Friends car running rich, idle issues.......

Hey everyone,
A friend of mine is having fits with his 91 Fox. Here is his issue...

"I have a msd pro billet distributor on my car with a factory ford motorcraft TFI module on it(msd module broke). today when i was putt'n around in it i noticed that it got hot to touch.should it be like that? i recently cleaned and got all grounds taken care of checked for vaccum leaks checked timing 3 times and im stumped on the horrible idle and performance of the car, it seems to be dumping WAY too much fuel and floods its self out until higher rpms . even put a obd1 scan tool on it and no codes so maybe its not communicating with the pcm as well? cant see how there isnt a fuel air metering code up for the amount of fuel it comsumes.

I have a C&L mass air sensor 76mm and 30lb injectors i ran last year with the old motor and it acts like it did then now. i honestly believe the maf isnt calibrated. i talked to loren about it on sunday and he mentioned sample tubes, can some one fill me in on what these are?

do i have to send that maf away to be calibrated?

I never ever had any type of performance issues with the car before i installed the old motor with that maf and injectors last year.

Vince was kind enough to give me a se of stock injectors, so it looks like i will be installing them and the stock maf."

Any ideas are greatly appreciated!!! Have a good one!




"

I told him I thought one of the issues was the fact that the MAF was not calibrated for his new injectors and this possibly could cause issues with the PCM. I am just learning as I go as well, so any ideas appreciated.
Vince...aka Maui Built

I ran a 76mm w/ 30's w/ no problem. The only calibration it needs is the correct sampling tube. If its got the correct one, the electrical part of the mass air could be bad, or even an ecm issue. O2's. Could be a few things. Maybe the fuel regulator took a dump. hard to say w/o actually getting to look at it.

yea its hard to figure it out without seeing it. mine did something similar when i first bought it and it was stock. a ford tech told me to unplug the mass airflow sensor and drive it. i did what he told me and it ran much better. weird but it worked.

Like Bernie said, the C&L meter using an air sampling tube to calibrate for different injectors, which vary in the size of the orifice to acheive calibration. For 30lb injectors, the sample tube should have a red mark on it. Id venture to say that either the meter isnt calibrated or the injectors are malfunctioning. Your friend said that there were no issues until those parts were installed, so that would definitely be the place to start troubleshooting. Either could cause the rich condition, which would also cause the idle issue.

Hey all,
Thanks for the good advice and places to start for my bud Aaron! I passed it along to him and will see how it goes. He put the stock MAF and my 19lb injectors back on it and it still is having the same issues. Hopefully we can get to the bottom of it soon. Again, we appreciate your help! Thnx.

has he checked for codes or checked the f/p?

as "B" SAID check Fuel pressure

hello everyone im vinces friend off another forum. bcp, ranx93, i know you from sefb, pro5.0 talked to you a long time ago on mustangforums i believe heres my response


no cats, stock injectors and maf now, same thing. checked grounds going to take the module and test it at work, i dont think its just the maf and injectors anymore, its something that has happened since the old motor was pulled. in installed a 255 intake pump but surely that wouldnt have done much but increase volume unless the regulator has failed, im leaning to pcm issues it has NO codes which was very odd, im thinking its not communicating with the obd1 tool but then i noticed it came on when the stock maf and injectors were installed.

im going to take a volt meter to the output of the maf it should increase as the engine speed rises, im going to check the c&l for the red tip install it and the 30's do the same as i did with the stock set.

grounds checked out ok no vaccum leaks everything on the trickflow intake its self is capped except fuel regulator and one to the vaccum T to the brake booster, no emissions on the car at all evap solenoids are un plugged i dont even know where the line is ran for it to the intake but it has to be capped.

I dont have the car readily available to work on everyday so it wont be a day or too until i can figure things out. i think im going to bring it home, i really took it to the wrong place to be worked on.

thanks for your time guys

fuel pressure was in the mid fifties if i remember correctly as well

1loudmouthpony wrote:fuel pressure was in the mid fifties if i remember correctly as well

OMG way off

38 - 40

TT_05_Stang wrote:

1loudmouthpony wrote:fuel pressure was in the mid fifties if i remember correctly as well

OMG way off

38 - 40

Boy I'll say!!!

what about 44? i could have been wrong this was two weeks ago my memory is shot. i know for sure it wasnt in the 30's.

is the pressure regulator shot? seriously when you stand behind the car you can smell the fuel and lots of smoke not white or blue but the smell of fuel is there i wounldnt suggest standing behind it for very long

Stock Fuel system should be set at 38-40. With HCI you can bump it to 42.

With your set-up and 30lb injectors, i'd def put it at 38-40 psi.

What do your spark plugs look like? Id imagine they are soaked in fuel.

Did you test the TFI module?

Whats the timing set to?

BAP sensor plugged in?

TT_05_Stang wrote:Stock Fuel system should be set at 38-40. With HCI you can bump it to 42.

So you're saying mine shouldnt be at 60 psi?

LOL well depends if you're running 19lb injectors at 100% dc on your 351 HCI making 500+, then yes you might run it close to 60

TT_05_Stang wrote:LOL well depends if you're running 19lb injectors at 100% dc on your 351 HCI making 500+, then yes you might run it close to 60

Well....i dont have a 351 or 19 lb injectors.

I do have 42 lb injectors with a mostly stock fuel system though. Dont recall what duty cycle they are running at, will have to pay attention the next time im WOT.

If you have a 302, with HCI, you will have to be close to 600 hp to max those out at the intended flow rate of 43.5lbs. So at 38-40 base you will be fine. I thought you had a 351, and it was just and example.

TT_05_Stang wrote:Stock Fuel system should be set at 38-40. With HCI you can bump it to 42.

fuel system is now stock minus the fuel pump, what would cause such high pressure could the regulator be a problem?

Do you have an adjustable regulator? If not then you have a bad regulator.

I have to look through my old 302 parts, I have so many parts, I prolly have a billet adjustable regulator that will fit on your stock rails.

TT_05_Stang wrote:Do you have an adjustable regulator? If not then you have a bad regulator.

I have to look through my old 302 parts, I have so many parts, I prolly have a billet adjustable regulator that will fit on your stock rails.

check fuel pressure again 41 psi im not sure what i was smoking this morning when i said uppier 50's but i was way off.

tested my tfi module failed,

funny thing now that i remember it ran perfect 2 months ago when we bolted everything up just didnt run it long smooth responsive no hesitations, then suddenly shut off no spark went through 4 old modules (including the msd module that was formerly on the car but the backing ground plate on the back of the module was cracked somehow) laying around til i got to this one now this one,it did enough to give spark but it seems like in no sequence to the injectors it failed but until i buy a new one i wont know for sure if thats excatly what is causing all of this. if its the same old story with the new one could the triggering device in the distributer be bad?

now as of the regulators i have another i believe it is adjustable its still on stock rails it had a vaccum line and a nut on top next to it maybe thats where the adjustment is, i have no clue about these sadly so i really couldnt tell you anything other than that.

1loudmouthpony wrote:

TT_05_Stang wrote:Do you have an adjustable regulator? If not then you have a bad regulator.

I have to look through my old 302 parts, I have so many parts, I prolly have a billet adjustable regulator that will fit on your stock rails.

check fuel pressure again 41 psi im not sure what i was smoking this morning when i said uppier 50's but i was way off.

tested my tfi module failed,

funny thing now that i remember it ran perfect 2 months ago when we bolted everything up just didnt run it long smooth responsive no hesitations, then suddenly shut off no spark went through 4 old modules (including the msd module that was formerly on the car but the backing ground plate on the back of the module was cracked somehow) laying around til i got to this one now this one,it did enough to give spark but it seems like in no sequence to the injectors it failed but until i buy a new one i wont know for sure if thats excatly what is causing all of this. if its the same old story with the new one could the triggering device in the distributer be bad?

now as of the regulators i have another i believe it is adjustable its still on stock rails it had a vaccum line and a nut on top next to it maybe thats where the adjustment is, i have no clue about these sadly so i really couldnt tell you anything other than that.

I would try another TFI Module. If your FPR has a nut on it, it's adjustable.

TT_05_Stang wrote:If you have a 302, with HCI, you will have to be close to 600 hp to max those out at the intended flow rate of 43.5lbs. So at 38-40 base you will be fine. I thought you had a 351, and it was just and example.

Weird, my A/F ratio looks pretty good, albeit a bit lean on the big end.

Dunno where you got the impression i had a 351!