DOH! Another thought just struck me...... The engine IS indeed computer controlled, so, when you disconnect an injector, and idle drops, the computer will compensate for that by opening IAC some more....... (been a while since I had to deal with that kind of thing, so, sometimes I am a tad slow.....) For this test to be meaningful, you have to disable IAC in any event.

 

Can I just unplug the vacuum line for the iac and unhook the cable to disable it for that test?

 

IAC has a 4 pin connector, and that's it. It is on the back side of the throttle body. Simply unplugging it should be adequate to the task. Provided it isn't back out to far.... (high idle.)

 

Ok I will try this tommorow morning and report back

 

Pull the brake booster hose, that will make a big vac leak.

Then wait until the idle drop drops just a bit. That's the pcm closing the IAC, trying to get to the target idle. It will fail, and the IAC will close completely. Now unplug the IAC, then slowly reconnect the brake booster line, and do your tests.

BTW, if you put a screwdriver to each injector, and your ear to the handle, if you hear a click, click, click, it's firing.

 

Alright I cleaned up the injectors really good and did an ohms check on them and they were between 12.4 to 12.6 which is well within proper spec I'm going to clean up the throttle body while I have it off and then I'll try the test again. Is there anyway to Just delete the IAC all together permenatly or is that a bad idea

 

Ok put it back together and ran it. At first it would not start unless I held the peddle to the floor and thn backed off when I finally got it to start. First start up since cleaning the injectors and it threw a code for every single injector I then cleared the codes and they did not come back the second time I started it but it sounds like it has a bad miss and it will not idle on it's own I have to keep on the gas peddle to keep it running. It also threw a code for the throttle position sensor the IAC and the evaporative purge control which has been on for awhile now because I removed the emissions controll from the engine and had The SCT tuner set up for that.

 

Gotta have the IAC system. It regulates idle. (though apparently not very well on your truck......)

Having to hold the pedal on the floor to get it to start makes me think it is running TOO rich. What size injectors do you have? Stock? Was your tune set up for those injectors??

Reset the PCM again, then, turn the key to ON, but, don't start the truck. Wait until the fuel pump STOPS running, and THEN try and start the truck. Do what ya gotta do to get it to fire up. I am hoping that will take care of some of the codes you are seeing, as, when you reset the PCM, the computer will re-initialize TPS, and IAC motor.

You have the neat little clips that hold the connectors onto the injectors don't ya?

 

Yea stock size injectors which is what the tune is set up for. I tried to reset the PCM with the SCT tuner before and it would not let me

 

Disconnect the battery, turn on the headlights for 30 seconds, turn them off, hook the battery back up. PCM will be reset.

In this instance, when I refer to "reset", I am just saying the computer forgets anything it learned about the engine from before. You still have whatever tune currently loaded, the PCM is just starting with a clean slate on its learning process.