vacuum gauge reading problem

[JanGeo]

That is a standard vacuum gauge - the hole needs to be the size of a pin - really small. You can also put a glass bottle in line with the gauge to smooth out the pulses. Make sure you are not connecting to a electrically operated air bypass valve instead of the intake manifold near the throttle plate for the gauge.

[holypaulie]

I connected right next to MAP sensor by throttle body just like my car manual says. When I look inside of the hose connector of my gauge there is needle size opening, it just look so big from outside (3/8")

[Ford Man]

The vacuum gauge is very simular to the one I have on my '88 Escort with the exception that mine doesn't have the economy markings. Mine is one that is really meant for engine diagnosis.

[dkjones96]

I think you're reading too much into the fluctuations. If there really was a burnt valve or something causing an issue like this you would feel it. After all, your Civic is a 4 banger. It's not like a V10 thats dropped a cylinder and you don't even feel it. You'd notice a problem with your car.

What you are seeing is normal for a 4 cylinder. Nothing is smooth with these engines and what they meant about the needle sized hole wasn't the one in the gauge itself but the connection to the manifold. The hose will provide your buffer for smooth readings after that.

You get to choose, a smooth, slower reading or a speedy, jumpy one.

[holypaulie]

Originally Posted by dkjones96

I think you're reading too much into the fluctuations. If there really was a burnt valve or something causing an issue like this you would feel it. After all, your Civic is a 4 banger. It's not like a V10 thats dropped a cylinder and you don't even feel it. You'd notice a problem with your car.

What you are seeing is normal for a 4 cylinder. Nothing is smooth with these engines and what they meant about the needle sized hole wasn't the one in the gauge itself but the connection to the manifold. The hose will provide your buffer for smooth readings after that.

You get to choose, a smooth, slower reading or a speedy, jumpy one.

I can hook my gauge between intake manifold and brake booster and see if that is going change anything (I'd doubt it). I rather choose smooth, slower and able to read reading off course. I made restriction at the T-connetor where clear hose is conneted to.

[JanGeo]

Yeah exactly - you can have a big hose going to the gauge and that will smooth out the pulses but you need a really small opening in the hose to the engine intake so that only a small amount of air flows to the gauge. Think of it as a tiny tail pipe on your exhaust system so that you get a steady air flow instead of pulses. Too much movement in the gauge for a long time will wear out the movement and break the bernoulli tube from metal fatigue.

[holypaulie]

I connected in two different cars my vacuum gauge and it works like a charm. Now, I know there is something wrong with my engine, not the gauge.