Sluggish and now much low end torque.

[drewskiw]

Not sure if this is the right place to ask for advice, but I’m giving it a try. I have a 1995 K1500 5.7 TBI. It runs kind of doggy. Not much torque off the line. I noticed after putting a can of seafoam in the fuel tank just to clean up the fuel lines, it ran so much better with power. Next fill up without a can, it was back to running a little slow. Any idea’s? Fuel Filter was replaced along with plugs, wires, cap, and Rotor.

 

[sntrym]

Check your gasoline source. If you got gas from the same place both times, you may have gotten bad gas. it's happened to me a few times. The ECM will retard the timing if the knock sensor detects pinging or knocking causing loss of power.

 

[Schurkey]

Connect a scan tool, find out what the computer is trying to tell you.

Verify fuel pressure.

 

[drewskiw]

Check your gasoline source. If you got gas from the same place both times, you may have gotten bad gas. it's happened to me a few times. The ECM will retard the timing if the knock sensor detects pinging or knocking causing loss of power.

I’ve gotten gas different places. It always runs like that, unless there’s some sort of octane booster it seems. You can physically feel the difference. Slow to accelerate/not much power. That is unless you press the gas harder. I heard checking my timing may be a solution. No codes when I scanned.

 

[Schurkey]

Stop looking for "codes", start looking at the sensor data, and the computer output data.

 

[sntrym]

I’ve gotten gas different places. It always runs like that, unless there’s some sort of octane booster it seems. You can physically feel the difference. Slow to accelerate/not much power. That is unless you press the gas harder. I heard checking my timing may be a solution. No codes when I scanned.

I would definitely check the timing then. Make sure to disconnect the tan wire behind the glove box then set to 0 degrees BTDC. Once you've done that, reconnect the wire, clear codes, and take it for a spin. If that doesn't fix it, you'll need to look at the sensor data.

 

[drewskiw]

I would definitely check the timing then. Make sure to disconnect the tan wire behind the glove box then set to 0 degrees BTDC. Once you've done that, reconnect the wire, clear codes, and take it for a spin. If that doesn't fix it, you'll need to look at the sensor data

Update: I checked the fuel pressure and it’s only running about 7 psi. I think spec is supposed to be between 9 and 13? I believe I need a fuel pump. Thanks for the suggestions! I still will check my timing just to make sure.

 

[RichLo]

Dont worry about a fuel pump yet. Its probably just your fuel pressure regulator. You can either get a new spring and diaphram or do the right thing and take the top of the TBI off and add a quarter or two (yes, the USA currency) under the FPR to bring the fuel pressure up a few PSIs.

Bolt it back together with the same gasket and see how it drives.

-Just my $0.50, lol

 

[BOOT]

Fuel filter before or after seafoam? If after, it could possibly be clogged again with gunk the seafoam loosened up, not likely but possible. I've herd of people switching to E85 and it cleans the system n clogs stuff up.