need help fast hot headers

QCmustang94 · May 20, 2010

Yesterday I had to change the battery and the starter. Will work on the car next week.

QCmustang94 · May 24, 2010

I have the same F***** problem... when I drive the car at around 3k, there's some backfire and when I'm at WOT, the car have no power.

modo · May 24, 2010

rz5.0 said:
this is what i was talking about fuel pressure "Fuel pressure ? Increasing fuel pressure on a stock or ?bolt on? Mustang is going to do more harm than good. Everyone thinks bigger is better but that is rarely the case with anything. When you increase your fuel pressure the EEC will reduce the injector duty cycle because the oxygen sensors will tell the EEC that the engine is running rich. Even worse, the EEC could get confused enough and go into limp mode causing the car to run poorly. On stock or close to stock Mustangs there is actually a benefit to reducing the fuel pressure to about 28-30lbs. This is typically worth about 4-5 horsepower across the entire rpm range. Once again, bigger is not always better. Don?t increase fuel pressure unless the engine requires it. Removing the vacuum line is not a good idea either. All you are doing there is raising the fuel pressure at idle and part throttle without changing it at wide open throttle. This will get you some worse fuel economy and most likely worse performance. " reinhold racing website

there is no benefit from changing fuel pressure on any mustang period. injectors are designed to have optimum spray patterns at a specific fuel pressure. pulse width is what should be used along with with the proper size

rz5.0 · May 25, 2010

my car was running like crap at 40 psi now at 43 and runs better. no more popping from the exhaust. if more pressure does not help y do people run fmu with boost and small injectors. it worked for me might not work for him who knows.

modo · May 26, 2010

rz5.0 said:
my car was running like crap at 40 psi now at 43 and runs better. no more popping from the exhaust. if more pressure does not help y do people run fmu with boost and small injectors. it worked for me might not work for him who knows.

stock fp is 42-43

just because people do it does not mean it is the right way. its a band-aid and the motor would make more power more efficiently with a properly sized injector.

think about it. a injector can only be open for a finite amount of time (cam timing). if you can't get enough fuel in that short amount of time with a particular sized injector then you need larger injectors. by increasing pressure you are forcing more fuel through a hole that wasn't designed to flow that much... that fine spray pattern is now changed or in the worst case senario the injector is now static and is just a piss stream vs a spray pattern.

look at any injector sold, they aer rated at a specific flow rate at a specific pressure

QCmustang94 · May 26, 2010

So? my Fuel pressure is wrong? and if I put the timing at 10 it's worse... I have to set the timing around 9 degrees.??

rz5.0 · May 26, 2010

i agree that its not the best idea but if it helps till you can get the right part or tune. do what you have to do

QCmustang94 · May 28, 2010

Now I have some bucking at low end. before 2k. The previous firing order was : 1-3-7-2-6-5-4-8 and I changed it for : 1-5-4-2-6-3-7-8. The car runs better but there's some backfire in the exhaust at low end and the car have no ''power''. I don't know what's the problem. With the previous firing order, the car has backfire in any gears and any rpm.

modo · May 28, 2010

QCmustang94 said:
Now I have some bucking at low end. before 2k. The previous firing order was : 1-3-7-2-6-5-4-8 and I changed it for : 1-5-4-2-6-3-7-8. The car runs better but there's some backfire in the exhaust at low end and the car have no ''power''. I don't know what's the problem. With the previous firing order, the car has backfire in any gears and any rpm.

previous firing order?

efi has one firing order, its not a 289 dude

rz5.0 · May 28, 2010

the e303 cam uses 1-3-7-2-6-5-4-8 r u sure you didnt have any wires crossed

rz5.0 · May 28, 2010

QCmustang94 · May 28, 2010

modo said:
QCmustang94 said:

Now I have some bucking at low end. before 2k. The previous firing order was : 1-3-7-2-6-5-4-8 and I changed it for : 1-5-4-2-6-3-7-8. The car runs better but there's some backfire in the exhaust at low end and the car have no ''power''. I don't know what's the problem. With the previous firing order, the car has backfire in any gears and any rpm.

Click to expand...

previous firing order?

efi has one firing order, its not a 289 dude

1-3-7-2-6-5-4-8 is the first one I tried. I was worst than the 1-5-4-2-6-3-7-8. When I tried the 1-3-7-2-6-5-4-8 the car was too ''loopy'' and had a lot of backfire with the 1-5-4--2--6-3-7-8 there's only backfire at low rpm.

modo · May 28, 2010

the firing order is 1-3-7-2-6-5-4-8

its not running right because the timing is off which is why the headers are also glowing

QCmustang94 · May 30, 2010

they're not glowing anymore. I will switch to 1-3-7-2-6-5-4-8 then...

QCmustang94 · Jun 1, 2010

I redid the firing order and the car was running pretty good. Now, I saw that the vaccum line on the EGR wasn't plug, so I plug it. The valve seems to be always up ?

And, now the car want to stall. Vaccum problem?