Mass air flow voltage issues
Thread Starter
|
Freshman User
Joined: Jun 2015
Posts: 29
Likes: 0
Ok. Converter is out and the modulator is changed. Drove it around t block and had a 2-3 flare. Called my transmission guy and apparently I left the pin out of the modulator. Didn't even see the pin when it fell out. Just letting anyone know for future reference. Replaced fuel pump assembly, float had a hole in it causing sender no to work. Truck idles much better. Drove better but still has a slight hesitation. I am really starting to think I have a leaking injector. Pressure on the rail is still dropping. I am going to do a little more testing before I start with them.
Thread Starter
|
Freshman User
Joined: Jun 2015
Posts: 29
Likes: 0
Ok back at it again. Lots of replaced parts new MAF, CTS, IAC, TPS, O2s, new fuel pump. filter, injectors. Truck runs better but still hesitates at start and runs rich. On my list of other possibilities are Crankshaft sensor, camshaft sensor, ignition module, PCM.
I have read of some failing crankshaft sensors causing similar problems. Is this a plug and play or are there specials steps involved?
I am getting 2 codes from my eec reader. Key on engine off I get 10 and 157. Although the MAF is test correctly now. I'm not sure what the 10 is.
I have read of some failing crankshaft sensors causing similar problems. Is this a plug and play or are there specials steps involved?
I am getting 2 codes from my eec reader. Key on engine off I get 10 and 157. Although the MAF is test correctly now. I'm not sure what the 10 is.
Moderator
Joined: Jan 2004
Posts: 13,851
Likes: 111
From: SW Va
Lets think about this some more & back up to where you left off on the last page, with ordering a new fuel pump assy & testing the old fuel pump at the tank & finding voltage to it & fuel pressure output was ok there & were about to remove the old pump for inspection, so what did you find & did you install a new fuel pump assy???? If so, how did the new pump fuel pressure & flow rate check out at the fuel rail Schrader valve test port????
Code 10 = cyl #1 low on cyl balance test. Had you performed a cyl balance test???
P0157 = MAF sensor below minimum voltage. So for some reason the computer is still unhappy with the MAF sensor.
Code 10 = cyl #1 low on cyl balance test. Had you performed a cyl balance test???
P0157 = MAF sensor below minimum voltage. So for some reason the computer is still unhappy with the MAF sensor.
Thread Starter
|
Freshman User
Joined: Jun 2015
Posts: 29
Likes: 0
I did install a new pump assembly. The old one was losing pressure slowly and the sending float was ruptured. Fuel pressure is good now. I did not do a cylinder balance test because I had read the code 10 was not a fault code but rather a separator. My code book that came with the reader doesn't show a code 10. I know it is getting fuel because I can hear the injector pulsing, and the injector is new. I will check for fire, it does have a new coil pack, wires and plugs.
Will have to wait to it dries up a little.
Will have to wait to it dries up a little.
Moderator
Joined: Jan 2004
Posts: 13,851
Likes: 111
From: SW Va
OK, good feedback on replacing the fuel pump assy. Now you need to check fuel pressure & delivery rate at the fuel rail Schrader valve test port. KOEO fuel pressure should be 35-45 psi. At idle, with the fuel pressure regulator vacuum hose attached, fuel pressure should drop to 25-35 psi. At idle with the fpr vacuum hose removed & plugged, fuel pressure should go up to 35-45 psi.
If the pressure is corrupt, look for fuel in the vacuum line from a ruptured pressure regulator diaphragm. If the diaphragm is leaking, it'll corrupt fuel trim rich, as the vacuum will suck it into the intake manifold!!! If the fuel return line between the regulator & tank is clogged, pinched shut, crimped or otherwise restricted, it can cause over pressure woes & the pump to draw too much current from trying to pump into a dead end load/clogged/restricted return line.
Fuel pump delivery rate should be 1/2 pt/15 seconds. So get us some fuel pressure & delivery rate data, to make sure the new pump, lines & fuel pressure regulator are doing their thing & post the numbers.
If the pressure is corrupt, look for fuel in the vacuum line from a ruptured pressure regulator diaphragm. If the diaphragm is leaking, it'll corrupt fuel trim rich, as the vacuum will suck it into the intake manifold!!! If the fuel return line between the regulator & tank is clogged, pinched shut, crimped or otherwise restricted, it can cause over pressure woes & the pump to draw too much current from trying to pump into a dead end load/clogged/restricted return line.
Fuel pump delivery rate should be 1/2 pt/15 seconds. So get us some fuel pressure & delivery rate data, to make sure the new pump, lines & fuel pressure regulator are doing their thing & post the numbers.
Thread Starter
|
Freshman User
Joined: Jun 2015
Posts: 29
Likes: 0
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Moderator
Joined: Jan 2004
Posts: 13,851
Likes: 111
From: SW Va
OK, that's good feedback, so we now know the fuel pump, lines & pressure regulator are doing their thing. So what remains are fuel injectors, spark & spark timing & compression to make er run.
You can use an inductive timing light to safely test for spark & timing.
If your scantool will perform a cyl balance test, it can point out problem cyls, so you can go there to look for compression, fuel injector, or spark delivery problems & that can shorten trouble shoot time. Let us know what you find.
You can use an inductive timing light to safely test for spark & timing.
If your scantool will perform a cyl balance test, it can point out problem cyls, so you can go there to look for compression, fuel injector, or spark delivery problems & that can shorten trouble shoot time. Let us know what you find.
Thread
Thread Starter
Forum
Replies
Last Post
wantaford
1987 - 1996 F150 & Larger F-Series Trucks
6
Jun 7, 2009 01:20 PM