All cylinders misfiring

hotcobra03

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2003 PCED On Board Diagnostics


SECTION 5: Pinpoint Tests



Procedure revision date: 08/19/2002




DU: Intake Air Temperature 2 (IAT2)

Introduction


DU: Pinpoint Tests→
Note
This Pinpoint Test is intended to diagnose the following:

  • Intake air temperature 2 (IAT2) sensor (12A697)

  • Integrated intake air temperature 2 (IAT2) sensor portion of the ThermalManifold Absolute Pressure (TMAP) Sensor (9F479).

  • Harness circuits: IAT2 and SIG RTN

  • Powertrain control module (PCM) (12A650)
Tables and Graphs
AA4397A.gif




Click to Enlarge
TEMPERATURE SENSOR VOLTAGE AND RESISTANCE SPECIFICATIONS


Temperature Temperature Sensor Values
°C
°F Voltage (volts) Resistance (K ohms)
120 248 0.27 1.18
110 230 0.35 1.55
100 212 0.46 2.07
90 194 0.60 2.80
80 176 0.78 3.84
70 158 1.02 5.37
60 140 1.33 7.70
50 122 1.70 10.97
40 104 2.13 16.15
30 86 2.60 24.27
20 68 3.07 37.30
10 50 3.51 58.75
Pinpoint Test Schematics and Connectors
For PCM connector views, refer to Section 1, Powertrain Control Hardware.

AA4400A.gif




4.6L 4V SC Mustang

A0039436.gif




5.4L SC

A0052725.gif




Click to Enlarge

DU: Pinpoint Tests→
 

xtreme_exploder

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By the way, I have the manual containing the tests you're posting, and that's what I've been using to troubleshoot my car.
 

xtreme_exploder

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Sensor disconnected: 4.77V at the computer
Sensor disconnected: 4.99V between vref and sig rtn
Everything connected: 3.00V at the computer, engine at ambient temperature
As you can see, all good there. I'm not having any IAT2 issues. I believe the reason the code originally showed up was the intake got hot enough to be outside the sensor's range, which is the equivalent to a low voltage input (hotter the sensor gets, lower the voltage). I believe that intake reversion from it running like trash and the lack of vacuum keeping the supercharger bypass closed, in turn causing supercharger cavitation/even more air heating, made the intake hot.

I've discovered that it's basically shutting down two cylinders on each bank (2 hot, 2 cool header tubes on each side). I got thinking and the way it runs is like when traction control engages when you spin the tires. I found that there's a diagnostic self test procedure for the instrument cluster. Running that, I got the following DTCs:
D043, invalid or missing data for traction control
D262, missing SCP message
I feel like I should get to the bottom of what those really mean before I do anything else.
 

hotcobra03

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Have you done a compression test?

Other than valve issue.

I had a cam gear explode and that was tricky parking lot repair

But it was still running on 4 cylinders
Plugs were wet.

I will look for cluster codes.
1 sounded like u1262 network

My car popped abs this last week for the first time
B1342/c1266
 

xtreme_exploder

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I have the bottom of the blower plugged. Did that when I deleted the PCV system. I looked for vacuum leaks and haven't found any. Wouldn't the car have a high idle with a vacuum leak though? I'm still probably going to pull the blower and check intake gaskets, etc. I'm running out of ideas. I think I eliminated the abs and dash errors from causing this. I disconnected them from the PCM and ran the car, didn't change anything. Coils, computer, and injectors seem to be getting good, steady voltage while running. Can't find anything in the factory service manual that will help me.
 

hotcobra03

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Have you owned this car since new?

Pprv has been an issue for many that have them causing this issue of running like crap

Manual has steps for no dtc and misfire

You are just missing something.

You send car to ford and they use this book to fix it

But. What numbers did you see on compression test.

Mine are 180 plus.

Anything thing lower on mine has been a issue.

I also had a follower fall off during valve issue. Tap tap quiet run like crap
 

xtreme_exploder

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I've had it for about 9 years. Mostly stock when I bought it, but it's heavily modified now. I have a return style system, so pprv isn't applicable anymore. Built motor with high duration/overlap cams and 8.5:1 cr, so my cranking compression will be lower than stock; it cranks at only about 140psi, but that's always been the case.
 

xtreme_exploder

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So finally messed with the car again after having to set it to the side to finish other projects. I did a compression check on one of the cylinders that I didn't check before (I only did a couple on each side initially) and found that #8 had zero compression. I pulled the intake and one of the intake valves was stuck open. I pulled the valve cover and it turns out the valve guide seized to the valve stem. Not a good find after spending a ton of money having the heads built, I sure hope they can back up their work.
 

hotcobra03

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So finally messed with the car again after having to set it to the side to finish other projects. I did a compression check on one of the cylinders that I didn't check before (I only did a couple on each side initially) and found that #8 had zero compression. I pulled the intake and one of the intake valves was stuck open. I pulled the valve cover and it turns out the valve guide seized to the valve stem. Not a good find after spending a ton of money having the heads built, I sure hope they can back up their work.
Ouch.

Strange how good engine does run on 7 cyl.

Glad you did find something

A lot of work for this.

I have long tubes. Last time I did mine I left header on head and pulled as one. Using a come along.

Just sucks to work over fenders but doable without removing motor
 

xtreme_exploder

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Thanks for the tip, I have long tubes as well. I've got a engine hoist that's been handy for things like this. Unbolting my headers is impossible without dropping the k-member, so it would be nice to not have to mess with that.
 

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