Prelude H22A swap help!!!

[blackshine007]

I have a 1995 Prelude Si which originally had the H23 motor. It currently has the H22A4 motor and to my knowledge, I thought everything was hooked up properly. It ran excellent with the H23 computer (P14) and I bought a JDM P13 ecu from another member (who will remain nameless for the time being) and hooked it up. Before then, I made certain to run pins A4 and D6 (the VTEC pressure switch and solenoid) to their correct spot, which come to find out the H23 harness already had the wires in place. I found the black and green wire for the solenoid sitting in it's connector on the firewall so i extended the wiring harness to the solenoid. There was a greyish/baby blue looking wire or the oil pressure switch sitting off in a connector harness by the fuse box. I extended the wire for it. I ohm'd out every thing and all as it should be so I thought.

I also have the VTEC controller on it and I followed the instructions so it works properly. On the stock P14 ECU, I programmed the VTEC to come on at 4800 rpm. It comes on as it should and pulls good all the way to the stock ECU's 6500 rpm.

Ok, so I unplug the stock ecu and plug in the JDM ecu and go to start it. It feels like it's misfiring, it bucks and when you rev it, it don't have any power and will occasionally backfire through the intake and once in a while stall out. But all the time while it's running, the check engine light doesn't come on.

So I drive the car and with basicly no power and it slugs it's way to a really short fuel cut of 6500 rpm. Once again no check engine light. I haven't attempted to turn off the VTEC controller to see if that should help it any but I don't think that would make a difference. Is there a difference between the some of the MAP sensors to where it would run that bad or are they the same? Do I have a bad ECU or did I miss something?

[G.C]

...

[00CelicaGT]

sean just call davis, that way u will get ur answer tonight. he should be able to answer all ur ?'s, u know he is the H & F series encylopedia.

[blackshine007]

I think your ecu is bad or does not have the right map. Contact Scotty from Mainstream and let him fix it for you.
What do you mean the right map? the map sensor? So is there a difference between the H23 map sensor and the H22?

sean just call davis, that way u will get ur answer tonight. he should be able to answer all ur ?'s, u know he is the H & F series encylopedia.
Yes, I called the human encylopedia the 1st day I had the ecu. He said the same thing I was thinking but I would like to borrow someone's ecu to confirm it or put the ecu in someone else's car that's in known good condition. Anyone here willing to help me?

[Vteckidd]

it IS possible to have a BAD ecu. Plug the H22 ECU in and if you get a SOLID CEL then its bad. If it gets NO CEL then it can still be bad.

Usually if its sluggish or something its got nothing to do with the ECU. if you say it runs FINE on a H23 ecu then id try to locate another H22 ECU or even a p28 an test it out.

Map sensors are the same so thats not the problem.

[blackshine007]

it IS possible to have a BAD ecu. Plug the H22 ECU in and if you get a SOLID CEL then its bad. If it gets NO CEL then it can still be bad.

Usually if its sluggish or something its got nothing to do with the ECU. if you say it runs FINE on a H23 ecu then id try to locate another H22 ECU or even a p28 an test it out.

Map sensors are the same so thats not the problem.
It runs perfect on the H23 ecu. No running problems. It just runs like crap with the JDM H22 ecu. Would anyone be willing to test this ECU in their car?

[Vteckidd]

you should be able to find any OBD1 car an test it.

Locate a any OBD1 ecu an try it out

[blackshine007]

Alrighty, I appreciate you.


On a side note, when I bought the ecu from him, I was wanting to try the ecu out in his car and he was saying that he would have to pull the carpet up and all and it's a whole lot of work. He drives a Sol with a swap and wasn't willing to plug in the ECU but insisted it worked. I'll make sure he sees this thread.

[Vteckidd]

is it chipped or STOCK?

[blackshine007]

Stock. I'll send you a PM

[EmminoDaGreat]

sounds to me you need to check the differences in ecu plugs wiring, it is possible that a sensors location on one ecu is not the same on the other, (maybe not the case) but I have had that prob before... needless to say, that should be an easy swap simply wiring in vtec sol,press, knock...

[blackshine007]

sounds to me you need to check the differences in ecu plugs wiring, it is possible that a sensors location on one ecu is not the same on the other, (maybe not the case) but I have had that prob before... needless to say, that should be an easy swap simply wiring in vtec sol,press, knock...

According to Alldata, we pulled up a wiring schematic specifically for the H22 and it matched completely at the ECU. Like I said, pins A4 and D6 had had wires going into it. BTW, I'm running the ground off the oil pressure switch to the chassis. Like I said, no CEL's and the light does light up when the key is first turned on.

[Vteckidd]

unplug VTEC and see if that helps. Ive had a car one time that was running "in vtec" cause of a crossed wire. it was hard as hell to diagnose

[blackshine007]

unplug VTEC and see if that helps. Ive had a car one time that was running "in vtec" cause of a crossed wire. it was hard as hell to diagnose
Ok, so my boss called me and told me he was gonna be at the shop so I had to pick up a couple of things anyways so I decided to try it out. No dice. It runs the same way. The light don't even come on. The way it's running is like it has a bad MAP sensor. So I unplug it the idle drops and the CEL comes on. I cut it off and plug it back in and it still runs the same. I'm gonna put the ECU in someone else's car. ANy volunteers? Southside crew, holla @ me.

[Vteckidd]

next thing to do is test taht H22 ecu in someone elses car. if its a stock ecu it should run fine.

[hseries4]

Have you undone the VAFC? You mentioned it, but never said you did. You need to be able to cancel out all other variablse as to why it's not working. It would seem to me that the controller is trying to override the P13 since it redlined at 6500rpm.

Also on that note, it's bad enough that you're using the P14, but are you sure that it's an H22a4? The a4 is an OBD-II motor...or do you have a converter?

[blackshine007]

^^You make a valid point. I tried the JDM P13 in a car that has an LS VTEC swap and it was kicking in, despite the fact that it was breaking up from possibly bad plug wires. I would love to try another car that's running an H22 because of when I swapped the LS VTEC's P28 computer. When I installed the P28 ECU, It spun all the way to like 7400 rpm with no problem, just running a little lean. It was really weak in the lower rpms, but you can expect that from a ECU designed for a smaller motor.

I'm gonna have to bypass the VAFC and go from there. I need to install some bullet connectors to see if it makes a big difference or not. I'll have to do that tomorrow when I find the time. I'm in the middle of rebuilding an engine so I haven't played with it much today.

[94ludeguy]

Have you undone the VAFC? You mentioned it, but never said you did. You need to be able to cancel out all other variablse as to why it's not working. It would seem to me that the controller is trying to override the P13 since it redlined at 6500rpm.

Also on that note, it's bad enough that you're using the P14, but are you sure that it's an H22a4? The a4 is an OBD-II motor...or do you have a converter?


exactly what i was thinking... the a4 is an obd2 motor and if your using an obd1 harness that could be where your problem is. what you would need is a OBD1 to OBD2 conversion harness. but using a p28 is not the problem unless its just a bad ECU or unless is was chipped or something. its a really common ECU to use... the only diff is i think the p13 has a speed limiter on it but the normal redline and fuel cutoff.

but i would find another ecu thats the same to plug in. that would be the easiest route.

i think you might need an obd2 ecu to be honest

[blackshine007]

Ok, I got updates. I ran the green/yellow wire and the greyish blue looking wire the way it's supposed to be instead of running it into the VAFC. Even though It still crunk up and popped and spit and sputter a bit, I was able to take it all the way to what looks like 7400 rpm after it warmed up. It was a bit sluggish but it did eventually hit VTEC as it should. Are they supposed to feel that sluggish off the line like that or I have other issues going on?

[hseries4]

It sounds like there are still some other issues...The way you say it popped/sputtered and eventually hit VTEC doesn't sound right.
Exactly when did VTEC engage and to what extent did it stumble? It would seem that if it were running that horribly that you wouldn't run it to redline, sooo details...how did it compare to when you put the P28 in there?

[blackshine007]

^^When it was cold it would run crazy and you would have to slowly accelerate the throttle to keep it from popping and backfiring. But I don't have that issue with the H23 ecu. I crank it up cold and it revs just fine. In fact, if it weren't for the extra rpms, I think the car is actually quicker with the H23 ECU. Honestly. It's pretty gusty with that ecu.

With the P28, it also felt lazy. With that one, you can feel the dual phase intake runner kick on right before VTEC. And after that it was progressively ramping up speed. Like I said, I thought it was due to the the maps of a smaller car.

[dakilla4ever]

^^When it was cold it would run crazy and you would have to slowly accelerate the throttle to keep it from popping and backfiring. But I don't have that issue with the H23 ecu. I crank it up cold and it revs just fine. In fact, if it weren't for the extra rpms, I think the car is actually quicker with the H23 ECU. Honestly. It's pretty gusty with that ecu.

With the P28, it also felt lazy. With that one, you can feel the dual phase intake runner kick on right before VTEC. And after that it was progressively ramping up speed. Like I said, I thought it was due to the the maps of a smaller car.

Yo like I said before it sounds like the ecu. You have a Jdm P13. That is an OBD1 Prelude ecu. If it's in an accord/or prelude it will plug in perfectly fine no problems with that. If you REALLY have an H22A4 then the distributor is different than the one in the OBD1 H22A/A1. Without the proper harnesses it will not run properly. Catch up with me this Saturday. I would like to look at this personally. The syptoms that you are referring to sounds like your firing order is off. Pick any honda motor, mix up the spark plug wires and watch it do the same thing your saying. If the ecu is telling the igniter in the distributor to fire at a certain time but the distributor's sensors are reading something totally different your gonna spit, sputter, and back fire through the intake as if the wires were mixed up. I don't have anything planned early Saturday. You got the number just call me and we'll figure this out. I'll bring all the data, and information I've compiled so we can have a better idea of whats going on also. Remember think about how a system works, then think of the simplest things first. Surprisingly it always tends to be the simple things we over look.

[dakilla4ever]

Also I forgot to say the fuel maps are completely different between a P14, P13, and P28. And H22a will feel like it pulls hard because the fuel maps are designed for a motor WITHOUT vtec. So it's gonna allow the most amount of air/fuel to produce more torque on the bottom end of the rpm band. We all know H23's have no top end .....(except mine). J/K. But the P28 is designed for a motor with no where near the same amount of torque. So of course the fuel maps are completely different to maximize a vehicle with 1.8L's of displacement. You will only feel the true power of an H22 with a P13 ecu or a chipped/remapped P28 ecu. Anyone please correct me if I'm wrong. I gladly admit to my mistakes and I don't want to pass on incorrect informtion.

[hseries4]

Well, I get what you're saying, but the fact that the P13 is OBD-I would seem to have nothing to do with his issue because he was using the P14, which is also OBD-I. I don't think his problem is there (although the fact that he was running the P14 is scary enough, but I guess the VAFC is taking care of the air/fuel ratio)... Anyway, it doesn't seem like the firing order would be an issue because he never should have had to touch any of that whilst swapping ECUs.

It sounds more and more like an ECU issue, because the P28 ran well without having to bypass the VAFC. It's really hard to diagnose things like this when you don't know everything though, like who did the swap, programming, wiring, etc. Good luck if y'all meet up this weekend, though. Hope you get it sorted out

[dakilla4ever]

Yo like I said before it sounds like the ecu. You have a Jdm P13........................

....Sounds good.

[blackshine007]

^^You're gonna have to come up to the shop because it's not my car, but the boss's car here at the shop. I would drive it but it takes a real man to get caught dead driving a pink car. Yes, I said it. It's pink. Davis, please come to the shop sometime. Thanks.

And one last question..... Would you think that it was the way the VAFC was wired up bcause I was just looking at it and the wire that they say was supposed to be hooked up to the green/yellow and greyish blue wires.... Are they only supposed to be tapped or are you actually supposed to bypass it giving the VAFC full access to the VTEC? Only when I bypassed it was when VTEC comes on. And lets say I just tap into the wire, will that hurt anything or will I still be able to adjust when VTEC comes on?

[dakilla4ever]

^^You're gonna have to come up to the shop because it's not my car, but the boss's car here at the shop. I would drive it but it takes a real man to get caught dead driving a pink car. Yes, I said it. It's pink. Davis, please come to the shop sometime. Thanks.

And one last question..... Would you think that it was the way the VAFC was wired up bcause I was just looking at it and the wire that they say was supposed to be hooked up to the green/yellow and greyish blue wires.... Are they only supposed to be tapped or are you actually supposed to bypass it giving the VAFC full access to the VTEC? Only when I bypassed it was when VTEC comes on. And lets say I just tap into the wire, will that hurt anything or will I still be able to adjust when VTEC comes on?

Not 100% sure. Last time I looked at, I think it's only meant to be connected to it. Not replace it.

[blackshine007]

Yo, this ECU isn't any good. To confirm it, let's test it in your car and while you're at it, we can try out the ECU that's in your car. When you wanna meet up? VTEC is working and all but the car don't idle when cold and it's extremely sluggish under acceleration. I'll be certain to bring the tools needed to remove your ECU. Let's do this pretty soon. Hit me back, thanks.



ive been reading your "general tech" thread and it seems to me you have a h23 motor for some reason. yes, i heard people saying the ECU could be bad but some people were saying that the base maps were different and thats the reason why your cars running like that. its a valid point. what you mean "test it in my car?" it would do no good plugging a h22 ecu in my b16 del sol. what i really think is that you need to retest into a obd1 h22 with Vtec of course and see.
http://www.supermotors.net/getfile/685176/fullsize/100_0166.jpg
http://www.supermotors.net/getfile/685175/fullsize/100_0165.jpg

I guess he must believe that I'm a dumbass or something :thinking:

[IndianStig]

I'm glad you finally converted to the darkside Shaun.

How have you been though? LONG TIME NO SEE

I got a TL that im working on now but let me know if you need anyhelp with your Prelude.

with your question:

I would get a P72 if you are looking to tune (p13=no tunability). your ECU might just be bad cause p13 and a4 should go together like the varsity and chilli dogs.

[blackshine007]

^^I can assure you the 6 is still very much intact and faster since the last you saw it. It looks worse but you know I was never too keen on looks anyways ;)

[00CelicaGT]

shaun real men can pull of a pink car!!!

[Franco Tirador]

im having that same problem with my accord, i have a JDM H22a, the engine had to be incorporated into the stock accord harness, and when i use the stock accord ecu the engine runs like a dream, you know minus the vtec, but when i put in the same ecu, JDM p13, the car idles rough when the engine is cold, and it also backfires, and sputters, i got the ecu from a guy that had it in a modified car, he said it was good but i doubt it, because i can narrow the problem straight to the ecu, i have a cel but thats for the egr valve, and the ecu says that, i just found someone with a chipped p28 with h22 basemap, so maybe by this coming weekend we are going to swap ecus to see if indeed my p13 is bad

[Ludester]

Also I forgot to say the fuel maps are completely different between a P14, P13, and P28. And H22a will feel like it pulls hard because the fuel maps are designed for a motor WITHOUT vtec. So it's gonna allow the most amount of air/fuel to produce more torque on the bottom end of the rpm band. We all know H23's have no top end .....(except mine). J/K. But the P28 is designed for a motor with no where near the same amount of torque. So of course the fuel maps are completely different to maximize a vehicle with 1.8L's of displacement. You will only feel the true power of an H22 with a P13 ecu or a chipped/remapped P28 ecu. Anyone please correct me if I'm wrong. I gladly admit to my mistakes and I don't want to pass on incorrect informtion.

you're not wrong. each ecu makes the h22 idle and pulls a little differently.

[SiR EG2]

im having that same problem with my accord, i have a JDM H22a, the engine had to be incorporated into the stock accord harness, and when i use the stock accord ecu the engine runs like a dream, you know minus the vtec, but when i put in the same ecu, JDM p13, the car idles rough when the engine is cold, and it also backfires, and sputters, i got the ecu from a guy that had it in a modified car, he said it was good but i doubt it, because i can narrow the problem straight to the ecu, i have a cel but thats for the egr valve, and the ecu says that, i just found someone with a chipped p28 with h22 basemap, so maybe by this coming weekend we are going to swap ecus to see if indeed my p13 is bad

Maybe the one you have is bad reason may be b/c your is throwing a CEL code. OP's ECU seems like its not throwing any codes. The ECU isnt bad, its just a common thing, p13 cannot interact with anything else but stock. Go with the chipped p28

[blackshine007]

Ok here's the updates. I had DaKilla4ever (the walking prelude encyclopedia) come by and install it in his car and it pretty much ran fine while the car was warm, just like mine. So I had him take it home and install it in his car to see if it will do the same thing. It didn't so I guess that puts the theory out as far as having a bad ECU. But why would it only run bad with that particular ECU installed while cold? And since the car pretty much felt like Dakilla's car, why are they that slow before VTEC? I would assume that if you ran the H23 maps with an enhanced H22 top end it would pull ferociously. Anyone cares to dwell on that?