Idle speed? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

the_scotsman · 10-13-2002, 01:53

I have 88 Falcon S MPI 3 spd auto.
What speed should the engine idle at?
I can't remember off hand, but I think mines is a bit low, about 450 RPM.
Also, after reading a similar post about someone having a problem of the car stalling in drive, mine too stalls now and again in drive or reverse when I am not moving, say sitting at the lights or in Maccas drive through queue!

I have a gregorys, I assume this will tell me how to adjust the base idle speed?

Thanks

David

10-13-2002, 02:07

Your car idle should be at about 650RPM... and you should probably go buy one of those engine analystic multimeters which show accurately your RPM speed. They are about $80 from Jaycar.

To set your hard idle there is a screw on the side of the intake manifold next to where the accelerator cable is that screws in and out.

Turn it until the right spot is reached to get your idle of 650RPM. If you can't reach that RPM or it keeps changing by itself, that means one of your sensors or idle speed controller is faulty.

the_scotsman · 10-13-2002, 02:22

Ok thanks, I'll check that in the morning...actually, I think we have one of those engine multimeter thingys, it shows rpm.
The car doesnt idle very smoothly, it sometimes blips a bit, or rises and falls in a rythm, moving about 50-100 rpm either way.
Guess one of those sensors is faulty then!

Thanks!

sleepwalker · 10-13-2002, 06:46

Just remember to adjust the idle speed when your engine reaches the normal working temperature. If you adjust it when its cold, it's gonna stall when it warms up.

the_scotsman · 10-13-2002, 20:17

Ok, I connected up the external tach that i found in the shed

In adjusted the idle speed to about 700. Now the car idles at about 700 for about 20 seconds, then falls to almost 400 again...so i tried adjusting again, same thing happens.
I ran the diagnostics check, all ok, got the 11 signal.
The idle is not very good, its a really rough idle, it stutters now and again, also, the revs climb about 50 revs, then fall again after 5 or 10 seconds...wehat would be a possible cause of this? I know the plugs and leads are ok,, could it be the dizzy? I have no idea when it was last replaced. Any of the sensors gone maybe?

Please help, its not a big thing, but it's VERY annoying having a really uneven, rough idle, it doesnt sound nice at all!

Thanks!

Oh yea...I am doing all this when the engine is hot!

10-14-2002, 02:22

If it's dropping in RPM by itself then I'd say it is one of the sensors, simply for the fact the ECU keeps adjusting the idle speed so that it's lower.

I don't know which sensors would affect the idle speed, but you should probably try the MAP sensor and Oygen sensors and see if they are the problem.

the_scotsman · 10-14-2002, 02:58

ok thanks for the help.
is there a way i can test them or do I just need to go out and buy new ones?

Thanks

sleepwalker · 10-14-2002, 06:05

How long have you had the car? Maybe the last owner changed the cam. Aftermarket performance cam usually have rough idle.
The oxygen sensor can be easly checked if its faulty by measuring the voltage. Check that in the Gregorys. If you haven't got it , let me know and i'll look it up for you. Check the MAP sensor connector. Make sure that its clean.
Theres a ton of things that might cause this. Also check the fuel filter, see if it's blocked.

TopGhia · 10-14-2002, 11:51

Yeah, check and clean the connectors to the sensors, especially the O2. A lot of sensors are replaced when the only fault was high resistance in the connectors. A bit of dielectric grease (Jesus in a Tube) around these things is a big help too, (after they are clean)