Codes (update)
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Junior User
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Codes (update)
My truck has been getting some bad mileage lately (10-14mpg) and I normally get 17-19mpg. So I pulled the codes to try and fix the problem and this is what I got:
P0135
P0141
P0155
P1131
P1151
P0174
I have replaced all o2 sensors about 5,000 mile ago and I still get these codes.
The truck is a 1996 f150 4.9L.
Thanks
P0135
P0141
P0155
P1131
P1151
P0174
I have replaced all o2 sensors about 5,000 mile ago and I still get these codes.
The truck is a 1996 f150 4.9L.
Thanks
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 12
From: Sand Lake, MI
Did you check all the fuses? I don't have a diagram for your model so can't tell you which one/s to check.
Odds all three had burnt out heaters be slim before installing new ones, all three new and again are burnt out/fail? Gotta say I doubt it, suggests a burnt fuse or power wire to them has been damaged or both.
Both P1xxx codes as well as 174 suggest system is lean (lack of switching), low fuel pressure and or vac leak/s? gonna need look into that find out what the cause is.
Getting those 02 sensors built in heaters working again be a good starting point. Clear the codes drive it some then retest see what if any over all effect doing that has.
Odds all three had burnt out heaters be slim before installing new ones, all three new and again are burnt out/fail? Gotta say I doubt it, suggests a burnt fuse or power wire to them has been damaged or both.
Both P1xxx codes as well as 174 suggest system is lean (lack of switching), low fuel pressure and or vac leak/s? gonna need look into that find out what the cause is.
Getting those 02 sensors built in heaters working again be a good starting point. Clear the codes drive it some then retest see what if any over all effect doing that has.
Thread Starter
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Junior User
Joined: Sep 2011
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I cleared the codes and drove about 50 miles and these 3 codes showed up again:
P0135
P0141
P0155
(haven't gotten around to checking the fuses yet)
I also got a fuel pressure gauge today, I will test the pressure as soon as I have time. Also noticed when I filled up today my front tank was almost 1/2 full and when switched tanks earlier in the week I had it below a 1/4 tank, so what do I have to replace to fix this problem?
P0135
P0141
P0155
(haven't gotten around to checking the fuses yet)
I also got a fuel pressure gauge today, I will test the pressure as soon as I have time. Also noticed when I filled up today my front tank was almost 1/2 full and when switched tanks earlier in the week I had it below a 1/4 tank, so what do I have to replace to fix this problem?
Elder User
Joined: Jun 2010
Posts: 568
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From: Northern IL
The rear tank is back feeding into the front tank, you need to replace some doohicky that is known around here as the "Fuel Delivery Module" The farthest I got with that is a complete fuel pump kit(float and such) but I never bought the parts because I wasn't sure if those were the correct part(s). I wish I could be more help but I can't. I've been stuck using just the front tank since last February for the same reason.
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Junior User
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The rear tank is back feeding into the front tank, you need to replace some doohicky that is known around here as the "Fuel Delivery Module" The farthest I got with that is a complete fuel pump kit(float and such) but I never bought the parts because I wasn't sure if those were the correct part(s). I wish I could be more help but I can't. I've been stuck using just the front tank since last February for the same reason.
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Junior User
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update
I checked the fuses and all looked good, if anyone knows which fuse controls the o2 sensors let me know and I will replace that fuse anyway. I will hopefully get around to checking the fuel pressure on monday or tuesday, what is normal fuel pressure for a 1996 F150 4.9L?
Thanks
Thanks
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fuel pressure
I checked the fuel pressure today and this is what I got:
Key on: Front tank selected 14 (first check only)
Back tank selected 10 (first check only)
After I released the pressure to check again with the key on I kept getting:
Front tank 47
Back tank 38
Idle: Front tank 47 Back tank 46
Key off: Front tank 50 Back tank 53
After 2 min: Front tank 53 Back tank 56
Key on: Front tank selected 14 (first check only)
Back tank selected 10 (first check only)
After I released the pressure to check again with the key on I kept getting:
Front tank 47
Back tank 38
Idle: Front tank 47 Back tank 46
Key off: Front tank 50 Back tank 53
After 2 min: Front tank 53 Back tank 56
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Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 12
From: Sand Lake, MI
I checked the fuel pressure today and this is what I got:
Key on: Front tank selected 14 (first check only)
Back tank selected 10 (first check only)
After I released the pressure to check again with the key on I kept getting:
Front tank 47
Back tank 38
Idle: Front tank 47 Back tank 46 Key off: Front tank 50 Back tank 53 After 2 min: Front tank 53 Back tank 56
Key on: Front tank selected 14 (first check only)
Back tank selected 10 (first check only)
After I released the pressure to check again with the key on I kept getting:
Front tank 47
Back tank 38
Idle: Front tank 47 Back tank 46 Key off: Front tank 50 Back tank 53 After 2 min: Front tank 53 Back tank 56
Engine off = 50 to 60 psi
Engine on vac line connected to FPR = 45 to 60 psi
Engine on vac line disconnected from FPR = increase 5 to 10 psi.
You're no doubt suffering lean condition due to fuel delivery issues, might not be all the time but certainly not up to par 100% of the time based on figures you've posted here. You had no leaks at gauge? screwed down on valve all the way and was tight?
I'd have to review however if you haven't replaced the fuel filter on it yet I'd surely start with that, put a fresh one on and then recheck fuel pressure after doing so.
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 12
From: Sand Lake, MI
Oh missed that part, you gotta correct any fuel transfer issues it suffers from too. If fuel is pumped from one tank to another its the receiving tank that has the problem. As stated you must replace the FMU – "Fuel Management Unit" in that tank, sounds like in your case here the front tank.
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Junior User
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Need to look into that furter as its too low 4.9L should be,
Engine off = 50 to 60 psi
Engine on vac line connected to FPR = 45 to 60 psi
Engine on vac line disconnected from FPR = increase 5 to 10 psi.
You're no doubt suffering lean condition due to fuel delivery issues, might not be all the time but certainly not up to par 100% of the time based on figures you've posted here. You had no leaks at gauge? screwed down on valve all the way and was tight?
I'd have to review however if you haven't replaced the fuel filter on it yet I'd surely start with that, put a fresh one on and then recheck fuel pressure after doing so.
Engine off = 50 to 60 psi
Engine on vac line connected to FPR = 45 to 60 psi
Engine on vac line disconnected from FPR = increase 5 to 10 psi.
You're no doubt suffering lean condition due to fuel delivery issues, might not be all the time but certainly not up to par 100% of the time based on figures you've posted here. You had no leaks at gauge? screwed down on valve all the way and was tight?
I'd have to review however if you haven't replaced the fuel filter on it yet I'd surely start with that, put a fresh one on and then recheck fuel pressure after doing so.
Thread Starter
|
Junior User
Joined: Sep 2011
Posts: 69
Likes: 0
Oh missed that part, you gotta correct any fuel transfer issues it suffers from too. If fuel is pumped from one tank to another its the receiving tank that has the problem. As stated you must replace the FMU – "Fuel Management Unit" in that tank, sounds like in your case here the front tank.
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 12
From: Sand Lake, MI
I guess I might if things didn't tend to get so rusty here, had ready available help handy at the time too. All my buddies are at work when I'd be most likely to do the job.
When I pull a tank for a fuel pump replacement I either replace the tank then if border line condition, or at minimum have new straps on hand to put the tank back in place with.
That depends too though, I give everything a real good looking over first before ordering parts, got to around here see what might come apart be useable again and what clearly won't.
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Junior User
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Yes you have to drop the tank, some guys pull the box do it but I don't.
I guess I might if things didn't tend to get so rusty here, had ready available help handy at the time too. All my buddies are at work when I'd be most likely to do the job.
When I pull a tank for a fuel pump replacement I either replace the tank then if border line condition, or at minimum have new straps on hand to put the tank back in place with.
That depends too though, I give everything a real good looking over first before ordering parts, got to around here see what might come apart be useable again and what clearly won't.
I guess I might if things didn't tend to get so rusty here, had ready available help handy at the time too. All my buddies are at work when I'd be most likely to do the job.
When I pull a tank for a fuel pump replacement I either replace the tank then if border line condition, or at minimum have new straps on hand to put the tank back in place with.
That depends too though, I give everything a real good looking over first before ordering parts, got to around here see what might come apart be useable again and what clearly won't.
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