4.0, or 4.0 H.O.

[85zebracherokee]

Does anybody know the differance in the 4.0 and the 4.0 H.O. I know there is a differance in horsepower, and torque, but is it from the ECU, or other parts internally?

 

[jay79cj7]

There was the carbureted 4.2 and now the injected HO 4.0. Somewhere in the middle was a non-HO 4.0. I can tell you that the HO 4.0 has a superior head design than the 4.2 and the fuel injection is a big plus. I think the non-HO 4.0 probably doesn't have the new head design if I remember correctly.

 

[Cherokee_MZ]

it was te cylinder heads, as well as exhaust... while its not flowmaster, the 4.0 HO has somewhat better exhaust(more of a haux than anything really), but the cylinder heads and fuel injection are the real difference)

 

[XJNick]

Hi,

As a general rule of thumb, always use an Electronic control module (ECM - OBD-I) or Powertrain control module (PCM - OBD-II) which matches the model year of the engine you use. :mrgreen:

-Nick :!: