Son's car needs ideas

'94 Honda Accord w/'96 or '97 Honda Prelude Motor. The original motor is a F22 which is a SOHC 2.2 liter non-VTEC. The Prelude motor that is in it now is an H22A which is a DOHC 2.2 liter VTEC. Had mechanics check vaccuum hoses, they say they are setup correct. When I have the car at idle, about every 30 seconds the car will jump from 1500 RPM’s down to about 700 RPM’s and then smooth out at about 1300 RPM’s. I know the idle is high and the timing is off. But they are set that way because that?s the only way I can get it to run as smooth as it does. Also it runs very rich, still gets good gas mileage, but runs very rich. Supposedly has a new O2 sensor and new plugs, haven’t checked for sure. When it is driven the check engine light comes on and the codes are Oxygen content and EGR system.

If you know the timing is off, why not fix that first, it may clear up your problems.

Did they swap over the ECM as well? These engines are different, and the '94 ECM cannot properly manage the '96 VTEC. Plus, the '96 ECM uses more sensors than the '94.

I would not even want to start guessing on this one. So if the timing is off why not set it correctly?
Are you aware that too much advance combined with some extended highway speeds may lead to an engine roasting? Timing with too much advance will also cause a high idle.

Since the car has gone from an OBDI to an OBDII engine (you have ONE O2 sensor?), and it sounds like you’ve been dinking with the throttle plate adjustment (a no-no) and timing to cover up problems, I could not even begin to list the what-ifs. Altering throttle plate position, which influences the EGR, is one of them.
This “VTEC swap” was not influenced by that Fast and Furious movie by any chance.

Yes they did swap this out.

Also it runs very rich, still gets good gas mileage, but runs very rich. Supposedly has a new O2 sensor and new plugs, haven’t checked for sure. When it is driven the check engine light comes on and the codes are Oxygen content and EGR system.

OK here’s a list of things to do:

Reset the ignition timing to the proper setting. Screwing with the timing is not something you want to do unless you know what you’re doing.

It could be that this will fix your running rich issue as well.

The CEL codes are probably as a result of the car running rich.

If the car’s running rich, it may well foul the oxygen sensor - so that might need to be replaced.

Once you’ve accomplished all that you’ll finally be ready to figure out why you’re getting the idle drop.

Every 30 seconds- - - your AC wouldn’t by any chance be on when this happens would it?

If not that, check ALL of your grounds carefully and replace any that are corroded or damaged. Hondas get very unhappy when their grounds aren’t good.

After that, you need to (and I know this is a royal pain, but it’s gotta be done) check the main wiring harness. Engine swaps are notorious for being hooked up with spit and bailing wire. People just don’t take the time to do it right, and you end up with bad connections or worse. I even saw one that had been completed with stereo wire.

Oh, and another thing - - did they swap ECU’s along with that engine?

First having the timing about 3-4 degrees advanced is the only way I can get it to keep running. The AC belt is currently off the car (compressor seized) so that gets rulled out. The ecu was replaced along with the motor, tranny. I haven’t checked all the ground wires yet but will get on that as soon as possible. Thanks

The car does only have one O2 sensor. I will look into getting another one thanks. By the way the motor swap was done before the Fast and The Furious movie was made.

When the swap was done did they also change out the MAP sensor? I just did a 1995 H22A JDM engine swap on my sons 1992 Honda Accord with the F22. It was a OBD I engine to an OBD I car which was a lot easier swap than what your swap is.

Do you know for sure that the ECM is wired correctly? If whoever tried to use the 94 Accord wiring harness they may not have the ECM wired correctly. On mine I had to wire in the VTEC Pressure Switch, VTEC Solenoid, Intake Air Bypass Solenoid and the Knock Sensor to the ECM. I think that these would have to be wired in also on yours. What ECM are you using? You may be using the wrong one. From what I’ve been able to find out on your swap the best ECM would be the P72 from a 1996 thru 2000 Integra GSR.

To eliminate any wiring issues you can buy an OBD I to OBDII wiring harness for this swap from

Did you also do the transmission swap? Just curious. When we did my sons we also changed out to the M2B4 JDM 5 speed with limited slip differential. His car already had the 5 speed for the F22 but the M2B4 has shorter gearing wich allows for faster acceleration.

The place that did the swap for me did enough things wrong. If the ECM isn’t wired correctly I wouldn’t be suprised. They didn’t even have the front engine mount bolts in (one was about half way screwed down and the other was missing). I will check on what the ECM is. The transmission was also swapped out. Thanks

also, why do you suggest the GSR ECM? What makes it better to use then the one out of a 97 Prelude? Just curious. If it would work better I will definately look into getting one. Thanks.

check for vacuum leaks at the intake manifold.

I’m unsure as to what ECM you currently have but the P72 ECM from the Integra you are able to upgraded the prom chip for any later mods. You can also take your car to a dyno shop and have it specficly tuned for your engine setup. I believe you can also adjust the revlimeter and your VTEC kick in point. If I’m wrong about this I’m sure someone will correct me.

I was doing a little searching and here is what I came up with for the different ECM’s.
P13 - This is the stock H22 ECU. It’s good for a stock motor (duh ). It has the capability to be chipped, but the maps that are available are very limited in scope. If your motor is near stock, you will be fine with this ECU. You can get programs that have slightly more timing and fuel with a lower VTEC engagement and still be fine. If you want the capability to do some tuning and change VTEC engagement, an Apexi VAFC or similar MAP signal altering piggyback will work well. This ECU cannot be used with Hondata.

P14 - This is the stock H23 ECU. I would assume this ECU can also be chipped, but I’ve never seen it done and don’t know of any available programs for them. This ECU cannot be used with Hondata.

P28 - The civic ECU and the cheaper most common choice. The P28 will NOT control the secondaries (IAB’s) in the intake manifold on the H22, H23, and B18C motors. The intake manifold will stay on the shorter runners, and you’ll usually lose 5-10ish horsepower from your powerband under 5500ish RPM. After 5500, the air velocity will be high enough that the shorter runners will start making power. Unless you plan on racing in the 2K to 5500 rpm range, this shouldn’t affect you much. The P28 also doesn’t have a knock sensor like the P13, P14, and P72 ECU’s. These ecus only use the knock sensor to alter timing under 5500 rpm. After 5500, the knock sensor can no longer make timing adjustments anyways. If you think that having a functional knock sensor under 5500 rpm is going to save your motor, you’re wrong. The P28 IS Hondata compatible. In addition, there are TONS of various chipped programs available for the P28. If you’re planning to run a chipped program in a P28, make sure the program is for your motor and not a civic. There are P28 programs available that mimic the stock P13 fuel and timing maps, but I don’t see the point in changing out your ECU so you can run the same maps…

P72 - The GSR ecu. This ECU does control the IAB’s and also has knock sensor capability, but is more expensive than the P28 ECU. Technically this is the best ECU to use, because it has all of the features, but usually these ECU’s are overpriced. Knock sensor capability is mostly useless, but if you’re running an N/A motor the IAB control might be something you want. I’ve heard stories about people running stock P72’s on prelude motors and claiming power gains. These people smoke crack. The maps on the stock P72 ecu are designed for the B18C1 motor, NOT for the H22. If this ECU makes more power, it’s probably because it’s running more timing or less fuel than it should be. The P72 IS Hondata compatible. In addition, the Hondata software allows you to change where the IAB’s open/close, so you can engage the shorter runners earlier or later if you’d like.

P74/P75 - The integra LS ecu’s. These ECU’s do not offer VTEC control, IAB control, or knock sensor control, and thus are perfect (and the cheapest) options to use on the H23 motors. These ECU’s ARE Hondata compatible.

P13 93-95 OBD-1 Prelude VTEC

P28 92-95 OBD-1 Civic Si/Ex

P72 94-94 OBD-1 and 96-00 OBD-2 Integra GSR

P73 96-00 OBD-2 Integra Type-R (JDM & USDM)

P5P 97-00 OBD-2 Prelude Type-S (JDM ECU)

I got all this info out of “Ultimate H22A Swap Guide”

You may need a swap guide to get everything corrected.
I believe this is the web site you can buy a swap guide for what you are doing:

Did you ever find out which ECM you have?

I posted the above two postings. Didn’t relize that I was’nt signed in.

The ECM is the P13. So according to your guide that would be the wrong ECM because the numbers on the block indicate it to be a 97. But that’s just the block.

Also, over the weekend I reset the timing to what it’s supposed to be. Now it has a little lower idle when it smooths out. The only problem is the idle is much more spuratic. It jumps from about 500 to 1500 rpm’s every 15-20 sec. In between the jumps it sits at about 600 rpm’s.