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Old 04-18-2008, 03:54 AM   #1
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Default High idle Trouble

Now that I have that outta the way, I would like a little help please. I have a 1990 Miata with a 1.8 out of a 97. I have a t3/t4 .63 with a 50 trip. I do not have a wide band o2, yet. I do have an air/fuel gauge installed. I have an SAFC 2. I am running the 1.6 ecu and cooling system from the 1990. The stock injectors and fuel pump are currently installed. I am waiting for 550cc RC's to come and I have a Walbro 255lph to install tomorrow. I do not know if my troubles are related but here they are. 1.) I have a seemingly erratic high idle, up to 2.2k rpm and 2.) my cooling fans do not turn on.

1.) The idle increases when I stop and, now that i think about it, seems to be related to the brakes. I noticed that if i pumped the brakes the rpm increases up to 2-2.3k rpm. My tuner/mechanic cannot check/adjust my timing due to unstable rpm. It also goes to the same rpm if i turn the AC on.

2.) I know the fans will not turn on b/c the fuse is blown. I tried a 20, 25 and a 30 amp fuse and all were blown immediately with the engine off. The car started as someone else's project and I'm manning up to the task of finishing it. I chose to purchase an external thermostat from advanced auto ($20 quick fix instead of trying to figure out the electrical demon). The fans are working when powered directly by a battery. Even though I think I've fixed this problem, I mentioned it in case they are related.

I tried to cover everything without being too long winded. As a side note, my gf named the car......... "Lennard Lorance" a.k.a. "Private Gomer Pyle" because of the headaches it has caused.
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Old 04-18-2008, 03:57 AM   #2
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Check for vacuum leaks, you must have a huge one.
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Old 04-18-2008, 04:10 AM   #3
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I had 3 when I first took it to my tuner. Hes a nissan/honda guy but he knows his stuff. My BOV was DOA so that my be my leak. It was an ebay special that will be replaced by a real Tiel.
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Old 04-18-2008, 04:14 AM   #4
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OT, but you don't need a Tial unless you plan on running some major boost, the kind of boost you could only push with a built motor.

So has said vacuum leak been fixed? Try taking the Bov off and sealing the hole with your hand.
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Old 04-18-2008, 04:33 AM   #5
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The leak is fixed, as far as I know. BTW I'm running 9psi so... yeah. I'll double check for leaks tomorrow. Thanks for your help.
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Old 04-18-2008, 05:20 AM   #6
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The other thing it could be is the idle speed control motor, but I'm not familiar with the 1.8 motors as far as that goes.

Remember a boost leak can over-spin your turbo and damage it.
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Old 04-18-2008, 07:03 AM   #7
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Quote:
Originally Posted by Bryce View Post

Remember a boost leak can over-spin your turbo and damage it.
Hey Bryce, how will that damage the turbo. I just want to know.
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Old 04-18-2008, 02:01 PM   #8
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Thanks Bryce. I googled and found out how to "clean" my idle air. I want to clean it before spending the ~$500 on replacing it. I am still confused on how the applying the brakes causes the idle to increase.
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Old 04-18-2008, 02:29 PM   #9
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The brakes power booster works off of vaccume.
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