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Discussion Starter #1 (Edited)
well, i just got to the root of my surging upon startups. i have been trying to tune everything possible in order to get rid of it. i knew my fuel pressure and timing were right on the mark...

so i then began to think that it had to be mechanical. i started to think about how i had my PCV system now then when my idle was smooth.

i had put a breather in place of the oil cap!

so then i was thinking that since i had the PCV still hooked up in the back of the intake there had to be a huge vacuum loss because i didnt have the tube that goes from the throttle body to the oil neck anymore. the PCV was just pulling air in through the breather i had put on. there was a HUGE vacuum loss!!

what i did was instead of putting the tube back on that goes to the throttle body. i just put a airflow control valve inline of the PCV. so i could keep the vacuum down so it wouldnt be such a huge loss, yet keep enough to evacuate the crankcase gasses.

that little valve solved ALL of my idle problems.
i just wanted to let you guys know because i know there are a lot of people out there that have idle problems...

hope it helps,
adam
 

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OR you could install a PCV valve from a 1990 F150 with a 351. It has a stiffer spring in it.
 

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Discussion Starter #3
ya know, i tried that but i guess it wasnt strong enough. my idle was still surging...

take care,
adam
 

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i just put a airflow control valve inline of the PCV.
What is that and could you post a pick of one? I have a little surging idle problems too. Might try that F150 PCV trick.
 

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hey Adam...just out of curiousity...was your idle hanging up or just wandering? Have you tried to disconnect the TPS when the car acts up?? Doing this should stop it. A lot of the time the TPS is worn in one spot. Sometimes causing bucking at slow cruising speeds. It gets worn just like old TV volume knobs!
Also, on Speed Density cars the MAP sensor causes all the problems!
 

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Discussion Starter #6
yea, i have a new one and that wasnt the problem. im glad its all behind me now...

take care,
adam
 

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avbcon12:
can you explain a little more about how you just put an airflow control valve inline with the pcv? also where can you get an airflow control valve? pics would be sweet if possible...

my idle problems seemed to have started when i switched valve covers too, but i never found any fix

thanks

~paul
 

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Discussion Starter #8
paul, i will get some pictures as son as i can get a hold of my friends camara.

if you go to a hardware store they will have little air fittings for like compressores and paint sprayers and stuff. you will find a shut off that will work.
i just put it in-line between the PCV valve and the mounting mount to the upper intake.

the way i checked to see if it was the fault before i went throught the trouble to plumb the valve in was i got a little "C" clamp (tiny) and while the car was running stared to clamp the PCV hose. once i got it to a certain position (that sounded right) i would shut the car off and start it again (thats when i would get a HUGE surge). after doing this "trial and error" a few times i found the sweet spot. and now its starts and idles perfectly.

i hope this helps out,
adam
 

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Discussion Starter #10
hey guys, sorry but i dont have any pics yet. mine broke.

anyway,

i came across something interesting that i thought you would like to know. after putting that air valve inline of the PCV, i still hard hard start problems. but no surge anymore.
today i cut my tailpipes off because they were 2 1/4". after doing that ALL of my problems vanished! its like the 2 1/4" pipes were restricting my motor to the point it couldnt breath. i never though it would make such a difference. it honestly WOKE my mustang up! it pulls sooo much harder now....

and with BBK longtubes, 2.5" off road H-pipe and 2 1/4" flowtubes to 2 chamber flowmasters, it isnt much louder than with tailpipes. its just a deeper tone. i was shocked.

take it how you may, but it helped me. im just trying to give suggestions to others.....

take care,
adam
 
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