Sandwarrior

Hoping to get some help from people with more knowledge on Acura's than I have, I swapped out my turbo VW motor to an Acura J32A VTEC motor, the car runs fine but it wont tach above 4800-5000 RPMS. other sand rails I see are running 6500, Im thinking that because the ECU isn't seeing any signal from the trans it might think its still in neutral, could that cause the ECU to limit the rpms? its acting like its hitting a rev limiter . The engine, ECU and harness are all junk yard fresh with no mods, but the people Im comparing mine to tell me they are running all stock also. Thanks in advance for any advice

80%downtime

Are you running a stock ECU or what aftermarket solution are you using?

Sandwarrior

Its stock, I'm getting some trans codes that's why I was wondering if the ECU isn't getting any input from the tranny if it would keep it from revving over 4800 RPM'S.

80%downtime

It may be that the ECU is reading that the transmission is in neutral or your speed at zero so it's purposely limiting itself in case you do "launch" so you don't break anything.

Sandwarrior

Thanks 80%, that's what I've been thinking about the ECU not seeing the trans going in any gear, I'm going to figure out what needs to be jumped at the ECU to make it think its in drive.

80%downtime

I don't know the programming behind the stock ecu, but if anything, try bypassing the neutral safety switch. I think the lack of signal is limiting the ECU so on a launch, you don't break anything. If that fails, another thing I can think of is the vehicle speed sensor.
​​​

Sandwarrior

I don't see any pin out at the ECU for the neutral safety switch, I am playing around with the different trans inputs the ECU may be looking for but no luck yet, it hits 4800 rpms and acts like its hitting a rev limiter. Im not sure how I could simulate a VSS being this is bolted to a VW style trans. Thanks for the advice though, I'm still digging.

tealej2

anyone ever figure this issue out. 2020 and seems I'm having similar issue. 97 civic cx hatch obd2a,b18c jdm p72, idles fine, cel for knock and o2. Wont go past 4k rpms when driving. At idle it will redline.

JRCivic1

Ummmm... fix the Knock sensor and your issues with a 4K rev limit will go away. Fix the O2 problem and you will be golden.