Is it the fuel or what???

geronimo66 · 06-21-2001, 02:31 PM

Okay here is what I have: 88 LX Mass air conversion, TW heads, TW street heat, 65mm TB & EGR, 30# @ 30lbs FP, BBK Shorties, and the rest of the bolt-ons. I have notice that the car doesn't feel quite right. When I am in any gear and let the engine R down, in seems to load the motor with to much fuel. When I get bacl on the gas(lightly) it bucks, and kicks. If I push the cluch in and give it a quick jab(as if to clear it out) it is all okay again. Any ideas as to what the probles is. My thoughs:

Poss. 30# are to much for my combo.
Improperly set fuel press.

PS: I havn't put my 190L in yet or the TFS 1 CAM and MSD Dist.

Any help welcome

Thanks

geronimo66 · 06-21-2001, 08:01 PM

Hey, help me here guys.

jimberg · 06-22-2001, 12:58 PM

If your MAF sensor is calibrated for 30# injectors, run your fuel pressure at 39psi which is what will give you the 30# rating (You're currently running at about 26.3# capacity, which just happens to be what I'm running at with 47psi.

). Too low a fuel pressure can wreck the spray pattern of the injector, though. Think of a water nozzle when the faucet isn't on all the way.

24# injectors probably would have been better for you now, but you're set if you plan to get a blower or something.

30# injectors are way too big for the stock fuel pump and with your mods you should definitely be exceeding the limits of that pump. Get that 190 in there.

I should add that these things aren't necessarily the cause, there could be many others, but it's a good idea to fix the basics before addressing the obscure.

------------------
351W 89 Mustang GT Convertible

[This message has been edited by jimberg (edited 06-22-2001).]

geronimo66 · 06-22-2001, 03:32 PM

39# seems like a lot of fuel. It "seems" like it is getting to much fuel now. It seems like it's moving out okay but I don't have any reference. I need to hit the track, after I put the 190L in. Any more info out threir???

jimberg · 06-22-2001, 03:44 PM

The computer only dispenses as much fuel as necessary. The air/fuel ratio has nothing to do with injector size of fuel pressure. I think we all agree that your injectors are too big, it's just that too big doesn't mean that it will cause severe driveability issues. Setting your fuel pressure at 30 psi confuses the computer more than having 30# injectors.

------------------
351W 89 Mustang GT Convertible

geronimo66 · 06-22-2001, 04:29 PM

So setting the 30#ers to 39PSI will allow for a better spray pattern without over fueling the motor. I got the 30# injectors planning further fuel needs, now I am thinking I should have gone with the 24's then jump up to real big when the Turbo goes on. Thanks for the info. I'll try the 39# setting and see how it feels.

jimberg · 06-22-2001, 06:01 PM

This is all assuming that you have a properly calibrated MAF sensor. When you do raise your fuel pressure, make sure that you reset the computer.

------------------
351W 89 Mustang GT Convertible

06-21-2001, 02:31 PM	#1
geronimo66 Registered Member Join Date: Nov 2000 Location: Utica, MI 48317 Posts: 14	Is it the fuel or what??? Okay here is what I have: 88 LX Mass air conversion, TW heads, TW street heat, 65mm TB & EGR, 30# @ 30lbs FP, BBK Shorties, and the rest of the bolt-ons. I have notice that the car doesn't feel quite right. When I am in any gear and let the engine R down, in seems to load the motor with to much fuel. When I get bacl on the gas(lightly) it bucks, and kicks. If I push the cluch in and give it a quick jab(as if to clear it out) it is all okay again. Any ideas as to what the probles is. My thoughs: Poss. 30# are to much for my combo. Improperly set fuel press. PS: I havn't put my 190L in yet or the TFS 1 CAM and MSD Dist. Any help welcome Thanks

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06-21-2001, 08:01 PM	#2
geronimo66 Registered Member Join Date: Nov 2000 Location: Utica, MI 48317 Posts: 14	Hey, help me here guys.

06-22-2001, 12:58 PM	#3
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	If your MAF sensor is calibrated for 30# injectors, run your fuel pressure at 39psi which is what will give you the 30# rating (You're currently running at about 26.3# capacity, which just happens to be what I'm running at with 47psi. ). Too low a fuel pressure can wreck the spray pattern of the injector, though. Think of a water nozzle when the faucet isn't on all the way. 24# injectors probably would have been better for you now, but you're set if you plan to get a blower or something. 30# injectors are way too big for the stock fuel pump and with your mods you should definitely be exceeding the limits of that pump. Get that 190 in there. I should add that these things aren't necessarily the cause, there could be many others, but it's a good idea to fix the basics before addressing the obscure. ------------------ 351W 89 Mustang GT Convertible [This message has been edited by jimberg (edited 06-22-2001).]

06-22-2001, 03:32 PM	#4
geronimo66 Registered Member Join Date: Nov 2000 Location: Utica, MI 48317 Posts: 14	39# seems like a lot of fuel. It "seems" like it is getting to much fuel now. It seems like it's moving out okay but I don't have any reference. I need to hit the track, after I put the 190L in. Any more info out threir???

06-22-2001, 03:44 PM	#5
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	The computer only dispenses as much fuel as necessary. The air/fuel ratio has nothing to do with injector size of fuel pressure. I think we all agree that your injectors are too big, it's just that too big doesn't mean that it will cause severe driveability issues. Setting your fuel pressure at 30 psi confuses the computer more than having 30# injectors. ------------------ 351W 89 Mustang GT Convertible

06-22-2001, 04:29 PM	#6
geronimo66 Registered Member Join Date: Nov 2000 Location: Utica, MI 48317 Posts: 14	So setting the 30#ers to 39PSI will allow for a better spray pattern without over fueling the motor. I got the 30# injectors planning further fuel needs, now I am thinking I should have gone with the 24's then jump up to real big when the Turbo goes on. Thanks for the info. I'll try the 39# setting and see how it feels.

06-22-2001, 06:01 PM	#7
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	This is all assuming that you have a properly calibrated MAF sensor. When you do raise your fuel pressure, make sure that you reset the computer. ------------------ 351W 89 Mustang GT Convertible