i have a 93 lx 5.0 cobra upper and lower f cam motorsport lifters cnl 76mm maf bbk 70mm tb. im having the same problem i was at a red light and when i started to accelerate it popped through the intake and then it started running just like yours in this video. im thinking of changing my injectors also but was your lifters ok or any valves messed up. i found a vaccum leak under the intake manifold.
This is one of two things, Either your timing is way out, or plug wires crossed (which is what I'm betting on) or its lean pops. A bad vac leak will cause this as well as a bad MAF. Lean popping is also caused by a messed up injector or wrong injector size relative to MAF calibration. It really does sound like it's 180 out though.
Hey blues62. I think you're right. I recently purchased a set of roller rockers and went through the torque down procedure. I don't believe I did this before, or can't remember. Now that I'm done powder coating things under the hood I may get it running again this weekend. It makes sense that if the rockers aren't closing completed how I be hearing the popping noise. Thanks!
dude you have some messed up lifters I just built a 306 for my 88 lx had the same exact sound if you pull your valve covers off i would bet money your rockers are not opening and closing the valve properly re adjust them and try again if not pull upper and lower intake replace lifters and it will never happen again.
I wish I could tell you what it was. I was using the stock rocker arms with the GT40X heads and think there may have been a valve issue. I have since upgraded to roller rockers and am hoping for a smooth running motor. Once the motor is back together I post my results.
Well, its been running fine for quite a while now and the popcorn sound doesn't come around very often anymore. Thanks for all the input. I can tell you that it still might be a timing issue although that has been set and reset several times. Also, not 180 out on the distributor. All wires are correct too. Hopefully this beast will show itself in the summer and I can take another stab at it. Now to work on the sporadic idle issue.
Ive got the same manifold Gt 40X im building my motor in the spring this year, just wondering if you like that manifold please give me some feedback thanks
poor girl, that is my favorite intake for these too, does any one know what brand it is, i think it is called the gt40 intake, so it might be from the cobras or something....?
yeah my car did the same thing turned out to be a little of both. the timing was off by about a tooth or so and the the fiel pressure was way low. i had a adjustable fuel pressure regulator that jammed up on the inside not adjusting like it should and causeing the car to run lean.
I believe this problem has been solved. I changed out the injectors from 19's to 24's. I'm not sure if I had a bad injector if if the motor needed more juice. Seems fine now....finally!
what are the gains of switching out the injectors??? ... I've added a cam, cobra intake, rockers etc etc to my stock 5.0 ... and guys are telling me to switch injectors .. anybody?
I wonder they do that to open up the flow from the fuel pump, if you do that you might want to get a stronger fuel pump. Food for thought and getting hotter burning spark plugs and larger wires, if you run to rich then you could ruin your cats if you have them, and to lean you could ruin the top of your pistons!!!!
When you modify your motor you need to step up the injectors and have it tuned to get the most performance and not lean out your motor. You probably need about 24lbs injectors. Before you buy injectors you need to know what else you are going to do to the motor to get the right size the first time.
@kixsi yeah intake backfire is usually a lean condition, i was having the same thing and i gave it a little more timing and fuel pressure and it was like a completely different motor after.
I had the same problem. I had a couple of bad injectors. I put on a new filter and new 24# injectors and it runs great now. (306, cobra intake, SVO aluminum heads)
Well, nothing yet. I drove it around today and it only pops for a few minutes when it is cold. It may be a shot in the dark but maybe I have a bad injector that is causing a cylinder to run lean and detonate? Anyway, new 24lb injectors, cobra computer, and new exhaust for this weekend. I'll let you know what happens. Is your popping more constant than this?
yeah,it sounds like you got the spark plug wires all fucked up,the firing order should be (1-3-7-2-6-5-4-8) I would start matching the #1 cylinder from with the # 1 terminal on the distributor and work that order counter-clockwise,(cylinders 1 being on passenger side front of engine and cyl 4 being in backof passenger side.drivers side from front of engine to back should be cyl's 5-8)if it dont match,then you know you got the wires fucked up. hey,its an honest mistake anyone of us can make.
i heard that once with my 89gt. wasnt timing it was a stupid mistake. Plug wire on the wrong plug! was fireing right befor the intake valve would open an made the pop. checked the fireing order again and was fine.(i had goton the worn firering order for the car i wired it up like a non-HO car)
Well lets start off diagnosing that its a ford>>>> LOL IM kiddin Nah sounds like timing... if its not timing could possibly be a clogge intake manifold
My car is doing the exact same thing, we pulled the upper (GT40) because there was a vacuum leak, new gasket and checked hoses and the same popping noise still exists. Mechanics are telling me that sounds like a valve is sticking or stuck. Shouldn't be a timing issue becaue my car just started doing it one day. I also have gt40 aluminum heads with very little time on them and a powerdyne charger. Please post whatever you figure out.
Oh and another thin that might not be a vacuum leak that might be the Idle air motor and double check your lines by the Fuel pressure regulator make sure you don't have any crossed lines if you do u wont be able to time it right.
Yeah listening to it ide knows your timing is way off and depending on how many mods u done to the motor u might need to tweak the ECM but check the timing. and Make sure you pull the timing plug when you do it to disable the advance for the ECM not sure where its located on that year to buy a book.
Thanks for the comments guys. I can actually hear a vacuum leak now. Funny thing is that I hear it more with the hood closed than open. Once I find it I will redo the timing.
check your fuel pressure.24 pound injecters work good.mine would pop back like that.it was the fuel pressure.
jadagrace09 3 months ago
Mine was a vacuum leak under intake manifold causing lean pop
rexbluepit 5 months ago
Make sure your firing order is correct for an HO motor! I had this same issue and tthat fixed it
myfine86 5 months ago
i have a 93 lx 5.0 cobra upper and lower f cam motorsport lifters cnl 76mm maf bbk 70mm tb. im having the same problem i was at a red light and when i started to accelerate it popped through the intake and then it started running just like yours in this video. im thinking of changing my injectors also but was your lifters ok or any valves messed up. i found a vaccum leak under the intake manifold.
rexbluepit 5 months ago
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This is one of two things, Either your timing is way out, or plug wires crossed (which is what I'm betting on) or its lean pops. A bad vac leak will cause this as well as a bad MAF. Lean popping is also caused by a messed up injector or wrong injector size relative to MAF calibration. It really does sound like it's 180 out though.
Sidewinder9877 5 months ago
Comment removed
Sidewinder9877 5 months ago
Hey blues62. I think you're right. I recently purchased a set of roller rockers and went through the torque down procedure. I don't believe I did this before, or can't remember. Now that I'm done powder coating things under the hood I may get it running again this weekend. It makes sense that if the rockers aren't closing completed how I be hearing the popping noise. Thanks!
cdclark35 7 months ago
dude you have some messed up lifters I just built a 306 for my 88 lx had the same exact sound if you pull your valve covers off i would bet money your rockers are not opening and closing the valve properly re adjust them and try again if not pull upper and lower intake replace lifters and it will never happen again.
blues62 7 months ago
firing order is either off or Timing is seriously out.
JeffAMay 10 months ago
My 93' does the pop sometimes, but only when im driving it. its doesnt happen that often. What is it?
GuitaMasta1 11 months ago
@GuitaMasta1
I wish I could tell you what it was. I was using the stock rocker arms with the GT40X heads and think there may have been a valve issue. I have since upgraded to roller rockers and am hoping for a smooth running motor. Once the motor is back together I post my results.
cdclark35 10 months ago
@GuitaMasta1 Lol nevermind, just upgraded to 93 cobra
GuitaMasta1 3 months ago
sounds badass. REV IT A BUNCH TOO!
petarjuric 1 year ago
Well, its been running fine for quite a while now and the popcorn sound doesn't come around very often anymore. Thanks for all the input. I can tell you that it still might be a timing issue although that has been set and reset several times. Also, not 180 out on the distributor. All wires are correct too. Hopefully this beast will show itself in the summer and I can take another stab at it. Now to work on the sporadic idle issue.
cdclark35 1 year ago
Ive got the same manifold Gt 40X im building my motor in the spring this year, just wondering if you like that manifold please give me some feedback thanks
italiansexmachine 1 year ago
its ur firing order
elpony193 1 year ago
wow i love popcorn just not in my motor you need a tuneup and timing set proper.
watchforfinger 1 year ago
i have the same fk problem
rclssm 1 year ago
so what was wrong?
91mustang19 1 year ago
poor girl, that is my favorite intake for these too, does any one know what brand it is, i think it is called the gt40 intake, so it might be from the cobras or something....?
313foxbody420 1 year ago
yeah my car did the same thing turned out to be a little of both. the timing was off by about a tooth or so and the the fiel pressure was way low. i had a adjustable fuel pressure regulator that jammed up on the inside not adjusting like it should and causeing the car to run lean.
jimmyray0682 1 year ago
Bad injector. It is lean even at idle causing a backfire through the intake. Happens quite a bit with clogged injectors too.
Stickman53fe 1 year ago
valve knocking on a cylinder?
XxMusclecarsxX 1 year ago
good to hear you got it fixed now ...post some vid of some full throttle passes of somehting ...
oohklu 1 year ago
nothing like a ford
ghostshot1004 1 year ago
I'm going to say the MAF isnt calibrated right
shocktop1984 1 year ago
i think its timing
FORDGTFANATIC 1 year ago
its your timeing adjust the time and it will fire right guaranteed
acidropper13 1 year ago
mustve been a dwarf trapped in your engine ...
jason1160 1 year ago
its a bent valve
kidwell1988 1 year ago
ooh.. detonation.
-check your timing
-Your air fuel ration
-fire order
foxsetup 2 years ago
reversion?
gittyak 2 years ago
check your firing order. You also might be 180 out on the distributor.
mustangpapi76 2 years ago
that engine looks so nice man
LILMastamind13 2 years ago
probably a lean pop....mine did the same..but i had a clogged injector...and new ones fixed the problem..
atzert007 2 years ago
Sounds like bad compression or a bad valve
mattmiller6977 2 years ago
tight intake valve ?
inagod 2 years ago
timeing is off turn it to the right as far as u can get it it should be 14 degrees that should take care of it
richpopey 2 years ago
its a popcorn maker
buddah022 2 years ago 11
I need to get my hands on one of those Tubular intakes!
NightGod07 2 years ago 6
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PIECE OF SHIT ! HA HA HA HA !
SickdogX3 2 years ago
hey did you ever find out what was causing that i had the same popping problem and turned out to be my maf
kixsi 2 years ago
I believe this problem has been solved. I changed out the injectors from 19's to 24's. I'm not sure if I had a bad injector if if the motor needed more juice. Seems fine now....finally!
cdclark35 2 years ago
what are the gains of switching out the injectors??? ... I've added a cam, cobra intake, rockers etc etc to my stock 5.0 ... and guys are telling me to switch injectors .. anybody?
gotazman 2 years ago
I wonder they do that to open up the flow from the fuel pump, if you do that you might want to get a stronger fuel pump. Food for thought and getting hotter burning spark plugs and larger wires, if you run to rich then you could ruin your cats if you have them, and to lean you could ruin the top of your pistons!!!!
trombonedemon 2 years ago
When you modify your motor you need to step up the injectors and have it tuned to get the most performance and not lean out your motor. You probably need about 24lbs injectors. Before you buy injectors you need to know what else you are going to do to the motor to get the right size the first time.
72Horton 2 years ago
Could the fuel have running lean, for the set up you have, and did an engine knock sensor throw a code?
trombonedemon 2 years ago
@cdclark35 if it was the fuel injectors the car would die when you push the gas down!
diplomatic4 1 year ago
@kixsi yeah intake backfire is usually a lean condition, i was having the same thing and i gave it a little more timing and fuel pressure and it was like a completely different motor after.
greasegasandglory 1 year ago
@kixsi sounds like the air compression is either very low or high im guessin its the headers not letting the manifold breathe
diplomatic4 1 year ago
I had the same problem. I had a couple of bad injectors. I put on a new filter and new 24# injectors and it runs great now. (306, cobra intake, SVO aluminum heads)
mefordguy 3 years ago
any news???i' hoping you figure it out before i have to in the spring...
tnorris11 3 years ago
Well, nothing yet. I drove it around today and it only pops for a few minutes when it is cold. It may be a shot in the dark but maybe I have a bad injector that is causing a cylinder to run lean and detonate? Anyway, new 24lb injectors, cobra computer, and new exhaust for this weekend. I'll let you know what happens. Is your popping more constant than this?
cdclark35 3 years ago
yeah,it sounds like you got the spark plug wires all fucked up,the firing order should be (1-3-7-2-6-5-4-8) I would start matching the #1 cylinder from with the # 1 terminal on the distributor and work that order counter-clockwise,(cylinders 1 being on passenger side front of engine and cyl 4 being in backof passenger side.drivers side from front of engine to back should be cyl's 5-8)if it dont match,then you know you got the wires fucked up. hey,its an honest mistake anyone of us can make.
nitrostang50 3 years ago
i heard that once with my 89gt. wasnt timing it was a stupid mistake. Plug wire on the wrong plug! was fireing right befor the intake valve would open an made the pop. checked the fireing order again and was fine.(i had goton the worn firering order for the car i wired it up like a non-HO car)
5turbo0 3 years ago
so did u figure out the problem?
juztanotherday2 3 years ago
Well lets start off diagnosing that its a ford>>>> LOL IM kiddin Nah sounds like timing... if its not timing could possibly be a clogge intake manifold
DSMonDUBS 3 years ago
Did you cap the opening on the intake, on the front side, beside the TB?
tnorris11 3 years ago
My car also has a similar idle issue...
tnorris11 3 years ago
My car is doing the exact same thing, we pulled the upper (GT40) because there was a vacuum leak, new gasket and checked hoses and the same popping noise still exists. Mechanics are telling me that sounds like a valve is sticking or stuck. Shouldn't be a timing issue becaue my car just started doing it one day. I also have gt40 aluminum heads with very little time on them and a powerdyne charger. Please post whatever you figure out.
tnorris11 3 years ago
Thanks for all the comments! Finally have a little time to tackle this issue again. Thanks again!
cdclark35 3 years ago
TIMING!!
sn8kbite0304 3 years ago
your timing is way out... had this prob... it is easy to fix...
iaregod 3 years ago
oh and two items that wont hurt loosing is the manual fan and smog pump..
HotboyRizzle 3 years ago
Oh and another thin that might not be a vacuum leak that might be the Idle air motor and double check your lines by the Fuel pressure regulator make sure you don't have any crossed lines if you do u wont be able to time it right.
HotboyRizzle 3 years ago
Yeah listening to it ide knows your timing is way off and depending on how many mods u done to the motor u might need to tweak the ECM but check the timing. and Make sure you pull the timing plug when you do it to disable the advance for the ECM not sure where its located on that year to buy a book.
HotboyRizzle 3 years ago
your timing should be set at 14 degress, it sounds like your running to lean. Change the timing
fatracing20 3 years ago
I had the same problem with my stang and it was the timing let me know if you fixed it
superstang530 3 years ago
Thanks for the comments guys. I can actually hear a vacuum leak now. Funny thing is that I hear it more with the hood closed than open. Once I find it I will redo the timing.
cdclark35 3 years ago
ya thats a timing issue my friend u either have to much timing or not enough try pulling some timing out
JohnnyBeGood3323 3 years ago
vacuum leak. had that problem with my stang
motomonster525 3 years ago
timings to retarded
mstngsrule68 3 years ago
Recheck your timing and restab dizzy. Sounds like your dizzy is 180* out.
sheehy933 3 years ago