48snowman48

I installed a used hx35w on my truck today to replace mine that went out. The price was right and I needed it to get the truck going again. After getting it on with no problems, I noticed that the turbo doesn't like to build boost. The truck was a slug as soon as I hit 3rd gear, and it looked like I was followed by a freight train. I took the wastegate line off of the actuator and plugged it, thinking that maybe it was hanging the wastegate open for some reason. I took the truck down the road again, it seemed slightly better, but was still slow and still covered the road with smoke. I took the truck for a 15 minute road trip, parked for a few hours then 15 minutes back home. Still little change. There was very little shaft play and the wheel felt like it turned fairly easily. Is there anything that I may be missing? If it is just tight, would rebuilding it help out?

haloman

Do you have any gauges in the truck? Maybe one of your boots is loose, look at all your clamps and tighten them and check for boost leaks.

somis13

boost leaks make the E.G.T. go through the roof. be careful

gmctd

The wg is held closed to ~28psi by the spring in the cannister - Boost pressure counteracts the spring and opens the wg at ~15psi - Boost pressure also controls the AFC diaphragm, such that, with no Boost there should be minimal fuel and no smoke, and minimal power

Any leak in that line between the intake manifold, the AFC and the wg should result in reduced fuel and power, unless someone has jacked the plate and cranked the AFC

Best bet is to get a Boost guage on it to see where you're at in the grand scheme of things - if the wg is held closed by the spring you should be getting max Boost allowable within each rpm level, so it would help to know if the tc is Boosting at all, or not.

And, most important, an EGT guage is absolutely mandatory if you're upgrading power levels - doesn't take but a few seconds to melt a piston while stoking power - black smoke is a great melter of pistons

48snowman48

I have gauges. In 5th gear I could get it to 30 lbs. I didn't see any leaks anywhere, everything was tight. It just seemed like it didn't want to start spinning. I had to leave for school last night so I left the truck at home. I didn't want to chance anything.

gmctd

30psi and still black smoke? Even with the pump turned up, a larger turbo will spool slower, which will mean lotsa black smoke till it gets cranking - a warped wastegate will result in slower spool, as it bypasses some of the drive pressure, resulting in black smoke

What happend to the turbo you pulled off - how did it fail?

48snowman48

It clears up considerably at 30 lbs. The wastegate actuator was dented up like it had been dropped, but I unhooked it so I thought that took care of it. Would it still hold it open? The bracket looked fine.

Lil Dog

If it looks like its been dropped, the rod may be bent or the bracket bent that would cause you to have the WG open slightly. It may not be fully closed. Do you have the old turbo?? You might be able to swap out the actuator or the whole housing if you have to..

haloman

Incase your plug is loose try a set of vise grips on the wastegate line also.

gmctd

The spring-loaded wastegate actuator forces the wg closed against exhaust pressure - the pressure line forces the diaphragm against the spring, opening the wg as Boost overcomes spring pressure - possibly the damaged actuator has the wg slightly open, restricting spoolup

48snowman48

I do have the old turbo. As soon as I get a chance, I will switch wastegates and see if there is any difference. I thought about it before putting it on, but I figured if it was damaged I could just unplug the wastegate. I was in a hurry to get the truck going.

gmctd

You migh also check the fit and seal where the elbow clamps to the compressor outlet - 'course, any big Boost leak there will make a loud hissing sound, but may go unnoticed in winter weather.