2.9l low power after warm up

[F350CrewCab]

Got a similar problem. Runs good till it gets warmed up good, then starts that popping when on the throttle And looses power. Can't pull a small hill in 5th gear. It's a 90 model. No cat, new 02 sensor, new rotor/cap/wires/and plugs, new gray thing on side of distributor, timing checked, compression checked. I gave up on it and my son in law and grandson are now fighting it. Suggestions?

 

[F350CrewCab]

Delete this post

 

[lil_Blue_Ford]

It’s Federally illegal and against TRS policy to delete the cat, and your motor was designed to run with one so you hurt power and fuel economy deleting the cat.

When was the last time it had a fuel filter? Along those lines, is the fuel in the vacuum line on the fuel pressure regulator? Have you checked fuel pressure?

Also, being a 90 model, does this one have a MAF sensor? Or is it still the old Speed Density system? Both existed then.

 

[F350CrewCab]

If you deleted the cat we really can't help you, if it came to you without the cat then our help is always gonna start with replace the cat.

FWIW, if it is a single O2 sensor system you might be able to get it running ok (but that is before rangers started in 83, or the clean air act of 81).. In multiple O2 sensor systems (all rangers) the computer needs signal from after cat to adjust and without it will go wonky wild adjusting all over the place or just crutch out into limp mode and get what you have (runs good till warmed up, no power). So the only way to get decent results is to put the cat back.

The 02 sensor is before the cat which was removed because he thought it was plugged. The truck ran fine for a couple years until what I described. Truck had no cat when I got it/ just put it on a couple years ago.

 

[F350CrewCab]

It’s Federally illegal and against TRS policy to delete the cat, and your motor was designed to run with one so you hurt power and fuel economy deleting the cat.

When was the last time it had a fuel filter? Along those lines, is the fuel in the vacuum line on the fuel pressure regulator? Have you checked fuel pressure?

Also, being a 90 model, does this one have a MAF sensor? Or is it still the old Speed Density system? Both existed then.

Truck had no cat when I had my son in law to put it together. Ran fine for years without it. I put the cat on 2 years ago to pass inspection. This just started about 4 months ago. Cat will be replaced but not the issue.

 

[F350CrewCab]

From what you guys are saying the 02 sensor is in the wrong place.

 

[lil_Blue_Ford]

From what you guys are saying the 02 sensor is in the wrong place.

Single o2 sensor system goes before the cat.

 

[F350CrewCab]

No gas in vacuum system. Fuel. Pressure regulator is about 8 years old.

 

[lil_Blue_Ford]

Have you checked for vacuum leaks?

 

[F350CrewCab]

I can't remember whether he did or not. The gauge was in the truck as was the fuel pressure gauge/ I'm waiting on him to call me back so I'll find out. Sure wasn't expecting a legal response though.

 

[lil_Blue_Ford]

I can't remember whether he did or not. The gauge was in the truck as was the fuel pressure gauge/ I'm waiting on him to call me back so I'll find out. Sure wasn't expecting a legal response though.

I’m staff on here, there’s a higher standard. It’s been made very clear many, many times on here over the years on here (despite what my profile says, I’ve been a member since somewhere around 2002). We don’t mess with the Feds. Federal law is that if the vehicle came with a cat, it needs a cat. Most of the forums that have not enforced that no longer exist. Fact is, once we got past the very early cats, they no longer affected engines performance except for when the motor was designed for it and someone removed it thinking they were “fixing” it.

 

[F350CrewCab]

Fuel pressure good, no vacuum leaks. Injectors ohmed out ok. Coil replaced. No codes.

 

[Pat Kunz]

If I'm reading your story correctly, it does run fine until it is warmed up correct? On the old obd1 eecIV systems, they often ran better, when disconnecting the offending sensor. This is because the ecm will simply give the disconnected sensor a default reading and ignore it for the rest of that key cycle. Since it is temp related, try disconnecting your ECT when cold and see if it stays running better as it warms up. If it does, replace the ECT.

Pat Kunz

 

[F350CrewCab]

If I'm reading your story correctly, it does run fine until it is warmed up correct? On the old obd1 eecIV systems, they often ran better, when disconnecting the offending sensor. This is because the ecm will simply give the disconnected sensor a default reading and ignore it for the rest of that key cycle. Since it is temp related, try disconnecting your ECT when cold and see if it stays running better as it warms up. If it does, replace the ECT.

Pat Kunz

I'll check it out. Thanks

 

[F350CrewCab]

New ect

I'll check it out. Thanks

If I'm reading your story correctly, it does run fine until it is warmed up correct? On the old obd1 eecIV systems, they often ran better, when disconnecting the offending sensor. This is because the ecm will simply give the disconnected sensor a default reading and ignore it for the rest of that key cycle. Since it is temp related, try disconnecting your ECT when cold and see if it stays running better as it warms up. If it does, replace the ECT.

Pat Kunz

New ect