I don't have access to a scanner and when I did the six litre tune up I put in the MSD coil with accel wires and I can't remember the plugs but I think I put in motorcraft. I have never changed the MAP sensor but I also have never had a code from it. I am game for anything as long as we keep it under a hundred bucks or so. I am also running stock exhaust but plan on opening it up next year since I blew the truck wad on painting and other things this year.

 

OK so I plugged in the code reader and no codes are present KOEO or KOER. I looked in the exhaust pipe and itis a bit sooty and blacker than the inside of a bruised crows but. There is no smoke and my gas mileage is horrific for my driving. I have access to a Fluke 787 process meter but no O scope or scanner. Where do I go from here?

 

You actually need a scan tool. It plugs into the diagnostic connector or between the engine harness and computer and will tell you EXACTLY what EVERY sensor is doing. From there you can watch the values change as the computer compensates for input. I'm willing to bet that you've got either a bad fuel pressure regulator or a bad injector. What oil are you running in it? Anything over 10w30 will decrease fuel economy. Do you have access to non-blended gasoline? Ethanol is great for racing but bad for fuel economy. I'd gap your spark plugs back the .044 as well, you'll get a better quality spark and burn the fuel more completely. I'd try setting your timing at ~12dbtdc as well. You have a rich condition, and you don't have a code thrown. Which is odd, does it idle smooth?

 

96 F-150 SuperCab shortbed, 351, E4OD, 4x4, 3.55L gears. 31x10.50x15 tires, no lift, plugs gapped .055, stock ignition timing and components, no muffler.

Gets 16.5 MPG in town if I'm easy on her... which I usually am. On the highay I have seen 17+, highway speed limit is 70 and I usually do 65-70

 

In our 86 F150 4x4 302 auto transmission with overdrive regular cab long bed gets around 12 but most of time it is towing so I don't know not towing.
Trav

 

I don't have access to a scan tool but I will see what I can do. As far as oil I run 5w30 Full Synthetic in the winter and 10w30 full synthetic in the summer on 3500 to 5000 mile intervals. I will have to check but my money says I probably don't have a local station with non ethanol fuel. Plug gap is easy enough I can get that done but I seriously don't believe thats the problem since this was happening a long time before the regap. Timing at 12 will ping when either my cooker or my 5th wheel are hooked up so I leave it at 10 to 11 degrees.

I'll check some of the local auto parts stores for a scan tool I can rent but what exactly will I be looking for?

 

Oh yeah and idle is very smooth when warm but hasan occasional hesitation especially when turning thesteering weel quickly under low rpm manuvers.

 

You said it hesitates when you turn the steering wheel. have you checked the ignition switch?

You'll need an OTC scan tool with the OBD-I,ford EEC-IV harness. It should plug into the connector under the hood.

 

OK I have a Snap On Scan tool from now through the weekend. What data do I need to be watching and under what conditions? I hooked it up tonight at idle and the MAP sensor stayed around 103Hz, Injector voltage was about 5 I believe.

 

You said the map sensor stayed the same? It should increase at idle and decrease when throttle is supplied. If it's not changing reading that indicates a ruptured diaphragm and it needs to be replaced. That could cause a serious issue in fuel economy. What are the values from the oxygen sensor(s)? That will also tell you a LOT about how it's running.

 

'05 Reg Cab, SWB, 347 Mass Air, Quarterhorse Tuned, 3.55 LS gears, 275/45/20's, 4r70w tranny. Average 16-18 mixed, and recently topped 23 on a road trip to St. Augustine, Fl.....went 675 miles on 29 gallons (23.27mpg)...interstate driving.

 

So here is the data thus far and the conditions when the data was recorded. Keep in mind it is hard to gather the data while driving so driving data is minimal. The MAP sensor stayed at 103 unless there was acceleration and under full load going through the gears the highest it ever got was 156. O2 Sensor seemed all over the place to me buthave been close to failing inspection the last few years because of EGRand haven't been able to pinpoint why. I have changed the EGR vacuum controller and tested the pinnel sensor and the readngs seemed correct to my as in they were all inside the scale under full movement.

edit::: I apologise for the data all being crammed together the forum removed all my spacing when I posted and crammed it. The first number will be cold idle the second will be warm idle and the third was while driving.

Reading Engine Cold Idle Engine warm Idle Moving
RPM 870 775
MAP (HZ) 104 103 96-156
O2S (MV) 788 50-700 150-650
TPS .93 .93
CCC=TCC OFF OFF
ECT (*C) 13-20 93
TP MODE C/T C/T
ECT (V) 2.9 .55
IAT=ACT (V) 3.26 1.19
IAT=ACT (*C) 17 65
STE=EVP (V) .38 .38
STE=IDLE AIR (%) 51.5 20
EPC (PSI) 5 5
EVR (%) 0 0
INJ PW1 (ms) 6.52 4.91
SFTRIM 1 (%) 3 -1
BATT (V) 14.8 14.4
OP/CLL LOOP OPEN CLOSED
Spark ADV 24 17
V REF (V) 5.01 5
MAN LEV POS PARK PARK
TR=GEAR PRND PRND
CANP=PURGE OFF OFF
IFT=TOT (V) 3.04 2.25
P/NEU POS P-N-- P-N--
ACCS=A/C OFF OFF
Octane Adjust OFF OFF

 

I have to return the scan tool tonight, anyone have any ideas on this? I am guessing something may be wrong with the O2 sensor since the readings are all over the place.

 

O2 sensors are very hard to read without an oscilloscope, under normal operation they are switching back and forth between about 0.1v and 0.9v at a pretty high frequency and that makes it near impossible to get any meaningfull data from a digital device. If you just see a static low or high voltage that indicates the sensor isn't switching but that still doesn't mean the sensor is bad, if for example the motor is running stupid rich because of a leaking FPR or stuck injector the computer won't be able to compensate enough to get the fuel ratios into the correct range and the sensor will never switch. But this could also be caused by a blown fuse or broken/burnt wire on the O2 heater circuit too, or because some other sensor problem is causing the computer to run open loop all the time. When you tried to pull the codes did you get the all clear 11 or 111 codes or nothing at all? If you got all clear that's fine but if you got no response from the computer at all that's another thing and suggests user error, a wiring problem, or a bad PCM.

 

Computer read all clear.