ECU what should I DO?? - Honda Prelude Forum

Ezra · 07-09-2005, 01:07 PM

Ok here's the story i modified my engine to be an H23 vtec... bought all the stuff and what not ...well once the changeover was complete the jdm ecu i bought didnt seem to work correctly because the car would start in 4th gear and wouldnt move thru the gears ( the car is auto ) well my brother and i rigged up both the usdm and jdm ecu's to work together and made it run and vtec engages and what not ( i have to shift it manually ) however now im having problems with some weird overheating issues and it seems like the car is running extremely hot and burning up my alternator wires so im wondering if the ecu's are not working correctly... i found a JDM VTEC ECU for an auto tranny on ebay and i was wondering if it would work... it has the three prong connector but my car has the 4 prong connector.... so one plug wont be plugged in if i buy this new ecu... do you guys think this might help my overheating problem and would that fourth plug have any adverse effects since it wont be plugged in?????

Ludster · 07-09-2005, 01:42 PM

3 Plugs? I think ur seeing an OBD-0 ECU. Does it have a Green Plug? You need to find a OBD-1 ECU, so All four prongs are used. or it won't work at all.

Ezra · 07-09-2005, 02:04 PM

my harness does have the green plug you are talking about.. just that the ecu that im looking at online only hase three plug-ins ... so there is going to be one plug that wont be connected... from what the listing said... it seems like the fourth connector is for TCS (tranction control system ) so i dont know if it will work because i think the first ecu i bought that did not work was probably one for a 5 sp tranny and thats why the car didnt move so thats why im looking for a vtec ecu for an auto which i found on ebay.... just the only thing is that it has 3 plugins and my harness has 4 plugs... so what is that fourth prong for what does it control?>???

Ezra · 07-09-2005, 02:09 PM

This is what is posted under the item description ...:::::

JDM Honda Prelude 92-96 BB4 H22A Engine Vtec ECU Auto Trans Computer.P13 type.

This is the genuine JDM Honda ECU unit.Nos are 37820-P13-N51....553-300279....2W....3N5...,,,,Auto TRANSMISSION.Plugs are OBD1 all grey type.Has the 3 plug standard OBD1 JDM and USDM/EDM plugs.If you need to patch to other plug types go to www.rywire.com for the plugs.Is the 2W which means its for the 2WS (2 wheel steer) version.

***NOTE***This is the 3 plug standard USDM/JDM ECU version.The 4 plug type is for the TCS(Traction Control System),or ATTS,,"Active Torque Transfer System" and has 4 plugs,yes,,,,,4 not 3 as is on standard USDM and most JDM P13's.I see people saying that the 4 plug is for auto,this is INCORRECT,you can have 3 or 4 plug for auto or manual.***NOTE***This is the 3 plug OBD1 Grey plug type ECU (NOT for the TCS or ATTS).

UWNTSUM · 07-11-2005, 12:30 PM

man.. all this for a auto... i would have opted to do the 5sp swap.

Ezra · 07-12-2005, 08:28 AM

at the time i only had enough money to get the engine but yea with all the trouble im having im probably just gonna scrap the whole damn car ... its starting to be a POS... i dont really feel like wasting my money on it anymore oh well

preludestud11 · 07-12-2005, 11:03 AM

I think i remember something about your car being a 96? If so it is obdII. I think the best bet would be to get an obdII to obdI conversion harness then use the obdI auto p13.