I have a 2002 manual throttle body on my 5.3l vortec motor. Under the throttle body are two hose inlet/outlets. They are not hooked up to anything. Two issues I am suffering from at this point are poor milage, and when the thermostat opens up surging and sputtering. How do those un accounted for water coolant hook ups relate to this problem? Am I looking at the wrong thing.

When the motor is cold it runs smoothly with tons of power. As soon as the temp needle moves it goes into sputtering fits. it also runs cool enough that I don't get much heat from the interior heaters. What should I be looking for?

Thanks

I am not using those lines on my 6.0, all it does is send coolant through the throttle body. I have no problem running too cool.

I have a 2002 manual throttle body on my 5.3l vortec motor. Under the throttle body are two hose inlet/outlets. They are not hooked up to anything. Two issues I am suffering from at this point are poor milage, and when the thermostat opens up surging and sputtering. How do those un accounted for water coolant hook ups relate to this problem? Am I looking at the wrong thing.

When the motor is cold it runs smoothly with tons of power. As soon as the temp needle moves it goes into sputtering fits. it also runs cool enough that I don't get much heat from the interior heaters. What should I be looking for?

ThanksIt won't hurt anything all it does is heat the TB to prevent icing at near idle conditions.

It would appear that someone has done some mods to the truck. It might have a 160* thermostat in it, I would check it and replace it anyway. Start with the basics. Tune up plugs wires filters. Then check for intake leaks. Plus is it giving any SES codes.

It would appear that someone has done some mods to the truck. It might have a 160* thermostat in it, I would check it and replace it anyway. Start with the basics. Tune up plugs wires filters. Then check for intake leaks. Plus is it giving any SES codes.[/QUOTE]

I think the thermostat is working, but it might be a 160, so I will change it back to stock. Stock is 180 or 195 right? Everything changes as soon as the temp needle bumps up, that is the only corolation I can feel right now. I changed plugs during my 02 trouble shooting, mabye they are fouled agian. It runs very well for two or three minutes while it is cold then goes to s*#t.

What is the inlet/outlet on the side of the throttle body that is connected to the passenger side valve cover. When it is connected the idle surges, disconnected it idles smooth. The valve cover side seems to be pulling a significant amount of air. Other than playing with this connection I cannot find any vacume leaks.

The codes I am getting are high idle, and high voltage from the 02 sensors (only when I run a little e85).

I think the thermostat is working, but it might be a 160, so I will change it back to stock. Stock is 180 or 195 right? Everything changes as soon as the temp needle bumps up, that is the only corolation I can feel right now. I changed plugs during my 02 trouble shooting, mabye they are fouled agian. It runs very well for two or three minutes while it is cold then goes to s*#t.

What is the inlet/outlet on the side of the throttle body that is connected to the passenger side valve cover. When it is connected the idle surges, disconnected it idles smooth. The valve cover side seems to be pulling a significant amount of air. Other than playing with this connection I cannot find any vacume leaks.

The codes I am getting are high idle, and high voltage from the 02 sensors (only when I run a little e85).I can you post some pictures of the TB to make sure what your talking about.

That sounds alittle weird.

I just got my 5.3 running and am having a very similar problem. The motor started smoking on inclines and smelled like coolant. I'm pretty sure we connected the lines back to the proper spot on the intake but I unplugged the hose from the coolant return on the TB to the top of the intake and it was a vaccum port on top of the motor. I ran the line from the TB to the overflow outlet on my radiator and plugged the vaccum port. The coolant smell seemed to dissapear then but it was still running like dog shit whenver the motor was warmed up.

I did a little more investigating and it seems pretty normal to not run coolant through the TB. I am going to leave that part as is, and work on the problem from another angle.

The coolant temp sensor may have been the source of some of these problems. I replaced it, have cleared the computer, and gone through one heat cool cycle with good results. the idle is pretty smooth and slow (tachs not hooked up yet). Pulls strongly through the gears without any stumbling, and the gas needle is not moving at nearly the pace it was. It did stumble a little cruising in 5th, so I put it back in forth and cruised at 65 with no issues. I haven't floored it yet to see if it still cuts out, but this has been a big change in the right direction. I am letting it cool down for a couple hours and then I am going to go for another spin.

Really it felt pretty good. I think I am hyper sensitive right now because of all the issues that have been coming up.

Stock EFI needs that coolant input, if I remember right it runs rich until it reaches temp, then leans out some, and starts running off the O2 sensors.

Carry on. ;) And :beer: for not being a whiny bitch. Very refreshing!!! :laughing: