• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

my 393 started breathing today!

  • Thread starter Thread starter lickem
  • Start date Start date Jan 6, 2009
  • 1
  • 2
  • 3
  • 4
Next
1 of 4 Next Last

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 6, 2009
#1
  • Jan 6, 2009
  • #1
this thread will be sort of a continuance to my thread in 5.0 talk http://forums.stangnet.com/771722-my-393-pics.html but i got it running today and ive got a few problems so i wanted to get some advice or opinions of what you guys think might be my probem or problems....

here is my set up..

d4ae block bored .60 (actually makes it a 399)
3.85 stroke crank
stock d6oe football rods
kieth black pistons
f-303 cam
world products windsor jr heads
edelbrock performer intake (70mm)
1.72 scorpion rockers
mac headers
7qt oil pan
70mm BBK throttle body
70mm EGR spacer
42lb injectors
76mm C&L maf
stock tune A9L

she fired on the first bump of the key but was running really rough so i set my timing to 14 degrees and it smoothed out a bit but was barely running, it started reving and then almost dieing back and forth, about 500 rpm up to 1500 rpm. so then i moved my tps and that helped some but not that much. then i looked down at the idle speed screw on the throttle body and it wasnt anywhere close to touching so i screwed it in until it started pressing against the linkage and eventually got it somewhat reasonable. to make a long story short, i brought the timing down to 10 degrees, and messed with the idle speed screw and tps until it finally started idleing on its own at 900 rpm. anything less it would severely stumble.

that being said the car is running extremely rich, so rich that i opened both bay doors in my garage and the man door and it was still pretty hard to keep my eyes open at times and im blowin a pretty good amount of blueish smoke.

where i now have the idle screw on the bottom of the throttle body the butterfly is open alittle bit at idle (900rpm) yes i know its a stroker and its going to require more air

so what could be my problem here, is my intake, throttle body and spacer only being 70mm the cause since its not allowing it enough air??? are my 42lb injectors too big and i need to step down to 30lb??? is my stock tune A9L the problem since i have 97 more cubic inchs??? or is it just a combination of everything??

whats a good initial timing setting for a f cam?

any help would be highly appriciated
 

Cobra912

Active Member
May 1, 2005
1,777
11
39
Wish I was anywhere but here
Jan 6, 2009
#2
  • Jan 6, 2009
  • #2
probably felt good to get it running I bet. I know when I first cranked up my 331 it took me awhile to get things sorted out. I adjusted the TPS, idle set screw, bumped back the timing, set a higher gap on my plugs etc. but nothing worked. I traced everything back and after checking everything a thousand times my Dad came over popped the cap on my dizzy. I found out that the rotor inside my distributor wasn't seated properly causing igntion issues.

I can't say for sure but the 70mm should be more than enough for your set-up from what I have read about the larger strokers. I see you have a C&L mass air. I've read numerous places that they are particularily fussy. Try clocking the meter. And if that doesn't work try unplugging it. Does it change anything? The car was already mass air equipped to begin with correct? (not a conversion)

Oh and did you pull codes from it?
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 6, 2009
#3
  • Jan 6, 2009
  • #3
yes it was ABSOULTELY AWESOME hearing her breath fire for the first time!

just gotta get the bugs worked out of it now

yes its a 91 so it was already mass air.

i figured the 70mm set up would be alright as well, i mean to gain top horsepower numbers im sure if i stepped up in size id probably gain more power but it should still run fine i would think....

what do you mean by clocking the mass air meter? i ran a 73mm C&L with my 302 set up and i never had any issues with it.

cap and rotor both look good
 

Cobra912

Active Member
May 1, 2005
1,777
11
39
Wish I was anywhere but here
Jan 6, 2009
#4
  • Jan 6, 2009
  • #4
loosen the clamps, turn the mass air meter itself so that it the sensor sits in a differenet position. like a clock put in the 12o'clock then try turning it to see if it makes a difference.
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 6, 2009
#5
  • Jan 6, 2009
  • #5
tried clocking it, didnt make any difference anywhere i put it.

unplugged it and it made no difference at all in how it was running, does that tell anyone anything? how do you test the pigtail that plugs into the meter to make sure its doing what its suposed to? when the engine was out i pressure washed the entire engine bay, water could have got in that pigtail could that have any relevance? the plug looks good and no power was ever applied to it until weeks later when i put the engine back in.

the sample tube has green on the back of it so its for sure for 42's and the element is in known working condition but i changed it out just to see if it would change anything and it did nothing. however my idle went down to 750ish, maybe cause it was a cold start, didnt run it long enough to get it back up to temp.

anyone... anyone....

could this just be the computer learning the new engine? if so how long does it take?
 

riceslayer302

Banned
Oct 3, 2006
0
1
0
CT
Jan 6, 2009
#6
  • Jan 6, 2009
  • #6
did you set base idle? i just did it on mine tonight it made a big difference, not even sure if i did it right lol. get the car running to temp, (idk if its necessary but i did it,) shut it off, unplug IAC, disconnect (-) battery terminal, go eat sandwich, (give computer 2-5 minutes to reset with battery disconnected,) reconnect battery, start car, set idle screw to desired rpm, plug IAC back in, and shut the car off again. again, not sure i did it totally right but it made a big difference for me. good luck, its easy to get frustrated but remember its all learning, im learning as i go with everything. we still have a few months of winter to sort out all the bugs. good luck!
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 6, 2009
#7
  • Jan 6, 2009
  • #7
i know this might sound crazy but it does seem like every time i start it she will run alittle bit better each time. the first few times i could barely stand in the garage with the car running, both bay doors open and the man door open, now im fine with just one bay door open.

i just read all about setting the base idle, i didnt know you were suposed to set the tps by voltage, i just moved it to try and fine tune the idle by hearing it. sounds interesting, never heard of setting base idle before now, it cant hurt so ill try it here in a few.
 
S

SFC_R0CK

Member
Oct 30, 2008
81
0
7
AL
Jan 6, 2009
#8
  • Jan 6, 2009
  • #8
You progress looks good and it sounds like it will be a monster. I am not sure about the strokers but with my 306 I had to let it run for a bit when I first cranked it. It ran all weird also, and I had to feather the throttle to keep it running but after a couple of times of starting and stopping it the computer learned the settings and it smoothed out. Then I set the base idle and adjusted the tps and timing and its all smooth now.
 
5

57fairlane

New Member
Apr 2, 2005
560
0
0
Oakwood, GA
Jan 6, 2009
#9
  • Jan 6, 2009
  • #9
good times . . . its always fun to fire up a motor for the first time.

your a cam swap, head swap, and intake swap away from making serious power
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 6, 2009
#10
  • Jan 6, 2009
  • #10
sweet, thanks for the confidence booster of letting me know this is pretty normal. i really hope setting the base idle will definately help, ill find out here in an hour or so. the wiff has me trapped in the living room watching a movie with her. she says the mustang has been getting more attention then she has, the way i look at it building an engine is the closest a man will ever come to giving birth so its probably true.

how concerned should i be about getting a new tune for my computer since ive got 97 more cubes? is it only something i should worry about if im wanting to squeeze out every drop of power from my combo or is it a good idea to do anyways since my displacement is so much larger?

does anyone have any suggestions on a cam/intake? the car isnt ever going to be a dedicated track car just a serious street car so street manors are a must and i still dont plan on ever seeing over 6500rpm. im pretty set on afr 185's since they are the largest "smog legal" head that i know about. think they will be too small though? should i be looking more at the 205's or the 225's?
 

riceslayer302

Banned
Oct 3, 2006
0
1
0
CT
Jan 6, 2009
#11
  • Jan 6, 2009
  • #11
im getting my car professionally tuned, your computer is prolly pretty confused by 42# injectors lol. ide get it tuned. im not a pro at tuning these things yet so dont take my word for granted, im sure someone more knowledgeable will chime in. check out rjminjectiontech.com and fordfuelinjection.com they were both very useful for me.
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 6, 2009
#12
  • Jan 6, 2009
  • #12
ill check into those. ya im sure the computer was all sorts of confused with the 42's the computer is out of a car i wrecked awhile back and it just had 19's in it so thats quite the jump for the computer.

so i just set the base idle, then i set my voltage on my tps to .99 and started her up. night and day difference. got her idling at 750 now and its not as toxic in the garage. she still needs alittle more but im sure it will work itself out once i drive it alittle bit. after setting the base idle i found out that my timing was pretty far off, i had it set to 10 degrees but that was when everything was afu, so after setting the base idle i rechecked the timing and found that i was only at about 4-5 degrees so i put it at 10 for now. very very very VERY responsive now as well, couldnt get on it too much cause i got a new born in the house but just bumping the throttle it doesnt even think about hesitating, very satisfied with it now.

got another problem that has shown up after doing the above things. once i got my idle down i wanted to hear the cam so i went to the back of the car, well right below both pipes were 2 small puddles of what i assume is water. no smell and its not green, where did it come from? ive been running the car 5 minutes here and there since i got it running so it cant be from just being left over in the pipes from pressure washing everything. any ideas??
 

riceslayer302

Banned
Oct 3, 2006
0
1
0
CT
Jan 6, 2009
#13
  • Jan 6, 2009
  • #13
condensation is normal. its not smoking or blowing black soot on the ground anymore is it? it was probably running really rich, do you have an adjustable fuel pressure regulator on it? set the fuel pressure at idle to about 39psi.
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 6, 2009
#14
  • Jan 6, 2009
  • #14
still got some black soot but its probably left over in the pipes from how it was running before doing the base idle, it was bad, real bad, couldnt even see the wifes truck directly behind the garage when i first fired it up so it will probably take a bit to clear it all out the pipes.

no smoke at idle, i didnt take it over 1k rpm though so ill check tomorrow and see if it blows anything out at 2 or 2500ish. i have an adjustable regulator, im pretty sure im at 42 now, ill back it down in the morning as well.
 
T

tiptop

New Member
Apr 6, 2008
73
0
0
Jan 6, 2009
#15
  • Jan 6, 2009
  • #15
take er for a spin, he if she clears up
 

67coupe

Founding Member
Apr 5, 2002
658
402
93
Huntsville, AL
Jan 7, 2009
#16
  • Jan 7, 2009
  • #16
Glad you got it running!! Now...we demand a video!!

riceslayer302 said:
did you set base idle? i just did it on mine tonight it made a big difference, not even sure if i did it right lol. get the car running to temp, (idk if its necessary but i did it,) shut it off, unplug IAC, disconnect (-) battery terminal, go eat sandwich, (give computer 2-5 minutes to reset with battery disconnected,) reconnect battery, start car, set idle screw to desired rpm, plug IAC back in, and shut the car off again. again, not sure i did it totally right but it made a big difference for me. good luck, its easy to get frustrated but remember its all learning, im learning as i go with everything. we still have a few months of winter to sort out all the bugs. good luck!
Click to expand...

Just for future reference, anytime th idle screw is adjusted, you must check the TPS voltage to make sure its still in range. Riceslayer posted the proper procedure, just set TPS voltage last.
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 7, 2009
#17
  • Jan 7, 2009
  • #17
good to go on the video, im not very high tech so it might take me a bit to figure out how to take a video and place it on the computer.

setting the tps voltage was extremely easy, believe it or not once i set my idle stop screw i checked the voltage and it was dead nuts on .99 which i read was ideal is that correct? i read .98-.99 was ideal??

before setting the base idle i was seriously thinking my 42's were drowning the motor but now she is runnin pretty good, seems to realy like the 42's.

i read on a different thread to get a 351 to fit under a stock hood you gotta run solid or vert motor mounts, i have solids which are said to lower the engine 3/4 of an inch. then you gotta remove the insullating pad on the hood and possibly take out about 3 inchs of webbing on the hood where the throttle body is. anyone have any experience with that? id really perfer to run the stock hood for the sleeper look but if it isnt gonna happen then it isnt gonna happen and i dont really wanna hack up my good hood just to realize it isnt gonna fit anyways.
 

Cobra912

Active Member
May 1, 2005
1,777
11
39
Wish I was anywhere but here
Jan 7, 2009
#18
  • Jan 7, 2009
  • #18
what size of spacer are you needing? if you don't need the 1" go with the smaller one.

And yes everytime I ran my car it ran better everytime. Lots of bugs to sort out.
 

lickem

New Member
Sep 11, 2005
62
0
0
lake elsinore ca
Jan 7, 2009
#19
  • Jan 7, 2009
  • #19
well now im having second thoughts on the spacer and just going with different covers like you suggested before because id didnt think there was anyway the hood was gonna work but if the hood will work then ill find some different covers or maybe ill just "massage" the area under the throttle linkage. ill also have to trim the plate that attachs to the egr spacer and secures the throttle linkage if i go the "massaging" route.
 
2

2002BLGT

Well-Known Member
Dec 18, 2003
2,945
4
59
Bedford VA
Jan 7, 2009
#20
  • Jan 7, 2009
  • #20
Id find a local tuner to burn you a chip and to get the air/fuel adjusted on it
 
  • 1
  • 2
  • 3
  • 4
Next
1 of 4 Next Last
You must log in or register to reply here.

Similar threads

7
Engine Random hanging idle
  • 706 Saleen
  • Feb 11, 2026
  • Fox 5.0 Mustang Tech
Replies
9
Views
457
Fox 5.0 Mustang Tech Feb 19, 2026
86HO5.0
8
1
Engine 91 mustang 302 Low acceleration car backfires pops and acts like it doesn’t want to take fuel
  • 1991Fox5.0
  • Oct 4, 2025
  • Fox 5.0 Mustang Tech
Replies
16
Views
993
Fox 5.0 Mustang Tech Oct 6, 2025
1991Fox5.0
1
D
Engine Throttle sticky even after cable replacement
  • dqureshi06
  • Aug 16, 2025
  • Fox 5.0 Mustang Tech
Replies
6
Views
328
Fox 5.0 Mustang Tech Aug 17, 2025
AeroCoupe
M
Engine Unexplainable Exhaust Pop and Gurgle
  • Mrnissen122
  • Feb 14, 2026
  • Fox 5.0 Mustang Tech
Replies
12
Views
515
Fox 5.0 Mustang Tech Feb 18, 2026
Noobz347
Engine Surging idle on start-up
  • keel
  • Aug 11, 2025
  • Fox 5.0 Mustang Tech
Replies
16
Views
846
Fox 5.0 Mustang Tech Oct 31, 2025
keel
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?