1997 E7 Econovance Problem

[Moneypit]

Truck idled rough at low rpm, thought it was fuel problem. But it was timing sensor on fly wheel. Now when my truck hits 1800 Rmp its doing the same thing at a higher rmp and runs perfect at lower Rmp. Mack dealer told me it was the Econovance. They told me the housing was the problem and mack doesn't make one anymore. I found one in a junk yard. But is there another company that makes that housing or is there a way to replace it. I called all over the US today and found one. Why does Mack have this part on their trucks and no longer make it.  

Edited July 25, 2020 by Moneypit

[mrgumby]

Did you try pai I know they used to sell them

[Moneypit]

I tried, no results found.

[Mack Technician]

filling with rain water and freezing probably wouldn’t do that econovance any favors.............. 🤷🏿‍♂️ 

[Moneypit]

Oh I know that's why still looking. At least that one is in south texas. Doesn't get that cold there.

[theakerstwo]

That is a VMAC

[Moneypit]

I think it's the vmac 2. One ECM. God forbid that goes out. ANOTHER headack. 

[R.E.D]

Have you removed the two screws holding that solenoid?it's a hydraulic valve , it has orings that could have deteriorated and oil pressure could be bypassing and altering timing.

[fjh]

Have you replaced the line to the econovance, they can deteriorate overtime!

[R.E.D]

Also wouldn't hurt to check resistance in said solenoid to make sure it has continuity and the correct resistance.im not sure what resistance it should should have but someone here might know.

[Moneypit]

Was told today by the Mack dealer that they have not took off the encovance because the truck would be dead in the water and wait until I found one to rebuild. Does that sound right?  They told me that if they go out it's more than likely the housing. I asked about a rebuilt kit they said it's better to wait to take it out. Drove truck home today, drove great till 1800 rpms. Then went to shit. I can still work truck till I get that one in. Be a turd pulling if I cant get over 1800 rmp. But I got to work it.  What have other people done to fix this problem? Replace the motor, fuel system or what? All help needed thanks. He checked the line going to it and the solenoid. Both are good. I trust the mechanic, he has done wonders in the past for me. So not doubting the Mack Mechanic.

Edited July 25, 2020 by Moneypit

[fjh]

So Money pit here's a thought and some experiences for ya!

One test that can be performed is to put 12 volts to the solenoid  if the timing advances then the econovance is working and you may still have an electrical issue ! there is a spring inside the unit that can break and there are teflon piston rings that can wear and deteriorate !So in that sense the mech is correct ! IMPORTANT If the econovance is working correctly the engine should start and stumble and smoke blu white smoke till the oil pressure comes up once the oil pressure is up, the engine  should clean up and run smooth!  at that point the engine is running @ apporx 12 degrees advanced !Properly working the timing should increase with RPM up to 22/24 degrees depending on RPM  ! sounds like yours is not working! I suggest you put 12V to the sol and see if it advances the timing you will hear the difference if its working if you don't hear a difference then  the line across the front of the engine could be suspect change that Its Cheap!  And available anywhere! then try the test again Manually  if the issue is still there your  likely  going where they are sending you! If the issue goes away  and you still have a problem with the wire from the harness connected  then you got a wirring or ECU issue ! SO A possible  work around would be to cap that  line off to the econovance and set the base timing from where it is now  roughly ( 6-8 degees) to  19 t0 20 degrees this may get you to work with out spending a big bag of money on parts !

Because in my Opinion the econocance was installed as More of  an emissions issue! not that much of an economy thing! (And that there is  JUST AN OPINION!) not a fact!

 

[R.E.D]

7 hours ago, fjh said:

So Money pit here's a thought and some experiences for ya!

One test that can be performed is to put 12 volts to the solenoid  if the timing advances then the econovance is working and you may still have an electrical issue ! there is a spring inside the unit that can break and there are teflon piston rings that can wear and deteriorate !So in that sense the mech is correct ! IMPORTANT If the econovance is working correctly the engine should start and stumble and smoke blu white smoke till the oil pressure comes up once the oil pressure is up, the engine  should clean up and run smooth!  at that point the engine is running @ apporx 12 degrees advanced !Properly working the timing should increase with RPM up to 22/24 degrees depending on RPM  ! sounds like yours is not working! I suggest you put 12V to the sol and see if it advances the timing you will hear the difference if its working if you don't hear a difference then  the line across the front of the engine could be suspect change that Its Cheap!  And available anywhere! then try the test again Manually  if the issue is still there your  likely  going where they are sending you! If the issue goes away  and you still have a problem with the wire from the harness connected  then you got a wirring or ECU issue ! SO A possible  work around would be to cap that  line off to the econovance and set the base timing from where it is now  roughly ( 6-8 degees) to  19 t0 20 degrees this may get you to work with out spending a big bag of money on parts !

Because in my Opinion the econocance was installed as More of  an emissions issue! not that much of an economy thing! (And that there is  JUST AN OPINION!) not a fact!

 

If you do this test , remember that 12 volts applied might make the solenoid actuate but if orings are gone oil bypass will occur and timing won't change.

[Feeelburt]

Hello, I have an 04 mack ch613 with the ac460p engine. Monday the truck lost all power and came to cost, still running, but kicking tons of grey smoke. Got it towed and ended up replacing the fuel pump since the old pump wouldn't draw water from a bucket with a 1ft hose. New fuel pump installed, fired up with rough idle and more grey smoke. When the turbo actuator got air it closed the vanes and the truck killed, getting way too much fuel. If i unplug the variable turbo and speed sensor plugs, the truck runs. A little rough on the low end but can still drive smooth on the highway revs up solid with no smoke. I just came across this part and it sounds alot like the issues I'm having. The truck has 1,002,000 miles so very possible it's never been touched. I check position sensors and fuel timing sensor. Replaced the fuel timing sensor, checked fuel relief valve, opened all fuel lines and check for obstructions, hooked up to computer with no codes to guide me. Trying to avoid a visit to mack for $175hr. Tomorrow morning I'll check into this further, but i need guidance. Anything to help diagnose or test or any other direction to go... oh i also tried jumping ground cables to various spots just to make sure. Thanks in advance! 

[Joey Mack]

blown head gasket?   no loose C.A.C.  boot's? 

[Vmac3]

Sounds like the EGR is stuck open. What I would do is remove the EGR pipe coming out from the EGR cooler. See if there is flow exiting the cooler. See if it makes any difference with the engine operation. 

V