Hello all,
I have 94 civic with a b18b1 swap from a 95 integra ls. The head is stamped pr4-1 and the ecu is also marked pr4. My brother used the stock obd1 wiring. The car has no cel and runs smooth (aside from the very slight fluctuation in rpm at idle). The issue is that the rev limiter seems to be at 5800. I've never been able to get it to 6000. Any suggestions?

 

if the car is running smooth and pulling hard to 5800 most likely the tachometer is off.

 

Hmmm never looked at it that way. Is there a way to diagnose this? Like using an aftermarket tach or something?

 

And now that I think about it, I thought only b18a was pr4. Is it possible that someone changed the head out?

 

You should try the p75. It may take care of the idle issue also. Is your car an auto or 5speed because that ecu is for an auto.. The pr4 uses a couple other things on its intake manifold to control idle. Your intake is more than likely off the 95. Just a thought.

 

yes connecting an aftermarket tach will tell you if yours is off.

 

pr4 ecu's where obd0 and obd1. you have the correct ecu for that engine. pr4,p74 and p75 ecu's are all the same. THE PR4 IS NOT JUST AN AUTO ECU LIKE THE GUY ABOVE ME STATES.

As far as the idle issue clean your idle air control valve and the fast idle thermo valve. that should correct your idle issue. also check for vacuum leaks.

 

OF COURSE ITS NOT JUST AN AUTO ECU. I misread the a11 after the pr4. It should be a manual ecu. I realized I put the wrong info about the ecu when it was too late to correct it last night.