Boost in vacuum lines?

[Larry Smith]

Started having a problem yesterday. I opened the hood and noticed that my fuel pressure regulator vacuum line was off. I assumed that I forgot to re-connect it after checking my line off fuel pressure the day before. I re-connected it and checked it again after a few high speed blasts that didn't feel quite right and sure enough, it was off again. My first thought is...maybe one of those black and white vacuum check valves that keep boost out of vacuum lines has gone bad. Started looking around and can only find one.. in front of the EGR valve. I checked it and sure enough, I can blow through it from both sides.
Main questions: Are there more? and where are they located? Has anyone else had a similar problem?
All opinions appreciated,
Larry
p.s. I recently installed alky and am running 23lbs boost.

 

[noslo6]

That line is supposed to have vacuum and boost in it. At idle (vacuum) it lowers fuel pressure by pulling on the diaphram. At boost it applies pressure to the diaphram increasing the fuel pressure with the increased demand for fuel with boost. Get a ziptie and cinch it around that line at the FPR to keep it on. You definitely do not want it to come off. Ask anyone who's changed head gaskets because of a lean condition

 

[Larry Smith]

Thanks noslo6,
Makes perfect sense. Thanks for the explaination. I'd rather feel dumb than blow my 62,000 mile original motor! Easiest fix ever.
Best regards,
Larry

 

[Bescurred]

Lol my name is Larry Smith ahahahaha

/end highjacked thread

 

[Blazer406]

I had a line or two do that..... age makes them swell (along with being oily over the years) .... I replaced the ones givving trouble.... got the sizes off the originals.... vacuum line is cheap at the parts store.... problem solved....

 

[noslo6]

Thanks noslo6,
Makes perfect sense. Thanks for the explaination. I'd rather feel dumb than blow my 62,000 mile original motor! Easiest fix ever.
Best regards,
Larry

No problem Larry. I hear ya...I've changed head gaskets for that exact reason!!!! Was at the track and blew the line off sometime during a run and EGT's went

 

[rev. 3:11]

There is another check-valve coming off the charcoal vapor canister D/S front as well as a specific 3-line behind the block near the coil pack check-valve. I can't remember if there re more?
I swapped all my vac lines w/ silicone to hopefully eliminate old, dried -out lines as vacuum problems.
P.S. make sure you orient the check-valves properly I had mine in bass-ackwards. (the a/c will only blow through defrost if the check-valve is reversed)
D

 

[rodman99999]

The zip-tie thing? I do it to all the vacuum(usually boost) lines. Cheap insurance !

 

[Larry Smith]

Thanks for the replys . I'm gonna change everything out. The more I look, the more cracked and rotten looking hoses I find.
Funny...seems like just yesterday this car was new.
Regards,