Well lets start with a long story. This is a 99 accord f23a1 5 speed . Belongs to a college kid. Failed emissions has a cel. I cleaned the egr passages pulled the upper intake and the car ran bad afterwards backfired and would not restart. compression was low , pulled the head , had it reworked , new timing belt , new Idle air control motor the old 1 leaked coolant . new knock sensor , ran bad and was down on power swapped the connectors for the tps and map (saw this in another thread) runs good but has a surging idle and kicked a IAC code again . coolant has been bled , drove it for 1 mile so far . I am open to any and all ideas


there is a lesson here in volunteering

 

Look in DIY section for a post by me about setting the "BASE" idle speed.

You changed lots of stuff, should probably force the ECU to re-learn. But look over that base idle setting too.

 

I will look at base idle .I drove it further here is an update, no v-tec , throws a v-tec code as soon as you get to 4,000 rpm. not sure what happened as this was not a problem before the head was removed , checked and found the electrical connector was not very good on the v-tec solenoid , repaired that . It still surges at idle . I do have a low buck code reader it is showing an IAC code

 

I know you bleed the coolant, was the heat set to high?

Then double check your work, looking for vac leak-hose left loose, gasket, ect.....

 

did it again , did the idle thing and it did not help idles surges still and got a v-tec code again on a drive

 

What are the exact codes? Should begin with "P" and four digits.

 

I am down to just a surging idle and no code right now . It is much better I went over a whole bunch of stuff and found no real issue . I changed the oil and drove it 45 miles . no idle code but it surges and will not reset it self to be emission inspected . no v-tec code after the oil change. Other than the surge it runs great and pulls harder than it ever has.

 

A surging idle can be from air in the cooling system or a vacuum leak.

How did you bleed the air from the coolant?

Was the head milled when you removed it, so it was perfectly flat?

Did you spray some TB cleaner around the intake and fuel injectors to see if the idle changed at all?

 

turned on a P0505 today after 75 miles of driving. It showed a 9.8% tps which I thought seemed high and 948 rpm when the code set . My cheap reader does a freeze frame of when the code sets .
I am going to go over the idle setting tutorial again, when I unplug the iac the idle surges bad there is no setting it at any rpm due to the surge .

the head was flat and just cleaned up. .

The intake and head all passed when I did the spray test

 

any more good ideas ? I am taking 2 days off from this