Boost pressure sensor question - Toyota Nation Forum : Toyota Car and Truck Forums

browncat1977 · 05-29-2006, 06:21 PM

Hey guys,
I have an 1989 Supra Turbo with no mods.

The turbo is not boosting more than 3 psi.

I have checked pretty much everything that has to do with the turbo, including piping, IC, gaskets, BOV, wastegate, and have emptied the catalytic converter.

Anyway, my question is:

How do I check the boost pressure sensor and what are the specifications?

Any help will be appreciated!
Thanks.

theKnifeArtist · 05-29-2006, 08:01 PM

triple posting will get you crucified.

browncat1977 · 05-29-2006, 08:33 PM

Sorry...my computer was acting up and clicked more than once by mistake!
Any help???

Thanks

theKnifeArtist · 05-29-2006, 08:47 PM

check the accordian hose, vacuum hoses, that small throttlebody hose...maybe some other stuff too. post it up on supramania.com and you'll get allot more replies.

Jeeves · 05-30-2006, 11:26 AM

Now, here's the important question. Are you using the factory boost gauge as a reference? It's not accurate at all.

browncat1977 · 05-30-2006, 10:24 PM

Hey there Jeeves!
Well, initially I noticed the factory gauge was not showing over 3 psi, but also I didn't feel the turbo kick it like another Supra I had before.

I bought an AutoMeter gause and It also shows only about 3 psi.

So, I am pretty sure that it is something else.
I disconnected the turbo and took it to to Turbocity in Orange County, CA (a reputable place in my book) and they told the turbo is in good condition.

I have done so many checks. I've bypassed the BOV, I have bypassed the IC, I've changed the gaskets where the turbon connects to the manifold. I've checked all the hoses. There seems to be no leaks anywhere!

What can it be?

Thanks.

Jeeves · 05-31-2006, 09:47 AM

Quote:

Originally Posted by browncat1977

Hey there Jeeves!
Well, initially I noticed the factory gauge was not showing over 3 psi, but also I didn't feel the turbo kick it like another Supra I had before.

I bought an AutoMeter gause and It also shows only about 3 psi.

So, I am pretty sure that it is something else.
I disconnected the turbo and took it to to Turbocity in Orange County, CA (a reputable place in my book) and they told the turbo is in good condition.

I have done so many checks. I've bypassed the BOV, I have bypassed the IC, I've changed the gaskets where the turbon connects to the manifold. I've checked all the hoses. There seems to be no leaks anywhere!

What can it be?

Thanks.

Bypassed the BOV? Just about anything you can do to the BOV is a bad thing. It either works, or it leaked and you've replaced it. Bypassing it means you're feeding boost back INTO the intake, which would be a HUGE boost leak. Make sure that the coupler between the 3000 pipe and the throttle body is tight on both sides. That's a commonly missed spot.

***bgrieger*** · 05-31-2006, 11:09 AM

That coupler at the throttle body has a habit of tearing open on the underside as well as not being clamped properly. It may look fine from above. Remove it and see

Jeeves · 05-31-2006, 03:19 PM

^^^ that too

It's generally a problem area.

At least you don't have my luck, in finally replacing my intercooler, we found that I had SEVERAL ~1/4" holes in the intercooler.

browncat1977 · 06-01-2006, 11:14 AM

Thanks for all the great info.
How do I check the BOV to make sure it is working properly?

Jeeves · 06-01-2006, 12:17 PM

Quote:

Originally Posted by browncat1977

Thanks for all the great info.
How do I check the BOV to make sure it is working properly?

Pull it off. Blow through it, if you can blow through both sides, it's failed.

Gasoline Fumes · 09-14-2007, 09:03 AM

Old thread bump!

Anybody have the pinout for the 89420-14020 turbo sensor? It has a brown, orange and white wire on the connector. The connector is labeled on the wire side, but I don't know what B, O or a hollow cross mean. I picked one up at the junkyard and I'd like to try using it as a MAP sensor when/if I turbocharge my Suzuki Swift engine. I need a MAP sensor that understands boost. Obviously any other info on this sensor would be helpful too.

Thanks!

***bgrieger*** · 09-14-2007, 12:48 PM

when we need a map sensor we just use GM ones...why waste time trying to retrofit. Most piggybacks and standalones are designed to use them as well.

CRE · 09-14-2007, 02:35 PM

^^^Agreed.

For most applications you're going to need to know more than just the pinout. You'll also need to know the scaling and calibration information: ascending or descending, logarythmic or linear, base (0psi) voltage, and so on.

Gasoline Fumes · 09-14-2007, 11:21 PM

But I hate GM! And I love wasting time! I'm hoping it's pretty similar to the Suzuki MAP sensor. They're both made by ND and have similar ND part numbers. I wanted the pinout so I could hook it up and see what the output was a various levels of vacuum and pressure. Even if I end up not using it, I still enjoy playing around with stuff like this.