4.0 SOHC was jerking at 55-60 mph , now stalling every 2-3 miles.

[Maxmax19773]

When it stalls do you have a check engine light on the dash?
If so then that means the pcm is still getting battery power and it is still sending power out to sensors. This is why the cel is so important

So if your cel does not work we need to check for power and ground, when it stalls
The eec fuse, relay and diode are suspect so we need to rule a problem with them
Out. (Checking for battery power at the red wire at your coil pack will verify the same thing)

I will Post up the 02 pcm wiring diagram

Hi. Check engine light not working . If you remember I got no power on that wire pink green I believe. I have to drive it now so I put cluster back. I didn’t know how to perform other tests you suggested on that check engine light wire but I am ready to get back to it as soon as I have day off and don’t have to drive it . As for coil pack socket- I have pink /green wire and light red / yellow wire I dont think I have solid red one. So with key On I stick steel probe into it (with socket attached to the coil) I got 0.0032 on both. Multimeter on V position. If I did it wrong- please let me know how to do it right. Thank you. Max

 

[410Fortune]

Okay here is the pcm wiring diagram for 02

When the truck stalls out you need to check for battery power at the red wire (pcm) power distribution

Found many places, I was thinking at the coil pack but apparently not
So check at the mass air flow sensor

So by checking for battery + voltage at the red wire with key on and the truck just stalled out We are Confirming that the ignition switch is powering the pcm and the pcm is energizing the pcm relay which then sends power to all vital engine components and powers them Up. I’m thinking that an issue with a fuse, diode, relay or connection maybe why truck is losing spark and stalling out

So when the stall happens I would
First check for power at red wire
Then I would check for spark at a spark
Plug with a simple Spark checker

Battery power put
Multimeter on dc voltage check at battery -+ and - should be 12.2
Volts it ao 14.2 with engine running

Red wire should have battery power with negative
Lead on battery - post and positive
Lead poked into the insulation of red wire at the mas sensor
With key in the on position

 

[Maxmax19773]

Okay here is the pcm wiring diagram for 02

View attachment 458097

View attachment 458098

When the truck stalls out you need to check for battery power at the red wire (pcm) power distribution

Found many places, I was thinking at the coil pack but apparently not
So check at the mass air flow sensor

View attachment 458099

View attachment 458100

So by checking for battery + voltage at the red wire with key on and the truck just stalled out We are Confirming that the ignition switch is powering the pcm and the pcm is energizing the pcm relay which then sends power to all vital engine components and powers them Up. I’m thinking that an issue with a fuse, diode, relay or connection maybe why truck is losing spark and stalling out

So when the stall happens I would
First check for power at red wire
Then I would check for spark at a spark
Plug with a simple Spark checker

Battery power put
Multimeter on dc voltage check at battery -+ and - should be 12.2
Volts it ao 14.2 with engine running

Red wire should have battery power with negative
Lead on battery - post and positive
Lead poked into the insulation of red wire at the mas sensor
With key in the on position

Thanks for helping me out!!!! I got 12 volts on that red wire at mass air flow sensor. It was not stalling for a while and today it stalled again at my parking spot. I immediately checked the wire and got 12 volts ( 12.3 ) to be exact. Key was still in on position. I also connected the taster to the spark plug ( 1 first one in a fire order and got spark ) , what else can I check? Thanks in advance! Max

 

[410Fortune]

Good job

Okay so when it stalls out you still have all the sensors powered and you still have spark,
Nice work! You have eliminated half of the things that can cause stalling as the culrpit

This leaves timing and fuel as the possible issues

When it stalls out what is the fuel pressure? Have we covered this already?
Does it start right back up? Or do you have to wait?

 

[Maxmax19773]

Good job

Okay so when it stalls out you still have all the sensors powered and you still have spark,
Nice work! You have eliminated half of the things that can cause stalling as the culrpit

This leaves timing and fuel as the possible issues

When it stalls out what is the fuel pressure? Have we covered this already?
Does it start right back up? Or do you have to wait?

Hi we checked the fuel pressure with hose inside the cabin while driving and fuel pressure was perfect. I don’t remember checking the fuel pressure when it stalls but when I shot car off it kept the pressure for a while I believe. I got new motorcaft fuel pump unit couple of years ago installed. My original pump was dying and I replaced the whole thing. I might miss up with the timing. If it’s timing issue - what should I do? Retime it again? Okay when it stalled I can start it again and it may stall couple of more times, like in 5 or 15 seconds, or in a mile. So pattern is 2-3 times stalled and then running again, sometimes 20 miles, sometimes 240 miles, sometimes 60 miles. I think replacing pcm relay and cam sensor makes intervals longer between it stalls. Thanks for your help. Max

 

[Maxmax19773]

Good job

Okay so when it stalls out you still have all the sensors powered and you still have spark,
Nice work! You have eliminated half of the things that can cause stalling as the culrpit

This leaves timing and fuel as the possible issues

When it

Good job

Okay so when it stalls out you still have all the sensors powered and you still have spark,
Nice work! You have eliminated half of the things that can cause stalling as the culrpit

This leaves timing and fuel as the possible issues

When it stalls out what is the fuel pressure? Have we covered this already?
Does it start right back up? Or do you have to wait?

Hi . If it’s timing: I just got to remove covers and all stuff that is on the way , release tensioners and time it again? If I am not replacing anything I just got to release it and time it again right? Intake may stay bolted right? I also need advice on passenger side sprocket, the o camshaft one. I had a nightmare to torque it to original specs and after I broke one and paid 96 dollars for a new one I just hand tightened it. I may have couple of days to do this timing thing again if I have to. Please tell me what do you think. Thank you. Max

 

[410Fortune]

It runs fine between stalling and no codes?

If yes then I would tend tot think this is fuel related first timing second

 

[Maxmax19773]

It runs fine between stalling and no codes?

If yes then I would tend tot think this is fuel related first timing second

Hi . It doesn’t run “fine” , but running for a while))) it jerking at 45 -55 with OD jerks less on 55-60 or not jerking at all . I got spark knock time to time. No power) . But it runs sometimes 40 miles with no stalling, record 240 miles after I replace cam shaft sensor . It usually stalls few times in a row. Sometimes 2-4 times within a minute or two, Or stalls 2-3 times within 2-3 miles and then runs for a while. I got codes po 340 and p1309 or just po 340 after I cleaned them up . I am ready to try whatever you are suggesting to check fuel system if it’s not a fuel problem I am ready for timing. Hopefully it’s just release all settings and re time it . Thank you for your help.

 

[Maxmax19773]

It runs fine between stalling and no codes?

If yes then I would tend tot think this is fuel related first timing second

Hi . I may have day off to work on the car. Any tests I can perform to see is it fuel system or not? If I can get to the point that it’s not fuel system I can planning to get couple of days to work on timing. Thanks. Max

 

[410Fortune]

Yes when it stalls do you have full fuel rail pressure? Most sohc engines have a fuel pressure test port

 

[Maxmax19773]

Yes when it stalls do you have full fuel rail pressure? Most sohc engines have a fuel pressure test port

Hi . Just checked. While running it’s 68-69 , when stalling drop till 65 . Hose with gage inside the cabin so I was able to read it all the time. What else is there that I can check? Thank you.

 

[Turdle]

Did check engine light illuminate when it stalled?

 

[Maxmax19773]

Did check engine light illuminate when it stalled?

Check engine light not working since I got the car. I got no power on wire at instrument cluster socket. Could not find the reason yet .

 

[Turdle]

It sure would help, your symptoms match pcm power loss,

 

[Maxmax19773]

It sure would help, your symptoms match pcm power loss,

I got 12 v on red wire at mass air flow sensor at the moment it stalls . I think we eliminated pcm issue ( fortune410 Guide me through all this tests ) we ended up its fuel issue or timing issue. I was chasing the issue with check engine light not working but had to quit because I got to drive it now.

 

[Turdle]

Imo the " timing" as In timing chains are probably good.

Ignition timing , could be going away though.

Have you tried a new crankshaft position sensor?

 

[Maxmax19773]

Imo the " timing" as In timing chains are probably good.

Ignition timing , could be going away though.

Have you tried a new crankshaft position sensor?

Ignition timing?? What’s that ? How can I check it out? All sensors dpf, crank , cam , air flow ( new Ngk) other sensors are new motor craft of ford

 

[Maxmax19773]

Imo the " timing" as In timing chains are probably good.

Ignition timing , could be going away though.

Have you tried a new crankshaft position sensor?

I got old crank sensor around, I can try to replace motor craft one ( 2 years old from RA) .

 

[Maxmax19773]

Imo the " timing" as In timing chains are probably good.

Ignition timing , could be going away though.

Have you tried a new crankshaft position sensor?

Can you please give me more details on “ignition timing” I am getting myself more and more confused searching internet about it. Thank you

 

[410Fortune]

The ignition timing I believe is what tells the pcm “we are rotating go ahead and apply fuel and spark”
The crank sensor tells the computer the engine is rotating (via starter)
And the cam sensor is used to start firing in the correct time (time the injectors and spark to the camshaft)

This is a very odd issue you are having
You don’t lose spark and you have plenty of fuel pressure even when it stalls …
Very odd. Could be the pcm itself or something in the wiring/ grounds