Vacuum tube from EAC valve cut!

strunch · 05-13-2006, 03:22 PM

I just noticed that the manifold vacuum signal tube from the EAC valve is cut in half. The tube ran over the engine to some more tubes located by the radiator overflow tank and then it splits off in two or three directions. I started the engine and put my finger on the end that ran to the valve..it made a hissing sound like air was being sucked in or out. I put my finger on the other end and didn't feel much pressure. My question is how does this vacuum leak affect the system? I have been having cold start problems and unsteady acceleration problems for a few months and was wondering if this could be the smoking gun.

p.s. I have a 99 AWD chevy astro cargo van.

Thanks.

Kings-x59 · 05-13-2006, 06:08 PM

Vacuum leaks do all kinds of unpredictable things. Replace the hose, or if it's a hard plastic hose, sleeve it with a short section of fuel rated hose and some hose clamps to splice it together.
Someone will correct me here most likely, I don't know if the '99 has a MAP or MAF sensor. If it is a MAP, a vacuum leak will effect the fuel/air mix

strunch · 05-13-2006, 08:31 PM

thanks for the reply...after i hooked it up my fan started blowing out the main vents...it wasn't doing it before, it was only coming out of the defrost vents. My fan only works on high though. I miss the old days when vehicles were easy to work on and you didn't need thousands of dollars worth of diagnostic tools. My 77 vw van was way easy to troubleshoot...except that time i lost my gas cap and a grasshopper got stuck in my fuel line.

Blue Bowtie · 05-14-2006, 01:58 PM

The '99 models have a MAP and a MAF (as most do these days). Any vacuum leak will contribute to unmetered air entering the engine, and at low throttle angles (when the PCM is using mostly MAF information) it will cause a lean tendency.

The failure of the HVAC blower at everything but the highest speed indicates a problem with either the fuse for the blower (there is a separate fuse for the lower speeds, IIRC), the resistor array for the blower (right on the front of the blower core case - easy access from under the hood if you remove the window washer fluid and coolant reservoir), the high speed blower relay (failing NC contacts), or the switch. I'd start with the resistor, since it's the most accessible item. It's also a good place to check circuit voltages.

Kings-x59 · 05-14-2006, 03:57 PM

strunch, that last line makes me laugh every time I read it.
had a '68 VW bug years ago. I have a murphy's law merit badge too.

bodeen9 · 07-09-2006, 11:42 PM

Thanx guys. I also found the small hard plastic vacuum line broken into when I started having problems with my a/c. I figured that was the problem but I cant find where the other end goes. It appears to go across the top of the valve covers and then down towords the tranny but I cant see it anymore. Can anyone help?

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