Help with stumbling/misfire and p0148 p0316 p0457

CJ-

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Hey guys, I’m getting gas cap warnings on my dash. And usually after just starting the car after letting it sit for an hour or more, I’ll have a misfire and stumbling acceleration at 2500-3000 rpms that gradually goes away about 1/4 mike down the road. Not to mention the p0148 p0316 p0457 codes. The gas cap seal seem good.


I already replaced the fuel pump, fuel filter and fuel tank vent solenoid and checked the purge valve, it closes/seal and opens just fine.


Don’t know what to do or were to start at this point.

5CD389CF-27C0-4328-838B-1FE87A81CEC1.jpeg
 

bl817

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Alternator probably on its way out. good luck
 

sman247

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more info about the car, what year, any mods if any, and how many miles. however checking the battery voltage is a good start
 

redfirepearlgt

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Without more details, I would agree it sounds like a power source issue. Check DC output on the alternator for 13.8-14.4 DC and less than 1.4VAC ripple with the car running.

Otherwise start listing mods, things recently done that led up to this, and year, model mustang, and mileage would also help.
 

CJ-

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I’m sorry guys, I thought I had my mod list in my signature.

What led to this was, on again off again evap codes appearing and disappearing every few months.

Then had a 1.0 AMP diode in the engine bay fuse box go bad which would make the engine lose electrical or ignition power.

Then nothing for a couple months and then I installed the hot rod cams and uploaded the tune for it and great for months, no check engine light.

And then evap purge valve circuit fault codes and evap small leak detected codes would appear and periodically a fuel delivery error code and and O2 sensor bank 1-2 sensor 1 stuck on lean codes constantly appear simultaneously.

2005 Mustang GT 183k mileage,

Ford Hot Rod Cams
Jlt V3 CAI
Gutted cats
Diablo Tune 91 octane
O2’s after cats deactivated


Fuel filter replaced 2 years ago
Fuel pump replaced 10,000 miles ago with a low mileage used unit
New Fuel tank Vent valve
 
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redfirepearlgt

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^ You never know when a person makes changes and does not update that. With all of the erroneous codes you are getting I would once again direct you to inspect the voltage output of the alternator. That is the blood line of the electrical system which generates these codes. IF there is excess AC voltage being produced due to a failed voltage rectification module inside the alternator excess AC voltage will be present. Electronics do not like AC voltage. IT causes all kinds of problems. Neither do they like low DC voltage which can cause missed interpretation of digital I/O (on/off, 1/0, high/low) signals as well as proportional signals the PCM is being fed from various I/O devices.

So again check the DC output of the alternator as well as the AC output of the alternator with the car running and report that back. If AC voltage (aka AC ripple) is 10% or more of the dc voltage read you may want to replace the alternator with a good one. That would be the start wince the car has 183K on it.

Impressive mileage btw. Nice to see high mileage 3V engines still operational.
 

CJ-

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Don’t know how old the alternator is, I used my tuner to see the voltage with engine off (12.8 volts) and with the engine running (14.1-14-2 volts).
 

redfirepearlgt

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Did you measure for AC ripple on the alternator? Failing rectification (shorted diodes) will not rectify the AC voltage to DC. PCM's and other electronics made to operate on DC hate AC. remember an alternator is a 3 phase producing unit. Each AC phse is then rectified via its own fave wave circuit. Two could be good and one shorted andthe result is an AC and DC output that reeks terror on the electronics and battery.

So if you feel the alternator is fine, then move on taking each code one at a time. Starting with P0148 - Check/replace Fuel filter. Then datalog the fuel pump and fuel rail pressure to see how they are doing. Possibly a failing fuel pump or the in tank filter is clogging. Once that is resolved, see if the P0316 goes away.

The 457 could be something failing in the fuel neck possibly. If that all looks fine then just replace the cap, its not that expensive. I've had a cap fail and it visually looked fine.

Then once these are resolved you can focus ont eh A/C Clutch issue

That is how I would approach these
 
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CJ-

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Oh boy, I’m not ashamed to say testing the alternator as extensively as your telling me to do is beyond my expertise and knowledge, is the Autozone charging system test Cart something that could check the ripple?

As far as fuel pump, the sock and filter, all have been replaced in the past 9 months. I’ll try replacing the cap since it’s easy and cheap, then I’ll inspect the filler neck cause when I do push and twist the cap onto it, the neck falls back about 1/4 inch, so it’s got some play. Not sure it’s thats cause for concern but wouldn’t hurt to check.
 

CJ-

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I drove home from work and halfway I decided to data log the trip and I noticed once I got off the freeway and started to pay attention to the voltage (VPWR), the value dropped from 14.2v to 13.5-13.6v and a couple times dipped to 13.4, also noticed as I was stopped and then accelerated, the voltage would NOT climb from back to 14v range, the voltage would remain between 13.5 and 13.6 volts. When I finally parked at home, turned off the ignition and then turned the ignition on without starting the engine, the voltage was at 12.3 and within 15 seconds dropped to 11.9 volts. Then the wife soon told me to get my... and I quote “ass in the house” so the data log was promptly ended.
 

CJ-

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Not sure if these read outs help but this is while just sitting in the car idling with the headlights on.
1C2B4193-4A5C-4CFD-A382-27F05714C365.jpeg 036ED9C6-26C1-4F98-88C9-4CDFE7EBAE0E.jpeg 0BE8F110-0748-4886-AB6C-1B74AB9AD879.jpeg EB08B62C-9388-43E5-979A-3827D4528321.jpeg 92E73793-523B-41C1-8862-51369A6132AF.jpeg
 

redfirepearlgt

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you can try that.
Oh boy, I’m not ashamed to say testing the alternator as extensively as your telling me to do is beyond my expertise and knowledge, is the Autozone charging system test Cart something that could check the ripple?

As far as fuel pump, the sock and filter, all have been replaced in the past 9 months. I’ll try replacing the cap since it’s easy and cheap, then I’ll inspect the filler neck cause when I do push and twist the cap onto it, the neck falls back about 1/4 inch, so it’s got some play. Not sure it’s thats cause for concern but wouldn’t hurt to check.

You could take it to Autozone and run it up on their system. If you have areliable voltmeter there are some excellent youtube videos on doing the basic checks on an alternator. As far as the fuel pump, if it wasn't OEM I would be cautious. I have come across several cases where guys go cheap on that and find the pump failed in a very short period of time. Don't know if that applies here, but keep that in mind. 50% DC if I am reading your photos correctly and 28psi fuel rail pressure at idle is not a good sign. But I would first focus on getting the alternator verified. Unlike a Coyote it's accessible from the top easily enough. If it checks good then your other diagnostics could be more trustworthy. The odd ball in the group is that Clutch AC code. Assuming that pops up each and every time you clear and restart the car (with Defrost and AC shut off) along with the other codes I would be suspect that the codes may be erroneous due to possible alternator.
 

mauitom

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I had similar issues my ‘06. Check the ground wires attached to the left of the radiator. These get very corroded, sandpaper them, clean. I replaced the attachment bolt. Might be the simple fix I found on mine.

And check your other ground connections.
 

CJ-

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Not sure if these read outs help but this is while just sitting in the car idling with the headlights on.
Did you measure for AC ripple on the alternator? Failing rectification (shorted diodes) will not rectify the AC voltage to DC. PCM's and other electronics made to operate on DC hate AC. remember an alternator is a 3 phase producing unit. Each AC phse is then rectified via its own fave wave circuit. Two could be good and one shorted andthe result is an AC and DC output that reeks terror on the electronics and battery.

So if you feel the alternator is fine, then move on taking each code one at a time. Starting with P0148 - Check/replace Fuel filter. Then datalog the fuel pump and fuel rail pressure to see how they are doing. Possibly a failing fuel pump or the in tank filter is clogging. Once that is resolved, see if the P0316 goes away.

The 457 could be something failing in the fuel neck possibly. If that all looks fine then just replace the cap, its not that expensive. I've had a cap fail and it visually looked fine.

Then once these are resolved you can focus ont eh A/C Clutch issue

That is how I would approach these

So far replaced the gas cap, no gas cap warning since so that’s something. I got 3 codes, 1 o2 stuck on rich and 2 o2s stuck on lean. But no evap or gross leak codes since I’ve changed the gas cap.
 

redfirepearlgt

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Not sure if these read outs help but this is while just sitting in the car idling with the headlights on.


So far replaced the gas cap, no gas cap warning since so that’s something. I got 3 codes, 1 o2 stuck on rich and 2 o2s stuck on lean. But no evap or gross leak codes since I’ve changed the gas cap.

Any chance you recently installed a new clutch or LT's or OFF road pipe? Or any other reason the O2 sensors would have been disconnected for repairs or modifications? It is easy to cross the O2 sensor cables and have this symptom. Specifically the up stream HO2S primary sensors.
 

CJ-

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Any chance you recently installed a new clutch or LT's or OFF road pipe? Or any other reason the O2 sensors would have been disconnected for repairs or modifications? It is easy to cross the O2 sensor cables and have this symptom. Specifically the up stream HO2S primary sensors.
I did remove the mid pipe a couple times, I’ll check the o2 connections sunday
 

CJ-

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Just did the autozone charging system test, everything shows as “Passed”.

Here a picture of the ripple readout. Let me know if that looks within spec?

7991723C-0BA0-4C1B-8C69-490DA4AB68B0.jpeg
 

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