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Troubleshooting *Second turbo not boosting*

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Old 01-29-03, 11:30 AM
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OE2
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Troubleshooting *Second turbo not boosting*

Im relatively new to the boards but I have been lurking for a while. I registered so I could search but I am not finding the answers im looking for.

Mod's are cb,mp,dp, smic, pettit ecu, home depot boost controller, and a boost gauge.

i run a mix of 110 octane and 93 and can't get the second turbo to fire. at higher rpm's it just sputters then i get out of it so as not to do any damage.

within the next month I will be picking up a PFC and commander.

My question is do you think it's as simple as a vac leak or something more serious (turbo going bad) the car has 30k miles on it
'93 touring

Thanks for the Help
O
Old 01-29-03, 11:46 AM
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it could be a vacuum leak. one of the most common problems is the coupler off of the y-pipe splitting. i would check that first. i don't know what you mean when you say you can't get it to fire. what is your boost pattern?
nick
Old 01-29-03, 12:06 PM
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Yeah, the y-pipe coupling is a common problem but usually affects both primary and secondary boost. As nmo93 said, what's you're boost pattern. A good place for help when toubleshooting boost problems is here...

http://www.autosportracetech.com/RX-7/rx7stuff.htm

Basically, check all hoses, solenoids, and actuators. If they're all working fine it might be a turbo problem.
Old 01-29-03, 12:15 PM
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OE2
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Sorry guys what I mean by firing is that ususally i can feel the kick around 5k-6k rpm of the second turbo. Now I can't it just a sputtering feeling then I back off. I will get you the boost pattern when i have a chance the car has been sitting for a while with this cold weather.


thanks for the site Im hoping it's a hose problem, im going to get the hose techniques 'kit' and do some preventative stuff.

O
Old 01-29-03, 01:02 PM
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as soon as you get me your boost pattern i'll be able to help more. when i had problems i was able to get a full 12 lbs of boost on the primary, then only 7-8 on the secondary. i did the vacuum hose job but also replaced the 1" hose that goes to the crv. before i replaced it i put a screw clamp on and tightened it all the way down. and i was still able to twist the hose back and forth. as soon as i replaced it after the hose job i was able to hear that "whoosh" of air before 3500 rpms that you are supposed to hear. i'm glad i did the hose job but i feel that it was that hose causing the problems. my point is to check the easy things first.
nick
Old 01-29-03, 02:11 PM
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Its too easy to replace the vacuum lines near the turbos and intake piping so bust those out first to eliminate them as a problem area.
About 4' feet of some of silicone hose and you can bust all those out in about an hour and if it still isnt the problem then you will have elimnated it and you can get ready to do the ones under the Intake Manifold. Also check vacuum lines to the Vacuum & Pressure Chambers. The above things were my problems. my $.02
Old 01-29-03, 04:35 PM
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similar boost problem

Hey, I also experience the same problem and have written a couple of times to the forum for some help and haven't recieved much. I experience about a 12lb-7-back to about 7 or 8lb pattern and I can't figure out why.. My turbos have 87k on them, but the first one seems to spool up and pull real hard. My sequential is working properly, i think, becuase when i pull a couple of the crucial hoses they release pressure when i pull them off. could my 2nd turbo just be going bad, or could someone lead me right to a relatively quick and simple fix.. any help i would greatly appreciate.
Thanks.
Old 01-29-03, 04:54 PM
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Gil: It could be your 2nd turbo going bad, but you'll want to eliminate all other possibilities first. If you have checked all hoses, solenoids, actuators, and the vaccum and pressure chambers (thanks HeatTreated, I forgot those in my last post) then you might want to check the turbo.

The link I posted above, along with the shop manual, gives a pretty good idea of how to check all those things. Be systematic. Keep notes (otherwise you'll end up checking the same thing twice). You can still keep your fingers crossed that someone here has experienced the exact same problem and can point you to the exact solution, but while you're waiting for that, start checking all the things I listed.

I had a similar problem and checked EVERYTHING. Turned out it was just my altitude (I'm at 7000ft), and I needed a home depot boost controller. You can check out my troubleshooting log here...

http://www.geocities.com/laracers_vr..._problems.html

Good luck
Old 01-29-03, 05:20 PM
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get some BNRs...
Old 01-29-03, 05:58 PM
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mines happens sometimes..but sometimes it boosts hella good. then sometime, it just spikes.
Old 01-29-03, 06:54 PM
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when my vac hose job was done a bunch of selenoids were replaced and 2ndary worked much much better. hopefully it is only that. good luck.
Old 01-30-03, 06:56 AM
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LAracer,
Thanks a whole lot for the help. Those links look real informative. I am hoping that this weekend i can delve into trying to find the cure to my ill performing car. I would like to purchase some BNR's but i want to make sure that i cannot fix the ones i have and get a little more life out of them.. Once again thanks for the help and I'll be sure to keep you posted,
Gil
Old 01-30-03, 11:15 AM
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My turbos are old and the secondary has oil leaking from it.. but after I replaced the hoses I mentioned above and zip tied them (my BOV hose was leaking boost) man the secondary pulls. I really think its a hose problem.
Old 01-30-03, 11:22 AM
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es
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Check valves...
Old 01-30-03, 10:01 PM
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yes it may be check valve, same thing happened to me with the second turbo, it was the green check valve connected to the black chamber the one on top the check valve was cracked
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