hi, i own a 3dr cossie, its got a PJ stage 3 conversion and is now running a 4x4 escort cosworth engine.

now i have a problem with the idle speed, it wont go lower than 1200 rpm, the base idle has been set up and when the plug is put back on the engine revs then settles at 1200 rpm.
the idle valve has been swapped for another yet still happens.
is there a sensor that controls this or what else could it be?

cheers

 

was the base idle set with the engine at normal operating temp?

 

yes base idle was set after fans had cut in.

if the engine coolant temp sender was playing up and telling ecu it was cold would that make the idle high?

 

Would have thought so,but if coolant temp sensor was gone it would be overfueling like mad at idle when warm,is it?????

 

check your iscv could be need of a clean

 

as per original description, this has been changed already.

it does seem to over fuel and use more than the last stage 3 cossie i had.

will try another ECT sensor

 

Have you turned the Idle screw or has the screw fallen out ?

Make sure the TPS and ACT is in good working order.

 

How do i know if TPS and ACT sensors are working correct?

 

can be checked with a multimeter switched to ohms reading the TPS via the two outer wires.

ACT same as but with only two wires.

all the sensors can be checked with a meter one way or another.

 

you say you have fitted a new idle valve, check you have the correct one, as there are to types which look exactly the same, check the top of the valve there should be a stamp on the top, if your new valve has a different number than the old valve try swaping the wires around in the isv loom plug and see if it makes any differance, had the same problem on 2wd sapp, turned out that the new valve was for escos swaped wires around and was fine.

 

mate, my car was doin exactly the same.when you disconnect iscv does it tick over at about 850rpm?have you had to jump start it recently? what ecu are you running? mine was the ecu was fucked and i had to change the ecu AND iscv to get it to tick over correctly,try and borrow a ecu and another iscv and see if it makes a difference

 

Both the above statments do not sound right.

If and ECU is fooked. Its fooked, as in wont even start. If it was another problem with the ECU it will not effect the ISCV apart from making it tick as it is connected to the same wire that is used for the fuel pump and a few other sensors.

If the Air to Fuel ratio is wrong or out of adjustment etc.. it could lead to hunting as will some sensors being U/S.

Get it to somone who can check it all out with diagnostics equipment.