can anyone verify this (1996 blazer)

96 blazer with 4.3 vortec. cpi.

was just told by a mechanic that the fuel pressure regulator actually open and closed according to temperature. ie: when warm is closed and when cold is open.

is this true?

he is telling this is my no start problem when it is cold but when i have the oil heater pluged in the oil and engine is warm leaving the regulator closed and blazers starts fine.

Nope, regulator is pressure controlled not temperature controlled.

And your 1996 is not a CPI, it is a CSFI.

Actually, the force of the engine vacuum inside the upper plenium controls the regulator which controls fuel pressure.

Yes, that is what I said.

I think he was saying that there is a difference between "pressure" and vacuum. The regulator sees vacuum not pressure.

I think he was saying that there is a difference between "pressure" and vacuum. The regulator sees vacuum not pressure.

For crhist sakes , vacuum is pressure.

A bit defensive? If I'm wrong, I'm sorry, but at times that is how it seems to come across as.

I still would refer to it as vacuum instead of "pressure".

A bit defensive? If I'm wrong, I'm sorry, but at times that is how it seems to come across as.

I still would refer to it as vacuum instead of "pressure".

No, I am a trained and certified fluid power and pneumatic technologist and vacuum is negative pressure.

They are the same. So please stop arguing against me.

So please stop arguing against me.

You may have been here longer than myself, but that does not mean that I'm a lesser of a person. You've been wrong before as well. Please drop the attitude. We are here to learn and help each other. Many times when your advise or input is questioned, you get defensive and belittle them with an attitude. It would be nice if you would simply help me learn when I'm (or others) are wrong.

I honestly didn't think you could have "negative pressure". I thought that pressure was always positive.

You may have been here longer than myself, but that does not mean that I'm a lesser of a person. You've been wrong before as well. Please drop the attitude. We are here to learn and help each other. Many times when your advise or input is questioned, you get defensive and belittle them with an attitude. It would be nice if you would simply help me learn when I'm (or others) are wrong.

I honestly didn't think you could have "negative pressure". I thought that pressure was always positive.

Hmmm...

That's funny, I believe that you are the one that said I was wrong and now that I have proved that I am right you say I am pulling attitude?

How does rank come into any of this, I never pulled the "I've been here longer" crap so please just drop it.

Sad day when some can't prove he is right without having someone taking offense to it.

Please, just let it go.

How have you proved that you were right? You simply told me that you're "a trained and certified fluid power and pneumatic technologist and vacuum is negative pressure" and basically told me to shut up. How does that help anyone?

Sadly I didn't learn anything other than it confirmed that you often get defensive with an attitude when someone questions your input (regardless if you was right or wrong). You expect everyone to simply believe something without going into it a bit?

We are here to learn and help each other.

I did a search online and I often seen the phrase that it is "misleading" to refer to vacuum as negative pressure because pressure is "always positive".

You didn't offer any explanation to it.

I said I would refer to it as vacuum because that is exactly what it is, vacuum. I could be wrong, but I thought that generally in the real world, people refer to pressure that is often measured in PSI.

I was was trying to help the poster clarify any confusion, which is also what I think ricksza was trying to do as well.

Sad day when you can't help others without it turning into this.

To the thread starter, I am sincerely sorry.

Seems people can't let things go.

Again slreno1217, sorry about this.

Well you have PSI and PSIG. In the absolute the PSI is the pressure above no pressure, or perfect vacuum as we call it, the PSIG is what a gauge reads above the constant pressure of the atmosphere. So a perfect vacuum is only about 14.3 lbs negative pressure to put it in shadetree terms. PSIG is what we usually refer to. And the regulator controls the pressure from a spring inside the regulator and is also further adjusted by the engine vacuum once started. Temperature is not a factor in this deal, but it does control fuel mixture in other ways.