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I just installed 42# inlectors and had the mass air flow meter recalibrated. Im sure I dont have any vacuum leaks, but I could be wrong but my engine will not idle below 1200RPMs. Is this normal with a high compression 306 ci? my compressoin is 10.0:1. cam is a comp 544 lift 218 in 224 ex @ .050. I did set tps voltage at .99 volts but when I disconnected the battery to clear all the codes I did not relearn the ECM. could this be a problen? What are some of your engine idle speeds? :confused:
Are you sure the TPS is not holding the throttle open a little to get that voltage reading. Have you tried the manual idle screw to bring it down. I idle at 825-850rpm
The mandated idle speed within the ECM is 575-850 rpm and is trimmed accordingly internally. The screw on the TB is a minimum air adjustment, which corresponds to a set value within the EEC. There is no per-se direct idle adjustment in the standard EEC-4.
Check your vacuum reading, making sure your cam lets you have at least 15 inches at idle and, make sure the TPS is not over a volt at idle. Both, in addition to the more common vac leak, will cause racing idles. Also check the BYP (air throttle bypass) solenoid is not stuck and that it's clean. You can test the solenoid by *very briefly* hooking 12 volts to it and making sure it moves.
F=MA
Everything was fine before I installes the 42# injectors and the recalibrated pro-m airflow meter.I will double check for vacuum leaks. It will idle at 950-900 RPMs but it will surge( go from 500- 900 rpms).
You might need to clock the MAF. Rotate the MAF a little at a time till your idle levels out.
Think I have found the problem. Rotated the air flow meter a half turn then drove the car for 5 miles in stop and go traffic then drove the car on the freeway. Now it has a steady idle just a little high @ a grand will try for 900-950 rpms. Thanks agine for everyone's help. Will let you know the outcome soon.
Don't trust the stock tach, either. Your gut is a better gauge of idle speed than that thing is.
F=MA