The car is a 95 accord, was f22b2 auto, swapped in an f23a and an ms24 transmission from a prelude si. I used a P0A ecu and the external coil from the 95, and since the vtec solenoid did not have a pressure switch I jumped the wire at the ecu.

Upon startup the car had a hunting idle and had low power at higher rpms. I cleaned and adjusted the fast idle valve as well as cleaned the idle control valve and that fixed the hunting idle.

The car still does not have the power it used to at higher rpm (I took this motor and transmission out of my 96 accord that was in an accident). VTEC is working and no codes are being thrown. It feels similar to ignition breakup or something. Any ideas on what else to check? Also I have checked the timing and it looks spot on the center red dot with a light.

TLDR: Did motor swap, everything is good except missing/low power at high rpm, no codes.

Thanks, Levy

 

Ideally the engine would be mapped and the ECM chipped/tuned to match the engines VE. O2S can help compensate A/F correction, but at WOT the O2S is ignored and the engine runs off the ECMs pre-programmed tables. Without a retune/chipped ECM the VE, fueling, and timing tables are incorrect for your current combination.
The breakup you are feeling is most likely a lean misfire issue(due to incorrect tables), too much air, not enough fuel, and timing who knows where.

 

Thanks Mike,

That makes a lot of sense. The engine ran great on my OBDII f22b1 ECU so I thought it would work on the P0A but I bet the OBDII has more controllability. Luckily it still runs great under normal driving conditions, Ill look into getting it tuned!

Thanks again!
Levy

 

Are you trying to use the obd2 ecu in there ?

 

Using P0A ecu.

 

Are you using the tcu for the new tranny ?

 

Sorry, the ms24 is a manual transmission from a prelude SI, the P0A is an OBDI vtec, manual ECU. I looked at the timing and noticed its not quite on. The distributer is turned as much as it can be. I am going to take out all the bolts (and hold it in place) then see if I can get it timed by turning the distributor further than would normally be allowed. If so I will machine the grooves a little longer and report back.

Thanks for the input guys,
Levy

 

Check your camshaft belt. Tensioner may be loose or the cam is not properly timed to crank.
There is plenty of adjustment to time the ignition properly. Only thing that would prevent proper igntion timing is overly advanced or retarded camshaft timing. Check the cam to crank timing first and that the belt is not loose.

 

Looked at the timing again today. The red dot was so faded it looked white, so I THOUGHT I wasnt able to advance the timing enough to reach it when actually I had passed it. Surprisingly it seemed to run better with the distributor maxed out. I have put the timing back on where it should be and will report back if I figure anything else out.

Thanks for the responses guys!
-Levy

 

Overly advanced timing will make the car feel/sound peppier at idle, as well as raise idle rpm. But at higher rpms the total timing will be excessive and you will cause knock/detonation.

 

Since last post have cleaned out EGR manifold, new wires, and new injector seals since I developed a leak cleaning EGR manifold.

With the timing now (re)correctly set, back to the original problem. misses at high rpm, It ran much better with the distributer fully advanced but like you said MAD_MIKE, I dont want to run the car with overly advanced timing.

I understand that there is no stock ECU for my powertrain combination but what confuses me is that it ran GREAT in my 96 accord ex. The 96 had an f22b1, and that ECU controlled the F23 great so why doesnt an OBD I f22b1 ecu control it as well?

Another question I had. Instead of buying a vtec (internal coil) distributer I re-used the external coil distributer that came with the f22b2. does the vtec distributor advance timing more at high rpm for vtec?

Thanks,
-Levy

 

This may be irrelevant but when I bought my 2002 accord with an f23 it had low power at high rpm and my converter was melted and clogging. I put in a test pipe. Just a random thought. Best of luck in getting things worked out.

 

Thanks for the input! definitely worth a shot. I think i have a test pipe around somewhere and now that im OBDI I wont throw any codes with it huh?

Thank man!