I’ve heard conflicting information about this subject.
Apparently there are a few rare P72 Auto ECUs, and the car I bought has one in it.
From research I’ve done, it is clear that a P28 Auto ECU would have to be modified to work on a 5-speed car.
The person who sold me the car, believes “A P72 Auto ECU is not like a P28 Auto ECU and does not require modification to work in a 5-Speed car”
I’m looking for an absolute answer to whether a P72 Auto ECU will work without modification in a 5-speed car.
If I remember correctly, on a previous teg I had, I installed a P72 ECU, which had 4 plugs, so was an Auto ECU, and never had to do any modification to get it working, but my memory could be faded.
I need to know asap, if I should buy a new P72 ECU (non auto), and reselling the P72 Auto, or whether it will work fine without any auto-man conversion.
I already answered your question in your other thread but I will go into more detail here:
Your auto ecu will throw a CEL, but it will operate just as any manual ecu.
You can either chip (or tune through) software to remove the code or remove the code through hardware modification.
Software method: To remove the code through software, it’s as simple as loading any modern tuning system (crome,neptune,ectune). All current tuning systems are based off of the manual codebase, which do not check for the transmission lockup solenoid signal. There are some auto rom’s floating around the internet if you really want to retain auto functionality :).
Harware method: This is an outdated way to get rid of the code, and frankly if you are going to modify the board, you might as well just chip it. It basically tricks the software into thnking that the ecu is plugged into an auto tranny. This is because the ecu is still programmed to look for the signal and this is why changing the rom will get rid of the code. I actually had to use this method a long time ago for my car because chipping was not as accessible as it is today.
ok, I must have read your last post too quickly. This answers my question.
Having an Auto ECU should do nothing to prevent VTEC, or the engine from revving to 8200rpm.
The only difference between an Auto and a 5-Speed ECU, in a 5-Speed car, is a CEL.
I’m new to ‘software’ modding and honda…
Is the software you mentioned open source / freeware?
I have an OBD2 Port <-> USB Cable… I’ve used with ECU Flash…
(obviously works on a 2003 Eclipse, but probably not on OBD1 Integra, unless the OBD1 ECU reading port was the same physical shape and allowed for read/write)
What kind of ‘hardware’/cable to I need to run such modification software? (that is if the modification software is free)
If I can software modify the ECU for the small cost of a cable, I could remove the CEL, change VTEC, etc, and should stick with the ECU I have.
Otherwise it may just be easiest to buy a P72 Manual ECU, and resell the Auto.
Though from looking on ebay and other such places, I can’t seem to find a ‘real P72’, just a bunch of PR3s/Anything “reflashed to function as a P72”. Kinda ironic.
Still having issues with VTEC/limp mode? Did you ever check the codes using the described method in your other thread? I haven’t read it in a few days, so forgive me if you’ve checked them. Finding out what codes you’re throwing can help us diagnose your issues. Checking the codes is extremely easy, if you haven’t yet.
OBD1 ECUs (or Hondas in general, that I know of) aren’t “flashable” or modifiable in stock form. The chips in factory ECUs are more or less a “one and done” programming affair. Check the codes first. I’m still leaning towards the pressure switch being at fault. I have knock sensor codes from time to time, but my car doesn’t go into limp mode, AND I still have VTEC and full rev range. So, I doubt that the knock issue you mentioned in your other thread is the primary factor.
Don’t go off replacing parts and trying to diagnose the ECU if you’re not even sure what codes you’re throwing. You’re basically diagnosing the car blind if you don’t know why the CEL is on.