Turbo boosting 2psi only, stumped. - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 06-15-2014, 09:42 PM   #41
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If the above doesn't work. How would I be sure the turbo is ok? Like I said before, I tried to clock it, but the c clips I saw I did not have a large enough snap ring pliers to get them apart. Plus all the rust and stuff, the thing would not budge. I suppose I could take it back off (holy moly what a pain) and pb blast the **** out of it. Maybe I can get it to budge.

Do you think if I take a picture of the housing you could tell if it's apart at all?
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Old 06-15-2014, 09:58 PM   #42
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Have you run a compression test?
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Old 06-16-2014, 07:02 AM   #43
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I have not, I will bring home the tester today from work.
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Old 06-16-2014, 09:03 AM   #44
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I've not read all of this thread, but is it possible you've overlooked the wastegate actuator?

check for play on the valve lever arm. If you can wiggle it at all, it is too loose.

IF the actuator is set too loose, the boost can be way off, as well as very sluggish. IF the turbo has a turn buckle push rod, pull the circlip off at the valve end and shorten the rod until the turnbuckle hole is one diameter shorter than dropping onto the pin without any pull on the rod. THat should be enough preload to make 6 psi, or so.

If no turnbuckle, wire the valve shut somehow and drive it. IF this is the culprit, wiring it shut will eliminate boost control, so use a bit of caution.

corky
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Old 06-17-2014, 12:23 PM   #45
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Ok, so I tied the wastegate open, removed the FMU, and took it for a spin. Full throttle at anything under 3k, the motor searches between 13.9-15.3 afrs. After 3k, it dumps fuel and runs an almost steady 11.5 afr. Now I have the 99-00 injectors in there, so that's understandable. But what I don't get is why it's surging at the lower rpm. Is because of the bigger injectors as well?

Any ideas?
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Old 06-17-2014, 12:24 PM   #46
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And I did what you said corky before I did the above, no change in boost.
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Old 06-17-2014, 12:26 PM   #47
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I now understand why everyone says to "get rid of the bandaids", and glad I didn't go that route.

Your low boosting issues aside, it would drive me nuts to not know why my car was at a certain AFR.

You sure you ain't knockin?
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Old 06-17-2014, 12:34 PM   #48
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I have not heard any pinging or anything. Only thing I hear is when I free rev the motor, once it gets close to idle, I hear a few knocks. I think it has something to do with the transmission because I don't hear it if I rev it at the motor.
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Old 06-17-2014, 12:49 PM   #49
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in before blown motor.
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Old 06-17-2014, 12:50 PM   #50
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So, you've ruled out the following so far:
  • boost leak
  • wastegate

And you say it's not the turbo or the injectors.

As suggested earlier, run it with the catalytic converter/mid pipe off. It will be loud, but all you need is one run to see if it will build boost with an open pipe.

Which spot are you using as your signal line for the rising rate FMU? I've had good results with teeing off the stock FPR.
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Old 06-17-2014, 12:52 PM   #51
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Yeah, I dunno. Like I said, I've had this car for a few months now so I'm still learning how the PO took care of it. It very well could be on its last leg. I don't think the knocking sound is in the motor though. I can hear it when I'm sitting the car, but not outside at the front of the car.
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Old 06-17-2014, 12:54 PM   #52
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It was tee'd off at the FPR after I fixed the lines. They had like a mini vacuum block thing with about 5 lines coming off it. I didn't think that was good. I will have to see if I can get the bolts loose on the catalytic converter. If I can't I may just sawzall it off. Might be trying that today.
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Old 06-17-2014, 12:56 PM   #53
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Clogged cat is starting to sound more and more likely
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Old 06-17-2014, 01:20 PM   #54
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Turbo boosting 2psi only, stumped.-cat2.jpg  
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Old 06-17-2014, 04:51 PM   #55
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Ummmmmmmmmm. How do I turn the boost down?

Cut the cat out, holy ****. Runs 8psi, afr spikes to 14.2 around 5k. Bad. Bandaid, I know. Will be fixing soon.

EEeeeeeeeeeee!!!! It works!

I cut myself pretty bad, but worth it! OMG the pull!
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Old 06-17-2014, 04:58 PM   #56
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Extend the threaded wastegate actuator arm a little bit, but make sure that it's still pulling on the wastegate to keep it closed.
If it's too loose (too long), it will essentially keep the wastegate open or open prematurely, causing you to lose spool.

14.2 AFR @ 8 psi is dangerously *lean*. Once the FMU sees positive pressure, your AFR should start dipping into 13 and continue to get more fuel down to 11's the more you get into boost.
Fix/adjust that first.
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Old 06-17-2014, 05:05 PM   #57
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Quote:
Originally Posted by FRT_Fun View Post
in before blown motor.
Quote:
Originally Posted by whinin View Post
Ummmmmmmmmm. How do I turn the boost down?

Cut the cat out, holy ****. Runs 8psi, afr spikes to 14.2 around 5k. Bad. Bandaid, I know. Will be fixing soon.

EEeeeeeeeeeee!!!! It works!

I cut myself pretty bad, but worth it! OMG the pull!

Well then!
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Old 06-17-2014, 05:12 PM   #58
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Quote:
Originally Posted by whinin View Post
How do I turn the boost down?
On the right side of the car's floorboard there is a pedal attached to the throttle body via a cable. When driving, press lighter on that pedal. If you are still getting into boost, depress the pedal even lighter.
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Old 06-17-2014, 05:15 PM   #59
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You gays. I mean guys.

I think why I was boosting that much was because the clip fell off the actuator arm and the actuator slid off the valve. But fixed now, car hits 6psi then pulls back to 5psi, all under 12.1 afr. Sometimes as rich as 11.0.
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Old 06-17-2014, 05:18 PM   #60
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If not and that has nothing to do with it I will still make the arm longer.

Above question deserved that answer diesel, I was just too excited. Literally shaking, I held my hands out and they slowly started twitching, then onto full on seizure. Way too much adrenaline going, but so happy we figured it out.
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