Acceleration lags badly for the first 10 minutes (1 mile - residential streets with stop signs every 2 blocks) after a cold start. It feels like it’s sticking: I push the pedal to the floor, nothing happens, then it roars to full. I’ve replaced the fuel pump and filter, all the rubber hoses, rebuilt the carburetor, bought a new battery, spray a lot of starting fluid into the mouth of the carburetor. Drenching the outer workings of the throttle body with spray lube seems to help a little.
The Haynes says, ‘Verify that the throttle linkage operates smoothly by grasping it with the thumb and forefinger and opening and closing it a few times. If it doesn’t, replace they throttle body.’ Not the cable? And ‘smoothly’ is subjective. Couldn’t it operate smoothly but sluggishly?
Chilton’s says, ‘Check that the throttle linkage moves smoothly.’ , doesn’t say what to do if it doesn’t.
Would it be hard or crazy to pull the cable, clean the housing, lubricate - with graphite?
Toyota Pickup, 1987, 4-cylinder, 2WD, XtraCab, long bed, with platformate, GL-7, and green power crystals.
If you operate the throttle valve by hand, there is no cable involved. Does the throttle valve open as expected? If not, investigate why it is failing.
Look down the throat of the carb with the engine not running. Flip the throttle open about halfway by hand. Can you see the carb squirt a spray of fuel into the throat only as long as you are moving the throttle. It should stop squirting when you stop moving the throttle. No squirt? Your accelerator pump in the carb is broken.
I am also thinking the choke is no longer closing when cold. Check that on a cold-startup to make sure is is closing… and then make sure it opens when warm.
If there’s a cable than runs through a cable housing in the throttle linkage between the pedal and the throttle body, the cable may be sticking inside the housing. Common problem w/bicycles. Sometimes the cable-ass’y can be temporarily vertical-ized, so a little lube can be dribbled down the inside of the housing. Or the cable assembly has to be removed from the car and the inner cable removed from the housing to apply some lube. The inner cable can fray also, which causes it to stick inside the housing. Then you’d have to replace the entire cable ass’y.
I don’t see or smell gas. I replaced it 1,302 miles ago when I rebuilt the carb. The fuel pump is mechanical, thus isn’t running. Why would there be gas available? Why would it work after 10 minutes? Or is the question why the fuel line has dried out? Last October one of the hoses to the fuel filter started leaking, apparently it had gotten so slack that even the clamp didn’t hold it tight. I replaced the filter and all the rubber hoses in the fuel line. I neither see nor smell leaks now.
I don’t think it ever closed on cold. Before I start it I always pump the gas pedal to close the choke. That works.
Yes. I deal with it on my bicycle, which is less-robust deal. A search on lubricating the throttle linkage found a lot of advice on how to do it on motorcycles and Mercedes-Benzes. Odd that ‘regular’ cars don’t need it.
The choke works, at least cold. The linkage came apart in a freeze 20 years ago. The enclosure is riveted shut. I had to drill out the rivets to put the arm back in the loop on the coil. Because it was always closed it backfired. I have no backfiring. A choke problem now would be it staying open all the time, but it closes when I push the gas pedal.
@Mustangman said it could be an accelerator pump problem.
My gas will be 14 months old on the 28th. I added a can of Super Tech ™ motor treatment to the tank first, apparently a clone of Seafoam™
How do I both push the pedal and look at the throttle?
A comparison fyi. On my truck the choke plate is usually fully (or close to) open after an overnight rest, irrespective of how cold it is. After pressing the accel pedal with engine off, the choke plate closes completely. Then immediately after starting the engine, it opens just a little, which I believe is the “choke hold pull off” function. Over 5-10 minutes as the engine warms at idle, the choke gradually completely opens.
Concur ," pull off" is the usual terminology , not “hold off”. Corrected above.
As I recall the choke pull-off was a standing joke for a while on the Car Talk radio program. I’m not hearing it on the recent podcasts though. Probably earlier years.
There is fuel in the float bowl so you should see a squirt even with the engine not running, which you don’t. So your rebuild did not last or you did it wrong.
Hence my second post suggesting the choke.
Jeez, I am running out of crayons to explain this to you… Of course the choke is set when you press the throttle… That’s HOW you set the choke. So it IS closing when cold. Does it open back up when warm?
How do you know this? Maybe there isn’t. I have a hard time seeing the site level, have to take off the air cleaner and use a mirror and a flashlight. Isn’t @George_San_Jose1 having this problem?
I think I can work the fuel pump by hand. If that makes it go, what would that mean?
Others seemed to say otherwise. It could be stuck. I had to fix it before.
Have to wait until I drive it.
This vehicle has an auxililary accelerator pump in addition to the accelerator pump. It only works when cold. When I was having trouble with it @shanonia recommended eliminating it. The rebuild kit came with a new one so I installed it. The previous failure mode was leaking. It isn’t leaking now.
The rubber cover, a bellows-like thing, is cracked: does that matter?
Then your carb has an additional problem. Fuel should be retained in the float bowl at least for an hour. That is how they work. No fuel in the float bowl, the engine won’t run.
Crank the motor over to fill the float bowl, operate the throttle and see if it squirts.
So it IS closing when cold. Does it open back up when warm?