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Could someone with experience installing the Autometer 3376 electric boost gauge verify that the signal coming out of the guage should be 5.0 volts in order for the Autometer supplied (GM) MAP sensor to read correctly, allowing the gauge to function? All power and grounds were connected correctly but to my understanding unless the voltage is 5.0 on the dot, the MAP sensor won't read. I got 4.87 volts out of the gauge wire that feeds the MAP sensor.

JMBLOWNWS6

iTrader: (17)

I just finished my buddies Cobalt's on his ZO6. The bad news I have is that it is about 2 pounds off the mark. We installed the A&A kit on it and it was showing 10 pounds making 587 rwhp and 502 TQ. We were worried since this is on a stock bottom end. So we cut back the timimng to less than 15* and used my mechanical boost gauge and it is only going up to 8 pounds. I didnt test the voltage. Red is the Keyed +,White is the light + and Black is the ground. The connector will only plug in one way and tapped off the brake booster hose. Hope that helps.

Joe M

kp

iTrader: (34)

yes 4.8x is the correct voltage. It is very important with those MAP sensor auto meter gauges that they are hooked so the power does not get removed while cranking. When you first turn the key on it adjusts it calibrates itself using the MAP sensor as a Baro sensor. If its hooked up where the power turns off when the car is cranking it will read all kinds of funky numbers.

I have a mechanical autometer boost gauge in this car, a 2 BAR MAP used for logging boot and I have a reversable mityvac that has a pressure gauge and if I hook up all three and pump up the mitvac they arent even close to each other so most of these cheaper gauges are good for reference and not absolute numbers IMO.

JMBLOWNWS6

iTrader: (17)

Well I bench tested my mechanical in INHG and it worked flawless.

kp

iTrader: (34)

A 75 cent bourdon tube compound pressure gauge movement sure isnt the most accurate thing in the world and they are very non linear.

I'm not saying that YOUR MAP based gauge is right and YOUR mechanical is wrong - just hard to tell without some fairly decent test equipment. If it didnt come out of an airplane its not very accurate most likely.

JMBLOWNWS6

iTrader: (17)

Since I work in Instrumentation and have my degree from it I think using my fluke and my vaccum pump I know what Im talking about. Pics can be provided no problem.! I work with this stuff everyday. My plant relies on instrumentation. And the deadband was at 1.85 which =2 Not trying to start a war here just posting what I did when I was curious. Because this happened to another car and I was asked to test it. And since I work under a vaccum with a condensor I know what vaccum is all about. And I know that a map sensor is alot more sensitive. But in this case the refernce point I used the mechanical was within .98 of DB. Thats why I made that statement.

kp

iTrader: (34)

did you check the cobalt gauge on the bench?

JMBLOWNWS6

iTrader: (17)

Yes. Thats why I was suprised. We returned the gauge to autometer and got another one and it was nuts on. And last night when Dynoing my buddies car the same situation happened. But I am going to make sure the voltage isnt dropping on my constant+ Just to make sure. Because of what you stated Didnt mean to come off wrong. Friendly tech chat

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Kevin, thanks for the help. I did verify that the gauge didn't lose power when the engine was cranking and still no gauge functionality. I used a multimeter to verify input and output voltage and ground. I also put a mechanical vacuum gauge on the boost signal going to the MAP sensor and it was pulling 19 inches of vacuum. I am stumped!

kp

iTrader: (34)

At first you didnt say you checked them both right after each other with decent equipment

I think the MAP based gauges tend to read a little higher because they compensate for barometric bressure at power up and try to compensate for altitude somewhat. I'm not questioning your credentials, I have seen so many mechanical pressure gauges being all over the place its hard to be certain. Like anything else its possible to have a bad one I'm not defending any type of gauge, just these mechanical gauges are not the most accurate things in the world sometimes.

I dont mind discussing anything, thats what these forums are for - I'll be the first to admit I'm wrong when proven so

kp

iTrader: (34)

When you power it up does the gauge 'sweep' or does it just sit there? They have a little processor in there and its a stepper motor so there is a lot to go wrong.

JMBLOWNWS6

iTrader: (17)

And the worst part about this,Is I told him to buy the map based gauge because it is better And I got the red *** about it last night. Kinda blew up in my face huh ? No problem man. BTW you car is awesome. Nice to see you made Mags

JMBLOWNWS6

iTrader: (17)

Its doesnt sweep on ours. It just hits the stop (Backwards movement) and then zero's out.

kp

iTrader: (34)

I liked the MAP based gauge because of the recall function mostly, when I was having belt slip problems it was nice to be able to tell when to tighten the belt, not to mention I didnt have to stare at the gauge and the road at 100mph. Plus I used to use the programmable high boost warning as a shift light

Thanks, this has been a good car

kp

iTrader: (34)

You are probbaly be right, its been a while since I had a MAP based autometer but the gauge should do something when its first powered up.

JMBLOWNWS6

iTrader: (17)

Ya they kinda make a click sound when first powered up. LOL I dont post on this section too much. But I always do the gauges at my buddies shop.

kp

iTrader: (34)

Now that I give it some thought Randy, the phantom gauge I had here was wired incorrectly from the factory. The little plug in the back of the gauge had a wire in the wrong place and I had to switch it. May want to check all of those pins against the instructions. That was very early production unit, the last couple I had here were OK but there there may be more like that out there.

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The gauge does power up, make a little click and recalibrates to zeroes, but then doesn't read after that. Once Autometer sends back the gauge, I will hook the new gauge up and if it doesn't work, check the pin connections. Kevin, I do like the peak and warning functions of the gauge and according to the turbo system manufacturer, the mechanical Autometer gauges normally read about 1 psi short of the calibrations they have set up for their systems (which is probably why I was sent the gauges for an article, straight from Autometer via the turbo system manufacturer).

Ferocity02

iTrader: (60)

My Autometer electric boost gauge was right on the money! Fast too.