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  #16  
Old 07-27-2013, 09:54 PM
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Originally Posted by KarTek View Post
If you have access to a scan gauge, you can connect it to verify the boost levels and the MAP sensor operation. Conversely, you can also "T" a standard pressure gauge into the MAP sensor feed to measure boost.

Also, when the car is idling, remove the vacuum line on the waste gate and connect a vacuum gauge to it to verify there is 100% vacuum present. As a test, you can also connect the vacuum supply line going to the transducer directly to the waste gate so you get 100% boost all the time. If you regain your performance doing this, you can take a closer look at the transducer.

Rolf,

The transducers are variable vacuum devices controlled by a PCM signal from the ECU. If you can do with a "on/off" control rather than variable one, you might do well with an EGR purge or "switchover" valve.

ok i hooked the two lines together no change. i cleaned the MAF from all the black smoke from the exhaust leak and it seemed to make a little difference but it could be all in my head. i have a snapon verus scan tool what should the MAF and boost numbers be and under what condition?

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  #17  
Old 07-27-2013, 11:15 PM
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ok i smoke tested all the vaccuum lines and no leak transducers are good. maf numbers on the scantool were 400 mg/s and didnt change very much at all. what is good for this? anything else to test? still nails at idle can that be l;inked to the sluggishness?
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  #18  
Old 07-28-2013, 01:23 AM
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Quote:
Originally Posted by KarTek View Post

Rolf,

The transducers are variable vacuum devices controlled by a PCM signal from the ECU. If you can do with a "on/off" control rather than variable one, you might do well with an EGR purge or "switchover" valve.
Is it 12v or 5v max? I've considered this as a poor mans control for VNT's. The hella VNT controller is expensive.
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  #19  
Old 07-28-2013, 04:28 PM
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Ok I believe i have finally come up with a diagnosis. when checking the scan tool, i noticed the mass air flow was at arounf 400mg/s and didnt really change even under full throttle, and according to mitchell, it should be 275-300mg/s idle and 1000-1200 at 30mph wide open throttle. i suspect faulty mass air flow, 300 dollar sensor will get it this week to confirm fix.
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  #20  
Old 07-29-2013, 02:21 PM
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Don't be too quick to condemn the MAF. On these cars, I have always believed it is strictly for EGR flow validation but I can see it would be logical to use MAF to determine max fueling for a given air flow. I'd like to see readings taken from an identical working car for comparison. There is a simple electronic bypass for the MAF that I'm running on my car. I can't remember all the details but there's a thread about it on here somewhere.

On the scan gauge, you should be looking at a max of about 15-16 PSI (reads about 28-29 because it's absolute) or 1+ bar for boost. If you check the vacuum at the wastegate, you should see full vacuum at idle (same as whatever you read at the vacuum source)
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  #21  
Old 07-31-2013, 11:17 PM
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You were right the mass air flow didn't change the sluggish very much at all. Didn't change the numbers either. I can't seem to find boost with my scan tool. But I did hook the vacuum lines together to eliminate the transducer with no change. I have a mitt vac can I use that to check vacuum on this waste gate. How so?
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  #22  
Old 08-01-2013, 05:43 PM
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this might seem silly but have you checked the boot between the intercooler and turbo? when that sucker comes off you dont get boost at all and you will have a VERY sluggish car. It's happened to me... they should have a clamp on it but it's just a friction fitting. this would be the bottom right side of the car.
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  #23  
Old 08-01-2013, 05:46 PM
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Quote:
Originally Posted by pnolet View Post
You were right the mass air flow didn't change the sluggish very much at all. Didn't change the numbers either. I can't seem to find boost with my scan tool. But I did hook the vacuum lines together to eliminate the transducer with no change. I have a mitt vac can I use that to check vacuum on this waste gate. How so?
If you remove the vacuum line on the waste gate and hook it to the vacuum port on the mit-y-vac, it should register on the gauge how much vacuum is present.
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  #24  
Old 08-01-2013, 10:04 PM
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Saturday I am removing the intake for inspection and cleaning and a search for the source of my bubbles! I'll inspect them while I'm in there. On a side note I swapped the transducers and now the car is even more sluggish, what could this mean?
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  #25  
Old 08-02-2013, 01:05 AM
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Originally Posted by TMAllison View Post
Check transducer and wastegate, then for a plugged/restricted cat.
I swapped transducers and the car accelerates worse. Could this be an egr transducer problem or is my thought process incorrect? How pricey are these suckers? Thanks TM

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