Weird power band May 20, 2013, 11:27:26 PM I have GT40 (non P) Explorer engine with a HO cam and a Mark VII SD PCM, and at WOT I have a lack of power until about 5k, and then the engine seems to suddenly (and I mean SUDDEN) get a tremendous increase in power right up to redline. I'm pretty sure this isn't normal. I don't have TFI problems that I know of, but I am in the process of switching to a remote mount unit. I keep my timing at 14 degrees btdc, my idle at about 650, and my TPS is in spec. I also tried a different MAP. Still I seem to lag power at WOT until late in the rpm band, and then BAM! Any ideas? Quote Selected
Weird power band Reply #3 – May 21, 2013, 05:28:44 AM I'm leaning to it being fuel related. Be it fpr, or injector circuit somthing is making it take a second to think about what its doing. My bird did it ages ago with the aod also. Let off the gas, punch it again and it was all there again. Then again it might have been the transmission holding me back too. Quote Selected
Weird power band Reply #4 – May 21, 2013, 06:40:55 AM 155lph pump, TV cable is just right (finally). As for the fpr or the injectors, I can say I haven't checked fuel pressure in over a year but I'll check that it's ported to the right vac source on the intake, and for injectors, I really believe that the wiring is ok, but maybe 19#ers are getting too small. Quote Selected
Weird power band Reply #5 – May 21, 2013, 09:38:24 AM you got gray or gold tops?i suppose your saying you have gold tops, mason's bird has somewhat of the same issue and he had gray tops. Quote Selected
Weird power band Reply #6 – May 21, 2013, 09:51:47 AM TFYK, Sounds like you have about the same set up as I do with the exception of the GT40 heads. My car is "87" Mustang HO 5.0 engine, dual exhaust, AOD w/shift kit, and 19 lb. injectors. I still am not sure what my car is doing quite yet, but a couple of times at about 50 mph I have stepped on it and it did the same thing...BAM! My car will easily spin the tires from a stop, but it's like it has a cam that turns on at mid-high rpm's. Also, what I find strange is that right now at about 800 miles on the engine, I'm getting about 16-18 mpg in the city and on my 260 mile trip at 75 mph w/3.45 rear gears I got 27.61 mpg and my car was loaded on the way down. If you and I are having the same symptoms I can't wait to see what you find! Personally, my guess is toward the fuel, although in my case my poor EEC has been trying to learn on low voltage (bad alternator). My mileage sounds pretty high and that's got me wondering. I still haven't checked my plugs, guess I better. Quote Selected
Weird power band Reply #7 – May 21, 2013, 10:38:07 AM Yes J, they're 19s off of my old HO, and yes, yellow tops. I don't have the car at the shop again til Thursday and Friday, but on Friday I'll run fuel pressure and check that the regulator is reacting to vacuum drop. Quote Selected
Weird power band Reply #8 – May 21, 2013, 09:48:56 PM Mustang guys get 105mph in the 1/4 with a T5....so your heavier bird and AOD should do 100 or so in the 1/4...Probably not out of injector yet....although they maybe clogged...Travis Quote Selected
Weird power band Reply #9 – May 21, 2013, 11:10:07 PM Check the TPS voltage from idel all the way thur the range. Should be .8 volts at idel and go to 4.5 volts or better at WOT It is possable that the TPS has a bad spot in it and then the voltage jumps up enough for the ECM to switch to WOT fuelingIf you think it is fuel related pull the vac line off the FPR and see if the car runs better. Quote Selected
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