i see, well after i change the EGR, i should be able to see that it is working from the scanner, as i can see the sensor output. parts are here. i may install them tomorrow morning.

-J0N

 

It's always fun trying to find bad sensors when the ECM has to relearn all of the information and missing values after being parked for some time. If it's pinging it could be knock sensor, O2 sensor(s) and a functional EGR should help things out as well.

 

UPDATE:

ok, replaced EGR, replaced pick up in autozone distributor with a motorcraft unit, replaced O2 with motorcraft unit, and replaced tested good ignition module with another, much older, motorcraft spare. no change what so ever. still pings, still surges at idle, still has a nasty stumble from a dead stop. still also runs fine at cruising speed, and still gets horrid mileage.

i haven't replaced the throttle sensor, the MAP sensor, or the ECT sensor.

opinions on these? i think TPS due to the dead stumble from a stoplight, the map simply because its so important to a speed density motor, and the ECT due to the issues getting worse with heat.

i have tested the TPS and found no dead spots, looked at the MAP sensor with a scanner in liove mode and seen readouts that i THINK look ok, and the ECT reading on the same scanner co-incides with my infrared temp gun.

EDIT-i have a MSD streetfire coil in there. any chance its junk? its about a year old...

-J0N

 

Highly suspect piece right there.......their QC over the last few years has been very spotty.

 

agreed on the coil, get a motorcraft unit back on there.

also update your signature in the control panel with info on your rig so we know what we are dealing with.

 

OK, ill try a coil. i think i still have the factory one somewhere, it was fine ill bet. any way to test it?

-J0N

 

I'm sure there is a specification of DC ohm values for the primary, secondary and across both somewhere on the manufacturer's website. That's a starting point but take the results with a grain of salt. Nothing short of an oscilloscope and/or high voltage probe will tell you the true output.

 

Everything your truck is doing sounds like low fuel pressure! Did you put a fuel pressure gauge on it and drive it around and see as the engine gets warmer you lose fuel pressure? What did those fuel injectors come off of? the ones you got from ebay? fuel pressure is critical on these engines. If you don't have 55 PSI at the rail, your going to have problems. Do you have 2 tanks? Pump in the tank could be a problem, or the one on the frame, I have seen the fuel pump relay in the fuse box melt it's terminals and not give a full 14 volts to the pumps. I have also seen the connector on top of the tank melt, giving the same results, a fuel pressure test is first. you have a lot of parts in this thing and it's almost like your chasing your tail. Make sure the engine is getting the proper amount and volume of fuel. Especially if you used an airtex fuelpump. I had them bad right out of the box, some lasted a couple days, but non of them lasted more than a month. That's my 2 cents, from working on these fords. I have gotten burned before mostly by melted wiring to the fuel system. I have learned my lesson. Hope it helped you.

 

The OP's truck is a 5.0L V8. Max fuel pressure should never go above 45 PSI WOT, KOEO, or with the vacuum hose removed from the Fuel Pressure Regulator.

 

david7.3 - congrats on the "i didn't read this thread at ALL" awards. im glad your willing to help, but cmon man, dual tanks? its a bronco...

anyways, i think i fixed it. i replaced the MSD streetfire coil thats all of a year old with a stock coil from an 86 tbird. runs 80% better. no stalling, no surging, fuel consumption is MUUUUCH better. it does still ping a bit at higher loads, but i think i have an idea as to why. i lowered the base setting of the TPS from 1.05v at idle to .95v trying to lower the fuel consumption. i will put it back today when i get home (night shift FTMFW). i also replaced the FPR awhile back with a cheapie parts store one, and i plan to put the factory one back on, as it turned out my fuel pump had died, and the FPR was fine.

i also will need to find a coil that isn't 32 years old with 300,000 miles on it. i think ill hit the junk yard and look for a late model 5.0 for that. might also find some other stuff. like a mirror. and a gauge bezel.

i have another, unrelated trans issue, which i will post about in a new thread.

thanks for your assistance guys, it did help a lot.

-J0N

 

Do not reset the TPS, you got it within the normal closed throttle value (0.6 - 1.0 VDC). @1.05 you were just on the edge of triggering a code for TPS too high. Monkeying around with the TPS is pointless. The computer has a ratch algorithm that is constantly looking for the minimum closed throttle TPS values and adjusts itself accordingly. Manually adjusting the TPS to some other value inside that range is an exercise in futility.

BTW...glad you got to the root cause.

 

ok, i will leave it be. it has been about 80 miles now, mostly freeway, and the lean condition still persists. today i got the CE light twice. still runs ok, just feels like its starving. i will remove that cheap parts store FPR today, and put the factory one back on.

rla2005, you seem to have the knowledge base that could help with my trans issue. its in a separate thread. i would appreciate your input.

-J0N

 

wanted to update this thread for future searches:

the fix turned out to be a MAP, a TPS, and a shift lever position switch (neutral safety switch). the SLPS (tells the EEC what gear you are in) was causing the shifting woes, AND the stumbling idle and surging.

it now runs ok, only remaining issue is the fairly sever pinging. i get no codes, but it clearly is running lean. its worse towing my pontoon boat.

point is, with surging in gear, but not in park, look at that SLPS (sometimes called neutral safety switch in parts stores, at least it was at NAPA).

-J0N

 

Thanks for the update.

For the record you are referring to the Manual Lever Position Sensor (MLPS). You are correct many part manuals call it a Neutral Safety Switch which is completely wrong.

 

Ok, MLPS sounds right. Anyways, 4 days and it's still in good shape. Just pings real hard under load though, and doesn't have much power. I'm going to start all over with fuel delivery diagnostics, make sure I'm good there, and pull the plugs and have a look at them. The saga continues...