Low Boost

[cerberusiam]

Usually start getting the bank 1 or 2 codes indicating a problem that the ECU cannot track to a specific injector. Limp mode, rough idle, power loss, etc are the result then the code pops.



The injectors solenoids are monitored for draw and resistance. When those go out of range too long it throws a code and goes to limp mode. If it shorts bad enough the ECU will shut down the whole bank and not reset until the problem is found. Needless to say that usually means dead in the water.

 

[SShafranko]

Thanks. I was thinking about adjusting my valves and since i will be in there taking a shot in the dark and replacing the gasket. Maybe checking the resistance on the solenoids as well. Just started my truck, idling it sounds like a 96 powerstroke. I'm starting to get angry at Dodge even though i probably caused this issue. Thanks C

 

[cerberusiam]

I know its no concession but Cummins deisgned and built the motor, the hard parts are their design issues. The ECU program is a mixed bag of stuff from Cummins and Dodge but still uses a base Cummins program that controls engine operation.



Dodge is just easier to yell at and complain about. :-laf However, consider the options and maybe its not that bad, eh?

 

[SShafranko]

Yea i guess your right. I changed both front axle u joints today and i'm heading out to Ocean City Maryland tomorrow for a weeks worth of relaxing. While the wife and kids are by the pool i'll be in the parking lot on my creeper..... hope to find a bare wire rubbing something or other

 

[SShafranko]

I changed the oil today and flushed the cooling system to get ready for the trip tomorrow. I decided to change the cam sensor, coolant sensor and IAT sensor. No change.



After researching a bit on line i realized that my symptoms are very close to a faulty intake air sensor. From what i understand they will throw a code if completely whiped out. There have been a few cases where the IAT was reading out of its original parameters and not throwing a code. Some of the symptoms described by other people who found this issue were:

• 2 mpg loss
  
• loss of power
  
• EGT reading at idle 75 to 150 degrees higher than before the issue
  
• EGT reading at WOT 100 to 200 higher than before
  
• after coming to a stop the EGTs take a very long time to come down to an acceptable shut down temp.
  

All of these symptoms are a part of my daily driving experience. Lucky me back to square one... .

 

[TomJohnston]

I have been seriously considering the rectifier circuit on the alternator. I believe this problem to be somewhat related to rpm and if the alternator is not smoothing out the pulsed DC signal correctly it will corrupt any sensor return signal based on pulses instead of resistance or decreased voltage. So rpm, speed or position sensors could get confused by erroneous spikes in the signal causing the ecm to go to a default map or limp mode. This is something that could be well within limits at 1800rpm but cause havoc at 2300rpm and above. The circuit is engineered to work best at cruising rpm of 2200 or less. I wish I still had access to some o-scopes, I would be able to see the waveforms and know for sure. I am going to price out a new alternator and if it is not ridiculously expensive I will get one and see. I may be able to buy the rectifier board on the back of the alternator by itself and that shouldn't cost a fortune. I will let you know, Tom J.

 

[SShafranko]

Ty Tom. You may be onto something. I think the alt. plug and IAT or on same circuit. Actually i don't know if they are, i'm sure someone here does, but the wiring for the Intake Air temp. sensor comes together on the harness with the alternator plug wiring. Is there any way to unplug the altenator for a while and run without to test? Will the truck die? Hmm i' \m going to give it a shot tomorrow. Keep me posted please.

 

[Kday]

Figured out my dropping boost caused by electronic wastegate opening. I just unplugged the hose and tried it out. I know this isn't your problem but I figured I'd let you know since I chimed in a while ago.

 

[SShafranko]

Good for you. I love hearing about people resolving their issues. Yea mine has more to do with fueling. I did try the WG hose also and it did nothing for me. Thanx 4 replying and good luck.

 

[SShafranko]

I was wondering if any one knows the anwser to this:



When i finally find the cause of my problem and if it involves replacing a sensor, or a bare wire, etc. once i repair it will the computer automaticaly adapt to the fix or will i have to re- flash it/replace it, etc. ?



Tom, I unplugged the only plug i could find on the altenator and it seems like it is for the gauge/maybe the regulator? Anyway it didn't make a difference. I'm gonna lokk at it a bit better later.

 

[cerberusiam]

If its just a rubbed wire, noise, bad sensor, etc, then the ECU should go back to normal. If the short has done something to the ECU or TIPM thats another story.

 

[SShafranko]

I've been thinking today back to when i first recognized the problem and i keep going back to one particular time. That is a couple of months ago when i first saw that i could not boost past 30 or so psi. i took apart my intercooler piping and realized it was full of oil. That is when i replaced the turbo with the BD Special.



I wander if the oil was the cause of all of this? The oil got as far as the begining of the CFM intake and i was wondering if there was maybe some sensor in between the turbo and the CFM that may have been covered in oil but i cleaned everything with degreaser and put it all back once dry. I don't think there is any sensors in between the two.



But i wonder if the oil could have done something to cause this issue?

 

[cerberusiam]

Ahhhh, that is making a lot more sense now. There are no sensors between the intake horn and the turbo, however, you are probably dead on with that line of thought.



What do you think would happen if the IC tubes are partially plugged with congealed oil that has been pushed thru the IC? Heat from the compressed air and oil in small tubes? Me thinks you are replacing the IC next and solving the problem.



Nice thought if it works, eh?

 

[TomJohnston]

oddly enough, when I blew my stock turbo and put oil through my system is when all my problems began also.

 

[cerberusiam]

oddly enough, when I blew my stock turbo and put oil through my system is when all my problems began also.

Usually when this happens replacement of the IC is recommended. I think there is probably a very good reason for doing just that.



Time\opportunity to upgrade.

 

[SShafranko]

Really? i hope so that is an easy fix. but why did the dealer find that my computer was bad with the Star Scanner? Coincidence?



I gues i'm replacing the IC. I'll let you know what happens. Maybe i should switch it out with my buddies just to make sure? The IC is expensie and i don't want to install it unless i have to. $1,000. 00 down the tubes.



I guess it could explain the constant haze i get out of the exhaust and the rapid rising egt's. Not enough air getting through?



What if i pipe it directly to the CFM and bypass the IC?

 

[SShafranko]

What if i check the boost before the IC? Shouldn't it be a lot higher if the IC is shot before the air passes through it?

 

[cerberusiam]

Ye, you should see a large boost drop across the IC if its restricted. You can also plumb from the turbo directly into the intake to see if that helps. Wouldn't run it long like that but for a test it would work.



If you can swap an IC to check that beats the $$ unless its needed, I would do that if I had a choice. The bad ECU could just be a coincidence as you notthe only on to get bit by that.

 

[SShafranko]

I would like to mention that before i installed the new turbo i cleaned all piping and the IC. A friend of mine owns a powerwashing business and he helped me with the cleaning. We used a commercial degreaser which comes in 55 gallon drums and is very powerful, and his hot water power washing machine. I think we cleaned everything as well as it could be cleaned.



IU will swap it out anyway buti doubt thats it unless the IC was permanately damaged somehow?



Anyway i noticed something weird today. At idle the turbo side of the intercooler (the end cap) was cool, and the right side endcap by the CFM was warm. Shouldn't it be the opposite?

 

[cerberusiam]

At idle thats probably right. The IC is picking up heat from the AC condenser and maybe the radiator due to reduced airflow.



You would think cleaning the IC with degreaser would work but since the solution would just take the easiest route plugged tubes may not get thoroughly cleaned. Probably the only way to tell for sure is swap it for a known good one.