2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

So you drive a TII and your boost sensor takes a crap on you....

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Old Aug 30, 2006 | 08:16 PM
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So you drive a TII and your boost sensor takes a crap on you....

How is your car going to perform?
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Old Aug 30, 2006 | 11:08 PM
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Might be ok under vacuum, probably go lean and blow up if you boost it.
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Old Aug 31, 2006 | 01:42 AM
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From what I understand the boost sensor controls timing advance/retard and not fuel delivery. It can induce fuel cut because it's readings are used by the computer to determine that, as well, but as far as fuel volume calculation, the AFM, TPS, and water thermosensor do all the work.

From what I understand...I have never delved way into stock EFI with a scope or anything, but my own observations over time back this up.
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Old Aug 31, 2006 | 03:35 AM
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If the sensor dies the ECU will ignore it and default to a setting equivalent to ~4psi boost.

How do you know this has happened? Have you checked for ECU error codes?
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Old Aug 31, 2006 | 08:45 AM
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From: Philly | PA
Originally Posted by NZConvertible
If the sensor dies the ECU will ignore it and default to a setting equivalent to ~4psi boost.

How do you know this has happened? Have you checked for ECU error codes?
Im not 100% sure its the boost sensor, just a theory.

My car has a pretty noticable hesitation/misfire/somethingorother anywhere between 2-4k RPM, but as soon as I get about 4k it seems like the problem just goes away. So Im not really sure. I was thinking boost sensor or TPS at first.
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Old Aug 31, 2006 | 10:25 AM
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Originally Posted by Mindspin311
Im not 100% sure its the boost sensor, just a theory.

My car has a pretty noticable hesitation/misfire/somethingorother anywhere between 2-4k RPM, but as soon as I get about 4k it seems like the problem just goes away. So Im not really sure. I was thinking boost sensor or TPS at first.
Go to the boost sensor and pull its vacuum line off. Plug that line. Then go for a ride and try to duplicate what you've been seeing.

If it (the hesitation) goes away,you might try a orifice in that vacuum line and try it again with the vacuum line back on the boost sensor.

And while we're here, tell us what happens with your boost GAUGE (factory) when you go into boost. Does it move at all???? Any movement at all?????? NO movement means you have a problem with the boost sensor output not only to the gauge but to the ECU too. The signal to the ECU matters.

Last edited by HAILERS; Aug 31, 2006 at 10:29 AM.
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Old Aug 31, 2006 | 11:06 AM
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What should the signal to ECU look like at idle, 0 and ~5psi? Might add that to my list of things to tap into the ecu to watch and solve my hesitation issue too.
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Old Aug 31, 2006 | 12:24 PM
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From: Philly | PA
Originally Posted by HAILERS
Go to the boost sensor and pull its vacuum line off. Plug that line. Then go for a ride and try to duplicate what you've been seeing.

If it (the hesitation) goes away,you might try a orifice in that vacuum line and try it again with the vacuum line back on the boost sensor.

And while we're here, tell us what happens with your boost GAUGE (factory) when you go into boost. Does it move at all???? Any movement at all?????? NO movement means you have a problem with the boost sensor output not only to the gauge but to the ECU too. The signal to the ECU matters.
The gauge moves as normal. I will try taking the line off once Im out of work and see if anything changes.
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