vacuum improvement
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vacuum improvement
In my 86 F250 5.8 I just hooked up the vacuum gauge and it poor, fair, best economy, deceleration. For probably the first 15 minutes or so the gauge reads best economy but once I reach normal operating temp it reads fair and mostly poor if I'm picking up speed. Any way to improve my vacuum. Also when I go to stop the idle drops down till it just about stalls out but doesn't. Doesn't have as much power I feel it should please help
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It's supposed to read poor when accelerating, you are using more fuel to accelerate. For best economy, let it sit and idle in the driveway all day, that will give you the best reading on the gauge. Anything, else, the gauge will drop. That's how a internal combustion engine works.
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For your low idle speed when warmed up, that can be adjusted via the idle speed adjustment screw on the driver's side of the carburetor.
According to a Web page I found, your low vacuum could be symptomatic of a clogged exhaust system (although i don't understand how it could be clogged only while warmed up).
When is the last time you've done a general tune-up of the engine?
According to a Web page I found, your low vacuum could be symptomatic of a clogged exhaust system (although i don't understand how it could be clogged only while warmed up).
When is the last time you've done a general tune-up of the engine?
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Low vacuum can be due to essentially anything that makes the engine run poorly, including burned valves, low compression, retarded ignition timing, etc. And, I would guess that a bad or stuck-open EGR valve would do it as well.
So, I would suggest a logical diagnostic approach starting with a compression check, EGR check, and timing test.
So, I would suggest a logical diagnostic approach starting with a compression check, EGR check, and timing test.
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Well thanks. I already changed egr valve which was not bad. Don't know how to do a compression check or a timing test. But I did do the brakes front to back, lines, calipers, wheel cylinders, pads and shoes. After I did all of that it was just about gone then the 1 line I didn't replace sprung a leak and the problem got worse. I replaced it but have not bled the lines again yet and I would imagine that once I do that it should solve my problem seemed to be when I stop that I had a problem. I didn't think that the vacuum from my brakes would cause that much of an issue
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I'm sorry, but I don't understand everything you said. What was just about gone? What was the 1 line you didn't replace? I don't see how the brakes fit into this equation unless you have a blown brake booster which would be a huge vacuum leak.
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What happened was I blew a rubber brake line and lost just about all my fluid. Then I did a quick fix with a hose clamp to get me home and put just enough fruid in to have brakes cuz that's all I had with me. There the problem began cuz my master cylinder had so mush air in it and not enough fluid but I didn't realize that was my problem until I redid my whole brake system. Then the problem was gone until I blew another line and I've fixed the line but have not bled them yet. I haven't driven it yet to know if the problem is no longer a problem. I was just wondering if there were some ways to improve my vac system.
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I hope you've replaced all three rubber lines by now. But, that shouldn't have a bearing on the engine's vacuum.
You said you don't know how to do a compression test nor check the timing. A little Googling will tell you that, and I would suggest the first thing to check would be the timing. It'll require a timing light, but you may be able to borrow one from an auto parts store.
You said you don't know how to do a compression test nor check the timing. A little Googling will tell you that, and I would suggest the first thing to check would be the timing. It'll require a timing light, but you may be able to borrow one from an auto parts store.
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It does in fact have a bearing on the engines vacuum because when u step on the brakes the booster either takes or gives air from the motor to bring down the idle when your stopping so that your engine isn't fighting against the brakes. make sense? The only reason it was so convincing to me was because someone told me this then I did my brakes and bled them topped off the fluid and the problem of stalling when I stepped on the brakes was gone until I blew another line
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It does in fact have a bearing on the engines vacuum because when u step on the brakes the booster either takes or gives air from the motor to bring down the idle when your stopping so that your engine isn't fighting against the brakes. make sense? The only reason it was so convincing to me was because someone told me this then I did my brakes and bled them topped off the fluid and the problem of stalling when I stepped on the brakes was gone until I blew another line
If your brake system is way low on fluid it will make the pedal very low, and can draw way more vacuum when trying to stop than it should. So, your #1 issue is to fix the brakes.
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So I tried to bleed the brakes with the truck off and had fully pressure but when I took it for a ride the pedal goes right to the floor like there is more air. Not losing any fluid so no leaks bur no pressure and light comes on. Bled them twice. Help
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Did you start at the furthest wheel from the master cylinder and progress to the closest one last? And, did you make sure you kept the master cylinder topped up while bleeding so no more air got in?
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Yes. RR, LR, RF, LF. Twice. But now it stalls out when I step on the brake cuz it goes to the floor. But had a lot more pressure before I changed the wheel cylinders and shoes. Should the truck be on the bleed them.