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Discussion Starter #1
Obviously I'm no stranger to fox body's. I've had 35 plus foxbody's. This is a new one on me! I've always taken good running cars and modded them, did about everything under the sun, even took some basket case poorly built cars and fixed them, but I have ABSOLUTLY no dealings with speed density, much less a car that has been half ass done like this one.
So here goes. After selling my last fox I been looking for a new project, in the mean time my father (70 years old) buts a 1988 fox with a bad motor. He is a horse trader with alot of nice stuff, he proceeds to trade a 1969 mopar R block 440, that is brand new build with all alum heads, etc etc, long story short a 700 hp motor complete to some flunkies to put a good running stock 5.0 in his vert 88. after a year he gets a non running car back. I tried to tell him from day one just to bring it to me, and I would fix it for free. He loves to prove that he knows more than me hahahah. anyway now I have the car trying to get it running right. It would not even crank when I first got it, had been sitting for over a year. My first observation was the throttle position sensor had one wood screw in it, I fixed that, car barelt would turn over but i got it running, idle all over, surging badly, i checked timing, it was at 30 deg, retimed to ten deg, runs better, smelled badly of fuel, or runnign rich, i dumped 5 gal of 93 octane in it, let it run today, it is getting better, idles, like its got a cam (no telling where the bottom end come from, im told they used the stock top end off the old motor. throttle response is a bit poor, it has a little popping through the air box, did a leak test on the upper lower and seems fine, idle surges bad 500-1500, settles from time to time but really lopes like a alph cam. going to check firing order tomorrow. temp guage not working but hooked up correctly, so i wont run it more than 5 mins at a time right now. Keep in mind this is not going to be a perfomrance car, nor is it anything overly nice. he just wants to be able to drive it from time to time, but I want him to have a dependable car. where would you go from here?
 

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Find out what the cam is. SD is very finnicky about what cam you use in it. If it does have an alphabet cam in it or something that's not SD friendly, you'll always have issues with it.
 

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SD is very sensitive to the wrong cam changes. If your idle vacuum is 16 or below, you're going to have issues with a rich idle.
 

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I would purchase a maf computer ($100) and convert the harness over to mass air then throw a known good maf meter on the car and run it a bunch of times to see if the idle sustains... because that shti would be allot easier then having to yank the cam out and try to figure out what it is etc

/raptor jesus
 

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i would unplug the iac and do the idle reset with it unhooked and see if it runs better without the iac all together it may be junk with that long a sitting then just buy a new one and reset it again, i would also clean uo the salt and pepper shakers open em up and dialectric grease em then i would check the plugs and see if they give you a read on anything, after that i would runs the codes and see what you come up with, i had an sd car and if you clean up the codes , providing the cam isnt overboard it will go to the settings and run the car without issue , but like everyone is saying you divert from the factory parts and computer tries running at its settings and you have issues galore
 

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Discussion Starter #6
thanks for the advice, this thread got really strange with all this lizard head garb, I dont know how it went to that, but lets stick to the car!

thanks
 

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I just bought a rough running 88 mustang gt the former owner changed the intake upper and lower. Thanks to this site I pulled off the intake and went back to factory. Now she runs great, the speed density does not like any changes to the motor. Good luck and let us know if you fix it.
 

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My car when it was speed density had a holley systemax 2 intake, shortie headers, x pipe, catback... **** ran like a mofo now it's converted though because it has a few other mods.. speed density doesn't like **** that screws with the engine vacuum because it meters the vacuum to decide on fueling..

Watch for vac leaks and keep the stock cam and you'll be banging fat chicks in the back in for weeks
 

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I just bought a rough running 88 mustang gt the former owner changed the intake upper and lower. Thanks to this site I pulled off the intake and went back to factory. Now she runs great, the speed density does not like any changes to the motor. Good luck and let us know if you fix it.
Like Ryan mentioned about vacuum, who ever installed that intake I'm sure just installed it incorectly. Prob just had a vacuum leak. Since you appear to know what your doing, toss the other intake on. As long as its not a bbk or typhoon.
 
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