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Little truck little motor

petepilot

petepilot

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central shenandoah valley va,
86 ranger v6 gas.refuses to idle .everything has been checked &some obvious parts replaced .tps.ign.module' bypass air valve' plugs cap rotor.both fuel pumps are good.is fuel injected 42 psi fuel pressure anyone have any ideas?
 
funwithfuel

funwithfuel

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Will county Illinois
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MAF sensor, if it has one. They do all kinds of bad stuff. Aside from that, as Ianjoub mentioned, look for unwanted air.
Have you verified timing?, is it steady or jumping all over. Loose timing chain is possible on something that old.
 
petepilot

petepilot

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central shenandoah valley va,
funwithfuel said:
MAF sensor, if it has one. They do all kinds of bad stuff. Aside from that, as Ianjoub mentioned, look for unwanted air.
Have you verified timing?, is it steady or jumping all over. Loose timing chain is possible on something that old.
Click to expand...
I can start and run it if i pump the accel as if it had a carb. But very long .no way to check mafs. except replace it .am going to do a smoke check next see what that shows
 
Truck Shop

Truck Shop

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With the vacuum porting and vacuum controls for 80's Ford products it very well could be vacuum related. Most likely the spaghetti vacuum lines are brittle and have hair line cracks.
When those rigs were just four years old vacuum leaks were a problem. It should be a 2.8 IIRC.
 
B

BB64

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Dec 12, 2007
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Eden, Wisconsin
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Electrical Engineer
FWIW, my old 87 Bronco II (totaled but still driveable after a rollover in 2001) ate PCV valves something fierce and wouldn't idle for crap when they failed... I remember them getting oily and failing. Since they were fairly cheap and the truck had 230+k on the clock without having been opened up for anything else, I just bought them in pairs, swapped 'em whenever it idled rough and moved forward. I seem to remember that disconnecting the hose (and zip tying it to keep it from whipping around) let it run if I didn't have a replacement on hand.
 
dieseldog5.9

dieseldog5.9

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New Hampshire
Fuel pressure regulator on fuel rail, has a diaphragm that goes bad. Holding throttle to floor is clear flood mode and adds no fuel.
 
kshansen

kshansen

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Mar 11, 2012
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Central New York, USA
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First off I jealous of anyone who can have a 1986 Ford Ranger, up here in rust country the last one of those vanished before the turn of the century!

Been a long time since I worked on anything auto related but most of the previous ideas sound good. One time, not on a Range but an F150 with the 4.9 six, had one that ran terrible and we did not have computer to hook to it so ran it over to the dealer. On a nice warm day when they hooked the computer up they knew the problem real fast as the temp sensor was telling the computer that it was something like -20ºF. So computer was telling the injection system to adjust for that!
 
petepilot

petepilot

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central shenandoah valley va,
kshansen said:
First off I jealous of anyone who can have a 1986 Ford Ranger, up here in rust country the last one of those vanished before the turn of the century!

Been a long time since I worked on anything auto related but most of the previous ideas sound good. One time, not on a Range but an F150 with the 4.9 six, had one that ran terrible and we did not have computer to hook to it so ran it over to the dealer. On a nice warm day when they hooked the computer up they knew the problem real fast as the temp sensor was telling the computer that it was something like -20ºF. So computer was telling the injection system to adjust for that!
Click to expand...
well if you would like to refresh you`re memory take a shot at this one . still haven't figured out what the hell is wrong with this this thing. it will still start and run but only if you pump the accelerator and its fuel injected . not supposed to work like that
 
dieseldog5.9

dieseldog5.9

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Those had a MAP sensor that had wiring issues, and would cause some of these fuel related problems, thinks its at a different altitude and adds or removes fuel. also verify the harmonic balancer hasnt come loose, the rubber wears out and the timing mark moves, meaning you will set your ignition timing to a false position. Also i change the EEC module on any ford that has running issues. Was in the bush in Alaska once got 4 80's Vans started with one known good EEC module.
 
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