Big problem! Clutch or driveline, i dont even know

scottthomp · Jul 17, 2005

Big problem! Clutch or driveline, FIXED!!!

ok i have recently spent 6 years restoring a mustang. its a 1966 coupe with a mild 289 3 speed, 3.55 gears. everything is knew, i mean everything. So i have been driving it for about 400 miles now. Today i drove it for about 5 miles to my house then went to leave. when i hit the gas it was like it wasnt getting gas or was flooding out, basically it would fall on its face. so i drove it around a parking lot. it increases good slowly to 5 mph then the car starts physically bouncing, like it would go then bog down then go again, but with little change in the rpm. Here is the kicker when i push in the clutch or put it in netrual it revs to 4000 rpm very smoothly. so i drove it back to the storage shed 5 miles away, and noticed that in 3rd gear running about 2500 rpms it was like i was in a 5th gear going 20 mph (no throttle response, barely making it up hills like i have absolutely no power but i am still at good operating rpms). does anyone have any idea???? the clutch is new and was fine the first 400 miles or so, no problems. trans and rear are rebuilt and not making any noise. the car rolls in neutral so its not the brakes.

more background:
The clutch is adjusted to where you can shift after you push it about 3 inches from its resting position. when the car gets warm, and you are taking off from a stop the car shakes horribly unless you release the clutch fast and almost spin the tires. would having the clutch adjusted out like this cause this problem? how to i adjust it in?

So is it the clutch or do i look elsewhere? please help i need this car running.

fastdave · Jul 17, 2005

May be more than one problem. Having the clutch shake (slip/grab) could be oil on the disc. The other problem could be the fuel filter. It will not get enough fuel to pull a load-like going uphill or sometimes even its own weight. The reason it will rev w/ the clutch is is because you are taking the load off. If not the filter could be debris in the carb.

scottthomp · Jul 17, 2005

There is a see through fuel filter on it, it is not dirty but i have noticed low amounts of fuel in it. It just doesnt make sense though because it runs so good without the load on it, it almost has to be in the driveline.

fastdave · Jul 17, 2005

Jack up the rearend w/ both tires off the ground,put it in neutral and spin the tires by hand. This will tell you if the brakes are draging. It shouldn't be to hard to turn.You should be able to turn them w/ one hand.

scottthomp · Jul 17, 2005

The brakes arent dragging, i put it in neutral lastnight and pushed it with no resistance.

krash kendall · Jul 17, 2005

What type of ignition are you running?

6Stang7 · Jul 17, 2005

did you check to make sure your choke is all the way off?? what kind of carb do you have?

scottthomp · Jul 17, 2005

MSD 6a box, MSD distributor, Holley 600 carb.

remember this car ran great for the first 400 miles

fastdave · Jul 17, 2005

You said that you noticed that it has a low amout of fuel in the see thru fuel filter. An easy teat would be to pull the filter and install a piece of fuel line in its place...

krash kendall · Jul 17, 2005

When you say the car is bouncing up and down, is this a result of power surging, like you were pumping the gas and brakes? If so, it has to be a fuel delivery/ignition problem.

krash kendall · Jul 17, 2005

fastdave said:
You said that you noticed that it has a low amout of fuel in the see thru fuel filter. An easy teat would be to pull the filter and install a piece of fuel line in its place...

NO! NO! NO!!!! Then whatever has been clogging the filter will go right into the carb!

Run a flexible line from the outlet on the filter to a gas can and crank the motor if you want to check fuel supply. Does the holley still have the screw in filter as well?

fastdave · Jul 17, 2005

Hopefully you still have the filter in the carb,no reason to remove it. Maybe it could also be the coil. I do remember having a similar problem and the coil was the problem.

steel1212 · Jul 17, 2005

Hole in the fuel pump from dirt in the tank/lines? I had to change my pump do to this and went bigger when I did and also changed all the fuel lines and added a new tank. Its really not to expesnive for all of that stuff but gives you some assurance that the fuel system is clean. You should have seen the crap that fell out of my old gas tank YUCK!!

scottthomp · Jul 17, 2005

Yes the car bounces like gas, brake, gas would do. the filter is still in the carb, i will check it. I plan on unhooking the line and cranking the motor to see my gas flow. also how would i check if my coil was bad?

also there is no manual choke lever installed so the choke could be closing we never wired it up. would the choke cause these symptoms?

im going to the storage to work on it, wish me luck, thanks for the help and keep posting answers.

krash kendall · Jul 17, 2005

The choke opening and closing will cause problems. Fix it or wire it.

scottthomp · Jul 17, 2005

ok 4 hours later and still not fixed.

1. not the choke

2. not the brakes

i unhooked the fuel line in all 4 places and it still pumps. although when i pumped it into a regular size coffee can for about 3 seconds of turning it over it filled it only about a half inch, maybe a half cup of gas. but it fills the see through fuel filter. i looked into the carb while running it and could see the top jets injecting fuel on acceleration and then stop when holding rpm's. i guess there could still be a clog in the carb but how will i ever know. also the ignition system still could be the problem

more background:
this happened twice before for about 10 seconds each time. i was driving it many months ago and it did this and i just pulled over for about ten minutes while checking stuff and then went on may way without other problems. happened a second time also. so what could fail intermittantly and then run good and then fail for good and run like it is now?

any more ideas??

a.vannoy · Jul 17, 2005

"MSD 6a box, MSD distributor, Holley 600 carb.

remember this car ran great for the first 400 miles"

Do you still have the old dizzy? Long shot but it might be the MSD box.
I say its a long shot because you say it straightens out if you put it in nuetral.
I would check the fuel system first, try changing the filter to a new one and make sure you check the "flow" arrow on it, that should go toward the carb.
Just thought of something check the u-joint out's, When they start going on occasion they will make your car rattle and vibrate like if its falling apart. Unscrew one of them of completely because when the bearings go and get grounded up you cant tell from the outside, but when the driveshaft busts loose it wrecks some serious havoc.

a.vannoy · Jul 17, 2005

The clutch is easy to adjust , hard to explain . Look in the drivers side engine compartment by the firewall. You have a crank that runs from the frame to the bellhousing, this should have a long threaded rod with a nut on it that you can tighten or release to adjust the clutch. I am assuming you have the original 3- speed and linkage.

scottthomp · Jul 17, 2005

yes i got the clutch adjusted, i checked the u joints today there is no play in them. if the box and ignition were bad i would assume that in neutral it would act the same way. is this assumption ok?

i ran it without the fuel filter and it did the same thing, dont worry i still had the small screen one in the carb.

i still dont know, i think its a fuel problem but have no idea

D.Hearne · Jul 17, 2005

scottthomp said:
i unhooked the fuel line in all 4 places and it still pumps. although when i pumped it into a regular size coffee can for about 3 seconds of turning it over it filled it only about a half inch, maybe a half cup of gas. but it fills the see through fuel filter. i looked into the carb while running it and could see the top jets injecting fuel on acceleration and then stop when holding rpm's. i guess there could still be a clog in the carb but how will i ever know. also the ignition system still could be the problem?

Don't know much about Holleys or carbs I see. Those "top jets" aren't jets. Those are the accellerator pump squirters. They only squirt fuel when the accellerator is depressed suddenly. At a steady rpm, there should be no fuel coming from them. The fuel is drawn into the engine thru the small round "rings" in the center of the 4 barrels when the engine is run at a steady speed above idle. One more possibility is water in your fuel. To check for this, the best way I've found on a Holley is to either remove the carb and remove one of the bottom bowl screws and catch the fuel in a small clear cup. On some engines, you can do this while the carb is on the engine, using the bottom of a clear palstic coke bottle. If water is your problem, it will be readily apparent in the cup bottom.

Big problem! Clutch or driveline, i dont even know

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