HELP! Anyone who's H22A7 converted a 4th gen please!

[Jack]

In the process of H22A7 converting my 4th gen and running into a few issues, it seems a fair bit more complicated than I'd imagined.

If it makes any difference it's a top spec UK BB1 VTEC (Cruise, AC, ABS, 4WS) and I want to keep all of these systems present and working.

I've done a bit of research on the subject and most of what I've found is people saying it's pointless and the poster would be better off spending money tuning the H22A2. This is not up for debate, I'm definitely using the A7 as the engine and U2Q7 box don't owe me a penny (broke a rotten Accord Type-R for parts and kept the running gear). The A2 from my Prelude is drokked, a pulley or tensioner failed last year and the cams don't turn with the rest of the engine now... I don't think it was in VTEC at the time so the valves are probably okay, however it used to smoke like a Vulcan on takeoff so at the very least needs a rebuild. So I'm 100% using an A7 with the ATR U2Q7 LSD box of cogs.

Now for the issues that I've come across:

The fuel line from the filter on the Prelude bulkhead won't reach the fuel rail on the A7 inlet. I don't want to use the A2 inlet as the A7 one is much better (and I don't think the A2 one fits the A7 head anyway?) Can I fit the A2 fuel rail to the A7 inlet and use the A7 injectors? I want to avoid using aftermarket/custom lines and rail for now if possible, as I just want it back on the road.

I read that the VSS from the ATR won't work in the Prelude due to the power steering? I don't quite understand why, but what's the best way around this? I take it it's not as simple as swapping the Prelude VSS onto the U2Q7?

EGRs are different, does that matter?

Hoses. I've not had a proper look but it seems there's a few differences around the inlet. Also the Prelude has LOADS of vacuum lines, I've no idea where any of them go, the the ATR setup only has a couple.

I've got an IACV adaptor plate so should be simple there - just bolt the Prelude IACV to the A7 inlet using the adaptor plate

As for the wiring - I'm hoping I can just take the Prelude engine loom off the A2 and plug it all into the A7 with the exception of the IABs plug as the ATR doesn't have them? Is it plug and play?

There's loads of stuff I've forgotten but I'm sure it'll come to me.

Few pics to motivate me as I'm getting pretty frustrated with it all!





H22A7 in question:

[mart609]

the A2 is OBD1 the A7 is OBD2
IIRC they use different injectors one peak and hold v saturated?
Theres a few people on there thats done it... @jonja I think was one
I think its a matter of chopping and chaging a few bits to match

[K30DPC]

Can I fit the A2 fuel rail to the A7 inlet and use the A7 injectors

If this will work then I can't see why not

I read that the VSS from the ATR won't work in the Prelude due to the power steering? I don't quite understand why, but what's the best way around this? I take it it's not as simple as swapping the Prelude VSS onto the U2Q7?

Anybody who is using U2Q7 have this issue. The trouble is that prelude is using simple power steering fluid pump mounted on VSS to adjust the amount of help related to the speed while ATR have done this using VSS speed electric signal. So sensors itself are totally different. Also they using different gears, so you can't use prelude sensor on U2Q7. What I've done is swapping gears and I was able to use prelude VSS.

EGRs are different, does that matter?

OBD2 vs OBD1. This is not only one OBD difference. Injectors, alternator, dizzy IIRC and probably some more. You can find some usefull info online. I've never done this conversion so can't help you much.

Hoses.

Weĺl. I do believe some of them are not needed any longer. I've chop off some and car is still fine. Best to do is to label each of them and try to install into the same place. I mean if it's going to inlet mani then for sure it have to be there so after you put A7 in then the vacum line have to be connected to inlet mani. You can easily use Y or T connectors. Manual will be handy as well so download one and have a look.

As for the wiring - I'm hoping I can just take the Prelude engine loom off the A2 and plug it all into the A7 with the exception of the IABs plug as the ATR doesn't have them? Is it plug and play?

I'm afraid it's not that simple. Again OBD2 vs OBD1.

Another thing you should look at is ECU. Ideally you need tunable one as original one will be throwing one fault after another. Maybe you should use whole engine loom and ECU from ATR. But like I said I've never done this so it's more like my thoughts then the way to go.

I'm sure @batkosio have A7 in his prelude so he will be the best person to answer your questions.

[batkosio]

So I'm 100% using an A7 with the ATR U2Q7 LSD box of cogs.

You won`t regret the combo You should decide what OBD to run- if OBD1, which I did and advise you to do so, you will have more options for tunning. Without tunning, my setup was 160 WHP- JDM p13 ecu with injectors, with just tunning- 172 whp. Later I added Type S intake, and custom exhaust system, and now it sits at 206 hp at the hubs, and it isn`t even tuned since.

(Cruise, AC, ABS, 4WS) and I want to keep all of these systems present and working.

I kept mine, even installed the TCS fro a JDM Prelude

The fuel line from the filter on the Prelude bulkhead won't reach the fuel rail on the A7 inlet.

I don`t have that problem, because mine is LHD. Just use some adapter hose for the extra length, or maybe the fule hose from the Accord.

I don't want to use the A2 inlet as the A7 one is much better (and I don't think the A2 one fits the A7 head anyway?)

Definitely! A7 inlet, just fill in the air holes for the injectors if going OBD1, and the brake booster hose doesn`t need to be relocated, just turn it at a 90 degrees angle.

Jack wrote:
Can I fit the A2 fuel rail to the A7 inlet and use the A7 injectors

If this will work then I can't see why not

It`s the other way round- use the A7 fuel rail, with A7 injectors or some JDM H22A 345 cc injectors, depending on your ecu/management system. You will need to modify the A7 fuel rail with adding some spacers allowing to fit the Prelude injectors.

Jack wrote:
I read that the VSS from the ATR won't work in the Prelude due to the power steering? I don't quite understand why, but what's the best way around this? I take it it's not as simple as swapping the Prelude VSS onto the U2Q7?

Anybody who is using U2Q7 have this issue. The trouble is that prelude is using simple power steering fluid pump mounted on VSS to adjust the amount of help related to the speed while ATR have done this using VSS speed electric signal. So sensors itself are totally different. Also they using different gears, so you can't use prelude sensor on U2Q7. What I've done is swapping gears and I was able to use prelude VSS.

Use the Prelude VSS, open the U2Q7 gearbox, and replace the gear that drives the VSS with the gear from your Prelude gearbox, the code should be M2F5.

Jack wrote:
EGRs are different, does that matter?


OBD2 vs OBD1. This is not only one OBD difference. Injectors, alternator, dizzy IIRC and probably some more. You can find some usefull info online. I've never done this conversion so can't help you much.

You should decide what OBD to run, and use the relevant EGR, dizzy, alternator, air intake temperature sensor. If OBD1, which I did and advise you to do so- more options for tunning, use your Prelude ones.

Jack wrote:
Hoses.

Weĺl. I do believe some of them are not needed any longer. I've chop off some and car is still fine. Best to do is to label each of them and try to install into the same place. I mean if it's going to inlet mani then for sure it have to be there so after you put A7 in then the vacum line have to be connected to inlet mani. You can easily use Y or T connectors. Manual will be handy as well so download one and have a look.

I can only help you with pics here from my install, rather than explaining Let me know!

Jack wrote:
As for the wiring - I'm hoping I can just take the Prelude engine loom off the A2 and plug it all into the A7 with the exception of the IABs plug as the ATR doesn't have them? Is it plug and play?


I'm afraid it's not that simple. Again OBD2 vs OBD1.

Use the H22A2 wiring from your old engine, if going OBD1. The air intake temperature sensors have different connectors, so either use the Prelude sensor, or swap the Prelude connector onto the Accord sensor. You will have a connector for the fan switch sensor left, you can swap the part where the switch is onto the A7 engine- the top radiator hose goes into it, right below the dizzy, on the front of the engine.

I've got an IACV adaptor plate so should be simple there - just bolt the Prelude IACV to the A7 inlet using the adaptor plate

Yes.

[Merlin]

I have recently swapped two OBDII engines into my 4th gen.

The Prelude and ATR fuel rails are different in the way they attach to the IM.

The coolant temp sensor on the side of the head will be a different connector if going OBDI.

[Drax]

@W1ggz did you recently put in a U2Q7 on your 4g engine, how did you get around the VSS issue?

i would just buy a bit of braided line for the fuel line extension @Jack

[Jack]

I read that the VSS from the ATR won't work in the Prelude due to the power steering? I don't quite understand why, but what's the best way around this? I take it it's not as simple as swapping the Prelude VSS onto the U2Q7?

Anybody who is using U2Q7 have this issue. The trouble is that prelude is using simple power steering fluid pump mounted on VSS to adjust the amount of help related to the speed while ATR have done this using VSS speed electric signal. So sensors itself are totally different. Also they using different gears, so you can't use prelude sensor on U2Q7. What I've done is swapping gears and I was able to use prelude VSS.

So you swapped the gear in the gearbox or the gears in the VSS? Which is easiest/less likely to break things? Is there a guide on how to do it, not confident with opening gearboxes up lol.

EGRs are different, does that matter?

OBD2 vs OBD1. This is not only one OBD difference. Injectors, alternator, dizzy IIRC and probably some more. You can find some usefull info online. I've never done this conversion so can't help you much.

I will be running OBD1. The alternator on the H22A2 is an ATR one (the alternator failed a while ago and I struggled to find a replacement so got VtecDirect to change the plug on my loom and used an ATR alternator) I'll use the OBD1 Prelude dizzy. I intend on using the ATR injectors as that's the most simple way and they will have the correct flow rate. @Drax told me I should be able to do this fairly simply with a bit of soldering (although I'm not sure what I need to solder lol)

Hoses.

Weĺl. I do believe some of them are not needed any longer. I've chop off some and car is still fine. Best to do is to label each of them and try to install into the same place. I mean if it's going to inlet mani then for sure it have to be there so after you put A7 in then the vacum line have to be connected to inlet mani. You can easily use Y or T connectors. Manual will be handy as well so download one and have a look.

Does it matter if it's all linked together pretty much? There's a lot less vacuum lines coming off the ATR inlet so can I just T/Y conect them all together? I don't really know how the vacuum system works...

As for the wiring - I'm hoping I can just take the Prelude engine loom off the A2 and plug it all into the A7 with the exception of the IABs plug as the ATR doesn't have them? Is it plug and play?

I'm afraid it's not that simple. Again OBD2 vs OBD1.

Another thing you should look at is ECU. Ideally you need tunable one as original one will be throwing one fault after another. Maybe you should use whole engine loom and ECU from ATR. But like I said I've never done this so it's more like my thoughts then the way to go.

As above, I'll be using mostly Prelude OBD1 ancillaries so things like the dizzy and most sensors should plug right in? The MAP sensor on the Prelude is on the bulkhead and the ATR one is on the manifold - which one do I use?

ECU wise I have a few options. I have a P28 on Crome which is currently on my Civic until the lude is up and running, this is chipped and socketed, just needs a chip to suit H22 and then mapping. Just to get it running I'll probably use my mates Hondata S300 which was mapped by TDI North on a H22A7 Integra using OBD1 so should work well on mine. I assume a P28 plugs right into a Prelude engine loom with no issues? The other option I have (which I'm unlikely to do due to as I'll have to buy a conversion harness) is to use the ATR ecu and remove the immobiliser chip. Another reason I don't want to do this is the ATR ecu isn't mappable.

(Cruise, AC, ABS, 4WS) and I want to keep all of these systems present and working.

I kept mine, even installed the TCS fro a JDM Prelude

Sweet, any mods needed to keep the cruise? Did you use the 4G lude AC pump?

I don't want to use the A2 inlet as the A7 one is much better (and I don't think the A2 one fits the A7 head anyway?)

Definitely! A7 inlet, just fill in the air holes for the injectors if going OBD1, and the brake booster hose doesn`t need to be relocated, just turn it at a 90 degrees angle.

Air holes? I haven't taken the inlet off then engine yet so don't quite know what you mean by the air holes? Is it simple to do? I will be using the OBD1 Prelude loom, dizzy etc. I was gonna just use the ATR brake booster hose as its just one rubber hose whereas the Prelude one is rubber connected to rusty metal connected to more rubber lol.

Jack wrote:
Can I fit the A2 fuel rail to the A7 inlet and use the A7 injectors

If this will work then I can't see why not

It`s the other way round- use the A7 fuel rail, with A7 injectors or some JDM H22A 345 cc injectors, depending on your ecu/management system. You will need to modify the A7 fuel rail with adding some spacers allowing to fit the Prelude injectors.

Do you know how to make the ATR injectors run on the OBD1 loom? @Drax says I need to solder something but I'm clueless regarding electrics.

Jack wrote:
I read that the VSS from the ATR won't work in the Prelude due to the power steering? I don't quite understand why, but what's the best way around this? I take it it's not as simple as swapping the Prelude VSS onto the U2Q7?

Anybody who is using U2Q7 have this issue. The trouble is that prelude is using simple power steering fluid pump mounted on VSS to adjust the amount of help related to the speed while ATR have done this using VSS speed electric signal. So sensors itself are totally different. Also they using different gears, so you can't use prelude sensor on U2Q7. What I've done is swapping gears and I was able to use prelude VSS.

Use the Prelude VSS, open the U2Q7 gearbox, and replace the gear that drives the VSS with the gear from your Prelude gearbox, the code should be M2F5.

Is there a guide/pics for this?

Jack wrote:
EGRs are different, does that matter?


OBD2 vs OBD1. This is not only one OBD difference. Injectors, alternator, dizzy IIRC and probably some more. You can find some usefull info online. I've never done this conversion so can't help you much.

You should decide what OBD to run, and use the relevant EGR, dizzy, alternator, air intake temperature sensor. If OBD1, which I did and advise you to do so- more options for tunning, use your Prelude ones.

Using the OBD1 loom. I'm not too bothered about running an EGR, can I just blank it off and/or leave it unplugged? I'll be using the Prelude dizzy. As above, I'm using an ATR alternator as the loom has already been modified to support that. IAT sensor is on the throttle body, right? Can I just swap this from the Prelude engine to ATR engine?

Jack wrote:
Hoses.

Weĺl. I do believe some of them are not needed any longer. I've chop off some and car is still fine. Best to do is to label each of them and try to install into the same place. I mean if it's going to inlet mani then for sure it have to be there so after you put A7 in then the vacum line have to be connected to inlet mani. You can easily use Y or T connectors. Manual will be handy as well so download one and have a look.

I can only help you with pics here from my install, rather than explaining Let me know!

Yes link me to some pictures please!

Jack wrote:
As for the wiring - I'm hoping I can just take the Prelude engine loom off the A2 and plug it all into the A7 with the exception of the IABs plug as the ATR doesn't have them? Is it plug and play?


I'm afraid it's not that simple. Again OBD2 vs OBD1.

Use the H22A2 wiring from your old engine, if going OBD1. The air intake temperature sensors have different connectors, so either use the Prelude sensor, or swap the Prelude connector onto the Accord sensor. You will have a connector for the fan switch sensor left, you can swap the part where the switch is onto the A7 engine- the top radiator hose goes into it, right below the dizzy, on the front of the engine.

Okay, that part sounds fairly simple, thanks.