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Breakdown #2 - this time it was the M-code
#1
Cone 
I was on the interstate cruising at 70mph & 3000 rpm when it sputtered a little. Drove a little farther and the sputtering got worse. Now I'm hoping to make the next exit 5 miles away. It backfired loudly and blew out my mufflers. Back fired 3 more times over the 5 mile trek to the exit. Took the exit and almost no power. It would run fine then cut out really bad then run fine & cut out. I pulled off the exit ramp onto the side of the road. It idled and reved just fine. Tried to pull forward and it sputtered under load. Oh yeah, prior to all this it dieseled every time the engine was shut off so I shut it off as I let out the clutch. Carb is an Edlebrock. Points under the distributor cap.

What gives? Timing?

PS. It sounds great with blown out mufflers...just the right amount of rumble.

[Image: 386_07_10_13_5_58_42.jpeg]
My Mustangs:
71 M-code Mach 1, Medium Blue/White Sport, 4R70W, 3L50, Factory Ram Air.
72 Q-code Mach 1, Pewter/Black Sport, 4-spd, 3L25.
65 Convertible, Britney Blue/White/White, more modified than original.
05 Convertible, Legend Lime/Tan/Tan, future classic??
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#2
Not sure if it helps but my 65 would diesel and it was vapor locking. Had to insulate my fuel lines. I'm no expert though I'm sure someone will chime in and tell you exactly whats happening.
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#3
Sounds like you have to buy another Mustang, Don! Big Grin

Steve



[Image: 25yvyp3.jpg]
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#4
sm3570;80292 Wrote:Sounds like you have to buy another Mustang, Don! Big Grin

If only it were that easy to convince the wife I need another one. If it were a new GT vert for her - then she might agree.

[Image: 386_07_10_13_5_58_42.jpeg]
My Mustangs:
71 M-code Mach 1, Medium Blue/White Sport, 4R70W, 3L50, Factory Ram Air.
72 Q-code Mach 1, Pewter/Black Sport, 4-spd, 3L25.
65 Convertible, Britney Blue/White/White, more modified than original.
05 Convertible, Legend Lime/Tan/Tan, future classic??
  Reply
#5
Bad points, condenser, or maybe on a slight chance the cap or coil but timing should not have changed unless the chain is wore and slipped. Sounds like it may be starving for fuel or fire to me
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#6
caspianwendell;80294 Wrote:Bad points, condenser, or maybe on a slight chance the cap or coil but timing should not have changed unless the chain is wore and slipped. Sounds like it may be starving for fuel or fire to me

I know nothing about the engine except that it dieseled when turned off since I've owned it and that it is a 73 4v block & heads that was put in until the original motor could be rebuilt. I've only had this car for a couple of months.

[Image: 386_07_10_13_5_58_42.jpeg]
My Mustangs:
71 M-code Mach 1, Medium Blue/White Sport, 4R70W, 3L50, Factory Ram Air.
72 Q-code Mach 1, Pewter/Black Sport, 4-spd, 3L25.
65 Convertible, Britney Blue/White/White, more modified than original.
05 Convertible, Legend Lime/Tan/Tan, future classic??
  Reply
#7
Start by checking fuel pressure, pumps fail. also inspect the condition of your wiring and the fusible link as it may be partially burnt and not feeding proper power to the coil to fire a decent spark.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#8
well could be fuel or ignition.

The fuel line could of clogged.
you could have a fuel boiling problem.
the carb could of clogged up.
the accelerator pump could malfunctioned.
the fuel pump could be going.

on the ignition end the points could of gone out of adjustment that would throw off the timing.
problem with the cap or loose ignition wires.

You want to look at the obvious first before digging in.

first now that the car is cold does the problem occur or still occur.

i would check timing first. see where the timing is without touching anything.
you can move the magnetic pickup for the timing light from from ignition wire #1 through #8 and see if all 8 are infact firing

if you find some cylinders are not fireing or the timing isn't right, pop off the ignition wires and reseat them in the distributor and the plugs. make sure the wires are tight nothing got loose.

lets say the timing is correct all cylinders are in fact firing. you could pull the plugs and look at them but i would tend to look at the fuel system at that point.

check the oil, does it have a super heavy fuel smell? if it does that the fuel pump as popped a hole in the diaphragm. if the oil smells fine. look at the carb. with the engine off press the accelerator pump plunger and see if you get a squirt out of the shooters.

replace or check the fuel filter for pieces that may have gotten into the carb.

with the basics looked at. if the car runs great until it gets hot then you could have a fuel vapor issue. does your car have a carb spacer? assuming the car runs awesome until warm then you may want to try a fiber carb spacer or double the gaskets under it to prevent the fuel from boiling.

i would also check your choke. make sure the choke is opening up all the way.

lets say from cold or hot the car runs awful. look at a vaccum leak. maybe a hose poped off or a cap came off. vacuum leaks can cause all kinds of problems as well. in this cause i suspect a fuel problem where suddenly the car is running lean not enough gas getting to the motor. most suspect is fuel line clog or clog in carburetor or fuel pump failure.

but check all the visual stuff first.
ignition wires not loose fully seated. seated firmly on plugs.
check choke.
check timing.
check carb make sure fuel is going down into the intake.
check how throttle behaves hot and cold.
check vacuum leak

with the vaccum leak one option is disconnect all vaccum accessories and plug up the tree and see if the engine is happier.
I had a blown Vacuum booster that i did not know about until i used a vaccum hand pump and started manually vacuuming lines one at a time until i saw the vacuum booster was no longer holding pressure.

you may want to check the PCV or EGR valve as well.

don't forget the vacuum advance on the distributor if that diaphragm blew that would cause vacuum leak and timing problems

if you look at the timing and it has moved a lot somehow then you may suspect either the engine jumped time or something happened to the distributor gear. I've heard stories where somebody slammed on the pedal on the highway and all of a sudden the distributor moved because the base screw was loose and the timing jumped 20 degrees stalling out the car. or somebody that did the same and the engine chain jumped time.
I will mention i had points on my car that kept drifting wildly after 200 miles i gave up on it and installed electronic ignition which also has its host of problems like cylinders not firing or bad pickup for the sensor


The more info you can post the better like if the problem only happens at a certain time or now its happening all the time. You can go further with more tools like a vacuum gauge on the motor and a fuel pressure gauge on the fuel line. these would be temporary and removed once the problem is found.

I would also say bad gas can happen also. if you had water in the tank and suddenly the tank got low enough that the water content of the gas went up then suddenly you have problems.
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#9
I had a similar experience many years ago and it was the screw that holds the condenser down came loose and it was not getting good ground. I tightened up the screw and it ran fine.
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#10
just to apologize for my spelling and grammar, etc... i wrote that post on my cell phone on the train going to the office.
Doh!
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