Originally Posted by jdbaugh1

I can't remember if we've covered this yet and too lazy to go back and read through but do you have any fault codes set? From what I've seen the LSJ formulates it's boost reading from the reading on the MAP sensor. Your MAP sensor could be faulty and reading wrong. As far as that goes your gauge could be faulty as well. How does it feel when you accelerate? If your supercharger actually was only making 3 psi the car should accelerate like an absolute turd.

For you to have that large of vacuum leak I'd think you'd have a high idle rpm and if you looked at the fuel trims with an OBDII reader it should have high fuel trims at idle as well. You could connect the hose that runs to the back side of your bypass solenoid (this line taps directly into intake manifold) directly into a cheap boost gauge to verify the manifold pressure.

Originally Posted by FrankieD

I have no fault codes. The only fault code I had was for my intercooler pump; which was fixed. Since the fix, there have no fault codes.

Where is the MAP sensor located? I've changed my gauge; I still have the same results. The car is a snotty little thing, so acceleration is fine.

Should I change my MAP sensor? If so, which one should I buy?

P.S. I cleaned my throttle body, it was filthy.

Originally Posted by jdbaugh1

I wouldn't do anything with the MAP sensor until comparing the readings to a mechanical boost/vac gauge. What does it read at idle?

Originally Posted by FrankieD

It reads 20 hg give or take.

What type of boost/vacuum gauge should I get? Any suggestions? I've been wanting to change my boost gauge for a while to something like an Autometer Phantom 2 or something similar. What do you think? I know that some of those gauges use their own MAP sensor, at least that's what it says on Autometer's website.

Now, if I get a mechanical boost/vacuum gauge and I start getting the proper boost for a stock car, would that mean that the MAP sensor is bad?

Originally Posted by jdbaugh1

If you use an OBDII reader to verify the MAP readings don't match the readings on a accurate boost/vac gauge then yes I would say the MAP sensor isn't reading correctly. I wouldn't rely on the boost gauge readings because there could be something interfering with the signal out to the gauge that makes it display differently than the MAP sensor.

Originally Posted by jdbaugh1

If you use an OBDII reader to verify the MAP readings don't match the readings on a accurate boost/vac gauge then yes I would say the MAP sensor isn't reading correctly. I wouldn't rely on the boost gauge readings because there could be something interfering with the signal out to the gauge that makes it display differently than the MAP sensor.

Originally Posted by FrankieD

1.What should I be looking for on the OBD 2 11 reader?

2.Also, what kind of boost gauge should I get? Something cheap from Ebay just for testing purposes?

3.Where are the MAP sensors located?

Originally Posted by jdbaugh1

1. I already stated which is to look at your MAP sensor readings and verify they match the physical gauge
2. That is really up to you. You could get one that's decent you want to leave installed or just the cheapest thing that has fairly accurate readings.
3. MAP sensor is on top of intake manifold, under the fuel rail, on the passenger side close to your upper coolant hose.

Originally Posted by jdbaugh1

If you use an OBDII reader to verify the MAP readings don't match the readings on a accurate boost/vac gauge then yes I would say the MAP sensor isn't reading correctly. I wouldn't rely on the boost gauge readings because there could be something interfering with the signal out to the gauge that makes it display differently than the MAP sensor.

Originally Posted by FrankieD

So, today I took my car for a ride with my OBD II reader hooked up; I was monitoring the MAP sensor and when I gave it full throttle in 3rd gear, the reader was saying 29.9 hg, which converts over 14.69 psi. Does this indicate anything? What could be interfering with the signal to the boost gauge?

I am still waiting for a boost gauge to come in the mail.

Originally Posted by jdbaugh1

Depending on how you have your OBDII reader configured you may be reading absolute pressure instead of gauge pressure. Does it show between about 4-10 in-hg at idle?

Originally Posted by jdbaugh1

Depending on how you have your OBDII reader configured you may be reading absolute pressure instead of gauge pressure. Does it show between about 4-10 in-hg at idle?

Originally Posted by frankied

repost of last in case it was not seen:

at idle it shows 20ish hg on the reader.

Originally Posted by jdbaugh1

-20?

Originally Posted by jdbaugh1

...replace it with a mechanical...