When will it end !?!?!? (problems with JDM Civic VX engine swap into CX)
 

I've gone through so many dashed hopes with my JDM VX engine swap into a Canadian CX.
This is what I've done; got the proper exhaust manifold with cat, brand new NTK 5 wire O2 sensor, cleaned the injectors, new rotor, plugs, air filter, put on EGR valve with solenoid and constant vacuum valve, had the O2 sensor wired into the PO7-AO1 ECU, today I took out the 2nd CX cat under the engine, tomorrow I'll put in a new fuel filter. When my mechanic played with the fuel pressure the code 48 engine light took longer to come on (45 seconds), with higher pressure than lower fuel pressure, but I can't get it not to come on! My mechanic told me that when it throws a code 48 (lean air fuel), the ECU goes into a default setting which is giving me bad gas mileage and terrible emission numbers for our mandatory Canadian emissions test.

Can anybody please help me? give me suggestions?,
We've triple checked the wiring, but the EGR solenoid and constant vacuum valve aren't the stock ones.

I've got to figure this out, I'm going crazy!:eek:

you need to find someone with a wideband and see if your engine is really running lean, or the ecu just thinks it is.

i still bet you don't have the 02 sensor wired correctly.

Is it true that once the engine light goes the engine goes to a default (rich), setting?, because my emissions are REALLY bad.

It might or might not go into open loop, it depends on the CEL, but yes you're likely to have bad emissions if it is.

I had a problem on my motor where the TPS was actually turned a few degrees, and it was causing all sorts of wackiness - bit no TPS CEL.

Sorry but what is TPS?, CEL?

Throttle position sensor, it's on the throttle body. CEL = check engine light.

short answer: Usually.

Longer answer: CEL means computer says something is wrong. If something major is wrong, then your statement is correct - ECU goes into "limp mode", runs plenty rich, emissions go up, MPG goes down.

Sometimes the computer says something non critical goes wrong - classic example is the computer detects the gas cap is loose, and the evap system has a leak. The computer throws a code, and lights up telling you to tighten your gas cap, but continues to run efficiently. Off the top of my head, the only other examples are an inefficient CAT and no flow on the EGR and transmission problems - computer runs correctly but throws a code.

Every other possibility (and there are hundreds) the ECU goes into limp home mode and burns gas and makes emissions, possibly ruining your CAT costing you LOTS of money.

Send me a PM with where you live and I'll help you find a good tuner in your area to help you troubleshoot this.

This weekend I took the 2nd under engine CX cat out replaced with a straight piipe, new fuel filter, checked for intake leaks (none), reset the computer, and still after around 45 seconds the engine light comes on. I did put in the NGK ZPR 5F plugs in, and not the 4F, is that a big deal?

I'm leaning towards the O2 sensor as well. So its got the engines ecu... Is the wiring on the motor the same as the car (didn't have to swap pins)? Do you have access to another ecu?

I had a good looking used O2 sensor but I bought a brand new one to see, same result. I didn't do the wiring of the 5 wire O2 sensor to the PO7 ECU but the mechanic, Joe at Altech, Toronto, (built a 10.22 second CRX!) knows Honda's and double checked the wiring and we tried another PO7 ECU he had at the shop, again, same result. I'm going to change the thermostat next (180, 195 degrees?), put the 190cc ultrasonically cleaned injectors back in.

Still stumped!:confused: