I have a 97 civic ex with h22a jdm swap and a p75 chipped ecu. Recently my speedo quit functioning and now the car won't rev past 3500 rpms. There was a cel code 9 but was a loose wire in harness but now there's no cel and it still won't rev past 3500 rpms. Wondering if my ecu is fried and how I could check it or if maybe there's another explanation. Thank you

 

Check vtec clean it may be clogged

 

A clogged vtec solenoid will not cause limp mode, this is a crank sensor problem regardless if the code is gone. First of all, check every fuse.

You can check if your ECU is fried by using another ECU. There's no other way.

99% of the time, code 9 is caused from bad wiring. I guarantee you still have a wiring problem, or a faulty ground. Especially because it's an H22 swap, which never comes without at least one issue.

Do a proper wire continuity and short check, try another ECU, replace the distributor.

 

Do you have 2-step setup on the ecu? If the speedo stopped wotking, and the ecu is not getting a signal from the vss, you make be stuck in 2 step mode.

 

He says it's a JDM H22A, doesn't that mean it doesn't have a crank position sensor or cam position sensor?


I had this problem, as well with my F20B. I used a chipped ECU and it wouldn't rev past 3,500RPM. Plugged in an OEM H22A ECU and it ran fine.


Then I started having misfire problems at the same RPM, the VTEC plug wiggled out.

 

vtec plug wouldnt have anything to do with misfire. If it's unplugged, vtec just wouldnt engage.

to OP, if speedo doesnt work, i would check the vss, the vss sensor, or wiring. if it wont rev pass 3500, then you're in limp mode. check the CEL to see what the issue is. usually its the distributor.

 

All Hondas including the JDM H22A use all three position sensors. Some engines have a fluctuation sensor, but the P75 doesn't check for CKF.

 

Fix your speedometer or get the 2-step removed

 

I had the same problem I had s300 with coil on plug setup went to get tuned wouldn't rev past 3500 just dumped fuel. swapped s300 for chipped p28 on the spot. worked fine. try a friends ecu if same problem check wiring harness for loose wires and go from there.

 

I had a similar issue with my old chipped p06. Does sound like your in limp mode. My advice to you is definitely find some way to swap your ecu with a different one before you go tearing into your dizzy. I did the dizzy before the ecu swap test and lost some valuable time. Do a decent visual inspection of your dizzy wire plugs for damage or green corrosion. Check all your grounds in the engine bay as

 

VegasInvasion is right. Check for continuity.

 

 

The car fries what ??? The ECU ??? If so, separate the s300 and the ECU and try them independently and see which part is the problem.