P0172 code woes

[5.0 Hatch]

I picked up a high mileage Cobra a while back that was completely stock and neglected from a maintenance standpoint. I've been able to resolve every single issue with the exception of a P0172 code.

Symptoms
- Erratic idle
- heavy fuel smell
- black smoke when stabbing gas
- Long crank times - it takes 3 key KOEO cycles to get 39psi. Pressure drops to 0 after ten seconds of turning off car.
- long term fuel trim appears maxed out at about -25%

Things I've done
- Looked for vacumm leaks
- verified no leaks between maf and throttle body
- changed o2 sensors
- changed plugs
- changed injectors
- changed fprs

It seems the long crank times and fuel pressure bleed off is fuel pump check valve related and I'm guessing not related to the p0172 code since it maintains fuel pressure when the engine is running??

 

[01yellercobra]

I'm going to guess it's an injector issue. It sounds like you have a leaking injector. I'd pull them and get them serviced. Were any of the plugs overly black compared to the others?

 

[Vinnie_B]

Step 1 : CHECK FUEL PRESSURE​

ENGINE RUNNING​	​	​	​	Hot Idle 39 PSI 275 kpa​
KEY ON ENGINE OFF​	​	​	​	35-40 PSI 240-280 kPa​

Step 2: CHECK SYSTEM'S ABILITY TO HOLD FUEL PRESSURE

Pressurize fuel system per step 1
Visually look for fuel leaking at the injector O-ring, fuel pressure regulator, and the fuel lines to the fuel charging assembly
Key on, engine off.

Does fuel pressure remain at specification for 60 seconds?


There are several more things to do and isolate this issue. I'll check back when these are confirmed.


Lightning FastElectrical Automotive Repair LLC
PM Me or [email protected]
Remote or Local (On Site) Technical Repair

 

[5.0 Hatch]

Vinnie, I managed to get rid of the p0172 code by isolating it down to either a bad coil or plug on that bank. I changed both out and the code disappeared and the idle is much better.

However, now I have a p1132.

Key on engine off, pressure goes to around 14 kPa and then bleeds off in seconds. Engine running, holds steady in the 270 kPa range. Again, turn the engine off and it bleeds down quickly.

Almost seems likely I have another bad injector Or fuel pump check valve. But would a bad pump cause a p1132??

 

[cobracide]

|What are the Possible Causes of the P1132 Code?​

• Faulty Upstream Oxygen Sensor Bank 1
• Fuel pressure high or low
• MAF sensor dirty/defective
• Vacuum leak on engine
• Leaking fuel injector or fuel pressure regulator
• Faulty Powertrain Control Module (PCM)

|How to Fix the P1132 Code?​

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

 

[Vinnie_B]

Vinnie, I managed to get rid of the p0172 code by isolating it down to either a bad coil or plug on that bank. I changed both out and the code disappeared and the idle is much better.

However, now I have a p1132.

Key on engine off, pressure goes to around 14 kPa and then bleeds off in seconds. Engine running, holds steady in the 270 kPa range. Again, turn the engine off and it bleeds down quickly.

Almost seems likely I have another bad injector Or fuel pump check valve. But would a bad pump cause a p1132??

What year is this cobra?

 

[5.0 Hatch]

2001

 

[Vinnie_B]

P1132 - Lack of HO2S-11 Switch, Sensor Indicates Rich

A HEGO sensor indicating rich at the end of a test is trying to correct for an over-lean condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.


Your gonna have to go thru to isolate this issue.

• Electrical:
  • Short to VPWR in harness or HO2S
  • Water in harness connector
  • Open/Shorted HO2S circuit
  • Corrosion or poor mating terminals and wiring
  • Damaged HO2S
  • Damaged PCM
• Fuel System:
  • Excessive fuel pressure
  • Leaking/contaminated fuel injectors
  • Leaking fuel pressure regulator
  • Low fuel pressure or running out of fuel
  • Vapor recovery system
• Induction System:
  • Air leaks after the MAF
  • Vacuum Leaks
  • PCV system
  • Improperly seated engine oil dipstick
• EGR System:
  • Leaking gasket
  • Stuck EGR valve
  • Leaking diaphragm or EVR
• Base Engine:
  • Oil overfill
  • Cam timing
  • Cylinder compression
  • Exhaust leaks before or near the HO2S(s)

Please verify and check !!

A fuel control HO2S PID switching across 0.45 volt from 0.2 to 0.9 volt indicates a normal switching HO2S.

 

[Vinnie_B]

Vinnie, I managed to get rid of the p0172 code by isolating it down to either a bad coil or plug on that bank. I changed both out and the code disappeared and the idle is much better.

However, now I have a p1132.

Key on engine off, pressure goes to around 14 kPa and then bleeds off in seconds. Engine running, holds steady in the 270 kPa range. Again, turn the engine off and it bleeds down quickly.

Almost seems likely I have another bad injector Or fuel pump check valve. But would a bad pump cause a p1132??

If there is anything else I can help you with just let me know. To bad you werent local to me I could scan this and isolate this within an hour using Ford IDS and special diagnostic tools. Good luck and hope you get this cobra fixed @5.0 Hatch

 

[5.0 Hatch]

P1132 - Lack of HO2S-11 Switch, Sensor Indicates Rich

A HEGO sensor indicating rich at the end of a test is trying to correct for an over-lean condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.


Your gonna have to go thru to isolate this issue.

• Electrical:
  • Short to VPWR in harness or HO2S
  • Water in harness connector
  • Open/Shorted HO2S circuit
  • Corrosion or poor mating terminals and wiring
  • Damaged HO2S
  • Damaged PCM
• Fuel System:
  • Excessive fuel pressure
  • Leaking/contaminated fuel injectors
  • Leaking fuel pressure regulator
  • Low fuel pressure or running out of fuel
  • Vapor recovery system
• Induction System:
  • Air leaks after the MAF
  • Vacuum Leaks
  • PCV system
  • Improperly seated engine oil dipstick
• EGR System:
  • Leaking gasket
  • Stuck EGR valve
  • Leaking diaphragm or EVR
• Base Engine:
  • Oil overfill
  • Cam timing
  • Cylinder compression
  • Exhaust leaks before or near the HO2S(s)

Please verify and check !!

A fuel control HO2S PID switching across 0.45 volt from 0.2 to 0.9 volt indicates a normal switching HO2S.

I made some progress over the weekend. I changed the fuel pump and that 100% took care of the long crank issues and pressure bleed off. Overall the car seems a lot happier in all aspects.

I'm still getting the P1132 code but no longer have visible exhaust smoke. I'm just about sure it's not Electrical unless I got a bad o2 sensor out of the box. The entire fuel system is new. No vacuum leaks that I can find. I'd like to test the EGR but not sure how.

I drove it over 50 miles this weekend and there is a random misfire at around 1800rpms that comes and goes. 2nd gear seems to be more prevalent. Could all of this be related to a bad coil? Is there a definitive way to test coils?

 

[Vinnie_B]

Did you verify this?

Please verify and check !!

A fuel control HO2S PID switching across 0.45 volt from 0.2 to 0.9 volt indicates a normal switching HO2S.

No. A coil issue wouldnt cause this DTC! Forscan can also help you find which cylinder is missing. Youtube has a bunch of videos showing how to test coils if you prefer to do it that way.

 

[shurur]

P1132 looks to be the B1S1 o2 sensor.
If you replaced it with some cheapo O2 sensor, you can still have problems.

I think I replaced both of my S1 sensors with NGK or Motorcraft. See what Rockauto carries. It is kinda a big deal what you use.

B1 is the passenger side...cylinder 1 side
B2 is the driver side.
S1 is the precat o2 sensor that controls whether you go lean/rich, and how the car runs.

S2 is the postcat o2 sensor that only tells you whether the cat is still good.

 

[shurur]

Yes as far as the misfire goes, use torque pro to find the offending cylinder....swap COPS and see whether misfire follows the COP.!

If one COP fails, the others will soon follow.

 

[shurur]

Also...when you replace the COP, You should grease with the proper grease.

IMO the grease is not for conduction; it is to keep the boot from tearing should you twist it too much. You want to push the COP on, not twist it or you will be hunting down a torn COP boot problem...ask me how I know..

 

[5.0 Hatch]

Just to close out this thread for anyone who experiences this same issue.

Long story short, DO NOT use Bosch o2 sensors in your mustang. They only switch between .4 and .6 volts and switch very slow.

Changing to NTK completely resolved my issues. The NTK switch between .2 and .8 and switch at least 3 times faster than the Bosch units.

Also huge shout-out to Vinnie_B for walking me through the troubleshooting process.

 

[claybeatz]

Vinnie is the best!

 

[Vinnie_B]

Vinnie is the best!

Thanks for the compliment @claybeatz But im not the best. But i do my best to help as many ppl as i can.

 

[claybeatz]

Thanks for the compliment @claybeatz But im not the best. But i do my best to help as many ppl as i can.

That’s what matters buddy!