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Old 09-02-01, 08:02 PM   #1
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symptons of a faulty internal wastegate?

What are the symptons of a faulty internal wastegate? I'm trying to figure out what's wrong with my car and a fellow rotary head mentioned this as a possibility.
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Old 09-02-01, 09:09 PM   #2
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ummm...

stuck open - no boost! (or maybe a little bit)

stuck closed - too much boost!
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Old 09-02-01, 11:18 PM   #3
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Here's my stab at it..

You're making good boost (according to an aftermarket boost guage right?)
You've done the throttle body mod and so the secondary plates are not the problem..
You've got an upgraded fuel pump and running 720 injectors in the secondaries..

Okay..
If you are making good boost, your wastegate shoudl not be the cause of your lack of power, as Gene mentioned. if the wastegate wasn't working as it should you would be seeing uncontrolable high boost, or really poor boost buildup..
The other thing that affects boost would be the twin scroll system.. But from you're description of the problems I would doubt it's the twin scroll either..
Have you checked your ignition timing and the boost sensor? I would assume those were a couple thing syou have checked long ago..
So what does that leave? in my opinion I would start checking you initial tuning of your car.. It could jsut end up that you are running overly rich with your set up .. doing so will definitly make power sluggish (blowing flames out your exhaust, backfireing etc do not necessarly need to happen if you are runnign too rich to be making proper power)

You mentioned you have a s-afc installed in your car right? What mods do you have (injs, fuel pump, etc) what are your correction settings on your s-afc for both high and low throttle settings, what is your low and high throttle point set at? what are the initial settings you have selected under the etc menu?
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Old 09-03-01, 12:54 AM   #4
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Quote:
Originally posted by Chris Ng
Here's my stab at it..

You're making good boost (according to an aftermarket boost guage right?)
You've done the throttle body mod and so the secondary plates are not the problem..
You've got an upgraded fuel pump and running 720 injectors in the secondaries..

Okay..
If you are making good boost, your wastegate shoudl not be the cause of your lack of power, as Gene mentioned. if the wastegate wasn't working as it should you would be seeing uncontrolable high boost, or really poor boost buildup..
The other thing that affects boost would be the twin scroll system.. But from you're description of the problems I would doubt it's the twin scroll either..
Have you checked your ignition timing and the boost sensor? I would assume those were a couple thing syou have checked long ago..
So what does that leave? in my opinion I would start checking you initial tuning of your car.. It could jsut end up that you are running overly rich with your set up .. doing so will definitly make power sluggish (blowing flames out your exhaust, backfireing etc do not necessarly need to happen if you are runnign too rich to be making proper power)

You mentioned you have a s-afc installed in your car right? What mods do you have (injs, fuel pump, etc) what are your correction settings on your s-afc for both high and low throttle settings, what is your low and high throttle point set at? what are the initial settings you have selected under the etc menu?
Alright, now we're getting somewhere. Mods are dp, mp, catback, walbro, tb mod, new vacuum hoses, bov, and SAFC. Still running stock injectors in primaries and secondaries. I have not tuned the SAFC yet and am currently running ruch, flames and all. Thing is before I upgraded the exhaust and fuel pump, car still had the same problem. So I don't think tuning is the main issue. As far as settings go, I selected 4 cyl, and for throttle sensor type, the arrow starts at the bottom left and points diagonally to the upper right. Closed throttle 0V-1V and open 3V-5V. Timing is on but I've never checked the boost sensor. How do I do so? New plugs and wires as well. Also, in a previous post, you mentioned how you tied your SAFC into your boost sensor so it was boost as well as rpm dependant. How did you do that as well? Seems like a safer setup. Thanks for the thorough response Chris. Have you ever heard of these cars being equipped with lame ecu's? Think that's a possibility?
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Old 09-03-01, 02:00 AM   #5
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The ECU would be the last thing I would suspect.. if something is wrong with it then it would jsut result in inncorect fueling and/or timing.. Do you have an a/f meter? do you have any idea how rich ou are running when you get on boost? I would still lean towards an improper tune situation.. wether it was caused by some other component failure or a failure of the ecu.. You can basically rule out any mechanical problem since anything mechanical that could cause low power/good boost has already been ruled out..

As for the hookup of the s-afc, I replied to your priv e-mail a few days ago with detailed info on the hookup, as well as how you can use it to monitor your a/f levels..If you didn't recieve it, I can see about sending it to you again..
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Old 09-03-01, 01:09 PM   #6
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Thanks for the response to the pm. I do have an a/f guage, but I can't say exactly how rich I'm running. Just rich. All the way over into the green when I get on it. Just cruising around town, it's usually just a little past stoich, but still all the way in the green. It's an Autometer a/f guage. New O2 sensor as well so I should be getting a fairly good reading. Thanks for trying to help me out with this, and if you can think of anything worth trying, I'm definately willing to. Oh yeah, how do I check the boost sensor?
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Old 09-03-01, 01:09 PM
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boost, faulty, hp, internal, low, mazda, mod, open, opening, power, rx7, stuck, symtoms, wastegate, wastgate

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