For about 3 weeks now I have been noticing the smoke come out the pipe being worse than it has been for the past 2 years of owning the truck. At Idle I get a grey smoke. Under heavy accelleration 2nd and 3rd gear I get thick black smoke that takes up the whole other lane. at 70mph cruising down the hwy I'm trailing light black smoke that increases with load. EGT seems about 100-200 hotter running about 600F@70MPH. Boost seems slightly higher but I would count it just about as no change. Fuel Mileage has dropped by about 3mpg with some rough #'s I just did maybe more. Truck performs just fine. Recent mods were in august. I rotated the fuel pin, put on the HX35. Turned the star wheel about 2 turns down I Think? what ever way is the good way. After All that I did not notice a big drop in the MPG or any smoke like now. Are the injectors possible going bad? truck has 210,000 miles. I have not changed the fuel filter in a long while if that means anything. Any Ideas? The smoke is neat but I would like a little less. The MPG could be better.

 

Change filter, sounds like your losing timing from a clogged filter(reduced fuel pressure to the pump)

 

Ditto. I'd do it to at least rule out a simple solution instead of spending big money or unneeded work.

 

Although changing the filter is a great idea, especially since you've not done it for a long time, I don't think that's the problem. A clogged filter will never result in thick black smoke. Black smoke is the result of too much fuel or too little air. A clogged filter will put out white smoke under acceleration and it smells like kerosene/jet fuel...you're basically pouring some unburning fuel down the pipe.

If your boost is normal I would suspect an injector problem. I'm no guru on the ins-and-outs of injectors, but that's my guess. If your boost was down and your EGTs up a lot I would suspect an air leak in your induction system, or a plugged air filter.

 

Sounds like a boost leak. Check your intercooler boots and piping for leaks.

 

x2 on the injector. Boost leak possibly but that wouldn't explain the haze @ idle. Dripping injector is my guess... replace it now or melt a piston!!!

 

I would think if there was a boost leak I would notice a decrease on the boost gauge? Its the same or better than before the smoke started. I'm going to throw a filter at it and hook up the Fuel pressure gauge. Any easy way to rule out or zero in on a bad injector? Stheoscope? I'm going to start with a good look under the hood.

 

I had a huge boost leak coming from underneath one of my pipe couplers on my 96, boost was the same, I think becaue HX35's are wastegated. My EGT's were up a bit and my mileage was off.

 

Air filter clogged or a boost leak.

 

The wastegate on the HX35 is a good point as to why the boost ain't dropping. That makes alot of sense now that I sit down and think about it. The air filter was changed in july but I'll check it out anyhow since something could be stuck or living in there.

 

Yup its happened.

 

On all these boots I'm not seeing anything obvious. I took off the one tube and the boots have no holes or tears. could a pin hole leak cause issues? where can I find boots locally in the chicago area? I'll just change them all as a precaution because they do have some iffy places on them but nothing broke thru. Do the Intercoolers go bad on these? any other areas to check? what about the waste gate actuator and hose?

 

The cores crack and become separated by the tanks, possible damage from road debris, chafing against something etc. Leaks can come from anywhere, pinholes/cracks in the cast elbows, intake gaskets, turbo housings, guage plumbing etc. With the leak I found, the boot had just barely slipped under one of the clamps and would move under pressure, causing a huge leak, there was nothing wrong w/ the boot. My boost leak checker is the best tool I ever made, takes all of 5 minutes to put on, and when the truck's off you can easily hear/feel where leaks are coming from. Something like my leaking coupler looked fine, but with 35 psi on it I easily found the problem.