Does any have 42Lb fuel injectors in there 4.6L mustang?
07-08-2010, 05:37 PM
#11
1st Gear Member
Join Date: Sep 2007
Location: Pa.
Posts: 92
If it was a fuel issue, it wouldn't present itself on shifts, rather during high load.
The most likely cause of your issue here is the throttle body install. There are several guides around the net on setting the throttle stop screw on our cars. If you haven't done so already, start there. Getting the stop screw set correctly in turn should have your IAC valve functioning correctly. If the IAC valve isn't functioning correctly then your dashpot values will be wrong and you won't get the proper amount of air during shifts.
Now, on to the smaller pulley. If you are running a smaller pulley, there is a good chance that you are maxing your injectors/fuel pump. If you don't have a wideband on the car then you'll need a tuner or a buddy with datalogging capabilities to let you know where you stand.
The most likely cause of your issue here is the throttle body install. There are several guides around the net on setting the throttle stop screw on our cars. If you haven't done so already, start there. Getting the stop screw set correctly in turn should have your IAC valve functioning correctly. If the IAC valve isn't functioning correctly then your dashpot values will be wrong and you won't get the proper amount of air during shifts.
Now, on to the smaller pulley. If you are running a smaller pulley, there is a good chance that you are maxing your injectors/fuel pump. If you don't have a wideband on the car then you'll need a tuner or a buddy with datalogging capabilities to let you know where you stand.
07-14-2010, 03:33 PM
#12
2nd Gear Member
Thread Starter
Join Date: Oct 2007
Posts: 221
Thanks for your guys help. I am getting ready to install the 42 injectors today. Then we will go from there and see what happens. So the car is not a stock 255LPH fuel pump then? I just assummed it was a 255 fuel pump. If not was size is the stock fuel pump?
07-14-2010, 07:37 PM
#13
2nd Gear Member
Thread Starter
Join Date: Oct 2007
Posts: 221
I got the 42Lb injectors installed. Rev it up in the garage and its doing okay so far. Right now its 92 degrees. I will run the car at 230 n the morning when its 70 degrees and then run it around noon mountain time when its close to 90 degrees and get back to you guys to c what u all thinking. but still need to know what the OEM LPH is on a 2003 mustang GT fuel pump.
07-15-2010, 05:41 PM
#14
2nd Gear Member
Thread Starter
Join Date: Oct 2007
Posts: 221
Okay I have the 42LB injectors in took it out today and the herky jerky when flooring the car in 2nd and 3rd gear are gone. So it help awhole lot. but now it seems a little slow at getting the gas fast enough. Just alittle hesitation thru the rpms range in 2nd and 3rd gear like the fuel is not being delivered fast enough. So Im thinking a bigger fuel pump and a tune what do you all think since it seemed to fix my biggest problem of being herky jerky. And if anyone knows still would like to know the size of the stock fuel pump on 2003 mustang GT.
07-15-2010, 09:59 PM
#16
2nd Gear Member
Thread Starter
Join Date: Oct 2007
Posts: 221
how about a kenne bell boost a pump then I wouldnt need to drop the fuel tank to change out the fuel pump? And I have complete control of the flow even when its 18 degrees out side in the winter so I can dial it down or up when its warm. You think thats the best way to go its only $220.00?
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