Tulo Posted November 6, 2004 Report Share Posted November 6, 2004 I've got a friend with an Autometer Boost gauge. When the car starts, it reads about -3psi(it should be like -20). Then while boosting it will show alot more boost then what he's actually running(off by about as much as the vacuum is off). It calibrates itself each time the engine starts. It consistantly gives readings, they're just wrong. Anybody have any ideas of what it could be? TIA. -JP Quote Link to comment Share on other sites More sharing options...
Mallard Posted November 6, 2004 Report Share Posted November 6, 2004 My friend has the same problem with his. I heard you can send them back and have them re-calibrated. Quote Link to comment Share on other sites More sharing options...
Alex1647545498 Posted November 6, 2004 Report Share Posted November 6, 2004 Bleh, just cut out a hole on the side of it and fix it. Me and Mike did. Quote Link to comment Share on other sites More sharing options...
Guest timmybgood Posted November 7, 2004 Report Share Posted November 7, 2004 did you just install it or has it been working then just started doing this? because if you just installed it you might be using the wrong source Quote Link to comment Share on other sites More sharing options...
Tulo Posted November 7, 2004 Author Report Share Posted November 7, 2004 I'm pretty sure it's always been like that. How could it be hooked up to a wrong source? Just splice it into a vacuum line, right? Quote Link to comment Share on other sites More sharing options...
Berto Posted November 7, 2004 Report Share Posted November 7, 2004 the plating in the back ban be rotated. so disconnect itand turn the plate so the it reads 0 at atmosphere. then plug it back in and try (obviously check it with the reading of another boost gauge. Quote Link to comment Share on other sites More sharing options...
Razorback Posted November 7, 2004 Report Share Posted November 7, 2004 Just replace it if it's gone bad. Jeg's carries them. Quote Link to comment Share on other sites More sharing options...
Tulo Posted November 7, 2004 Author Report Share Posted November 7, 2004 Originally posted by Razorback: Just replace it if it's gone bad. Jeg's carries them. They'll replace it for free? Quote Link to comment Share on other sites More sharing options...
Razorback Posted November 7, 2004 Report Share Posted November 7, 2004 Of course not, but it's not like they're that expensive. Atleast the security of having a properly functioning gauge will be there and that's the important thing. Quote Link to comment Share on other sites More sharing options...
pg Posted November 7, 2004 Report Share Posted November 7, 2004 Wow mines never had a problem. I feel special. Quote Link to comment Share on other sites More sharing options...
Tulo Posted November 7, 2004 Author Report Share Posted November 7, 2004 Originally posted by Razorback: Of course not, but it's not like they're that expensive. It was like $200... He's gonna call Autometer tomorow and see if they can work somethin out. [ 07. November 2004, 06:47 PM: Message edited by: Tulo ] Quote Link to comment Share on other sites More sharing options...
Razorback Posted November 7, 2004 Report Share Posted November 7, 2004 The one in my car which is both Boost/Vacuum was $60 at Jeg's. The fuel pressure gauge was $200. Maybe we're looking at different gauges? Mine is the Autometer Phantom white face gauge. Quote Link to comment Share on other sites More sharing options...
Tulo Posted November 8, 2004 Author Report Share Posted November 8, 2004 http://www.egauges.com/vdo_mult.asp?Type=Turbo_Boost&Series=Cobalt&Cart= Quote Link to comment Share on other sites More sharing options...
Razorback Posted November 8, 2004 Report Share Posted November 8, 2004 http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1575&prmenbr=361 Part #: 105-5701 Bought mine at the Jeg's on main street in Reynoldsburg. And I was wrong about the price, it's only $47. Quote Link to comment Share on other sites More sharing options...
Trouble Maker Posted November 8, 2004 Report Share Posted November 8, 2004 I'm going to assume with how Tulo describes the gauge as self calibrating and the price it is one with an electric transducer/sending unit (looks like the cobalt series can be had in mechanical and electrical units). Those are usually more expensive. The one you quoted is a 'mechanical' gauge, meaning the pressure/vacuum line comes right to the back of the unit and the pressure/vacuum acts on a diaphragm which directly moves the needle. With the electric ones, there is an electromechanical transducer (converts a mechanical signal into an electrical one), then the electrical signal goes to the unit. I've never taken one apart before, but I would assume there is a steeper motor (and the required driver for it), and some gears. I'm sure you could see how this would be more expensive. Only thing this inherently show gains by whatever the 'signal' is, doesn't have to come into the cockpit. No big deal for boost, but I personally wouldn't want an oil pressure, and god forbid a fuel line, coming into my engine compartment. With temperature, I'm sure a mechanical wouldn’t work well, if at all. The electrical can also gain you memory features in a gauge. Like peak and hold, memory play back, visible/audible warnings. All very nice features, but you will pay for it. Quote Link to comment Share on other sites More sharing options...
Razorback Posted November 8, 2004 Report Share Posted November 8, 2004 Originally posted by Neo: I'm going to assume with how Tulo describes the gauge as self calibrating and the price it is one with an electric transducer/sending unit (looks like the cobalt series can be had in mechanical and electrical units). Those are usually more expensive. The one you quoted is a 'mechanical' gauge, meaning the pressure/vacuum line comes right to the back of the unit and the pressure/vacuum acts on a diaphragm which directly moves the needle. With the electric ones, there is an electromechanical transducer (converts a mechanical signal into an electrical one), then the electrical signal goes to the unit. I've never taken one apart before, but I would assume there is a steeper motor (and the required driver for it), and some gears. I'm sure you could see how this would be more expensive. Only thing this inherently show gains by whatever the 'signal' is, doesn't have to come into the cockpit. No big deal for boost, but I personally wouldn't want an oil pressure, and god forbid a fuel line, coming into my engine compartment. With temperature, I'm sure a mechanical wouldn’t work well, if at all. The electrical can also gain you memory features in a gauge. Like peak and hold, memory play back, visible/audible warnings. All very nice features, but you will pay for it.I actually do have the mechanical water temperature gauge as well. Works far better than the stock temp gauge ever did. Accurate as all hell. I stay away from electrical gauges. Too many end up taking a crap (like this one apparently did). As far as his is concerned, I didn't realize it was electrical, or that it mattered as I figure if it were me in his place and I had the choice of a $200 gauge that will probably break again, or a $50 gauge that will just take a little more time to install but will probably work for far longer (I've never had a mechanical gauge break on me, ever), I'd take the mechanical. Keep it simple. But then that's just how I am with things -- I don't like to complicate things any more than they need to be, heh. Quote Link to comment Share on other sites More sharing options...
Trouble Maker Posted November 8, 2004 Report Share Posted November 8, 2004 Originally posted by Razorback: I actually do have the mechanical water temperature gauge as well. Works far better than the stock temp gauge ever did. Accurate as all hell.So you physical have a water line going from somewhere in the bay to the back of the gauge, which is in the dash area? I would just think it would take forever to make that stagnant water change temperature over that much distance, unless it cycles the water through somehow? For certain gauges, I'd definitely say it's really hard to pass up a mechanical for the price. But others, I would never want to give up the peak and hold, memory playback, and warning point. Boost gauge could probably matter less (although I would think you could get an electrical one with all the bells and whistle for much less than $200). EGT gauge, I've been in cars that have a good electrical one (obviously they all are), with memory stuff, and I wouldn't want anything else. I really wouldn’t personally want coolant, and especially fuel coming into the cockpit. I’ve heard of peoples mechanical liquid gauges failing and their carpet gets soaked with coolant. Quote Link to comment Share on other sites More sharing options...
SHIEF Posted November 8, 2004 Report Share Posted November 8, 2004 Originally posted by Neo: So you physical have a water line going from somewhere in the bay to the back of the gauge, which is in the dash area? I would just think it would take forever to make that stagnant water change temperature over that much distance, unless it cycles the water through somehow? For certain gauges, I'd definitely say it's really hard to pass up a mechanical for the price. But others, I would never want to give up the peak and hold, memory playback, and warning point. Boost gauge could probably matter less (although I would think you could get an electrical one with all the bells and whistle for much less than $200). EGT gauge, I've been in cars that have a good electrical one (obviously they all are), with memory stuff, and I wouldn't want anything else. I really wouldn’t personally want coolant, and especially fuel coming into the cockpit. I’ve heard of peoples mechanical liquid gauges failing and their carpet gets soaked with coolant. That's why you get a splitter at Jegs or the like. Basically it takes whatever fluid your pulling from the engine and turns it into water or even Kool-Aid, whatever you put going into the car to prevent fuel and such from spraying in your car if something happens smile.gif As for the boost guage....your friend isn't using the fitting on the turbo going to the hotpipe is he? This will cause weird boost/vac levels on the guage also depending on the turbo. Quote Link to comment Share on other sites More sharing options...
BiG BeN Posted November 9, 2004 Report Share Posted November 9, 2004 w3rd. best to get signal from the manifold(intake) Quote Link to comment Share on other sites More sharing options...
desperado Posted November 9, 2004 Report Share Posted November 9, 2004 OK, yall are scarin me. As far as Mechanical gauges, Oil Press, Vaccum/Boost, brake pressure and a couple others simply tap into a line or fitting on what they are meant for. And yes, there is oil or whatever (even Nitrous) in the dash in the line. Mechanical Fuel gauges MUST be either mounted outside in a cup or use an isolator. The isolator mounts in the engine compartment, a high pressure line runs from one side to the gauge, and the line and half the isolator is filled with antifreeze or some non compressible liquid. The isolator has a rubber diaphram in it that seperates the fuel from the antifreeze. As pressure is applied to one side of the diaphram, it moves in, since antifreeze is noncompressable, it flows up the line (high pressure because it has no inflation properties that a regular rubber hose would have) That applys pressure IN the gauge and you get a reading on the gauge, without a fuel line running inside your car. The ONLY gauge I have seen with am isolator is a LOW pressure (15 PSI) fuel gauge. The EFI gauges that go in the car are electrical. Temp gauges are a bit different. Mechanical temp gauges, be it water, oil, or trans work different. There is a sensor bulb on the end of a mechanical temp gauge, it is emersed in the fuild that it is sensing the temp on. Of course from science we remember that most all gasses tend to expand when heated, this is how a mechanical temp gauge works. The gauge is actually a pressure gauge, the bulb and copper line connecting the bulb to the gauge are filled with a specific gas at a certain pressure. Because this gas will expand and create a specific pressure at a specific tempature, the pressure gauge is then calibrated at the factory to display a specific pressure in the bulb, which is then indicated as a tempature on the dial. This will work up to 400 or 500 degrees, then the pressures get too high. EGT gauges. An EGT gauge, is more electrical in nature. But it's sending unit (thermocouple) is a bit different than oil and water sending units that vary their resistance with change in tempature. Thermocouples are two dissimilar metals (nickel and copper) that a joint is welded together, joining the two. That junction, when heated will actually generate a small electric current. Because all thermocouples are nickel and copper, the current is always the same for a given tempature. So electrical gauges, with additional circuits to convert the current to a voltage high enough to move the meter are made to be stuffed in your dash. Copper and Nickel both have VERY high melting points so they make idea senders for tempatures that can not be sensed by pressure bulb temp gauges. Quote Link to comment Share on other sites More sharing options...
Razorback Posted November 9, 2004 Report Share Posted November 9, 2004 Originally posted by Neo: So you physical have a water line going from somewhere in the bay to the back of the gauge, which is in the dash area? I would just think it would take forever to make that stagnant water change temperature over that much distance, unless it cycles the water through somehow? For certain gauges, I'd definitely say it's really hard to pass up a mechanical for the price. But others, I would never want to give up the peak and hold, memory playback, and warning point. Boost gauge could probably matter less (although I would think you could get an electrical one with all the bells and whistle for much less than $200). EGT gauge, I've been in cars that have a good electrical one (obviously they all are), with memory stuff, and I wouldn't want anything else. I really wouldn’t personally want coolant, and especially fuel coming into the cockpit. I’ve heard of peoples mechanical liquid gauges failing and their carpet gets soaked with coolant. No, I apologize, the water temp gauge is electrical, and the boost gauge is mechanical. My previous nitrous gauge which just came off the car a few months ago was mechanical (physical nitrous line). The water temp uses a sensor similar to the sensor that turns the fan on and off, just taps where the cluster's sensor usually would be (I have the cluster water temp gauge disconnected). Got them mixed up, sorry. And surprisingly the electrical water temp gauge is well priced (like $40 something) so I would highly recommend it. Quote Link to comment Share on other sites More sharing options...
Trouble Maker Posted November 9, 2004 Report Share Posted November 9, 2004 That's cool Brandon. Desperado thanks, that was a very informative post. Some of that I knew, but some I did not know, that's why I was asking questions. Please don't take any offense to this. You seem very knowledgeable in some automotive areas and have alot you can bring to the board, but it seems like 99% of what you say on here is pointless and (trying to be) offensive. I guess I'm just trying to say, you should make more post like this and less other post. That mantra could be applied to alot of people on this board, but yours seems an extreme case. Quote Link to comment Share on other sites More sharing options...
Tulo Posted November 10, 2004 Author Report Share Posted November 10, 2004 Ok, here's the deal. This particular gauge automatically calibrates itself to zero psi everytime it is turned on. So when you put your key in the ignition and flip it to "acc" or "on" it calibrates itself. What I just found out it is doing is that when the key is flipped to "start" and the engine is cranking, the gauge loses power and turns off. Then when the key returns to the "on" position after the car is started, the gauge turns on again and re-calibrates while the engine is running. Thus giving the inaccurate reading. It needs to be wired to an accessory that does not turn off while the engine is cranking, so that it will keep the initial calibration. Make sense? I'll post back later after I rewire it to verify my hypothesis. Thanks for everyones help, by the way. Quote Link to comment Share on other sites More sharing options...
Tulo Posted November 11, 2004 Author Report Share Posted November 11, 2004 All is good. graemlins/thumb.gif Again, thanks for eveyones help. Quote Link to comment Share on other sites More sharing options...
Trouble Maker Posted November 11, 2004 Report Share Posted November 11, 2004 Originally posted by Tulo: All is good. graemlins/thumb.gif Again, thanks for eveyones help.Was it what you thought it was? It makes sense, but I'm just double checking. smile.gif Quote Link to comment Share on other sites More sharing options...
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