Help with my F20B swap and PCB ecu

[ali954]

PCB is the code for the F20B ecu. I have two of them. The one that came with the swap, and a newer one that i bought. I bought the second PCB ecu thinking it was the issue, but both PCB ecu's make the engine run the same way. It would be very bad luck for both ecu's to be bad with the same exact problem.

The engine came from an engine importer and this is my first time getting it running in the car. I've had the firing order off before and it would not start. Fixed the firing order and it fired right up.

[toycar]

PCB is the code for the F20B ecu. I have two of them. The one that came with the swap, and a newer one that i bought. I bought the second PCB ecu thinking it was the issue, but both PCB ecu's make the engine run the same way. It would be very bad luck for both ecu's to be bad with the same exact problem.

The engine came from an engine importer and this is my first time getting it running in the car. I've had the firing order off before and it would not start. Fixed the firing order and it fired right up.

can you elaborate on how you wired the dizzy?

[toycar]

seems like its common on f20b swap to run h22 manifold for iacv purposes.

did you do that?

im reading that f20b comes with 8 wire dizzy and there are sensors the f20b is going to be looking for that your factor harness doesnt have. did you correct that? how? im assuming this is why you swapped dizzy, but it seems like people frequently have issues here.

[ali954]

For the dizzy conversion, I tackled it as a usual honda dizzy conversion as far as OBD stuff and then external to internal coil.

Off the top of my head, 8 wires:
2 wires for TDC, CYP, CKP
Ignition Power
Tach Signal


OBD1 and OBD2a have all wires to match up. The OBD2b is missing one wire that is the tach wire, which comes from the ecu for OBD2b. I have the tach wire in my engine harness and the distributor is an 8 wire OBD1 prelude distributor. My tach works and the signal comes from the distributor. The conversion harness does not have this engine pulse wire. From my research, this is an output from the ecu, not an input. OBD1 ecus don't get the tach signal, they use the other dizzy sensors.

The complete intake manifold, including injectors, rail, EGR, and plenum with IACV is the stock F20B. The IACV is 3 wire. Continuity is good on everything here.

I didn't want to go the common or "easy" route with this. I really want to run this engine with the correct computer. I don't like either option of OBD1 tuning myself or getting tuned. This with be my daily delivery driver and I want that ULEV F20B mpg vtec yo...

[deevergote]

I do like the idea of running everything the way it was meant to be run in the car it came from. The lack of an easily usable factory ECU is one of the reasons I don't care for the F20B. I'm glad to see it being done this way, though. It'll provide a few more options for others in the future if you can get this all ironed out! I'm all for custom tuning when appropriate, but if you can't install the engine to be like it was from the factory first, I see that as a halfassed job. I really admire you for taking the difficult route on this one!

wow, i really wish i could help. But I'm going to say assuming your sensors (TPS, MAP, ECT, etc.) are correct, then it's your distributor or spark plug wire order. Your plugs are firing at the wrong time, causing all the symptoms we are seeing here.

The car will not function properly with either ECU/PCB. What you need is a F20B PCB that is functioning and just work out the bugs.

Have you ever had this engine running properly in the past?

I'm with you on the distributor timing. It seems like that's the only thing it could be!
Still, he says the engine ran well on a PT6 and a chipped P06 with the CEL on. Even with the CEL on using the PCB, it has this same issue. So it's definitely associated with the PCB, and seems to be associated with the ignition timing (but only with the PCB.)

[deevergote]

This is a total shot in the dark... probably meaningless, and I assume something you've addressed already... but are the spark plugs the proper type and gap for the engine?

[ali954]

The plugs I'm using are NGK PZFR6F11. They say NGK's don't have to be gapped, but I checked anyways and the gap is correct. Also tried the NGK plugs the motor came with and same result.