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*HELP* The EVIL H22a4 to H23a VTEC swap

27K views 52 replies 20 participants last post by  bloodSHed 
#1 ·
Hi all,

I have a complicated and frustrating situation that I could use some advice on. Here's the background info:

- I hydrolocked my 1998 automatic base prelude. (F***!)

After measuring the piston heights (and seeing water in a cylinder), it was clear that I bent a rod pretty good. I opted to replace the engine instead of a rebuild. After researching extensively about which engine to choose, I decided on the H23A VTEC. I planned on making the new engine run as an OBDII.

- I bought new: oil pump (H22 for crank sensor issue), timing belt, water pump, spark plugs, tensioners, spark plug wires, starter, rotor, distributor cap, oil pan gasket, front main seal, rear main seal, alternator belt, power steering belt, intake manifold gasket, motor mounts, headers and VTEC oil pressure sensor.

- We used from the old H22a4: fuel rail, injectors, dizzy, crank pulley (for power steering), and the throttle body (I believe).

The new engine is in the car and all hooked up. When my mechanic tried to fire it up, he said that he was getting a crank sensor error. He tested the sensor and said it was dead.

I bought a new crank sensor, and he put it in. Now, we aren't receiving any spark or fuel. My mechanic says that he can turn the fuel pump on manually with a scanner, so it's not the fuel pump or the main relay. Also, the coil in the distributor is new, so he ruled out the dizzy.

The check engine light comes on for 2 seconds, turns off, then stays on. In his opinion, my ecu was likely damaged in the flood and needs replacing.

I have a couple of options for replacing the ECU. I can go with a P13, P28, or P72. I ruled out the P28 since, from my understanding, they will not operate the IAB butterfly valves. That leaves either the P13 or P72.

In an effort to avoid potential problems with the demobilizer in my Prelude, I've decided on a chipped P13 - OBDI. I know I will also need the OBDII to OBDI conversion harness. From what I've read, the chipped OBDI P13 ECU should run my H23a VTEC with OBDII engine setup (dizzy, oil pump, etc) just fine.

- Can anyone confirm this information for me?
- Does anyone (that has the H23a VTEC) have any other suggestions as to the best choice for an ECU?

Also, I read on this thread something about having to switch the balancer belt pulley.

- Are they referring to the crank pulley, or something different?

This job has been the bane of my existence, seems like one problem after another. My car has been out of commission since late September, and I've spent something like $3k so far...I would GREATLY appreciate any advice or help you all can offer to get my lude back on the road as quickly and cheaply as possible.

THANKS!
 
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#3 ·
Yeah, you need to swap all the parts on the crank snout to the US OBD2 stuff, including the gears themselves which have the pickups.

That said, you'd be throwing crank position codes and a CEL if the stuff wasn't swapped over.
 
#14 ·
Hi All, thanks for your input - you were a great help!! We've swapped over the timing belt and balancer belt drive gears, and the car FINALLY starts!

One problem though: The car can't rev past 3k rpm. My mechanic says that it is throwing a Throttle Positioning Sensor (TPS) code, and that the car shuts off after running for a little while. My mechanic thinks the TPS is dead, but I want to make absolutely sure there aren't any other possible causes for this issue.

- Anyone heard of this before, or experienced this during their swap?

Thanks again for your help so far, it's unreal how much relief I got from just the car starting...
 
#18 ·
#26 ·
H22a4 oil pump needs to be swapped over since the H23 vtec oil pump does not have mounting holes for the crank position sensor.



oil pump, balance shaft crank gear and sensor
 
#27 ·
h23a in 5th gen cranks but wont start helppppp!!!

New to this but need help. Figured forums are my best option. I have a 5th gen with jdm h23a car was running fine but decided to swap everything over to be able to pass this bs ny inspection. I bought new h22a oil pump dizzy and crank sensor . Now for some reason car cranks but does not start. Any info would help please . Thanks.
 
#29 ·
Dunwoody: make sure you have the correct plug on the TPS. I know the TPS and MAP sensor use the same style plug and they are pretty close together, easy mistake to make, easy problem to fix. Double check that and then make sure the TPS is calibrated as BBnineone6 stated earlier
 
#30 ·
h23a vtec swap update



Hi all! Just an update, I got this job finished in approximately November 2012. The car originally failed to start because it was in limp mode from not having the right cam gear on. We needed to put in the US one with the magnetic pickups for the TDC CKP Sensor to work. After we got that installed, it started running great! I replaced the tranny last April and she's been driving real strong. Lots of lowend torque compared to the H22A4.

I am getting a check engine light right now however past 30 mph. When I last ran the code I thought it said Crank Position Sensor but I'm not 100% sure. I don't think it can be a bad CKP sensor since the car wouldn't run if that sensor was bad. I'll find out the code and report back soon.
 
#33 ·
Hey YouNeek, the problem was during the swap we broke off the knock sensor. It's very easy to do and to overlook. Check out this picture http://www.ff-squad.com/tech/block/B18C_ks_1.jpg The black plastic was completely broken off and when it breaks off, it looks just like a regular bolt. I had to take off my intake manifold just so I could finally find it because it's very difficult to find without the plastic. Once I got the new sensor in though, my engine hasn't thrown any check engine lights at all. As far as advice goes, I'd say replace as many things as you can afford while the H23A is out of the engine. Front main seal, rear main seal, waterpump, oil pump, etc. It will be worth it in the end since you save so much time on labor. Also, DO NOT forget to use the crank gear from the US spec H22a4. It has magnetic pickups on it that are slightly raised up from the gear and it's very easy to miss. The engine will NOT run if you forget and it's a bitch to do it after the engine is put in. I would stick with OBD2 if you can. Also, be wary of the revv limiter. The h22a4 rev max is much higher than the h23a. Don't rev your engine past 6k RPM, since that is what the rev limiter should be set at. Some people get a new computer programmed for that, but I never did. I'm just wary of how high I rev the RPMs. Enjoy the low-end torque, it's a big difference. Let me know if you have any questions at all. I have been through hell and back with this.
 
#32 ·
I have a list in the 5th gen section of preludecentral.com

Check it out, its only missing 2 things from the list that I will try to add later
 
#37 ·
@dunw00dy24 or anyone else that can help! I just swapped a jdm H23 bluetop into my 98 prelude. I swapped the intake throttle body, intake manifold, dizzy, oil pump, tranny from the H22 etc. I am using the obd2a ecu and wiring harness. I bought new crank position sensors, new knock sensor and installed them. The car turns on but once you accelerate it turns off. It turns off after 1500 rpms. The CEL is on it flashes 4 times and it gives the CKP code. My understandings was that if the CKP sensor doesn't work the car technically can't start. I attempted the ckp bypass trick from ffstechnet and I had no luck. All advice is welcomed thanks.
 
#42 ·
You need the bslance shaft cog, and the timing belt cog. Also, the h22a4 distributor.
 
#46 ·
I like the H23A dizzy and oil pump better. Less shit to deal with if one of those sensors goes bad since they're up in the dizzy instead of behind the timing belt. :cool:
 
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