Engine/Transmission (1994 - 1998) Black Smoke/Low Power Troubleshooting ?

[LJHagen]

I don't know if it's just me or what, but my rig seems to be chugging a little more black smoke than 'normal' when you begin to accellerate, power feels down, and my turbo PSI doesn't seem to go much over 18 PSI (have NEVER really had good turbo pressure). My EGT's seem ok (never get over 900). Unfortunately, my local shop is good at taking $$, but poor at diagnosis so I'm pretty much on my own... . Anyone have a 'checklist' of what to look for (preferably from easiest to hardest)?



Many thanks!!

 

[SEmerson]

Check your aircleaner.

Then check for boost leaks from turbo to intake.

To do this you really need to make a presurizer. You can make it out of a sewer pipe cap and regulator. Take off the aircleaner and cap the hose with the cap. Have a hole on the cap to hook to a aircompressor. Pressureize the system to 5 psi or so and look for leaks.

 

[jtwcummins]

The most common cause of this symptom is a leak in the intake system. Check the boots that connect the metal plumbing everywhere and inspect the boots for wear from rubbing,etc. The clamps on the boots have been known to come loose. Your EGTs seem low, even stock the temp should go to 1100-1200 under a hard pull.

 

[pwerwagn]

I had the same problem with mine. when I got the truck, it would make about 22-23psi, but it started to decline. When i got to about 16psi max, I started checking things. I had looked over stuff real well (so I thought) and had just made the pvc cap thingy to pressurize the system. I figure while i am doing this, I can check the accuracy of my boost guage. While I was putting the cap on, I somehow happened to notice that the boost guage had a fray in it. It was leaking. I fixed it (I used barbed fittings and better, more flexible hose than the junk stuff banks sends with guages) and the boost was back up, now to about 25psi. About a week later I put in a new air filter. Wow! it now makes 29psi. Sometimes it is the obvious that goes wrong. Oh, BTW, even thought I gained right around 4psi with the filter, my filterminder never moved before even with that much restriction.

 

[BPonci]

Also check your afc line it is 1/4 synflex and is known to break.