2.9l low power after warm up

[Pat Kunz]

Even if new, does it run better if disconnected? eg. possibly a wiring issue to it? Also I may have missed the post, Is it throwing any codes?

Pat Kunz

 

[F350CrewCab]

Catalytic converter has been reinstalled. No change in the truck. Changing 02 sensor did make an improvement but did not fix the issue. That's where I'm at right now. Still no codes.

 

[mr_manny]

You mentioned fuel pressure was good.
What were the readings before and after it's warmed up?

They sell adapters that mount to the schrader valve on the fuel rail.
Makes it easy to attach a mechanical or a sending unit for a remote gauge.

 

[F350CrewCab]

You mentioned fuel pressure was good.
What were the readings before and after it's warmed up?

They sell adapters that mount to the schrader valve on the fuel rail.
Makes it easy to attach a mechanical or a sending unit for a remote gauge.

I'll have to check that and let you know.

 

[bobbywalter]

i dont think i would have put the cat back on but it probably helped. the o2 sensor needs to be in a certain temperature range to work effectively.


sometimes the heater circuit for them fails and causes issues ect on some systems.

the throttle position and map sensor are key components it uses for load, to determine fuel and timing once it warms up and starts looking at the o2 sensor. if the exhaust has a big enough leak that can contribute to stumbles and rough running.

maybe disconnect the map and observe the change after checking the vacuum line and signal.

can you retrieve codes?

often these days at this vintage the pcm is an issue.

 

[F350CrewCab]

i dont think i would have put the cat back on but it probably helped. the o2 sensor needs to be in a certain temperature range to work effectively.


sometimes the heater circuit for them fails and causes issues ect on some systems.

the throttle position and map sensor are key components it uses for load, to determine fuel and timing once it warms up and starts looking at the o2 sensor. if the exhaust has a big enough leak that can contribute to stumbles and rough running.

maybe disconnect the map and observe the change after checking the vacuum line and signal.

can you retrieve codes?

often these days at this vintage the pcm is an issue.

No change unplugging ECT. Still no codes. Did not check fuel pressure after warm up, but will try that. It does back fire through the air intake when you punch the throttle. Also will play with mapp sensor. Dry AC System was unplugged and seemed to help a little. Still pondering all the info. So far, no joy though. We'll keep chasing it.

 

[Brain75]

Heated O2 sensor is on a circuit all by itself if I remember right - listed as HEGO Heater (Heated Exhaust Gas O2).... name didn't stick

 

[gaz]

@F350CrewCab
How exactly did you verify the timing and where did you decide to set it?

 

[F350CrewCab]

@F350CrewCab
How exactly did you verify the timing and where did you decide to set it?

After warm up I pulled that jumper plug or whatever it's called, hooked up my Craftsman timing light, loosened the distributor, shot the harmonic balancer where the marks are and moved it from 12 to 10 btdc. Locked it down, and put the jumper plug thingy back in.

 

[F350CrewCab]

After warm up I pulled that jumper plug or whatever it's called, hooked up my Craftsman timing light, loosened the distributor, shot the harmonic balancer where the marks are and moved it from 12 to 10 btdc. Locked it down, and put the jumper plug thingy back in.

To anyone interested, it was the ECU or computer or whatever you want to call that fancy electronic box thing.