I have a 1991 CRX HF with a ZC block and a SOHC VTEC head, mini-me. I have a couple problems with the motor, one is that i have a pretty bad idling problem, when i turn on the car the idle ranges anywhere from 1k to 4k by itself almost like someone keeps pressing gas and letting off, this stops when the motor gets hot. Another issue i have is that the car wont engage VTEC, i had the PR4 ecu which i believe is the stock ecu and when i change it out for the P28 i get a check engine light and the car bogs in every gear, not drivable. Anyone have an idea what my issue could be? Thanks in advance.


Modified by snowwhiterex at 11:06 PM 6/5/2008

 

For the idle problem search for iacv and follow those instructions.

PR4 is not the ecu for that car. It is not designed to run a VTEC car. A p28 is but its obd1 did someone do a conversion to the car?

 

the car seems like it is wired for the vtec and also obd1 the plugs match right up for both the pr4 and p28 ecu and looks there is a harness that converted the stock plugs to obd1, im not sure on the accuracy because i dont think the guys who worked on this car before had any idea what they were doing, thanks for your response.

 

hey guys, so i followed all the directions for the iacv and still have the idling problem, the car goes from 1k to 4k for about 5 minutes until it idles at 1500. i dont know what else to do, any ideas?

 

check the pcv valve (positive crankcase ventilation) its right on the top of the valve cover and can be pulled out by hand for inspection/replacement.. just pull the hose off of it and pull it out of the valve cover and shake it.. if it rattles, its goo, if not, then it needs to be replaced.. this is normally the first thing to check when the idle becomes irratic.

 

I replaced the PCV valve and still have the same issue, i have no idea what else to do, i checked the hoses and from what i can see there are no leaks. what goes on top of the throttle body? it looks like the guy who owned the car before me took whatever it is off and plugged the hole with a screw.

 

so i finally figured it out, the throttle body on the car was wrong for some reason, the map sensor was teed into the fpr line and thats what was causing the erratic idle thanks for ur help guys