F22A6 Swap to F22A1

[ryaloo74]

I've got a 1992 EX Wagon with 300K miles on it. The F22A6 in the wagon snapped its timing belt and bent its valves. At around the same time, I met an old man with a 1992 LX sedan rusting away in his backyard. The body was toast, but the motor was mint with 47K miles on it. So I bought the sedan with the intent of using the motor in my wagon.

I bought the LX Sedan off of him and I have the F22A1 motor out. I just got the F22A6 motor out of my wagon.
- I've kept the exhaust manifold and downpipe from the F22A6 and have lengthened the wiring to the O2 sensor on the F22A1 engine with some soldering to reach the rear location of the O2 sensor on the wagon.
- I've put the F22A6 motor mount bracket on the F22A1 so that the motor will fit around the beefier rear motor mount on the wagon.
- I am planning to use the stock camshaft in the F22A1 (as the motor is so low miles)
- I am planning to use the stock intake manifold for the F22A1
- I am planning to use the stock wiring harness on the F22A1 engine and plug it into the wiring harness on the body of the ex wagon. I am planning to take out the PT6 ecu from the wagon and plug in the PT3 from the sedan.
- I was thinking of removing the camshaft and intake manifold from the F22A6, and the PT6 from the wagon and saving these parts for use at a later date if I ever wanted to increase the hps of the F22A1.

I have a few questions:
(1) is it okay to leave the wiring harness on the F22A1 engine or should I really remove the wiring harness from the F22A6 engine and put it on the F22A1 before I drop it in the wagon? Similarly, is it okay to just swap the ecu from the PT6 to the PT3 since I am putting in the less aggressively tuned engine?
(2) If I were to Frankenstein my F22A1 engine at a later date, are the camshaft, PT6 ecu, and intake manifold the only things I would need to keep off of my old F22A6 engine? or, should I also save the engine wiring harness from the H22A6?Reminder, I have decided to run the F22A1 with the exhaust manifold from the F22A6 engine, so I am already saving that.

[deevergote]

The F22A1 block, head, and internals are identical to the F22A6. If you have the PT3 ECU and plan to use the F22A1 camshaft and intake manifold, then go with that. If you swap over the A6 stuff, use the PT6. No real harm will come from a mismatch, but you won’t get the best performance.

If you end up getting an ECU code (Code 43 especially), your o2 sensor is the likely culprit. It’s never a good idea to mess with the o2 sensor wiring, as it can change the signal sent to the ECU. I’ve seen it done successfully, but it causes problems more often than not.

[ryaloo74]

The F22A1 block, head, and internals are identical to the F22A6. If you have the PT3 ECU and plan to use the F22A1 camshaft and intake manifold, then go with that. If you swap over the A6 stuff, use the PT6. No real harm will come from a mismatch, but you won’t get the best performance.

If you end up getting an ECU code (Code 43 especially), your o2 sensor is the likely culprit. It’s never a good idea to mess with the o2 sensor wiring, as it can change the signal sent to the ECU. I’ve seen it done successfully, but it causes problems more often than not.

Thank you very much for the reply, that is good information. So the wiring harness that was stock, attached to the F22A1, should work in this application? No need to take the engine wiring harness off of the F22A6 and put it on the F22A1?

Thanks for the note about the O2 sensor. Unfortunately I had to re-wire in order to get the plug to reach. Hopefully it will be okay.

[deevergote]

The A1 harness should work.

If you used the A6 exhaust manifold, why didn’t the original o2 sensor go with it?

[ryaloo74]

The A1 harness should work.

If you used the A6 exhaust manifold, why didn’t the original o2 sensor go with it?

A6 exhaust manifold had the o2 down low near the flex pipe.
A1 exhaust manifold had the o2 on the front of the engine sticking out underneath the heat shield.

So putting the A1 into the car, the plug for the o2 on the engine wire harness was at the front of the car, whereas the o2 sensor was on the rear. I took off some of the wrap as some forums said sometimes there is extra wire for the o2 plug stuffed up there, but wasn't the case in my situation. So I spliced and soldered the 4 wires and extended the plug on the engine wire harness side so it would wrap around to the back of the engine to reach the o2 sensor. Used aircraft-grade wiring and heat wrapped it.

[deevergote]

But didn’t you reuse the A6 manifold and down pipe? It all bolts directly to the A1 block (all F22A blocks are identical castings)

[ryaloo74]

But didn’t you reuse the A6 manifold and down pipe? It all bolts directly to the A1 block (all F22A blocks are identical castings)

Hi deevergote,

I did use the A6 manifold and down pipe.
So I have:
(1) the A1 (PT3) ECU.
(2) the A1 engine and harness
(3) the A6 exhaust manifold and downpipe ... and thus the A6 o2 sensor further downstream on the a6 downpipe
(4) I rewired and extended the A1 engine harness to reach the o2 sensor in the A6 location
(5) I left map sensor and control box that was originally on the EX chassis and corresponded to the A6, because I didn't read anything saying I needed to switch this over when I put the A1 engine in
(6) During the engine swap I also replaced the fuel filter

Once I finished the swap, it was idling a little rough, so I cleaned the idle control unit. Still the rough idle (drops down to 400-500 rpms).
Then I was driving around a bit, and I would get a loss of power intermittently above 2000+ rpms. Then the car threw engine code 43. So I replaced the fuel pressure regulator. I took it on a short drive yesterday, and I still have the rough idle, but I didn't get any loss of power issues on the short drive. However, engine code 43 came back on at the end of the drive.

That reminded me to come back to this thread. So two questions:

(1) What would you recommend I do about the o2 sensor, should I buy a new one and re-wire yet again? Like I said, I used aircraft-grade wire and heat wrapped, I thought it was a pretty solid job of extending the harness. I understand these sensors can be very sensitive though.

(2) Does leaving the map sensor and control box from the a6 have anything to do with this problem? should I swap over the map sensor and control box from the a1?

Thanks,
Ryaloo

[ukemike]

I've read that only the NTK and Denso O2 sensors work well.