Running rich/rough?
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,736
Likes: 37
From: Stockton Ca
Running rich/rough?
My 74 w/healthy SB ran fine coming home from Dyno shop.
So it sat for a while and the smell of gas was strong.
I check my fuel line fitting and looked for any leaks, nothing.
Then checked for snug plug wires, they felt snug,
But that may have improved things, or my wistful thinking?
Now I'm wondering about a bad plug or wire?
Is it time to do the old pull plug wires until something changes?
This and the C6 seats are the big changes.
A world class 5 sp is in the works.
I have a friend at a wrecking yard.
What year mustang do I need for a donor?
TIA
R
So it sat for a while and the smell of gas was strong.
I check my fuel line fitting and looked for any leaks, nothing.
Then checked for snug plug wires, they felt snug,
But that may have improved things, or my wistful thinking?
Now I'm wondering about a bad plug or wire?
Is it time to do the old pull plug wires until something changes?
This and the C6 seats are the big changes.
A world class 5 sp is in the works.
I have a friend at a wrecking yard.
What year mustang do I need for a donor?
TIA
R
Burning Brakes
Joined: Dec 2017
Posts: 1,043
Likes: 414
2023 C3 of the Year Finalist - Modified
running rough, as in struggling to idle? Is it fine at higher rpm?
does it sound like it has a misfire?
Give your vacuum lines a once over, a vac leak can make the engine erratic.
I personally think using a timing light is easier than pulling plug wires….maybe I’ve been bit too many times…
does it sound like it has a misfire?
Give your vacuum lines a once over, a vac leak can make the engine erratic.
I personally think using a timing light is easier than pulling plug wires….maybe I’ve been bit too many times…
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,027
Likes: 4,174
From: US-PNW
What is your carb?
What do the plug electrodes look like?
If you have the fuel tank vapor canister, evap hoses, and PCV valve, are they connected and properly routed?
If you open the carb's throttle plates and look below the carb, is there liquid fuel sitting on the floor of the intake?
Would you post pics of the engine without air cleaner from both sides?
What do the plug electrodes look like?
If you have the fuel tank vapor canister, evap hoses, and PCV valve, are they connected and properly routed?
If you open the carb's throttle plates and look below the carb, is there liquid fuel sitting on the floor of the intake?
Would you post pics of the engine without air cleaner from both sides?
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,736
Likes: 37
From: Stockton Ca
The engine ran fine before I parked it.
It feels like a bad plug.
Idle is rough and slow.
I will pull wires until I find a bad cyl.
Then I can pull plug.
I did check vac, I will check harder.
It feels like a bad plug.
Idle is rough and slow.
I will pull wires until I find a bad cyl.
Then I can pull plug.
I did check vac, I will check harder.
Racer
Joined: Jul 2018
Posts: 331
Likes: 123
From: Sandusky, OH
Answer to your last question: Ain’t no Mustang T-5 gonna fit. Input shaft is all wrong for Chevy. You’ll need to do some research on World Class T-5. V-6 versions don’t have optimal ratios. Camaro V-8 versions have some differences. Search: lugnutz65chevystepside on the web for an excellent primer on the WC T-5. I do remember the driveshaft needs to be 3” shorter than a stock Muncie equipt vehicle. Shifter location is way different. It’s doable. I upgraded a 65 Chevelle, but modifying was unconstrained. Or just pony up and get the TKX conversion.
Steve O.
Steve O.
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Race Director
Joined: May 2006
Posts: 18,690
Likes: 2,572
Carburetor is clogged with residue from evaporated gasoline.
Rodents chewed on wires.
Water entered fuel tank due to bad seal on cap.
Drain the gasoline from tank.
Put Gumout or similar product in fresh gas.
Check all wires going to and coming from distributor.
Race Director
Joined: May 2006
Posts: 18,690
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Race Director
Joined: Mar 2017
Posts: 11,923
Likes: 4,495
From: Virginia
Is this only happening at idle, or driving down the street?
I'm still thinking ignition! Unburned fuel in exhaust is likely due to a miss. If you don't have enough advance at idle (for example, your vac advance is plugged into ported vacuum, instead of manifold), you could have a lean miss stumble. If the exhaust isn't hot enough to ignite the fuel, you'll get the "rich" smell.
Dunno why the change, but I bet the dyno tuner didn't care about anything that happened under 3000 rpm.
I'm still thinking ignition! Unburned fuel in exhaust is likely due to a miss. If you don't have enough advance at idle (for example, your vac advance is plugged into ported vacuum, instead of manifold), you could have a lean miss stumble. If the exhaust isn't hot enough to ignite the fuel, you'll get the "rich" smell.
Dunno why the change, but I bet the dyno tuner didn't care about anything that happened under 3000 rpm.
Race Director
Joined: May 2006
Posts: 18,690
Likes: 2,572
Is this only happening at idle, or driving down the street?
I'm still thinking ignition! Unburned fuel in exhaust is likely due to a miss. If you don't have enough advance at idle (for example, your vac advance is plugged into ported vacuum, instead of manifold), you could have a lean miss stumble. If the exhaust isn't hot enough to ignite the fuel, you'll get the "rich" smell.
Dunno why the change, but I bet the dyno tuner didn't care about anything that happened under 3000 rpm.
I'm still thinking ignition! Unburned fuel in exhaust is likely due to a miss. If you don't have enough advance at idle (for example, your vac advance is plugged into ported vacuum, instead of manifold), you could have a lean miss stumble. If the exhaust isn't hot enough to ignite the fuel, you'll get the "rich" smell.
Dunno why the change, but I bet the dyno tuner didn't care about anything that happened under 3000 rpm.
Race Director
Joined: Mar 2017
Posts: 11,923
Likes: 4,495
From: Virginia
Yup! So it's probably bad gas, or varnish in the carb, or whatever. Did you read where the OP said when this was happening (idle/driving, cold/warm engine, etc.)?
Making sure the timing is set correctly takes 15 seconds, and might fix the problem. The last time my car wouldn't idle correctly, it was because I accidentally plugged the vac can into the wrong carb port.
Photos help!
Making sure the timing is set correctly takes 15 seconds, and might fix the problem. The last time my car wouldn't idle correctly, it was because I accidentally plugged the vac can into the wrong carb port.
Photos help!
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,736
Likes: 37
From: Stockton Ca
Ign Testing?
I'm not real good w/elect.
I replaced rotor and cap, both were old.
After buttoning everything up carefully, NO START! WTF
I bought a replacement coil.
Before I can't return it, is there any way to test the coil?
What about the ign module?
I'm really at my wits end on this.
HELP
R
I replaced rotor and cap, both were old.
After buttoning everything up carefully, NO START! WTF
I bought a replacement coil.
Before I can't return it, is there any way to test the coil?
What about the ign module?
I'm really at my wits end on this.
HELP
R
Race Director
Joined: May 2006
Posts: 18,690
Likes: 2,572
I'm not real good w/elect.
I replaced rotor and cap, both were old.
After buttoning everything up carefully, NO START! WTF
I bought a replacement coil.
Before I can't return it, is there any way to test the coil?
What about the ign module?
I'm really at my wits end on this.
HELP
R
I replaced rotor and cap, both were old.
After buttoning everything up carefully, NO START! WTF
I bought a replacement coil.
Before I can't return it, is there any way to test the coil?
What about the ign module?
I'm really at my wits end on this.
HELP
R
If so, you miswired something.