Desperately Need Advice
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Desperately Need Advice
I have a 1977 F-250 Custom with a big block 460 and a C6 automatic transmission. There are three main problems that I've been having with it.
1. It has a hard time turning over. It tries, but I have to hold the key down for a few seconds and give it some gas for it to start.
2. When I back it out of my driveway, it dies on the way down. But it runs ok once I take off in drive.
3. This one is rare, maybe two or three times a day. I'll be sitting at a stop light, and when I push on the gas, it takes off very slowly and gradually. I can have the pedal on the floor and it only gets up to about 5mph by the time I hit the end of the intersection. The engine revs up like normal, but the wheels take forever to get going. It speeds up like normal after a while, but not at the start.
I'm relatively new to car stuff. This truck was my first project. With that being said, I have no clue what's wrong. Any information is very much appreciated.
1. It has a hard time turning over. It tries, but I have to hold the key down for a few seconds and give it some gas for it to start.
2. When I back it out of my driveway, it dies on the way down. But it runs ok once I take off in drive.
3. This one is rare, maybe two or three times a day. I'll be sitting at a stop light, and when I push on the gas, it takes off very slowly and gradually. I can have the pedal on the floor and it only gets up to about 5mph by the time I hit the end of the intersection. The engine revs up like normal, but the wheels take forever to get going. It speeds up like normal after a while, but not at the start.
I'm relatively new to car stuff. This truck was my first project. With that being said, I have no clue what's wrong. Any information is very much appreciated.
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 82
From: NorCal
Let's get back to basics.
Clean the start circuit terminals, battery hot, battery ground, and everything that connects to the starter solenoid.
These trucks are "ground deficient" in my opinion. I'd add extra grounds:
1. Bed to frame
2. Cab to frame
3. Core support to frame
4. Engine to cab (should already have one btwn the firewall and intake manifold).
... it sounds so me some carburetor adjustments and choke adjustments are necessary... the stall, slow acceleration, and hard-to-start. Adjust the float level, initial choke setting, and make sure the choke system is working.
Retest.
Clean the start circuit terminals, battery hot, battery ground, and everything that connects to the starter solenoid.
These trucks are "ground deficient" in my opinion. I'd add extra grounds:
1. Bed to frame
2. Cab to frame
3. Core support to frame
4. Engine to cab (should already have one btwn the firewall and intake manifold).
... it sounds so me some carburetor adjustments and choke adjustments are necessary... the stall, slow acceleration, and hard-to-start. Adjust the float level, initial choke setting, and make sure the choke system is working.
Retest.
Super Moderator
Joined: Apr 2004
Posts: 34,475
Likes: 2,800
OP has carb and maybe ignition troubles for sure, but also says this:
"The engine revs up like normal, but the wheels take forever to get going."
Check your transmission fluid. You may have deeper issues, and you WILL have deeper issues if you keep running it like that.
"The engine revs up like normal, but the wheels take forever to get going."
Check your transmission fluid. You may have deeper issues, and you WILL have deeper issues if you keep running it like that.
Cargo Master
Joined: Nov 2011
Posts: 3,354
Likes: 48
From: Great American SouthWest
1) if your primary cables are original or cheap parts-store cables, it's quite possible they're not carrying enough juice. If you don't know the condition of your cables you could ohm them out, but probably better to just get new cables-battery to solenoid, solenoid to starter, and block to battery ground. Also, you need a suitable battery with plenty of CCAs. I like the group 27f
2) Starts then stalls when cold...possibly choke
3) Revs up but truck don't go...that's transmission. Try changing the fluid, and flushing the lines. Possible that's it's just low on fluid...but get it fixed-they're expensive when they break
2) Starts then stalls when cold...possibly choke
3) Revs up but truck don't go...that's transmission. Try changing the fluid, and flushing the lines. Possible that's it's just low on fluid...but get it fixed-they're expensive when they break
Postmaster
Joined: Mar 2011
Posts: 2,698
Likes: 7
From: Taxachusetts
I have a 1977 F-250 Custom with a big block 460 and a C6 automatic transmission. There are three main problems that I've been having with it.
1. It has a hard time turning over. It tries, but I have to hold the key down for a few seconds and give it some gas for it to start.
1. It has a hard time turning over. It tries, but I have to hold the key down for a few seconds and give it some gas for it to start.
2. When I back it out of my driveway, it dies on the way down. But it runs ok once I take off in drive.
3. This one is rare, maybe two or three times a day. I'll be sitting at a stop light, and when I push on the gas, it takes off very slowly and gradually. I can have the pedal on the floor and it only gets up to about 5mph by the time I hit the end of the intersection. The engine revs up like normal, but the wheels take forever to get going. It speeds up like normal after a while, but not at the start.
I'm relatively new to car stuff. This truck was my first project. With that being said, I have no clue what's wrong. Any information is very much appreciated.
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Update
It even stalls after it's warmed up, and the transmission fluid is about twice as high as it should be. And it has a manual choke.
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Postmaster
Joined: Mar 2011
Posts: 2,698
Likes: 7
From: Taxachusetts
The C6 fluid is measured when the vehicle is warmed up and you ran through the gears, yes? Fluid too high is worse than too low! Correct the problem quickly!
Get back to us after the C6 fluid level is right.
Get back to us after the C6 fluid level is right.
Fleet Mechanic
Joined: Aug 2004
Posts: 1,311
Likes: 31
From: Nevada
C6 dip stick interpretation
Be careful when judging the C6 dip stick, It will read way low if its cold and not running and you may interpret it has having way too much if its showing a light residue on the stick above the arrows..... Its a PITA to really pin down where its at...... I can tell when its really low you will know, because it wont go into gear.... 
Cargo Master
Joined: Nov 2011
Posts: 3,354
Likes: 48
From: Great American SouthWest
There's no shame in getting a second opinion. Take the truck to an oil-change place, and ask them to check (and show you) the dipstick. It's hard to reach anyway, so just tell the guys you couldn't reach it.
Stop in when they're not busy, and they'll likely check it for free. Whenever I go, the guys love seeing and talking about these great trucks. And they've all got a story about them...
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New User
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Further update
I realized today that sometimes it won't downshift to 1st gear, so it's trying to take off in 2nd. This is what's causing the slow takeoff. Anyone know why it decides not to downshift sometimes?