Boost Guage Issues...

M

mazdaspeedpower

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2003.5 Titanium MSP
Yes, so my newley installed Autometer C2 boost/vac guage was installed today, by my dealership, and it seems to be reading boost ok, just not vac. It's as if it's not calibrating itself properly or something. When I start, it reads at 0psi....and I'm thinking it should be reading 20vac...is that correct? Also, when I drive, it reads about 7psi just cruising, and when I boost goes to about 18psi, and I know that aint right...I'm wonder, what could the peeps in the service area done wrong? When I start the car, they are not on, they where relayed through the light switch...I'm wondering if that is wrong? because I know they are to be hooked to a constant power source...correct?
Anyone wanna help out a bit here? please..thank you.
 
I've been starting and restarting the car, with lights on, off, and it appears as though they only wired the lights to my light switch, as the guages function without the lights...but WTF is wrong? maybe a vacuum line not hooked up or something???? or in the wrong place? I dunno, I'm no Corky Bell, so I really don't know that much about this sort of thing.
 
Ok, so now, after much research, I wondering if it isn't either my sender, or my cheapo boost line cracked, maybe I'll take the car back and ask that they replace the shittiest boost line ever with a nylon one...do you think maybe thats the problem?
 
ok, well, thanks to celdridge I have come to the conclusion that it is indeed the lack of a constant power source. Thank you for your help good sir. Now the new question is, what is a reliable constant source of power?(i'm searching now, but if you repsond, you get a.....a.....free Imaginary cookie, and some positive rep...lol)
 
If I keep replying to myself without anyone else, I am gonna be the biggest self post *****. GREAT!!!...lol. Any input at all would be nice at this point
 
Haha 5 self replys? New forum record! Way to go! lol :)

Sorry I wasn't helpful :), I just wanted to post so you didn't look like an idiot talking to yourself hehe
 
hey man, I have held entire pages to myself before, this is nothing. And I'm already an idiot, no need to mask that...lol. Thanks for replying though.
 
well, i don't see how the gauge itself would need power to operate. the power is only for the little light thats inside so that you can see the gauge at night.

a boost gauge is anolog... it is in no way digital. (unless specified)

i have an autometer... and i remember taking it apart before i put it in... the electrical wires only go to the bulb.. and no where else...

i would replace the vacum hose if were you. then i would check for vacum leaks.

after a good run of some boost... when you turn the car off... where does the needle stay?

-pedro
 
I doubt it's the vacume line or the boost wouldn't go up as youget on the gas. it would go up then fall back down quickly. But if your's starts at 7 then goes up to 18, then something is probably wrong with your gauge. It should read about 20-22 in Vacume when cruising, go up toward 0 with acceleration and into boost if you go past 1/2 throttle. Chances are it's your gauge. Can you get your hands on another gauge? You could pull your current gauge out and attach the vacume line to the new one. That's all you'll need to see if it is working. Plug the vacume hose into the new gauge, start the car and see if it reas vacume. If it does then you know your first gauge is toast. No need to unhook all the electrical wires until you determine what the problem is.

Also, you can switch to real vacume line, but it's a pain inn the ass to get through the firewall. I suggest keeping the small vacume hose you currently have through the firewall and cut it there. Then you can use real vacume hose and the small autometer nylon hose will fit right inside the vacume line. This way you can T into where you want, rather then where the dealer did it. I suggest either the brake booster line, or the line off the manifold. Check the how to for pictures. Since the dealer allready has it on record that they installed it, you can reinstall it correctly without worring about voiding the warranty.
 
Now that I think about it, it's possible your vacume line is pinched. Perhaps it doesn't read vacume cause it is piched closed until enough pressure builds up for the air to force it's way through. I'd think that less than 18psi would be needed to do this. And if your car was really running 18psi you'd know it. It's probably a faulty gauge.
 
yeah, It was pinched at the early stages, but I unpinched, and it reads fine now, I just don't wanna have that ******* cheapo ass s*** kinking again, which is Why i'm getting the nylon vacuum hoses...oh, and now that it works, I found out my car does 9psi in the cold, and 8-8.5 on the warmer days...sweet deal. Just gonna have to be careful on those really cold days. And this was verified by my friend who hooked up his Mechanical boost gauge to the car(with the nylon hose I want) and it was reading the same. I had always wondered why I seemed to be spinning so much, now it makes sense, I've adapted to it, and can now take off pretty good with minimal tire hope or spinning, but with snows, it took some getting used to with so much less traction...it kinda sucks when you launch on a wet hill forgetting you have snows on...heh, tirespin city.Oh well, it's all good now, thanks for all your help and ideas guys,
 
I still have some minor problems with it, and the ******* cheap hose, but other than that, she's working nicely...and I'm a bit happier, still gonna get the Nylon hose done, and I'll mention to go off the brak booster or mani lines. Thanks again man.
 
brake booster line is an awesome sorce for vac/boost. just make sure you tap into the line BEFORE the check valve. the check valve is pretty close to the brake booster so if you tap somewhere in the middle of the line... you will be alright.

good luck... enjoy the boost
-pedro
 
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