. temp, and oil pressure and fuel

 

[D.Hearne]

First chance you have, get rid of the points and condenser. Replace with any of the drop in electronic conversion modules. That will eliminate 99% of your starting problems. It's money well spent.

 

[mustang6tee8]

check your harmonic balancer just in case

 

[suki243]

What do you mean by the on position? do u mean listening to the stereo without the engine running? I didn't do that.


As for the points conversion, anyone recommend a specific kit, should i also replace the coil as well? I read in places that with Petronix it sometimes has problems with the stock coil. This is stock daily driver, what should the rev limiter be set to if it has it?

 

[MrTaco]

Do you remember the garage scene in Ferris Buehler?

 

[suki243]

Umm, kinda too young; wasn't born when the movie came out; and 1 year old at the time of the tv show =\ i've seen bits and pieces of the movie tho; don't remember a garage scene off the top of my head tho.

 

[D.Hearne]

I've used the Pertronix I & II and the Crane XR-1, all work great. two wires to the coil to hook up. I've used both a Pertronix Flame Thrower coil and a Mallory Promaster (points & electronic coil) with all.

 

[suki243]

So, i've been driving the car around; and it just doesn't run the same, i dont know what happened, i took it back to the mechanic and of course when i'm there it works fine but as soon as i get home its sloppy again.

When at low rpms the engine shakes but not violently like it used before the point was replaced. When it's idling for one sec it is fine the next second it shakes. not sure how to explain it. but its not a smooth idle it like speeds up then slows down every other second. It happens mostly in park. if that makes any sense. and the whole car shakes shortly after i put foot on the gas pedal. but as i pick up speed it stops.

It's the stock carb but rebuilt; i didn't rebuild it the mechanic did.

Thanks in advance,
suki

 

[69gmachine]

Take Mr. Hearne's advice and get rid of the points. I would also check to make sure the vacuum advance is working properly. Maybe it's sticking and causing erratic timing changes when the vacuum signal is low.

Have you checked for a vacuum leak or made sure you have a good vacuum signal? You need to have a timing light on while it's acting up to diagnose the source of the problem. Slowly raise the RPM while observing the timing light. It should be a fairly linear increase as the RPM rises from idle to around 3K, with total timing somewhere around 35 degrees, but not much over that.

 

[suki243]

Yah as soon as I get some more money i'll go ahead and get the conversion kit. Most probably going with petronix I; is there a significant difference between I and II?

Some new findings: I checked my shop manual and it told me to check the fast idle screw and make sure it wasn't touching the idle cam lever; well it was, not allowing the choke plate to move. So i unscrewed the fast idle screw till it allowed the choke plate to move freely, decided to drive up and down the street to test it real quick without the air cleaner on. Low and behold it was running fantastic! I came back put the air cleaner on (its the old, blue one that connects to the breather cap of the valve cover via a rubber hose. Decided to go around the block just to make sure, it was slightly shaking again, came back home opened the hood and it sounded weird, making a high pitch sound and this clicking. I look around and right in front of me I see a spark jumping from the spark plug wire to the rubber part of the air cleaner... So there is a fault, i went ahead and bought new wires from pepboys 7mm, the ones with a lifetime warranty.
I'm currently waiting for the engine to cool down so i can install the new ones. do you guys recommend putting the silicone connector thing that they supplied with the wires? I'm going to order new wire separators to keep it clean and tidy.

 

[Pakrat]

Do you remember the garage scene in Ferris Buehler?

LOL, are you saying the painter beat the snot out of it while they had it?

It may be wise to double check everything over, even the non mechanical items like the engine mounts for example. A worn or partially busted mount will certainly cause bad vibrations at certain rpms.