I recently swapped a 93 GSR 1.7L dohc vtec engine into my 91 CRX Si, repinned the ECU and added the necessary wires to make it run. Old engine died, but before it did, it had power issues at low to mid RPM range.
I replaced the fuel filter with that motor, but it only improved it a little. When I performed the swap, i noticed the same issue with my new motor, so i tried replacing the fuel pump. I had an extra fuel pump lying around from a 96 Prelude SR-V so i put that in but the problem still persists. Only when the vtec kicks in, do i feel any real power, seems to be lacking from 1000 to 6000 RPM.
I've owned a 90 CRX and i swapped in the 91 Acura Integra LS 1.8 dohc non-vtec motor and that thing went like stink. My new motor doesn't feel comparable to my old motor even though it has 30 more hp, anyone got any ideas?
Diagnostics already performed are checked fuel pressures 40PSI at idle, 50 PSI with vacuum hose disconnected and plugged, road tested and monitored fuel pressure under load, did not drop below 40PSI. Performed an injector power flush, checked distributor timing is dead on, checked MAP sensor was good but replaced it anyway with a known good. Fuel filter only has about 5k on it. Pulled codes when engine light came on after an engine shampoo and pressure wash, was code 1 and 43 (O2 sensor codes and fuel delivery code) but attributed that to water intrusion in the O2 sensor connector, codes haven't come back since Map sensor replaced.
My question is, do i have to upgrade my fuel pump to an Integra GSR one, or aftermarket H.O. unit? The specifications are different (364ml in 10 seconds as opposed to 230ml in 10 seconds for CRX Si), will that solve my problem? And any ideas as to whats wrong with my engine, or is it really that gutless?
Only thing that comes to mind, and it's a guess, is that maybe the VTEC solenoid is staying open/on at all rpm. When it's not up to temp. it shouldn't be, but maybe you don't floor it when it's cold (neither do I). That's just a vaque shot in the dark from me though, and easy to check by disconnecting it.
Otherwise, ignition timing comes to mind, but I doubt that would be that horrible all the way up to 6k, you'd expect it to start compensating by around 3k. I did read that you checked it, does it start to advance as soon as you give it some throttle like it should?(in other words, maybe it could be the distributor, but doubt it) (edit) it's a VTEC distributor, right? (for that engine or from another w/ VTEC)
As for the fuel being the issue, I don't think so as if anything you'd expect the opposite w/ the higher rpms lacking if it couldn't supply enough when the cam switched over.
Ignition timing is dead on, vtec seems to be working fine, power is not horrible but it feels like there should be more.. i guess i'm just used to my old LS motor where there was alot of power in the mid range. Thanks for the advice.. i'll keep you posted on what i find, if i can find it.
im doing a swap on my crx si with a gsr and ls tranny.now the motor dont start it sounds like if the battery is dead but its not that.also my cable clutch gets hot like if its ground i have the originall crx wiring harness they say i can still use it.and what distributer would i use the harness is obo0 but the motor is obo1 i have the obo to obo1 conversion harness but not for the distributer do i use a b16 but from what year what montifications would i have to do.i need help on this let me know asap thanks
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