93 xlt 4.0 rough idle issues

[Roadrunner777]

So, good information. Fuel pressures are all nominal. The funny thing is that your engine seems to like low pressure. Why. Fuel delivery depends on pressure and the amount of time the injector is open. So, it seems to me that the injector is open too long. What controls the injector? The computer. But, the computer is not talking anymore. That's 2 strikes on the computer.

Computers are less than $50 on ebay, and not a bad spare part to have around. A more intermediate step would be to test wiring at the computer, make sure it has good power, ground, all that good stuff.

 

[FEAR30X]

So, good information. Fuel pressures are all nominal. The funny thing is that your engine seems to like low pressure. Why. Fuel delivery depends on pressure and the amount of time the injector is open. So, it seems to me that the injector is open too long. What controls the injector? The computer. But, the computer is not talking anymore. That's 2 strikes on the computer.

Computers are less than $50 on ebay, and not a bad spare part to have around. A more intermediate step would be to test wiring at the computer, make sure it has good power, ground, all that good stuff.

Installing BackUp Ecm in morning after codes are run again

 

[FEAR30X]

update ecm swap proved to solve issues, i still have a hint of low noise popping in the exhaust at times

udate[/u] psi 34-36 koeo
psi 28-30 vac on at idle
psi 38-40 vac off at idle
psi 36 hold 5 minute

psi 28-30 runs rough,
then remove fuel pump relay pressure drops sorta slow and
begins to run normal until it hits (zero)


oldpost 93 xlt 4.0 rough idle issues

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93 xlt truck starts up and runs rough,warm or cold doesnt matter


truck runs like new 2-5 seconds after (fpr)= fuel pump relay is removed,
which then it stops loading up on gas and idles fine

f-pressure tested normal

no codes, cel does work

parts replaced or tested
new fpr,
new tps,
new coolant temp sensor=(solved black smoke issue)
new plugs,
new wires
fuel filter

 

[justin_b31]

Where did you buy the ECU?

 

[FEAR30X]

Where did you buy the ECU?

Ebay.com $40,

 

[Roadrunner777]

There's one reason why I don't like exhaust problems... I can never spell 'exhaust' right! Anyway, poping is unburned fuel. New computer, do you get check engine lights at all?

 

[FEAR30X]

There's one reason why I don't like exhaust problems... I can never spell 'exhaust' right! Anyway, poping is unburned fuel. New computer, do you get check engine lights at all?

DREADED C.EL. or check engine has retired for now,

no more problems pop is gone,
runs like a new truck, lol now on to gas gauge intermittin problems & maybe anew UnCracked fans