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Ranger5.0

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shit, im an idiot. high tps voltage can mean that the tps ground is damaged. the suply wire needs to be working to get suck a code, correct?
 


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Ranger5.0

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makg My mistake man, studying for the exemption test is makin my brain slowly turn to mush haha
 

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after a bit more thought, a bad tps wouldnt be the root cause of the problems tho..... a combination if that plus some other problems like fuel delivery could do it tho, no?
 

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after a bit more thought, a bad tps wouldnt be the root cause of the problems tho..... a combination if that plus some other problems like fuel delivery could do it tho, no?
Yes, I agree. My original thought was that a broken ground accounted for it all, but the TPS voltage measurement seems to isolate the ground to inside the TPS. I don't see how that could affect the torque converter.

The computer thinks the throttle is wide open, so it's probably very rich. That MAY account for the bad performance.

The right thing to do here is warranty the TPS (it's clearly DOA) and reevaluate. Check spark plugs for fouling and proper gaps.
 

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I hope that we hear more back from him on this one. I've seen people chase their tails trying to figure out weird problems, and it turns out to be something so simple it was overlooked all along. Ya'll all are making some good points and comments; I'd just like to be sure that the truck has both the engine and body well grounded to the battery, to get it ruled out as a factor.
 
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MAKG

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It's true. I've seen some really bizarre behavior from hosed battery cables and especially body grounds.

My former Bronco II was once getting negative oxygen sensor readings at the computer (curiously, it didn't flip a lean code, though it really should have -- it just fouled plugs). Turned out to be a poor body ground that let the HEGO sensor float a little with respect to the PCM.

It's gotten to the point that a new-to-me vehicle gets its charging system worked over, first thing. The Exploder didn't pass and I ended up replacing both battery cables (voltage drop on cranking). Emissions tests sure work better that way....
 

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Ya, It would be good to get some input on how the trucks doing. Your right, if the ecm thought the TB was wide open all the time, it would make it run rich, and would for SURE affect drivability. If the tps went bad, the rich condition would foul plugs and could maybe(depending on how long its bee ngoing on for) foul the O2s and partialy plug the cat'...Thats a "pull out of ass" therory tho...its actualy somthing were learning right now, cause and affect type stuff
 

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It's true. I've seen some really bizarre behavior from hosed battery cables and especially body grounds.

My former Bronco II was once getting negative oxygen sensor readings at the computer (curiously, it didn't flip a lean code, though it really should have -- it just fouled plugs). Turned out to be a poor body ground that let the HEGO sensor float a little with respect to the PCM.

It's gotten to the point that a new-to-me vehicle gets its charging system worked over, first thing. The Exploder didn't pass and I ended up replacing both battery cables (voltage drop on cranking). Emissions tests sure work better that way....
i'll be damned,battery cables?i've been chasing grounds all around this thing while waiting for the ford tech manuals to get here.the original cables are on it and look ok,any idea what the risistance should be through factory cables?
 

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Zero. But it's a lot easier to see if they work with a voltage drop test while cranking.

All the voltage drop should be at the starter.

Similar deal with the pigtails (though you don't need to be cranking -- but it might be a good idea to have it idling warm if it will do so).
 
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RobbieD

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i'll be damned,battery cables?i've been chasing grounds all around this thing while waiting for the ford tech manuals to get here.the original cables are on it and look ok,any idea what the risistance should be through factory cables?
Hey skippy. As close to zero ohms, as possible. Measured between the engine block (or frame, or body, for that matter), and the battery negative post with a ohm meter (VOM).

I'm still looking for a procedure on checking the SPOUT circuit, you get my PM from Friday evening? Have you figured out anything else on yours?
 

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Zero. But it's a lot easier to see if they work with a voltage drop test while cranking.

All the voltage drop should be at the starter.

Similar deal with the pigtails (though you don't need to be cranking -- but it might be a good idea to have it idling warm if it will do so).
never occured to me to check the cables,truck starts with a tap of the key and maintains battery charge.i'll check it out.thanks.
 

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as fas as the positive cable goes, the voltage drop is most crucial during cranking, thats when it(and the ground cable) are seing the most amps. Check from the center of the batt term' to the center of the B+ term' on the starter, then crank it over. Grounds on the other hand can be a bugger. A bad ground hear, bad ground there and life can get a bit frusterating. Sensors need a good ground to operate properly, the ecm needs a good ground to operate properly, tho, it has some redundent grounds internaly/externaly to compensate for ground issues. Lose damaged and corroded conectors are usualy the ones to blame for many "gosts" in an electrical system. The voltage drop on a ground cable/wire should never be more then like .5 volts, and on a power wire it should be no more then like, i think .o5 volts. I know half a volt doesnt sound like much, but when you add them up through out a circuit then it doesnt take long to cause some problems
 

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I do have a broken blk wire on the pigtail from probes. The other two wires are damaged also. I will get a new pigtail. Will the new pigtail being spliced in cause voltage to drop?
(p.s. you guys are cracking me up!)
 

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Then you found a broken ground. Good! FYI, one of those pigtails grounds the oxygen sensor and the other grounds the computer. If either is poor, you'll get wrong mixtures and false mixture codes.

Wires and direct connections should have no voltage drops. Voltage drops should occur at loads only (the starter in the cranking circuit example), and in reverse at the battery and alternator.

Those pigtails often come with battery cables. I recommend getting them that way, rather than splicing, for this particular application. Splices are hard to seal from the elements and are very vulnerable near the battery. But if you do splice, solder the splice (you'll need a VERY POWERFUL iron or a small propane/butane/whatever torch to solder 2 or 4 gauge cable) and seal it up with heat-shrink. Use electrical (rosin core) solder; the plumbing stuff (acid core or solid) will corrode connections.

The clamp-type battery connectors will work for a time, but they don't last.
 


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