Motor Vehicle Maintenance & Repair Stack Exchange
Motor Vehicle Maintenance & Repair Stack Exchange

Questions tagged [vacuum]

37 questions
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10 answers

How can I detect vacuum leaks without access to a smoke machine?

In the course of helping my friend sort out a lean condition with his Mercedes GLK280 we have to pinpoint the source of a vacuum leak in the intake plumbing. The interwebz tend to recommend having the car taken to a mechanic so that they can perform…
Zaid
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Leaking Fuel Injector Seal

I recently had to remove the fuel injectors and fuel rail to clean out the EGR ports on my Honda Accord. The EGR port was all clogged up with carbon build up. I replaced all the old o-rings, cushion rings and injector seals with new ones. One of…
William
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What problem does a negative vacuum reading indicate when blipping the throttle?

I was doing a vacuum test on my 99 Nissam Almera 1.6 ( GA16DE engine ) to kind of get an idea how the engine is doing after I homebrew seafoamed it, and when I blipped the throttle the vacuum reading dropped to -5 in.Hg before jumping to 23 and…
Robert S. Barnes
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How do I fix my Heater & A/C in my car, suspect vacuum problem?

I didn't see this question asked after a search so I thought why not. I have a 97 GMC Sonoma with 90k miles that I barely drive. Since the hot summer is coming fast I went to use the AC and I am only blowing warm air from the defrost and floor…
Hᴇʀʙɪᴇ
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High vacuum pressure on idle after timing gear and chain replacement

I just got my 1980 Chrysler LeBaron 318 V8 back from the mechanic, who replaced the timing gears and chain, which were the originals and very worn. Soon after leaving the mechanic, I noticed my vacuum pressure gauge was reporting high vacuum…
sehcheese
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Manifold vacuum vs performance

I've been reading around looking for data on how to interpret manifold vacuum. Why? Well, my original thought was that 0.0hg meant that there was no restriction in the intake system and would mean you're getting the most potential. I soon found that…
DustinDavis
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How brake vacuum booster works?

If the brake vacuum booster makes vacuum on one side and the other is with normal atmospheric pressure, why doesn't it get sucked by itself towards the vacuum side? If the vacuum isn't enough to pull it, how does the brake piston return back to its…
user3407319
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Is vacuum line still necessary with manual locking hubs on an F350?

Several years ago, on my gas engine 2003 F350, I replaced my auto locking hubs with Warn manual hubs. Recently I am experiencing the dreaded A/C defaulting to the defrost vents under low vacuum conditions due to a vacuum leak. I have isolated the…
Speedy Petey
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2008 Ford Focus 2.0 Zetec, wont rev higher then 4000 (redline 6.5), white smoke out the exhaust when petal is released

So about 500 miles ago I got a fresh oil change, new thermostat, new belt and new coolant. About 3 weeks ago I drove the car and it was fine, we parked it in the garage for as we where only needed to use one car. Started it today and started fine…
Dakoda
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Are there plugs for sale that are used to plug unused (thin) vacuum lines?

A bit of the background: I have a Mercedes that has a serpentine belt-driven air pump to help reduce smog in the exhaust. I heard this whole pump can be removed without causing any trouble, so I decided to go ahead to reduce repair problems. Then I…
David Xu
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Giulietta High LTFT & Low manifold vacuum

Im currently trying to get to the bottom of an issue with High long term fuel trims (+20-25% give or take) which is showing my car appearing to be running extremely Lean, struggling with this as the A/F ratio looks ok and o2 looks ok... Alfa Romeo…
james walker
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1996 Chevy G10 - Where Does "Hard" Vacuum Line Go?

I was attempting to replace the vacuum check valve in my 96 Chevy G10 with 5.0 V8 and approximately 144,xxx miles. The check valve has three fittings, the two opposite each other were "soft" 7/32" lines; the "other" one was a harder, thinner line…
KellyM
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Testing and diagnosis for hissing sound only in forward gears 2000 Toyota Camry-LE

I have a 2000 Toyota Camry LE, with 147,000 miles on it. At present, when sitting at idle with the transmission in park, neutral, or reverse, there is no noise, everything sounds normal. When the transmission is moved into any forward gear, there is…
cdunn
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"Slow" start diesel

Starting at low temperatures and sitting all night outside at below 5°C my car starts "slow". Like you can see in the video below, it will start with no problem but the engine hangs at 700rpm for a few seconds and only then it will start up the…
spaceman
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Tracking Down Excess Crankcase Pressure

So a problem I've been putting off dealing with for a long time is the excess crankcase pressure in my 99 Nissan Almera 1.6L. You can see here in the air box the results of this excess pressure: Blow by and crank case vapors are obviously being…
Robert S. Barnes
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