Every now and then, some of my vaccum lines blow off. After a spirited drive today I found the line to the FPR and to the banjo bolt coming off the manifold to be disconnected.
What is the effect of running with these lines disconnected? I still got 18psi of boost and 21hg of vacuum on my aftermarked gauge. It's not that I want to drive with these lines disconnected, but seeing that this happens quite frequently, I want to make sure that it will not cause any damage.

TIA

 

Get a bunch of little zip ties and secure them.

 

If the lines aren't in tip top shape, they lose their flexibility. When they harden up a little bit, they won't stick to their fittings. If this is the case, replace them.

If the inside of the line is dirty or the fitting itself is dirty, they could come off, clean them with silicon spray and put them back on.

If they're simply being blown off because of high pressure surges, then yeah, get some zip ties and clamp them down, or better yet, purchase some small one-ear hose clamps for a more professional look. I'd try to find out why they are coming off first though.

 

Sounds like they are getting old and hard. I'd replace the rubber and then zip tie or use the little spring clips. The effect varies depending on which hose comes off. The worst one in my experience is the diverter valve hose. When it comes off, the car runs bad/slow on my car. The FPR will make the car idle rough.

 

Both the lines to the banjo-bolt and FPR coming off can destroy your engine. The banjo-bolt supplies pressure to open the wastegate and without it, you'll get 30-45psi with the GURU wastegate and grenade the motor. The FPR line uses boost-pressure to increase the fuel-pressure to match boost. This makes fuel-calulations in the DME easier as it can ignore boost and go with just total air-flow volume. But losing that line would result in super-lean mixtures, again, threatening your engine.

 

Thanks guys! The banjo bolt I'm referring to Danno, is the one on the manifold (well it looks like a banjo bolt). It's the same one that feeds the signal to the KLR.
I'll get some replacement lines.

 

I ordered the vacuum hose kit from Lindsey together with their modified CBV and SS brakelines.
Judging from earlier posts on the subject, some say that Lindseys hoses easily split/are to thin, although only one has expierienced this. I'm very happy with earlier purchases from Lindsey and decided to shop there again. If only they were a RL sponsor they would get all my business. I need a new exhaust and although I love how Lindsey's system look, I will probably get the SFR system because of their sponsorship.

Thanks for the help!

 

Getting properly dimensioned rubber connectors and ensuring an oil-free connection is very important for a trouble-free joint. Using silicone spray on the joint is OK; even though it is a little slippery at first, it actually makes the joint slightly sticky over time.
I have only had one line pop off at 25 psi (no zip ties), but it was old, large and soft from oil. I have no experience with silicone hoses in this respect.