high idle and running rich
11-05-2006, 07:58 PM
#1
Thread Starter
Join Date: Oct 2006
Posts: 44
high idle and running rich
well i just got done my head gasket and now its running rich and high idle at times. Car is a 91 mercury cougar 5.0 ho/auto.
ive cleaned the iac(is new so wasnt that dirty) ,the mas airflow sensor, and also cleaned the throttle body. i pulled the code only one i got was 13 cannot control rpm?? Is this a vacum leak?? or what ? Anyhelp is appreciated david
ive cleaned the iac(is new so wasnt that dirty) ,the mas airflow sensor, and also cleaned the throttle body. i pulled the code only one i got was 13 cannot control rpm?? Is this a vacum leak?? or what ? Anyhelp is appreciated david
11-05-2006, 08:23 PM
#3
3rd Gear Member
Join Date: Nov 2006
Location:
Posts: 799
RE: high idle and running rich
Check your ECT sensor and all the connections at the iac, i bet the iac is stuck. Also engine coolant temperature causes a high idle and makes it run rich since its harder to vaporize the fuel in a cold motor.
11-06-2006, 05:43 AM
#5
4th Gear Member
Join Date: Nov 2006
Location: PA
Posts: 1,234
RE: high idle and running rich
ECT = Engine Coolant Temperature
The ECT sensor relays engine temperature to the computer.
I found a partial in an EEC-IV manual i have that just happened to use the ECT as an example.
"If the ECT signals an infinite resistance, as in an open, the control module ignores the input, which would otherwise drive the air-fuel ratio very rich. In that case, the FMEM (Failure Mode Effects Management) switches to a fixed resistance value for the ECT,allowing the warm engine to operate as a warm engine...at the same time, the control module turns on the 'Check Engine' light warning...Do not expect a cold engine to start properly with a fixed warm FMEM signal for a cold engine...FMEM is programmed to remember the ECT signal just before the failure and continue at that input value."
The ECT sensor relays engine temperature to the computer.
I found a partial in an EEC-IV manual i have that just happened to use the ECT as an example.
"If the ECT signals an infinite resistance, as in an open, the control module ignores the input, which would otherwise drive the air-fuel ratio very rich. In that case, the FMEM (Failure Mode Effects Management) switches to a fixed resistance value for the ECT,allowing the warm engine to operate as a warm engine...at the same time, the control module turns on the 'Check Engine' light warning...Do not expect a cold engine to start properly with a fixed warm FMEM signal for a cold engine...FMEM is programmed to remember the ECT signal just before the failure and continue at that input value."
11-12-2006, 08:50 PM
#6
Thread Starter
Join Date: Oct 2006
Posts: 44
RE: high idle and running rich
update ive replace the thermostat temp is down, replaced the fpr and the running rich is pretty much gone now ive got the idle problem still. it will idle fine till it gets warm. id hit the gas and it just hangs at 2k rpm and doesnt fall. I plugged the egr and it pretty much didnt do it till i shut it off then back on. Any ideas for this one. thanks guys im almost there car ran great took it for a ride and drove great.
11-12-2006, 08:51 PM
#7
Thread Starter
Join Date: Oct 2006
Posts: 44
RE: high idle and running rich
also iac is new and also the ect is withing ohm range for the temp its at. so that being said is my egr causing the problems or do you think the tps is gone? i also tested that and seems withen range.
