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Discussion Starter #1
I was wondering if my 66 mustang could be overheating because of a lean condition. When i first did the efi conversion the motor was a standard output 5.0 with speed density a few months later I converted it to maf with a 93 computer and maf meter from a mustang but I did not change the injector harness order. Since each injector is not firing in order with each spark plug would this cause a too lean condition and cause overheating? It only does it on hot days and if I really get on it I can hear detonation.I only ask this because I have heard of people slightly overheating when their timing is way to advanced and have severe detonation.Also befoe the conversion it ran a little warmer (200-205) in the summer but that is to be expected now it shoots up to 240 and i have to shut it down the radiator is only 2 years old heavy duty factory replacement new water pump t-stat heater core with hoses and new upper and lower radiator hoses thanks in advance for any ideas or sugestions
 

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Don't know if it would cause over heating, but it really couldn't run very well. When you say std 5.0, I take it the engine is from a Crown Vic, Tbird, F150 or something other than a Stang??? Are you using the orange top 19lb injectors??? If you're using the grey top 14lb injectors its probably extremely lean.

Actually a mass air conversion on a std 5.0 is a waste of time. It's not even necessary on a HO 5.0 as long as it remains stock. The '87-'88 speed densety 5.0 Mustangs were actually .2-.3 quicker in the 1/4 mile than their later mass air counterparts.

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1988 Turbo Coupe...5.0 Conversion... AOD... 3.73s
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<font size=-1>[ This Message was edited by: TurboCoupe50 on 8/25/03 9:46am ]</font>
 

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I've never heard of switching the injector harness around... I though the computer took care of that...Are you not useing a cam with the 5.0 ho firing order?
 

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When you switch from a SO SD setup to a HO mass air system you must use the injectors that the MAF is calibrated for. In this case, with a stock MAF, the stock 19# HO injectors must be used. Also switching the injector wiring to the HO order isn't hard at all just cut and splice the 4 wires that are incorrect and be done with it. It will then truly be a SEFI conversion.

BTW did you convert your MAP sensor to a BAP sensor?
 

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Discussion Starter #5
yes i did convert my map to a bap sensor and i am using the orange top injectors and i am using the cam with a 289 firing order so do you guys think i should change the injector harness around thanks for your replys keep em coming
 

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If you are using a 289 ignition firing order with a 5.0HO EFI setup, your injector timing will be wrong. The injectors are meant to spray in conjuction with valve lift, and if the injector spray is not in time, the fuel will puddle and not enter the chamber efficiently, which is also causing the engine to labor harder at idle. I wouldn't gaurantee this as part of your overheat problem, but it MAY help. I don't see the engine as running too efficiently if this is the case anyway. Either you need to install a cam with 351 spec firing order and change it, or possibily reroute your injectors to fire in 302 non HO order to get the injector timing right. Good luck
 
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