Hope someone can help. I have a 97 6.5 and am experiencing black smoke and loss of power at low rpm ie off the line. The code reads insufficient egr flow and my mechanic says he has replace a solenoid to the egr, cleaned the egr, checked the wiring to the egr and recently the vacumn pump was making noise and replaced. The problem persists. In the last few days I have a whistling noise that starts at ~1400 rpm and maxs out at ~1700 rpm. I suspect an air leak. any ideas???


Thanks

as soon as you hit the throttle, EGR System operation becomes a non factor, it only operates at idle. How much black smoke off the line are we talking about? If its just a quick whiff and goes away, then you have nothing to worry about, thats the nature of the beast in these things. Have you replaced the air filter recently? Could the whistling noise be the turbo spooling up?

Hi Diesel Guy:


Definitely not the turbo and huge quanti**** of black smoke. This sound is new and I recognize it as being a recent development. I've had the vehicle since new and am very tuned in to any changes in performance or new sounds. The air filter is a K&N and was recently cleaned. While the K&N was drying the stock air filter was replaced. The problem continued.


If I were to accelerate from a standing stop, huge quanti**** of black smoke are generated until about 2000 rpm and everything goes back to normal. Perfromance is also poor. A similar problem occurs after backing off on the fuel to go around a corner and then accelerating again.


The mechanic cringes when he sees me as he has done everything he knows how to do. I'm confident he is doing his best and is an honest guy. I won't go to the dealer as I know them to be dishonest from personal experience. My mechanic has suggested replacing the computer but won't guarantee that will solve the problem. I'm reluctant to spend any more money until I have a better idea of what might be wrong.


The only mods to the truck are the K&N, Banks downpipe, removed the catalytic converter and replaced it with a 3" pipe to the muffler. Downstream from the muffler is a 4" mandrel bent pipe. System purchased from BD. The truck has 275,000 km


I appreciate your help. Once this problem is solved I'm looking forward to exploring some of the performance options listed in these pages.


Thanks


Alex

Whistling noise you hear could be vacuum leak between wastegate plunger/vacuum pump and wastegate solenoid. This would also explain black smoke problem.

Not likely an audible vacuum leak, and Boost leakage would sound more like a hiss than a whistle. I suspect you EGR itself or the vacuum controller for it is hung open on you, or maybe a bad BARO sensor. You dont have a Mass Air Flow Sensor on this thing do you?Edited by: Texas Diesel Guy

Hi TDG:


the truck is a 1500 and therfore has a mass air flow sensor. Thanks for your suggestions. Thanks also to Wade. I will try your suggestions and let you know.


Thanks Alex

I've looked back over the forum and with the help of information posted in response to green95chevy's problems back on Jan.10/04, have learned the following. First of all the truck is a 1500 model "s" engine. Using the information provided I've determined there is 23 lbs of vacumn at the pump and ~22lbs at the waste gate. with the info from the flowchart posted there I've also determined the wastegate solenoid is functional.


There was no vacumn at the egr or in the hose to the baro sensor(on the firewall) at idle or at rpm. I'd shut the truck off and restart it and I'd get over 15 lbs at the pressure sensor on the firewall and 2 to 3 lbs to the EGR valve???? The problem is intermittent in nature. More testing is going to have to be done here as I would expect the vacumn to be the same at either end of this "T" connection. Leaking fitting perhaps on the EGR vavle side.


Voltage to booth the EGR solenoid and the EGR vent solenoid(the 2nd and 3rd solenoids going from front to back) was 13.8 volts at idle. Wiggling the conectors did not indicate a broken wire. There was also 23 lbs of vacumn at the line entering the EGR solenoid (2nd one)


It would appear the EGR solenoid (#2) is defective and not allowing any vacumn to the egr vent solenoid (#3). As this solenoid (#3)was recently replaced i don't expect it will be a problem.


What I don't get is the great clouds of black smoke as that would appear to be a boost problem?? Perhaps both the waste gate and EGR solenoids are intermittently defective!! I 've heard that this a possibility. I'm going to replace both, one at a time,reset the computer and go for a drive.


I'll let you know how it goes.


Thanks for the great site.