Disregard my previous post about adjustable TPS for '94-'95 cars. Didn't work and I have since found out it can't work.
My 347/Y302/Steeda 18 cam/TFS Street Heat engine wouldn't idle. I made the TPS adjustable, replaced it with a new TPS, replaced my IAB motor, replaced the throttle body from 65 mm back to stock and a few other things to get by. What I had to do to drive the car was replace the short threaded rod (throttle stop?) with a bolt that I used to turn the idle up to 1500. Was my wife pissed...
After all, it is "her" car...
I decided it had to be the computer so I converted my whole MAF sensor/ computer set-up from 1994 GT to 1995 Cobra R. Not wanting to hook up my cold air induction if the whole Cobra R thing wouldn't work, I started the engine without the filter. The car ran perfect. Perfect.
Once again happy (because my wife now thinks I know what I am doing!), I hook up the air cleaner and cold air induction to the MAF and start the car last night. Hunting idle is back worse than ever before.
I drove her car into work today (many resources here for questions) and decided to start from the beginning. After searching this morning, I decided to set base idle with the IAC motor unplugged. Car still would not idle unless the idle was set to 1500. I removed the cold air intake and filter and, guess what, idle was smooth as could be. I dropped the idle down to 700 and it would run there all day. I hooked the filter up directly to the MAF and everything is still ok.
I think that the 90 degree bend just before the MAF was too much for the meter and it would not be accurate (or even close) at low flow rates. I (now) remember that a good rule of thumb for MAF sensors is a straight inlet at least 2x the diameter of the MAF meter before you can have bends in the intake tube. My 80 would need at least 160 mm of straight pipe leading into the MAF and I had less than 100.
Wife has concluded that I do not know what I am doing.
Thoughts????
My 347/Y302/Steeda 18 cam/TFS Street Heat engine wouldn't idle. I made the TPS adjustable, replaced it with a new TPS, replaced my IAB motor, replaced the throttle body from 65 mm back to stock and a few other things to get by. What I had to do to drive the car was replace the short threaded rod (throttle stop?) with a bolt that I used to turn the idle up to 1500. Was my wife pissed...
After all, it is "her" car...
I decided it had to be the computer so I converted my whole MAF sensor/ computer set-up from 1994 GT to 1995 Cobra R. Not wanting to hook up my cold air induction if the whole Cobra R thing wouldn't work, I started the engine without the filter. The car ran perfect. Perfect.
Once again happy (because my wife now thinks I know what I am doing!), I hook up the air cleaner and cold air induction to the MAF and start the car last night. Hunting idle is back worse than ever before.
I drove her car into work today (many resources here for questions) and decided to start from the beginning. After searching this morning, I decided to set base idle with the IAC motor unplugged. Car still would not idle unless the idle was set to 1500. I removed the cold air intake and filter and, guess what, idle was smooth as could be. I dropped the idle down to 700 and it would run there all day. I hooked the filter up directly to the MAF and everything is still ok.
I think that the 90 degree bend just before the MAF was too much for the meter and it would not be accurate (or even close) at low flow rates. I (now) remember that a good rule of thumb for MAF sensors is a straight inlet at least 2x the diameter of the MAF meter before you can have bends in the intake tube. My 80 would need at least 160 mm of straight pipe leading into the MAF and I had less than 100.
Wife has concluded that I do not know what I am doing.
Thoughts????