Car Idle's at 2500 RPM, HELP!
 

Hi guys,

I just bought my dream car last week:). It's an RX7 FD3S Twin turbo and love everything about it! until now......

Two days ago the alternator was burnt out, so that was replaced....no problem.

Now when I start the car it revs up to 2500 rpm and stays there...even when it's hot it still stays at 2500 rpm....it's burning very rich too...:(

I looked at the forum and looked for vacuum leaks and if someone can put me out of my misery and tell me by this picture (quite poor) if two of the pipes are used for anything or not?

P.S second pipe is located right next to the threaded bolt and both of them dont lead to anything (which I'm sure is not right)

Cheershttps://cimg3.ibsrv.net/gimg/www.rx7...7dcaafffdc.jpg

If you don't find any vacuum leaks check the tos I have had issues like this.

Have you visited the Third Gen FAQ? To a new owner, the FD's turbo control system is a nightmare and have instigated many a single turbo conversion. However, I've never been a fan of branding the twins as "junk" based on erroneous/false information. A consistent high idle and running excessively rich sounds like a big vacuum leak somewhere around the Upper Intake Manifold (UIM) and Lower Intake Manifold (LIM). IIRC, the Third Gen FAQ has vacuum diagrams for the stock setup, simplified sequential and single turbo conversions.

Since it appears as a vacuum leak, the first thing I would check are the lines and solenoids connected to the UIM/LIM. If a solenoid leaks, it allows un-measured air into the engine. ECU says "hey, this air/fuel ratio isn't right for this intake pressure" and dumps in fuel to try and get it back to normal, but the idle rpm is increased as a byproduct. By the symptoms of it and how high it is suddenly idling, it sounds like one that would be connected to the front turbo inlet. See the vacuum diagrams to get a better idea. Be aware that if a solenoid isn't FLAWLESS in how it operates (opens/closes instantly and holds pressure AND vacuum), it is garbage and needs replaced. I'm not gonna lie to you, you're in for the most annoying and often maddening part of owning a FD: the dreaded vacuum hose job. Silicone is your friend here.

If you've not added a boost gauge yet, do so now. It is an invaluable tool in diagnosing issues in the turbo control system. Even a simple no-frills mechanical gauge with a vacuum line running from the engine will give you priceless information. Mine was $17 from Harbor Freight

Thank you for this! Really have helped, I took the car into a specialist yesterday and what we found was we were able to.manually put the idle back to 700rpm but once you put your foot down on the throttle (even a little bit) the idle would increase everytime. So I've bought a new throttle body to see if it's due to the primary butterfly valve is leaking air though.