This is topic cant get car to idle right in forum Tech Talk at Northern California Ford Owners  .


To visit this topic, use this URL:
https://californiafords.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=017710
Posted by Adam5.0 (Member # 6995) on :
 
i just put in a 306. I set fuel pressure a 40psi with no vacuum. I move the #1 piston to tdc and i cant get it to idle at the right speed without dying with the timing set at 10 degrees. when it is set at 10 it doesnt want to idle below at about 1000 rpm. i have adjusted the idle screw to get it to idle at the right speed the car will just die. the only way i can get it to idle is with the timing set at 0. with the timing set at 0 it does have a little bit of a surging problem. any input would help thanks.
 
Posted by Adam5.0 (Member # 6995) on :
 
a little more info. the motor will surge from about 700 rpm to 1200 rpm then settle down at about 900 rpm then start surging again and then eventually stall. checked tps and IAC both checked out ok.
 
Posted by TOPnotch (Member # 1340) on :
 
Vacuum leak
 
Posted by 92stangLX (Member # 3252) on :
 
quote:
Originally posted by TOPnotch:
Vacuum leak
big one [Smile] Check your upper to lower intake gasket and make sure it is seated properly.
 
Posted by Adam5.0 (Member # 6995) on :
 
double checked vacuum lines couldnt find anything. if it is a vacuum leak why would the idle be stable with base timing set at zero?
 
Posted by TOPnotch (Member # 1340) on :
 
The 5.0 cars tend to idle surge and do funny things when the tps voltage is out of range. If the car has an aftermarket cam you probably have the throttle blade open too far to get the car to idle and the tps voltage is over 1v Then you are compensating for it by retarding the timing. Put the initial timing off the crank back to 10 btdc thats where it should be. (with the spout connector un plugged of coarse) Adjust the idle and tps voltage from there. You will most likely have to slot the holes in the tps sensor to get it in range. You are looking for just under 1v at idle like .9 ect

Try that if you haven't yet

[patriot]
 
Posted by Blind (Member # 3052) on :
 
quote:
Originally posted by Adam5.0:
double checked vacuum lines couldnt find anything. if it is a vacuum leak why would the idle be stable with base timing set at zero?
how much vacuum do you get at idle?
 
Posted by Adam5.0 (Member # 6995) on :
 
i have a tfs stage 1 cam with 1.7rr. i havent hooked a vacuum gauge to it yet. i gonna try to play with the idle screw and tps some more. thanks for the help
 
Posted by 89saleen (Member # 3083) on :
 
Check the Idle Air Bypass solenoid- aka IAB..(the thing on the side of the EGR spacer)first check to see if its clogged with carbon, second see if it has smooth operation and isnt sticky, also try unplugging it & see if it affects the surge. Ford does make a plate to adjust the airflow to it, but I made my own; I cut out a gasket with smaller air holes to meter the air.. seemed to help my surge. Ive found that the IAB dosent deal well with aftermarket cams. Good luck.
 
Posted by BCINGUU (Member # 2397) on :
 
Be careful tampering with that idle screw. It can be very difficult to reset to the factory setting if you ever want to do that, which you probably will once you solve your idle problem.
 
Posted by Stan G (Member # 6226) on :
 
If you don't have a vacuum leak,

I think you're supposed to :

1. disconnect the battery, step on the brake 3 or
4 times to reset the ecu ,
reconnect the battery
2 warm up the car
3 disconnect the iac
4 set the idle speed using the idle adjust
screw.

5 plug the iac back in .

The computer will adapt after a while to what you set the idle to, but it may hunt for a while .

I think mine took a few days till It worked ok
 




Fueled by Ford Mustang Owners
on CaliforniaFords.com