Hello, I have a 2009 Ranger 2.3 L manual with about 100000 miles. The engine was bogging down and I just found out that the MAF sensor is bad from testing it. In the process, I measured my fuel pressure to be 73 psi (manual says 60-65 psi). So I have two questions if someone would please inform:

a.) Is there any chance of just cleaning the MAF sensor. The sensor has zero volts when running and warm (or .02 v) and barely changes when reving the throttle.

b.) Perhaps then the high fuel pressure is an unrelated issue. Is this so high that I must change the regulator as I have to change the pump as well? Might it be some other issue than the regulator which is what the Hanes manual says?

Thanks for your help.

p.s. one theory I had for the high fuel pressure is that the bad MAF was leading to bogging and lean conditions and the computer was running the pump more to compensate but I think the computer might run the pump based on fuel pressure not the o2 sensor (sorry, not a mechanic).

 

Welcome to FTE.
Seeing as how you seem to have more than one problem, with your ELM, or the like scan tool, scan the engine computer for trouble code clues & post All code Numbers, as they can help focus your trouble shoot. We're to work the lowest trouble code numbers first.
Good idea to have come by a repair manual & to have checked fuel pressure & the MAF sensor, as both are out of tolerance range & need attention.
Are you getting B+ voltage At the MAF sensor connector VPWR contact at KOEO????
Have you measured the MAF sensor heated element resistance to see if its open circuit/infinite resistance???
On our model Ranger, the fuel pressure regulator has been moved to the fuel tank as part of the fuel pump assembly.
Check & post the no electrical load B+ voltage with the engine at idle & about 2000-2500 rpm, then turn on some heavy electrical loads, like headlights, fog lights, heater/AC blower on High speed, cigar lighter pushed in & measure B+ again at idle & about 2000-2500 rpm & post the numbers, this will check the alternators output voltage regulation at no load & loaded condition to make sure you have a regulated voltage feed to the electrical system that's in spec.
Some starting trouble shooting thoughts for consideration, let us know what you find.

 

If you measured it correctly then no it needs to be changed. Does your truck have a K&N or some other brand of oilded air filter in it? If so that is likely responsible for the death of your MAF meter so you would be wise to remove it and install a dry filter.

Yes it is unrelated to the MAF issue.

Why do you have to change the fuel pump? I'd suggest you fix your MAF problem first and then drive the truck to see how it responds. If there still appears to be a problem or fuel consumption is very high then retest fuel pressure with a different gauge, if it's still over spec then replace the regulator.


No.. these systems don't work like that. The computer has no control over the fuel pump besides turning it on or off, and fuel pressure is modulated by the regulator which is not under computer control either.

 

Thanks.

--The only code I've gotten is Code p2195 (Bank 1 sensor 1 O2 sensor stuck lean). The engine light goes on and off. In terms of the other questions, I'm not sure how to translate that to the instructions I used but I did check the 'power circuit,' the 'ground circuit,' and the 'second ground circuit' and used the pin out diagram for my make and model from autozone. They all got 12.5 volts...which is actually .5 volts too high according to the instructions I used. I also checked one cable on the air temperature side (it has six cables) and got 5 volts which should be correct as well. When I got near zero volts on the signal wire and no change from revving the throttle, the vehicle was properly warmed up by running it 10 miles on the freeway (70 mph). The battery is 12.8 volts not running which is a little high but 14.2 running so I don't think the alternator is overcharging (I'm paranoid on this one because I had my alternator changed a few months ago and it was overcharging until it was changed again). 13.9-14.2 volts everything running. Same revving throttle.

--That's good info about the air filter. I forget which one I bought. I'll ask the parts store when I buy a new one. Also, I meant that, if I change the regulator, I need to change the pump as well if the manual is right which is why I don't want to change the regulator. I'll change the MAF sensor before I change anything more expensive or time intensive. That's a good point about the fuel gauge since I'm using a rental one from autozone—and I'd hate to know where that's been.

I just ordered an MAF filter so early next week I'll change that and see if it fixes the stuck lean code and check the fuel pressure again. If it's still high, I'll use a different gauge. If still high, I guess I'm in for it with the whole pump/regulator combined change.

 

No you don't need to change the fuel pump, I don't understand why a manual would suggest that but Haynes manuals are known to be packed with mistakes and lack info in other cases. That said the info I found suggest fuel pressure should be between 40-60psi at idle so if you get over 70 then the regulator is bad I would think unless you measured it under different conditions.

 

I just looked up my figures for the 99 fuel pressure & it specs 64 +/-8psi, as your measuring only 1 psi over max spec, I'd not worry about fuel pressure & focus on your MAF sensor woes & get that put right, as that could corrupt the fuel trim & muck up driveability.
Sounds like you have B+ to the MAF sensor. Is it's heated element measuring open circuit???
EDIT: Good feedback on the alternator output. When you did the tests with rpm change, did you also do the rpm output readings with the electrical system electrically loaded as described????

 

Before replacing the MAF sensor, try removing, letting it cool if just driven & try cleaing it with CRC or Valvolene non residual MAF sensor spray cleaner. Don't let the spray wand touch the sensor. Keep it squeaky clean when reinstalling so as not to contaminate its calibrated heated element & have it muck up its PID reading to the computer.
As mentioned, if an oiled foam, or cotton gauze air filter has been used, they're known to pass enough dirt, or if over oiled to have it migrate to & dirty up/corrupt the MAF sensor calibrated heated element, that's measuring true airfow into the engine by having its resistance change as cooling air flows over it. So, if its dirty that'll insulate it & corrupt its PID output to the computer & that'll cause the computer to muck up fuel trim, by thinking not much air is entering the engine, thus have the fuel injectors give a short shot of fuel & thus a lean burn reading reported by the O2 sensor, all a vicious circle. So find out what gives with the MAF sensor not properly sensing or measuring air flow into the engine.
With B+ going to the sensor, right now with what you've reported, it seems likely its either really dirty & not able to sense changes in air flow, or its open circuit.
If its dirty, its only to see filtered air, so you need to look up stream at the air filter, air box, air tube. Look at the air box & air tube for loose connections, loose or missing fastners, cracks. Replace the air filter with the specified Ford/Motorcraft air filter. More thoughts for consideration, let us know what you find.

 

Thanks, so I'm actually not connected to internet much until tuesday. However, in general, I'll wait to look at the fuel issue until after I fix the MAF issue. From what it sounds I will at most need to change the regulator but maybe I'm not actually that far out of specs. I've noticed the same thing about the Hanes manual in that it isn't very descriptive and has been outright wrong even with the few things I've had to do. MAF sensor is already on order. I tested all four circuits going to the MAF sensor according to the instructions I used. But after I replace it when I get it from ordering it, I don't want it to go bad again (!!) so I'll review the suggestions about the air filter and everything else when I change it next week. Yes, I had my radio, hazards, lights, windshield wipers, and AC on when I revved the engine and took the 13.9-14.2 voltage off the battery.

Thanks for all your help and have a great beginning to your weeks'.