mustang running really poor now

T

torchd

Forum Member
mustang running really poor now update: getting better

so here's the story... put on long tube headers car now runs black smoke can barely breath rich. emisions were not fully uninttalled and i believe that is my biggest issue. but i've enevr worked on a EFI mustang before anyoen that could lend a hand maybe come over and looka t the car would be greatly apreciated,... will gladly buy beer and pop if we can set something up next weekend. also any advice greatly apreciated. car ran and drove great before the headers.
 
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what year of mustang? i just put headers on my car also but didnt have this problem maybe i can think of something if i knew a little more info.
 
1986 car. did you finish the emisions removal?? ie the ports in the back of the heads being plugged? im told thats my issue by someone else.
 
you should definitely finish the removal of the EGR system, ideally you should also convert it to mass air aswell. the EGR will need to be tuned out if iam not mistaken so the computer doesnt add fuel pull timing ect. I could be wrong though, so if Iam I hope someone chimes in and corrects me so I know for future reference. that is how it was explained to me years ago though.

if you dont end up selling is there a specific direction you would like to take this car in build wise ? def. loose the e6se heads if nothing else.
 
im very partial to boost on everything... thinking going the junkyard twin t3 turbo setup on flipped shorties... running a used set of either iron or Al. heads that i can find for a good price. will loose the heads first thing if i keep her. then switch to the efi version of the carbed style intake (if you know waht i mean by that) cause it gives me great otions for the turbo plumbing.
 
you maynot be able to lose those heads. I had an 86 302 roller and those heads are special. terrible but special. I tried to put a set of twisted wedge heads on my car and it didnt work and then a set of e7s and they valves still hit the pistons. I didnt want to fly cut the pistons so i sold the short block.
 
the 86 motors are special they can only use the heads that came on them because of the piston design. i have a 86 motor in my 87 for now because the original motor let go. they only used that motor in 86 though.
 
i dont think it matters to switch it to mass air. i had a cam and heads and stuff like that done to my car and alls that meter does is up the price of stuff you have to buy. my car ran just fine with out one (speed density).
 
^dont know how to build the carb....

well damn guess i gotta switch out the pistons or go striaght to a 351.

so the pulse changes... any way to fix this issue? i am using brand new 02's which sucked to buy but i had to. i'm really debating just going megasquirt right now and having it ready for next summer.
 
I had the same problem on my 87 lx with speed density. Check the air charge temp sensor in the lower intake manifold. I think it is threaded into one of the front runners, drivers side? They are not that expensive. If thats not it, check every sensor one by one. I'll bet that it is the a.c.t. sensor.
 
awesome thanks man... im going to try vacuum leaks first. if that doesnt fix it ill check the sensors... then its straight to megasquirt im done messign with really old technology lol. same thing i ended doing with my silvia with the turbo motor. splicing harnesses never ran right lol
 
you could also try the coolant temp sensor on the the passenger side its right in front of the #1 injector it tells the computer how much fuel to use according to the engine temp. we just figured out is what is wrong with my car forgot to hook it back up. the computer automaticly senses -40 if its not plugged in
 
if i unplug that coolant temp sensor should something happen or change if its working properly??? it used to register the temp before the headers so i didnt think that was an issue but now its not reading at the temp gauge at all.
 
oh and if it helps at all its driving a little better... lots of smoke at idle not so much when driving but if i rev her hard it turns into a ton of dark black smoke....
 
its not the sensor for you gauge its the one that is hooked to the tube that goes into the intake on the passenger side it comes out of the injector harness it has two wires i think ones green and the other grey not sure on the colors tho.
 
if it cleans up when you drive it it has to be something like a sensor ummm maybe the fuel pressure regulator
 
did you check all your vacum lines i dunno i'm just trying to name things that would make it run rough did you get new o2 sensors
 
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