I bought my friends 99 Accord EX Coupe. It orignaly had the stock ULEV f23a4 motor in it. But it had low compression in one of the cylinders and was burning oil and the motor would only rev to 4k then it would hit the rev limiter.

So I bought a f23a1 motor which came out of a wrecked car but was a running car. I installed the f23a1 motor and now it does not run correctly.

Once it warms up it will have a lumpy idle but when you press the gas the and try to hold it at like 3,000 rpms it is still lumpy it'll bounce from 1k to 3k. Also if you try to go full throttle it will just die out.

Things I have tried / checked so far:
-Checked the timing belt I installed (timing is on)
-Tried changing the throttle body w/ TPS
-Tried another MAP sensor
-Compression test came out perfect

**Update**
Tried a new dizzy and still no luck. Im going to do a vaccum & fuel pressure test next.

Any thoughts or has anyone else had this problem?

 

im having same problem did you figure it out. help me out let me know how you fixed it.................email me back at joshtsaab@aol.com

 

Nothing yet Im gonna try another dizzy and check the fuel pressure. Let me know if you figure something out.

 

Did you try to adjust the FITV & clean out the IACV to see if it'll stop the erratic surge?

 

I cleaned out the IACV and used 2 different throttle bodies.

 

I don't know if the ULEV has any other special connectors, wires, or sensors that may need to be hooked up?

 

i wouldn't suppose those both use the same ECU? did you happen to try the F23A1 ECU?

 

I may be wrong, but I seem to rememeber the cam being slightly different between the 2 engines. If it is, then the stock tuning would also be slightly different. I'm not sure if it would be different enough to cause a problem though.

Met a guy a guy once that had performed the same swap, and he said something about a sensor being different. It was a long time ago though, so there's not a chance in hell that I would remember what he said.

 

Hmm never thought of that. From what I read the header is what is the main difference. I asked a guy who did the same swap as me and he said he just dropped the motor in.

 

To be honest, I'm taking guesses at this point. It's been a while I've been in the "Honda scene". Most of my attention has been either on work or my other car, and during that time I've forgotten a lot of things that I used to know. Maybe the old age is catching up to me...

Again, I'm not sure if it makes a difference, but I was under the impression that the motors used different ECUs. You should see if you can get an F23A1 ECU, or borrow a known-working one at least.

 

ECU has a different tuning.

 

I spoke with someone who did the swap and they said they never swapped out ecus. You are right the ecus are different but will run both engines with the correct oxygen sensor. I just tried a new dizzy today and I will have the same issue.

 

I thinks its an ecu issue as well, check plugs make sure they havent fouled out since using the wrong ecu/tune.

 

When you cleaned the IACV and FITV and put on new TB's did you also replace the rings and gaskets? I had a roaming idle for a while with my d16z6 tried cleaning and replacing things. finally replaced rings and gaskets and she run soooo smooth.

 

Well that's nice of you to share, but dude this thread is 2 years old...

 

Put the ecm out of the wrecked car and reset it. Used they range from 40-150 US$.