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Q&A regarding engines, turbos, and intercoolers and power upgrades
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ST-185 Sluggish before turbo spools

Tue Oct 03, 2017 12:02 pm

Probably a stupid question, but here it goes:

93 'trac, essentially bone stock with 155k miles. Newer plugs, wires, cap (18 months ago), new cat (2 weeks ago), all major services done/updated/taken care of by and large. Great car...runs really, really well.

Except for the last few weeks - whether the engine is cold or hot, engine feels like it bogs down significantly/loses power UNTIL the turbo spools and then it responds great - like always. I've done the usual checks and tests (per all the discussion I've seen and searched through in other posts in the forums) but I am stumped.

Could it be the 02 sensor? They've probably seen better days. Maybe the EGR valve? Of late, she smells like she's running a little rich.

Open to thoughts or things I should investigate and try - hopefully it's nothing major. This think has gotten a significant overhaul this year - can't afford much more!
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Re: ST-185 Sluggish before turbo spools

Tue Oct 03, 2017 3:19 pm

Sounds like it's running rich, maybe the O2 sensor or a pre-O2 exhaust leak. Try unplugging the sensor and see if it gets any worse?

Re: ST-185 Sluggish before turbo spools

Wed Oct 04, 2017 12:11 am

Unplugged the O2 sensor and it’s a bit worse (driven about 25 miles disconnected). I can always replace my to see if that helps matters. Only noticed it after the cat was replaced two weeks ago - but we’ve double and triple checked and no leaks or issues with the cat thus far.

Re: ST-185 Sluggish before turbo spools

Wed Oct 04, 2017 7:05 pm

Take a look at the spark plugs and if they are black on the ends your running rich and that can point at what underscore suggests.

Have you tried a compression test or leak down test?
Also , verify the engine timing

Re: ST-185 Sluggish before turbo spools

Thu Oct 05, 2017 3:32 pm

Have you checked the compression of each cylinder?
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