My original FORD IAC was dropped once when changing intake manifold. I am now getting code 13 KOER with. KOEO clear and a 1300-1500RPM idle. It has ALWAYS been at 650 or so.
I installed a new IAC and the idle dropped to about 11-12. I put my vac on the EGR and the engine dies at 5Hg. KOER Code 13 is still present and is my only code. Not sure what to check next except the EGR solenoid but I thought I would check here first. Thanks for any help. Sandy. Engine was at op temp.

 

the egr line has vacuum from the control solenoid at idle? This would not be correct... bad solenoid would be my first thought here.

The IAC not being able to control the idle usually indicates a vacuum leak or a stuck throttle. What does it do if unplug and cap off all the vacuum lines except MAP sensor and Fuel Pressure regulator?

 

I will be able to check it a little later. Good ideas. Also unplug the Iac on original and new one does nothing. Thank you R&R

 

you can test your new IAC, to make sure
How to Clean and Test your IAC - Ford Bronco Forum

 

The EGR does not have vac at connection that I can feel. In the picture below I plugged the two connections on the TREE with the red and blue caps. I left the egr unplugged and it idled at 800 very rough. I plugged the EGR vac back in with the TREE still plugged and the idle returned to 1400. The motor is still to hot to get the vac lines plugged up. I will have to wait till in the morning and then I will plug them all except MAP and FPR. Sandy

 

I cleaned the old one last night with no positive results and got the new one today and it is the same. The old one is probably good. Thanks Sandy

 

out of curiosity did you do anything to the throttle body or TPS?

 

No, nothing at all.

 

New gasket on the TB

 

so a simple test for you... unplug the IAC with the truck running. If it stalls or comes into a very low idle then most likely the IAC is not working or the computer is malfunctioning. If it doesn't stall then you have vacuum leaks or open throttle. Cap vacuum circuits and then restore them one by one with the engine running to see the impact on your idle. Cap anything non essential including the PCV.

 

I unplugged the IAC with it running last night and today ialso with the new one.
Will cap the vac lines tommorow. Sandy

 

I decided to test the EVP connector before I check all vac lines. With the ignition in the run position I probed the VFRE and the SIG RTN in DC Volts. I should get between 4 and 6 volts. At first I got no readings and then used a ground instead of the SIG RTN. Readings were all very high and moving up and down.

One thing that happened the other night when I was reinstalling the intake etc. The battery got low from trying to start before I properly set the timing so I pulled my charger out and went into the house for a second. My son connected the charger up with the connections reversed on the battery. Not noticing the mistake I tried starting several times and then noticed the negative charger line on the positive battery pole smoking. Then I noticed my son had reversed them, I changed them back and everything worked fine from there. Could this mistake cause the PCM to take a hit and cause my current problem being the high idle OR the weird readings on the EVP connector.

I haven't tested the EVP sensor yet so what do you recommend I do at this point with the above information? Throttle blades are fully closed at idle and are in great shape. Thanks Sandy. I was able to put another evp sensor Ion the truck. I had it from another truck. There was no charge.
Didn't get to do vac lines today. Lost my bro in law today to Covid and went to hospital with my sister. Will get the vac lines tommorow.

 

I am sorry for your family's loss.

If you can unplug the IAC and it still idles high you have too much air getting in somewhere. I don't know what if any damage would come from trying to start it with a charger hooked up backwards. I know there are fuses and diodes to protect the computer from that sort of thing...

I will say that I chased my tail for some time a year or two ago with a bad computer and sensors getting fried and never figured out if it was related/causal problems or just a bunch of unrelated problems at the same time. If it starts, runs, and reports codes I would roll like it is fine for the moment.

 

Thank you. Bro. In law was in ICU on a ventilator so it wasn't unexpected. My dad will be 99 Thur and is in Assisted living. Haven't been to see him in months. That really sucks.
Anyway I'll try the vac lines tommorow and see what happens. Get my mind off things. Sandy 😄

 

Sorry, to hear, about your brother in law.