Lemme start off by saying I have done multiple searches on how to convert a obd0 PR4 auto ecu to manual both here and at pgmfi.org and haven’t come up with any specific answers. Well my question is if anyone knows what exactly needs to be removed and or jumpered to make an auto obd0 PR4 ecu to manual without throwing a CEL. I have both an auto and manual ecu sitting in front of me and I was expecting to see two or three differences but when I look at the board I see at least 10 or more differences between the ecu’s. The reason why I don’t just use the manual ecu is because I have a 91 and the PA sensor is internal and the manual ecu is throwing a code for it while the auto is not. However I have a 5 spd obviously so the auto throws an EGR code. While I was searching thru sites I remember reading something about most “mugen” ROMs disable the search for auto hardware, so would chipping my ecu with a “mugen” ROM solve my problem on the auto ecu? Anyone who has converted from auto to manual by converting their auto ecu to 5spd please respond. Thanks in advance.
I followed the directions on pgmfi.org explicitly, to no avail. ECU works great, still throws code 12.
I checked the site and under the obd0 PR4 auto to manual the link is gone so I can’t read about it, maybe I’m doing something wrong. If you could link to me where you found the info about auto to manual for PR4.
Here you go (its a bitch to find) http://www.pgmfi.org/twiki/bin/view/Library/AutoToManual
I followed directions exactly, to no avail. I must have made a random mistake somewhere, but I dont think so, my ECU still works perfect. Shit happens.
Oh, I see, I have ODB1, and the ODB0 directions ARE gone, my bad. Well, I can tell you that the ODB1’s dont work, try to find another source for ODB0
Come to think of it, anyone got tips for me? I’m still pissed. CEL12 continues after a “succesful” patch job following the instructions.
i never got to fixing that either. at one point i tried clipping off all the resistors that were mentioned to no avail either.
perhaps if you revive the old pgmfi thread (i’m in it) and enough people request a fix, one of the gurus might be kind enough to trace it for us.
I have a spare auto ecu I could try stuff out on but the only problem is I have no experience with soldering or messing with the board at all. I also have a 5 spd ecu, I guess I could try removing all the resistors that the 5 spd doesn’t have from the auto, try to make them as identical as possible.
already tried by several people including myself. worth a shot if you can handle it i guess…
Done and done.
Can I bring this back from the dead? From what I saw on pgmfi the link is dead again? I want to do this just to do it on my auto to manual swap I’m working on now. The car was a running auto obd0 car and after my manual swap I would like to convert the ecu to manual to use that as well with the swap.
I was looking into this as well because I was having a hard time finding a manual ECU for my 91. I bought 2 ecu’s thinking one of them would work, turned out both were 90’s and they don’t work with 91’s. I opened up my ECU’s auto and manual to look at the differences to see if I could swap anything to make one work.
91’ Auto PR4-L60
Untitled by Michael McCown, on Flickr
90’ Manual PR4-A02
Untitled by Michael McCown, on Flickr
90’ Manual PR4-L02
Untitled by Michael McCown, on Flickr
Each one has its differences. The 2 Manual ECU’s gave me a code 13 because the 90 an external sensor where as the 91 didn’t or vise versa. I couldn’t get any clear info on the PGMFI forums and didn’t want to start killing perfectly good ECU’s so I rolled the dice with Ebay and ended up getting the right ECU for my car for $45. PR4-A10 is the OEM part number for a 91 LS MT and it works great.