I have a 2000 Prelude. I just bought a chipped P72 and ordered a basemap chip for my car from phearable and I was very specific about my setup. It is for the most part a stock JDM H22A from Hmotors. I just have an intake, lightweight flywheel, a stage 2 clutch, and I left the balancer shaft belt off because it isn't really needed and it just adds load to the engine. I converted the engine itself to OBD-II so it would work with the factory P5M ecu. I have a jumper harness for the P72 that I bought and the car runs pretty decently on the basemap but I decided before I get it tuned I should make sure everything is working properly.

Well, everything isn't working properly. The 2 step doesn't work at all. I specified to have it set at 3250 but phearable said that was too low and they said they would set it at 3800. Needless to say it just revs right past that. I know for sure that my clutch switch is working because if I set cruise control and press in the clutch it turns out the light and disengages cruise control. I know there isn't an issue with the speed sensor because my speedometer works just fine. I do not know what to check next but I am getting my car tuned next wednesday so I need things working by then.

The 2 step isn't really even a big issue. The big issue is that my vtec doesn't work. It's kinda hard to tune a car when vtec isn't working. The vtec engages perfectly normal with the P5M but when I plug in the P72 it doesn't work at all. The IAB's open up around 4700 and the sound of the engine changes but the vtec should engage at 5200 and it doesn't. I can tell because the car feels like any normal car. I specified 5200 as the engagement point when I ordered the basemap from phearable. I have no idea why it wouldn't work. I used the vtec solenoid from the H22A but I put the pressure switch in it so it would work properly with the P5M. All I had to do was take the big bolt out that was plugging the side of the solenoid assembly and thread in the pressure switch. I received a piece of paper with the basemap that has info about things that need to be done in order for it to work properly. One section of the page says:

JDM MOTORS: JDM motors do not have a vtec pressure switch. You may have to bypass the switch per the wiring bypass diagram on our website's tech section.

I don't believe that would be an issue as I do have the switch and it sounds like that is to modify the wiring harness to bypass the switch but honestly I'm not sure.

I guess if anyone has any ideas, help would be great! I need to figure out the vtec issue by next wednesday otherwise I gotta try to reschedule my tune and I already got the day off work.

 

Make sure the input for vtec oil pressure switch input is on pin D6 at the ecu. Use a meter and check for continuity at D6 and out at the plug that goes on the pressure switch. Thats where the the p72 should be looking for its vtec oil pressure signal at. Hope it helps.

 

okay thanks. I'm beginning to think that maybe I bought a bad wiring harness. I bought it off ebay so odds are it isn't right...

 

Yeap most likely its a wiring issue. you can test any of outputs and inputs this way just go to the end of the jumper where it plugs into to ecu and other lead of your tester to the appropriate connector. Make sure you disconnect the both ends of the connectors (ecu and vtec pressure switch in your case) before preforming a test across the wiring harness and jumper setup, reason why is, you dont want to read feedback from something else.

 

How are you going to tune? If you have a way to datalog it's usually pretty easy to look at all the sensor values and see what doesn't look right. If the other ecu works fine then it must be something to do with the parts you change out to arrive at the non-working condition. Can you test the P72 on a different car? Doing that would narrow the search. Also, it's pretty simple to disable the VTP check in most ROMs.

 

I looked closely inside the ecu and it turns out the little resistor at J1 on my ecu has an open so it is just reading the factory gsr maps and that explains why it doesn't run well at all. I just gotta try and solder it haha

 

Huh the j1 i think is just that a jumper. What color is the lines on the j1 or just a single line? Let me know if the solder jobbie works out.

 

J1 is the jumper that makes the ecu use the basemap chip instead of the stock ecu basemap so basically I was running a stock gsr basemap on my prelude. I soldered it and now everything works. It was just a single black line in the middle of the resistor so it is a 0 ohm resisitor. It's just a fancy wire

 

Glad it was an easy fix, I know that Phearable prides themselves on doing good work, and making sure the customer gets the best product possible. Have you let John know what happened?

Just to add info, his name on Honda-tech is "mtber".

 

is John the guy that owns phearable? I emailed phearable about it and they were very helpful and they even suggested that maybe the wire at J1 was broken and then I looked and it was. They know their stuff.

 

Yes John "mtber" is Phearable.

 

Yea very good people down there at phearable. Glad it worked out for you now go have fun!!