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.

 

Check for vacuum leaks, you must have a huge one.

 

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.

 

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.

 

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.

 

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.

 

Hey Bryce, how will that damage the turbo. I just want to know.

 

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.

 

The brakes power booster works off of vaccume.