Ecu ?

[kahaikapu]

did anyone purchase the 4.0 jeep high performance computer part no p4529334 and is there really alot of differance in power. aloha kahaikapu

 

[Eagle]

I didn't buy it, but someone did because it is no longer available -- all available units were sold a long time ago.

It was reported to produce significant power gains in the higher RPM range, at the expense of requiring high test fuel and increasing overheating problems. Also, the factory specifically recommended against towing with that computer, apparently because it reduced low-end torque.

You didn't post what year XJ you have, but that factory hi-po ECU was only offered for the Renix (87-90) model 4.0L

 

[Dr. Dyno]

It was reported to produce significant power gains in the higher RPM range, at the expense of requiring high test fuel and increasing overheating problems. Also, the factory specifically recommended against towing with that computer, apparently because it reduced low-end torque.

I think they recommended against towing because the higher ignition advance of the Mopar Performance computer made pinging more likely. That's why premium fuel is essential and it's probably a good idea to install a 180* t'stat to keep the engine running slightly cooler to reduce the risk of pinging.

 

[kahaikapu]

I didn't buy it, but someone did because it is no longer available -- all available units were sold a long time ago.

It was reported to produce significant power gains in the higher RPM range, at the expense of requiring high test fuel and increasing overheating problems. Also, the factory specifically recommended against towing with that computer, apparently because it reduced low-end torque.

You didn't post what year XJ you have, but that factory hi-po ECU was only offered for the Renix (87-90) model 4.0L

thank you yes my xj is an 87 with the renix