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04 Explorer 4.0 surges wont Idle


July 28, 2013
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Year, Model & Trim Level
2004 Explorer
So I figured out why it wouldnt start last time (jumped timing chain). I tore the motor down and installed all new chains, cassettes, gaskets, intake seals, and got a set of rebuilt heads. I now have it all back together and when i start it it Ides great for a couple seconds then runs rough, wont idle, and seems to be in safe mode. When I put the motor back in I also put new plugs, wires, EGR valve on. Ran code with KOEO and got p2197, p2023. I then put in a new 02 in bank2. Still runs the same. I went to a local yard and got another throttle body and installed that with no change. On a positive note every time I post on here I figure out my problems lol. Thanks in advance.

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P2023: Intake Manifold Runner Position Sensor/Switch Circuit Intermittent
P2197 Heated Oxygen Sensor (Bank 2 Sensor 1) Biased / Stuck Lean

I know that the 1997 and 1998 SOHC V6 had intake manifold runner control but I wasn't aware that your 2004 does. Are you sure the DTC was P2023?

If bank 2 (driver side) is running lean then you may not have reconnected all of the vacuum lines on that side. Have you checked all of the vacuum hose connections?

EDIT: corrected which side is bank 2

Is bank 2 the passenger side? I was under the impression that it was the driver side. That's were I put it anyways. I'll switch it an try. I can't find any hoses off. for the intake runner switch, I haven't heard of that before I'll check into that as well. Thanks for some ideas.

cylinder #1?


Bank 1 is always the bank that contains cylinder #1. Thanks for catching my error which I have corrected. When you timed the camshafts did you use the timing tool kit? Did you position #1 piston at TDC on the compression stroke when adjusting the camshaft timing?

yes we did use the tool kit on it at a dealership. There lead mechanic did it for me one night after hours as I sat there and watched and learned. He seemed knowledgeable and said hes done a few of them. What is the fuel rail pressure suppose to be while at idle? My scanner says its at 35-38. This is an 04, shouldn't the psi be up around 65ish?

fuel pump driver module

Your 2004 has a fuel pressure/temperature sensor on the fuel rail instead of the damper the earlier models have. The PCM uses its output to control the fuel pump driver module to regulate the fuel pump. For more information see: Fuel Rail Pressure Sensor I don't know what the desired fuel pressure is at idle but I suspect yours is within limits or the PCM would set an associated DTC.

Since you have a scanner I suggest reading your long and short term fuel trims for both banks.

Im going to go do that now


STFT1- High of 9 to -14. bounced all around
STFT2- High of 14 to -8. bounced all around

I dont know anything about this fuel trim stuff so I dont know what good or bad.

So I did a little research on STFT/LTFT, good stuff to learn. So I checked all my hoses and took them all off and sucked air out of them with a brake bleeder pump. The vac hose from the top of the intake by the throttle body to that bulb thing with the green cap would not hold any air and I could only pump it to 20inHg, soon as I stop it would fill with air. Im getting a new one of those tomorrow.

long term fuel trims?

The STFTs are constantly fluctuating under control of the PCM when it is in closed loop. The LTFTs are adjusted by the PCM to achieve the optimum air/fuel ratio. What were the LTFTs?

I'm not familiar with the 3rd generation intake configuration enough to determine what component you are referring to. Below is a photo of a 2004 intake manifold I found on the internet.

I suspect its the EGR valve which is round, black with a paper white label and a vacuum port on the top center in the photo. If so, then the vacuum diaphragm in the EGR valve is ruptured.

Is there any way to test the egr? I just bought it brand new out of the box. Mine also looks a little different (egr and manifold) I'd post pix but I don't know how.

testing the egr valve

Is there any way to test the egr? I just bought it brand new out of the box. Mine also looks a little different (egr and manifold) I'd post pix but I don't know how.

Post #3 of the following thread describes how to test the EGR valve on my 2000 Sport: EGR System O&T Even though your EGR valve is in a different location testing it should be the same process.

I tested it. Results are:
held 6 inhg with motor off
started motor, pumped up to 20 inhg noticed no change in how the motor ran
Backprobed wires I got .47 volts
started motor, droped to .12v
pumped to 6 inhg stayed at .12v
Maxed out volts at 4.8v @ 20 inhg
backprobed reference pin got 4.8v
This was all on the new EGR, Im going to take it off and put the old one on and recheck. also going to inspect exhaust tub for kinks, blocks.

Reswitched them again (back to the new one) still wont start. ran codes and got,

check electrical connections

P0104 Mass or Volume Air Flow Circuit Intermittent
P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input
P0403 Exhaust Gas Recirculation Circuit Malfunction
P0406 Exhaust Gas Recirculation Sensor A Circuit High

I suggest that you check the electrical connections to the MAF sensor and the EGR valve regulator.

Checked them. Ive got good ground, power etc. Started from the basics and pulled the plugs out and noticed they were flooded. Cleaned them up and it stared for five seconds and it died.:mad:

crankshaft position sensor?

Your plugs are wet from the injectors firing when the starter was cranking. You may have a problem with the crankshaft position (CKP) sensor. I suggest cleaning the sensor connector by disconnecting and reconnecting it a few times. Also, check the condition of the wires connected to it.

I think your 2004 V6 still has the coilpack unlike the V8 that went to coil on plugs. If the engine runs for five seconds then the ignition system (coilpack, wires and plugs) should be functional. However, if the PCM doesn't detect the engine rotating via the CKP sensor it may shut down the engine for safety reasons. On the 2nd generation it does that by disabling the fuel pump. On your 3rd generation it may disable the ignition. I only have experience with my 2nd generation so I'm only guessing on yours.

.............UPDATE PROBLEM SOLVED!......................

So we finally got it up and running, and Ive been driving it around for a week with no problem. The problem to why it wouldnt idle and always died was that the cats all melted down and plugged up the cat by the Y pipe. I took the cats out, cut them open cleaned them up, rewelded them and installed them. Runs like a champ!There was so much ash that I couldnt stick a welding rod through the cat. When I dumped all the ash filled a large coffee container. Thanks to all who hepled me chase my tail.