Crossfire Fast Idle
Thread Starter
Intermediate
Joined: Jun 2007
Posts: 35
Likes: 0
From: Bandon Oregon
Crossfire Fast Idle
I have an 84 with all stock crossfire system. At cold idle when in closed loop it idles around 1400. When the ECM kicks in it goes down to 1000. I replaced the TPS. When checking fuel pressure I found it was running 19 pounds. In checking the FSM it says check for return line blockage,,(I did) or replace the pressure regulator. I see references in this forum about adjusting fuel pressure....are you installing an inline regulator or am I missing something......?
Instructor
Joined: Jul 2007
Posts: 229
Likes: 0
From: FT Lauterdale Florida
I think you can get a ajustable fp regulator, that or you can modify your own on the car to make it ajustable, but its possible to mess it up when removing the block off plate,
every one tells me that my low idle on my crossfire is caused by a intake leak somewhere, wether it be in the throttle boddy shafts or on the intake it self, extra air is getting in somewhere.
where did you check the fuel preassure? I believe the first throttle boddy the fuel line runs to has the fuel preassure regulator there, so fuel leading up that line can have more preassure than the tb will actually see.
it is my understanding that a real rich fuel mix will not cause the idle speed to increase, it would just cause a poor idle. - but air leaking in the system some how will how ever cause the computer to read like you are giving throttle imput and boost the fuel supply to meet the air fuel ratio desired.
im not making sence to me.
sorry its past my bed time.
hope you get it worked out.
every one tells me that my low idle on my crossfire is caused by a intake leak somewhere, wether it be in the throttle boddy shafts or on the intake it self, extra air is getting in somewhere.
where did you check the fuel preassure? I believe the first throttle boddy the fuel line runs to has the fuel preassure regulator there, so fuel leading up that line can have more preassure than the tb will actually see.
it is my understanding that a real rich fuel mix will not cause the idle speed to increase, it would just cause a poor idle. - but air leaking in the system some how will how ever cause the computer to read like you are giving throttle imput and boost the fuel supply to meet the air fuel ratio desired.
im not making sence to me.
sorry its past my bed time.
hope you get it worked out.
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Your idle should be around 500-600 at warm idle which is slightly higher than the GM manual says. 19psi FP is rather high for a stock CF motor if it is stock. The FP is normally checked inbetween the two TBs. If you want, send me mail and I'll send you more info on that.
The FP can be changed via the rear TB under the tower. You must remove the anti-adjust plate in the bottom of the regulator first before you can adjust the FP. On a stock motor, 14psi works just fine and the ECM can handle it with no problem.
Your higher idle could also be your CTS sensor in the front of the intake manifold. If you have the original sensor, replace it with the newer two pin weather pack style. The higher idle could also be caused by the TBs not being balanced correctly and or the TB shafts are leaking and causing a vacuum leak. Send me mail and I'll give you more info on that as well.
Good luck.
The FP can be changed via the rear TB under the tower. You must remove the anti-adjust plate in the bottom of the regulator first before you can adjust the FP. On a stock motor, 14psi works just fine and the ECM can handle it with no problem.
Your higher idle could also be your CTS sensor in the front of the intake manifold. If you have the original sensor, replace it with the newer two pin weather pack style. The higher idle could also be caused by the TBs not being balanced correctly and or the TB shafts are leaking and causing a vacuum leak. Send me mail and I'll give you more info on that as well.
Good luck.
