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Boost Actuator / Valve

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Old 08-30-2004, 12:11 AM
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Originally Posted by Drifter420
OK.. puttin this out to see what everyone thinks.. I dump boost when not @ wot.. but when I went WOT last weekend.. I notice I get full boost and maintain it. What gives? Something have to do with pressure/vacuumm lines? Since I"m assuming @ WOT vacuum is '0'
Checked the MAP sensor?
Old 08-30-2004, 09:07 AM
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Doc J.. how do I check the MAP sensor??

Silver96.. long time no yak.. where you been? Coming to the meet?

Anywho.. k.. so you sucked on the top vacuum line going to the actuator? Going to check that out tonight and run a vacuum line test on all that I can and go from there. ( If I have enough time @ my bro'* tonight.. I'll check compression cause I'm curious )

Wish me luck folks..

P.*. So now I know how to check the actuator.. how would I know if it'* the BCS thats gone??

P.*.*. Doc J or somebody.. please let me know how to check the MAP sensor ASAP.. other then havin a scantool.. only have a code reader
Old 08-30-2004, 10:10 AM
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Its actually pretty easy. Take a look at it, there'* a plug with three wires going to it. The easiest way I've found is to take a sewing needle and punch the tip into the middle wire. Then test the voltage there. It should be 1-2v at idle according to Wells Manufacturing (people who make it). It gets a 5v feed so I'd assume it should be around there at WOT, much like your TPS. So watch the voltage and rev it a few times, the voltage should spike then drop quickly. I'm not sure how mechanically inclined you are so let me know if you need more details.
Old 08-30-2004, 10:32 AM
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Originally Posted by DrJay
Its actually pretty easy. Take a look at it, there'* a plug with three wires going to it. The easiest way I've found is to take a sewing needle and punch the tip into the middle wire. Then test the voltage there. It should be 1-2v at idle according to Wells Manufacturing (people who make it). It gets a 5v feed so I'd assume it should be around there at WOT, much like your TPS. So watch the voltage and rev it a few times, the voltage should spike then drop quickly. I'm not sure how mechanically inclined you are so let me know if you need more details.
I'm retarded.. where'* the MAP sensor again? It'* not the 2 black boxes behind the */C is it? I will try and get a reading of it.. so wat would I be lookin for 1-2V @ idle.. and 5V @ wot?? I will post the results after I get there.. I'm alright mechanically.. not like you guys.. but enough to get my hands dirty with.

Wat would the symptoms be if the MAP sensor is the culprit.. less the 1-2V @ idle and 5V @ WOT?? Wat bout part throttle? Guess good ol math will tell..
Old 08-30-2004, 10:43 AM
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Wow I didn't read your year, so used to Series I guys asking the q'* hahaha
Yeah those would probably be it. They're like 3" long, rectangular, say GM on the top, have a Vacuum line and a plug with 3 wires. I guess one is for the gauge and one is for the computer. Thats kind of cool though because you can use one as a reference to see how far off the other one is.

I'm not sure exactly what the voltage should read edit: as far as the WOT voltage. The TPS gets 5v but will only read 4.4-4.7ish as far as I've ever gotten it. Mainly just look for the correct idle voltage,1-2v, and a quick response when you rev the engine. If anything is fishy we can look further at it.
Old 08-30-2004, 09:37 PM
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they're both reading .78 to .8 volts on idle.. would they both go @ once???? Anyone with service manual to L67 series II?? Maybe can send me some schematics of the */c and all associated with it so I can troubleshoot from that point on??
Old 08-31-2004, 12:13 AM
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Vacuum leak? If you have a vacuum tester (pump) you can hook it to them and make sure they're reading right.
Old 08-31-2004, 01:25 AM
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Originally Posted by DrJay
Vacuum leak? If you have a vacuum tester (pump) you can hook it to them and make sure they're reading right.
checked the lines feedin the MAP sensor and they're fine.. and holdin vacuum.. checked the one going to the actuator.. same thing..

did the boost bypass while back and checked the BCSt.. and it'* not holdin vacuum ( probably cause of the boost bypass trick? )

Anyone with 96+ */C that can check the readings of their MAP sensor?

I was shocked when the first one read 0.8 volts area.. then we thought.. well the other should read better then.. BUZZZ nope.. reads the same.. Wat controls the MAP sensor'* readings?

Goin to have to ask around for boost system schematics to help troubleshoot the issue
Old 08-31-2004, 12:07 PM
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Welp sheit, I can't imagine they would both go out at the same time...Did the voltage spike and react quickly when you rev the engine?

Let me make sure I have this right...

Driving around town normally the boost never leaves -10 but at WOT it'll give you 10psi? If thats the case are you seeing a drastic drop in performance around town?

Did you ever check the movement of the BCA? Start the car and watch it while someone else revs the engine, you should see it move.
Old 08-31-2004, 12:38 PM
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That sounds familiar. That should be the first thing checked. Did you ever do it?


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