Jump to content

Possible torque loss? E7 etech 460hp


Cl713
 Share

Recommended Posts

Hello all, I have a '99 cl with e7 etech 460. I seem to be plagued with low power, I have owned the truck for two years and it has never performed the way it should. I will start with what I know; no intake leaks, boost at 25-27lbs, no miss or rough running, not much black smoke, no fault codes. Now for the kicker, dyno test at 370hp, which is 80% of rated hp. I am told the 20% loss from flywheel to ground is acceptable. This truck is set up for heavy haul, 20k front and 46k rears, double frame, 18 speed, LOW rear end gears. I should have all the power I need to haul 80-85k loads and yet I'm passed by every truck on the road. Do I have a torque issue? Ecu issue? Is the turbo not spooling up fast enough to make the torque I need when I need it? Do I have fuel unit pump problems?

I'm stumped! And just about fed up! The mack dealer told me it's just my perception and that the truck is fine. I need help please!

Link to comment
Share on other sites

You should have more turbo pressure. Have you checked the fins on intake and exhaust on the turbo? put a plug on the air charge cooler on the right side and put about 35 lbs of air pressure on the system and you can ck the cooler, intake manifold, and the tube at back of intake manifold that goes to the air compressor intake for leaks. If no leaks and no exhaust manifold gaskets leaking I would lean toward the turbo. Have you checked if it has a torque limit switch on the transmission, it could be bad. if you have one just unplug it and see what happens. I had a truck that was low on power but did not have the torque limit switch on the transmission but somebody had the transmission out and when they went back with it plugged the harness in to the air dryer harness. unplugged it and it was fine. You need more turbo pressure.

Link to comment
Share on other sites

You should have more turbo pressure. Have you checked the fins on intake and exhaust on the turbo? put a plug on the air charge cooler on the right side and put about 35 lbs of air pressure on the system and you can ck the cooler, intake manifold, and the tube at back of intake manifold that goes to the air compressor intake for leaks. If no leaks and no exhaust manifold gaskets leaking I would lean toward the turbo. Have you checked if it has a torque limit switch on the transmission, it could be bad. if you have one just unplug it and see what happens. I had a truck that was low on power but did not have the torque limit switch on the transmission but somebody had the transmission out and when they went back with it plugged the harness in to the air dryer harness. unplugged it and it was fine. You need more turbo pressure.

Where would I look for the torque limit switch.

Link to comment
Share on other sites

On the mack transmission it should in the shift cap behind the gear shift. See if you have a wiring diagram in the fuse panel box door on the dash on passenger side and get the wire for the torque limit switch and trace it down it should be around the top of transmission.

Link to comment
Share on other sites

  • 6 years later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...