1996 Mack e7-350

[BigRigRepair]

1996 Mack e7-350 between 1400 and 1800 rpm’s is smokes and misses really bad. I’m thinking something might be wrong with the econovance. Truck came in with fuel in the oil. Got that fixed and replaced several fuel lines. Any help would be appreciated. I’m not very familiar with Mack engines. 

[fjh]

1 hour ago, BigRigRepair said:

1996 Mack e7-350 between 1400 and 1800 rpm’s is smokes and misses really bad. I’m thinking something might be wrong with the econovance. Truck came in with fuel in the oil. Got that fixed and replaced several fuel lines. Any help would be appreciated. I’m not very familiar with Mack engines. 

Do you have a check engine light on? You can try put 12v to the econovance ! this will prove out whether it is mechanical or wiring/ software issue! if the stumble goes away you have a wiring issue! If it does not you have a physical issue with the econovance! broken spring or sealing issue! ect  !  Also check the line from the block to the econovance if the line has pluged it won't work either!  on older models There are also screens that can plug up in the econovance block remove the plugs and check these if you take the block off be sure to try and save the gasket or  get the right gasket for the year there are two different gaskets!

[BigRigRepair]

26 minutes ago, fjh said:

Do you have a check engine light on? You can try put 12v to the econovance ! this will prove out whether it is mechanical or wiring/ software issue! if the stumble goes away you have a wiring issue! If it does not you have a physical issue with the econovance! broken spring or sealing issue! ect  !  Also check the line from the block to the econovance if the line has pluged it won't work either!  on older models There are also screens that can plug up in the econovance block remove the plugs and check these if you take the block off be sure to try and save the gasket or  get the right gasket for the year there are two different gaskets!

No check engine light. I tried putting 12v to it yesterday and nothing happened. I’ll pull that line off today and check it out. When replacing the econovance anything I should know? Things to do  or don’t do?

[fjh]

Do you have a replacement? Try a solenoid first wouldn’t go pulling the econovance parts are near impossible to get! I believe I would disarm the econovance and set the timing to 20 or so and call it a day! Just my thoughts on it!is this a customers truck? If so the afore mentioned fix may not be viable! With out permission! 

[BigRigRepair]

12 hours ago, fjh said:

Do you have a replacement? Try a solenoid first wouldn’t go pulling the econovance parts are near impossible to get! I believe I would disarm the econovance and set the timing to 20 or so and call it a day! Just my thoughts on it!is this a customers truck? If so the afore mentioned fix may not be viable! With out permission! 

How do I disarm the econovance? Never missed with the timing on a Mack either. Would you mind walling me through it? 

[fjh]

To disarm you want to cap off the oil line! To the econovance!

remove the timing event sensor turn the engine till the spade shows up in the hole where the timing event marker gets its message! Remove the 5 bolt cover at the front of the fuel pump. Remove the bolts holding the pump gear remove the gear! Go to the flywheel housing at bottom remove the six bolt cover observe where the timing is set should be 6 or 10 initial timing! Advance. The engine to timing up to 15-20 put the gear back in ensure the spade stays central in the timing event hole as you tighten the gear bolts the (holes are slotted)and reassemble you can run the engine with the cover off to test run not much oil in that area !  See if that works ok you can tweak the timing higher if you wish ! Just remember that you started with six or ten initially!  
good luck with it bro!

Note that the econovance  when working advances to a max of 22 - 24 degrees ! So you should pick a happy medium! Econovance was added to meet emissions.
 

[BigRigRepair]

5 minutes ago, fjh said:

To disarm you want to cap off the oil line! To the econovance!

remove the timing event sensor turn the engine till the spade shows up in the hole where the timing event marker gets its message! Remove the 5 bolt cover at the front of the fuel pump. Remove the bolts holding the pump gear remove the gear! Go to the flywheel housing at bottom remove the six bolt cover observe where the timing is set should be 6 or 10 initial timing! Advance. The engine to timing up to 15-20 put the gear back in ensure the spade stays central in the timing event hole as you tighten the gear bolts the (holes are slotted)and reassemble you can run the engine with the cover off to test run not much oil in that area !  See if that works ok you can tweak the timing higher if you wish ! Just remember that you started with six or ten initially!  
good luck with it bro!

 

Thank you!! I’ll let you know how it goes! 

[fjh]

3 minutes ago, BigRigRepair said:

Thank you!! I’ll let you know how it goes! 

Please do!  I am not a fan of doing this but it has worked as a get by  in the past !  As parts have been hard to get for a long time! 

[JoeH]

Is this a short term get you back to the shop or can the truck be left like this and run indefinitely? I don't have one of these engines, I'm just curious.

[fjh]

22 hours ago, JoeH said:

Is this a short term get you back to the shop or can the truck be left like this and run indefinitely? I don't have one of these engines, I'm just curious.

The This is a keep it working fix ! Don’t forget these engines ran good for years with fixed timing econovance was added for emissions reasons! The 350 was offered with either or in the transition year!