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No boost - I'm stuck

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Old Mar 15, 2012 | 08:28 PM
  #1  
jon8rfc's Avatar
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1993 Red RX-7 Touring
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From: Austin, TX
No boost - I'm stuck

On 2012-03-14, I was lightly accelerating under a little boost from about 10-15mph (7-8psi at most), then I heard a loud pop and lost all boost. That's where it all started. I put the hose back on, but I'm still without boost. Did I kill one of my turbos?

I drove the car home after I lost boost, and when trying to accelerate from a near stop on the highway, the car died--I'm not sure if I was in 3rd gear or not though, so that may be irrelevant.

Issues/troubleshooting:
**I reseated the hose, no resolution.
**I swapped out my stock intercooler to the Greddy SMIC with new piping and hoses--no resolution.
**I have a Pettit Y-pipe, so there isn't the connector hose, I believe.
**Checked my blow-off valve--it's fine.
**Vacuum under swarm-up is 19-20in.
**I'm running a bit richer at warm-up compared to normal...low 12s now. (I can't recall AFR on the highway on the way home)
**I smell raw fuel under the hood, not so much out the exhaust.
**My oil has always smelled heavily fueled, but I think that's due to running overly rich until recently. This new raw fuel smell is VERY strong and VERY noticeable, aside from my oil.
**Looked at all the vacuum lines I could see and hoses I could see, which all appear fine.
**When revving and releasing, the BOV functions, but I can't remember how much air used to come out before this happened. It did sound quieter when I tested last night, however.

Relevant details of car setup:
**1993 Touring with stock twins in sequential setup at ~110-113k miles (odometer is out)
**Motor rebuilt at Rotary Performance at 103k
**"Rat's nest" was overhauled/reduced during the RP rebuild
**One/both turbos are leaking some oil, but not terribly; I was told by RP and Alamo Rotary that my secondary is on its way out.
**Pettit blow off valve (stock BOV is still there, never had issues)
**Pettit Y-pipe
**Pettit Blueprinted Charge Control Valve (what part is this, and could this be related?)
**Pettit TKT Cold Air Intake
**RP high-flow fuel pump

Please forgive me, I've received some medical treatments the last 5 months and my memory has gone kaput, so the most history of the car I can share without cluttering the thread--including all modifications--is listed here:
http://jon8rfc.homeip.net/rx7

Any thoughts?

I'm at a loss since I don't know RX-7s or turbos as well as y'all. If anybody happens to live in Austin (I'm at I-35 and Yager/Tech Ridge), I'd be happy to buy you a meal and some beer if you can help me troubleshoot one evening.
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Old Mar 15, 2012 | 08:54 PM
  #2  
AzEKnightz's Avatar
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From: California, SF
did you check your boost sensor to make sure the hose is plugged in?

-AzEKnightz
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Old Mar 16, 2012 | 04:35 PM
  #3  
jon8rfc's Avatar
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1993 Red RX-7 Touring
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From: Austin, TX
Originally Posted by AzEKnightz
did you check your boost sensor to make sure the hose is plugged in?

-AzEKnightz
The hose is connected and is displaying appropriate values in my PowerFC. The BOV will expell air, so it seems like the primary is working, but I don't understand why boost never goes above atmosphere.
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Old Mar 16, 2012 | 05:29 PM
  #4  
DaleClark's Avatar
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You've got a boost leak SOMEWHERE. Anywhere pressurized air goes through could be the culprit - loose hose clamps, flanges that got something stuck between them and won't seal, throttle body elbow on finger-tight, something. That's the only way to get no boost.

If the turbos were so bad they weren't generating boost you'd probably have god-awful noises and smoke to go with that.

Dale
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Old Aug 12, 2012 | 06:30 PM
  #5  
jon8rfc's Avatar
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1993 Red RX-7 Touring
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From: Austin, TX
Thanks for the tips. I looked under the hood, a LOT, and found that a hose in the rats' nest was broken. I started to disassemble the intake manifold so that I could get at the hose to replace. When I got a better look at it, I looked at the colored vacuum hose diagram and I'm pretty sure it's the one leading to the CCV. I think that hose just gave out because it was rock-hard, as I found multiple hoses were...so not all of them were replaced during the rebuild, I guess.

I couldn't get to a point where I could replace that hose myself, so I just decided that since my twins are the originals (with ~110k miles), that I should just swap them out. The car has been at Rotary Performance since July 17. It's getting a TD06, my FC2000 installed (which has been sitting in the box for a year) and many other things I've asked Chris to have done on the car. It should be coming back to me this week!

Thanks again for looking =)
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