94 explorer codes 411 412

[mxz583]

i have a 94 explorer that has rough idle and above idle is rough at times it will run smooth than rough has code 412 and 411 with KOER and sometimes with KOEO there is a code 211 some black smoke i had spare parts so swap out just about all senors still no inprovemet not sure what to try next fuel pump has 36 pounds and replace the fuel filter

 

[rhauf]

maybe you have a bad injector, is there more black smoke at idle and lower rpms?

 

[Iron Weasel]

Continuous Memory Diagnostic Trouble Code (DTC) 211 indicates two successive erratic Profile Ignition Pickup (PIP) pulses occurred, resulting in a possible engine miss or stall.

Possible causes:

Arcing secondary ignition components (coil, cap, rotor, wires, plugs, etc.).
On-board transmitter (2-way radio).
Loose wires/connectors.

Check the basic stuff for this one first. Spark plugs, wires, make sure you're getting a consistent spark from the coil pack. If everything is good with those, then you'll have to start troubleshooting the Crankshaft Position Sensor and the Camshaft position sensor.

DTC 411
Cannot control RPM during KOER self-test low RPM check.

DTC 412
Cannot control RPM during KOER self-test high RPM check.

Your IAC (Idle Air Control) motor is either gunked up something fierce or the solenoid is bad. Take the IAC off and give it a good cleaning, preferably do it a few times, then put it back on and see if the idle is any better. If the little rod inside the motor doesn't move freely, you might be looking at a new IAC motor.

 

[mxz583]

I have replaced the IAC so maybe its in the wiring, black smoke seem to be more at higher rpm what is is the best way to check the injectors

 

[mxz583]

I replaced the IAC and still getting codes 411, 412 not sure what to check next

 

[Iron Weasel]

Wiring is a good place to start.

First off, start the engine up and let it run for a minute or two then disconnect the wiring harness from the IAC motor. Does the engine RPM drop?

If it does, turn the engine off and disconnect the PCM harness connector and check resistance between pin 21 and the IAC harness. You want to check the wire that's opposite of the retaining clip on the IAC harness. Resistance should be less than 5 ohms between pin 21 and the IAC harness.

If it is, leave the PCM and IAC harness disconnected and check resistance between pin 21 and pins 40, 46 and 60. Each one should be greater than 10k ohms.

If that's OK, check for power at pin 21 on the PCM harness. Test light would be quickest, but a meter between pin 21 and a ground should show less than 1 volt.

Less than 1 volt? Good, continue on to check for IAC signal at the PCM. Connect the PCM and IAC harness and then backprobe the pin 21 and 40 on the PCM. If you can't backprobe the harness, then insert a small needle into the wire and do it that way. Increase engine RPM to about 3k and check voltage, you should be between 3 - 11.5 volts. If you don't have that and all the wiring checked out, you have a bad PCM.
If voltage is within range then check the idle....it should be consistent and not fluctuating wildly. If it idles all over the place, then you could have a vacuum leak causing extra air to enter the engine.

All in all, it's rather odd that you're getting both low and high self-check failures. Those are the only two codes you're getting though, right?

 

[mxz583]

Thanks Iron Weasel for your help, just got home from driving kids to college will check out what you described tomorrow. The only other code that has come up is with Key On Engine Off 211 but that has seem to have gone away.

 

[mxz583]

the other thing i dont understand is why when you hold the idle at let say 2000 rpm it runs fine then is will start to miss like you just pull off two spark plug wires then go back to running fine again and still get no codes just 411 and 412 i would think with a miss like that i would get more codes

 

[Iron Weasel]

The 211 DTC could be pointing you towards the cause of the miss. The fun part is tracking down the offending part.

Here's a document that can help you narrow down the 211 code the next time it comes up.
https://docs.google.com/document/ed...eAOcBROFCrovzfFZakkp5o&hl=en&authkey=CLiQpOkP

 

[mxz583]

Iron Weasel the document link does not go anywere but to google the is no doc thanks

 

[Iron Weasel]

I checked it with Google Chrome, Internet Explorer 8, and Firefox and it came up correctly each time.

https://docs.google.com/document/edit?id=1dCAIqHopcMiWTarLITbfxeAOcBROFCrovzfFZakkp5o&hl=en

Try that link, if it doesn't work, send me a PM with your email address and I'll convert it to a PDF file and send it to you.

 

[mxz583]

iron weasel i think i need to find a breakout box i still have a bad miss above idel but no codes should i still check things out like the document states even if there is no code 211

 

[Iron Weasel]

If you want to spend the money on one, go for it.....they run anywhere from $500 - $700 for a EEC-IV breakout box.

You can accomplish the same thing, though not as easily, by either backprobing the terminals or piercing them with a needle.

I updated the diagnostic document and added the PCM connector pinout as well as the list of what each pin is, hopefully that will help you out a bit more.

Here's the link to the revised document:

https://docs.google.com/document/edit?id=1MboXap0BaKzCT42tqv4mldK9iE-oBtjbXqkCxCrPkG4&hl=en

 

[mxz583]

iron weasel thanks for the help it turn out to be the pcm the only problem i have now it cranks longer then usual before it starts any thought on this i have installed a new fuel pump

 

[Iron Weasel]

Does it start and run without any other issues?

If so, I wouldn't worry about it. Mine takes a couple seconds to start up and it runs just fine and doesn't have any codes in it.

 

[waskly]

4.0 or 5.0?

 

[mxz583]

it runs fine. it is a 4.0 i retested the fuel pressure and and when i turn the key off it drops like a rock if i hit the tank presure will hold a few times then go back not holding it is a new pump maybe the ckeck vavle is bad

 

[ruclassic]

Continuous Memory Diagnostic Trouble Code (DTC) 211 indicates two successive erratic Profile Ignition Pickup (PIP) pulses occurred, resulting in a possible engine miss or stall.

Possible causes:

Arcing secondary ignition components (coil, cap, rotor, wires, plugs, etc.).
On-board transmitter (2-way radio).
Loose wires/connectors.

Check the basic stuff for this one first. Spark plugs, wires, make sure you're getting a consistent spark from the coil pack. If everything is good with those, then you'll have to start troubleshooting the Crankshaft Position Sensor and the Camshaft position sensor.

DTC 411
Cannot control RPM during KOER self-test low RPM check.

DTC 412
Cannot control RPM during KOER self-test high RPM check.

Your IAC (Idle Air Control) motor is either gunked up something fierce or the solenoid is bad. Take the IAC off and give it a good cleaning, preferably do it a few times, then put it back on and see if the idle is any better. If the little rod inside the motor doesn't move freely, you might be looking at a new IAC motor.

I have same codes 411 and 412 with no vacuum leaks, IAC replaced, TPS replaced and fresh PCM and still CEL goes on and off sporadically??