Flushed heater core now truck won’t run, misfire on all 6 cyclinders.

[Angie]

Pull engine, replace w/ 5.0L and upgrade tranny etc. Problem solved.

lol... just that easy.... sounds like mis placed wiring to me.... sometimes it is best to track back and see what has been done to this point. cheers

 

[smythcounty]

Okay I rechecked the firing order again and it is correct. It started doing this after I flushed the heater core and before I swapped out the coil. I only swapped the coil out because I thought I had messed it up with water. I’ll try to replace the plugs and wires tonight and see if that makes a difference. Thanks for all the tips.

 

[RonD]

I would do the 50/50 test before deciding it is a spark issue

Spray fuel into the intake and try to start engine
See if it starts up better and then runs rough after added fuel is used up
If so then you don't have a spark issue its a fuel issue

You could have got some "bad gas" or a clogged fuel filter, totally unrelated to your heater core flush
It happens

 

[SenorNoob]

It happens

Every #%@$ time.

 

[smythcounty]

I would do the 50/50 test before deciding it is a spark issue

Spray fuel into the intake and try to start engine
See if it starts up better and then runs rough after added fuel is used up
If so then you don't have a spark issue its a fuel issue

You could have got some "bad gas" or a clogged fuel filter, totally unrelated to your heater core flush
It happens

I sprayed some carb cleaner in the intake and it idled until the fuel was up. Was able to throttle it up while spraying the carb cleaner and it died after it burned up the carb cleaner. I tried to start it afterwards, rough idled and died.

 

[RonD]

Now that reads like a fuel issue

When did you get gas last?

When was fuel filter last changed?

And can you test fuel pressure?
1999 should be 60psi

 

[smythcounty]

Now that reads like a fuel issue

When did you get gas last?

When was fuel filter last changed?

And can you test fuel pressure?
1999 should be 60psi

Got gas a few days a few days before It happened. Fuel filter been about 4 years and I‘ll have to get a loaner fuel test gauge I don’t have one.

 

[bobbywalter]

Make sure your maf plug and air intake hose is not knocked loose or out of position. Is the air filter dry? Did you pull it right out and test it?

 

[smythcounty]

Make sure your maf plug and air intake hose is not knocked loose or out of position. Is the air filter dry? Did you pull it right out and test it?

I replaced the air filter thinking it may have gotten wet during this ordeal. I’ve checked and resecured the intake hose. I did wonder if I messed up the MAF sensor with the water. I did spray MAF cleaner on it with the same results.

 

[bobbywalter]

I replaced the air filter thinking it may have gotten wet during this ordeal. I’ve checked and resecured the intake hose. I did wonder if I messed up the MAF sensor with the water. I did spray MAF cleaner on it with the same results.

Did you try just leaving the maf unplugged and see how it runs??


Same with cam sensor.


Mat have just fouled plugs from initial wet wire misfire if wires are bad. Does it spark in the dark spraying wires?

 

[smythcounty]

Did you try just leaving the maf unplugged and see how it runs??


Same with cam sensor.


Mat have just fouled plugs from initial wet wire misfire if wires are bad. Does it spark in the dark spraying wires?

Okay so quickly at lunch I unplugged the MAF sensor and it runs better. It idled normal for a minute and then dies. If I try to give it fuel it takes it for a few secs and dies. As soon as I plug the MAF back in it goes back to rough idle and dies. I unplugged the other sensor where the air intake hose goes into throttle bottle, not sure which one that is and it made no difference.

 

[bobbywalter]

So.... Maybe something loose in the intake tract or you broke or loosened some other vacuum hose or sender causing a vacuum leak.

Maybr actual power to maf is not right or meter is fouled.

 

[smythcounty]

So I ordered a new MAF sensor, Throttle position sensor, and idle control valve and Air charge temp sensor and fuel filter and fuel pressure testing kit. I’ll keep you posted with the progress. They probably all needed changed anyways, it never has idled right for the past 12 years.

 

[rumblecloud]

I do it all the time -- even when I know what I'm doing - which is rare...

 

[RonD]

My 1994 4.0l 4x4 manual has all its original sensors and controls, except for O2's which are the only sensors that do wear out, 12 years or 100k miles

I did change the 3 capacitors in the computer a few years ago

HEADS UP
Assume any new part DOES NOT WORK right out of the box
So only swap out 1 thing at a time, or you will end up chasing your tail

If "new" part doesn't change anything then swap back in the old part and move on to the next "new" part
Once you have the vehicle running "like new", you found the problem(s), then you can swap in the "new" parts as you see fit

30 years ago "new" meant "tested and working"
"New" now means "YOU TEST IT, and we will replace it if it doesn't work"

Quality control is labor and that is very expensive, and we wanted cheaper parts, so...................you now get a warranty

Motorcraft(Ford) parts are very expensive, that's because Ford requires Quality Control on parts, tested before being shipped
For most parts its silly to pay the extra costs, but for some...................well its your time wasted in warranty exchanges


Ranger IAC Valves are true solenoid valves, so only Motorcraft or Hitachi IAC Valves can be used for reliable performance
Other brands are hybrid stepper/solenoid valves so can cause issues in Rangers