Trevor Posted October 31, 2003 Share Posted October 31, 2003 I've been reading a few articles that tell how to replace the AOD with a T-5 in 5L Mustangs, Cougars, etc. None mention replacing the computer with a 5-speed specific ECU. My question is - Is the ECU dependent on the transmission. My confusion comes from researching conversion from SEFI to (89-up) Mass-Air parts and advertising for the ECU part always says what type of trans it is for - Auto or 5-speed. Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted October 31, 2003 Share Posted October 31, 2003 From what I understand, its is safe to put an EEC-IV computer from an automatic powered vehicle into one with a standard, but not the other way around. I can't recall why this is. I can look it up in the EEC-IV bible: "Ford Fuel Injection & Electronic Engine Control : All Ford/Lincoln-Mercury Cars and Light Trucks 1988 to 1993" http://www.amazon.com/gp/reader/0837603013/ref=sib_dp_pt/102-8064934-4883336#reader-link I have a 5.0L and T5 in my 1974 5.0L Z, and I am using an A9P processor(automatic) without any troubles. I have tried a processor from a stick car (A9L), and I couldn't tell any difference. Quote Link to comment Share on other sites More sharing options...
Guest bluex_v1 Posted October 31, 2003 Share Posted October 31, 2003 I don't remember seeing this addressed anywhere in the bible when I was considering which one to use, but I did see what was reported to be a data-logger dump from the two different computers (otherwise stock). The timing curves on the a9p processor (automatic) were advanced a good deal more on the lower end (I presume because of the torque converter putting a load on the engine at idle, and the greater load under minimal throttle up to 2000 RPM compared to a manual) but over 2000 or so, there was only a half degree of advance difference or something similarly negligible compared to the A9L. Sorry I don't have specific numbers, but I'm sure you could find them if you searched a few mustang boards. There is some misinformation that the neutral safety switch and clutch switches only exist in each case with the associated computer...as I understand it though, any computer will observe both inputs, its just that one or the other will be jumpered closed depending on which one you want to use. The general consensus is as 74_5.0L_Z mentioned, you won't notice a difference. Quote Link to comment Share on other sites More sharing options...
JoshB 240Z Posted November 1, 2003 Share Posted November 1, 2003 You can use the automatic ECU in either a T5 or auto equipped car but cannot go the other way, just as 74_5.0L_Z has said. The reason is that there is a 12V+ signal coming from the transmission that will damage the ECU. This signal isn't present with the manual tranmission. Just do a search on http://www.corral.net in their EEC section on the A9L and A9P ECU's and you should find the accurate reason for the difference. Josh Quote Link to comment Share on other sites More sharing options...
Trevor Posted November 1, 2003 Author Share Posted November 1, 2003 Thanks for the answers Quote Link to comment Share on other sites More sharing options...
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