What is going on with my fox

5.0 street stanger · April 24th, 2009, 12:35 AM

Ok so I recently put my exhaust back on my car and it now runs like shit. It was straight header for a little while. I put the dual exhaust back on and it now runs like worse than it did open header. I did change the timing to 14degrees. i did run it after that open header like it was and it ran fine. didnt notice any gains with the timing but i figured i wouldnt really notice much to begin with. I have had the exhaust on it and it never had a problem like it does now. Its got long tube headers and dual 2 1/2 exhaust with an H pipe and flowmaster super 40's or 44's. Not sure exactly which. but now it runs like SHITS. it has nothing off the line. The car basically rolls. Im thinking that it doesnt like the timing. But like I said I did run it after the timing with open header like it was and it ran good. Any ideas as to whats going on? If I cant figure it out ill put a video up of it reving and u guys can tell me what u think. Im going to get out the volt meter tomorrow and check what codes are being thrown with the check engine light cause the light has always been on.

1slo5.0 · April 24th, 2009, 07:53 AM

Check codes and did you set the timing correctly?

5.0 street stanger · April 24th, 2009, 10:15 PM

well i set my timing gun on the number one cyl. and started it up and let it warm up and turned the dist. until i saw 14degrees advanced. Did i do it right? I have a haynes but it sucks! doesnt explain much. I would also like to drop some fuel pressure at idle for a little more power. Or so I have read. Can I do this on my stock fox? Is the regulator adjustable? and Im thinking its that chrome thing that sits on the fuel rail close to the fire wall. Correct? And I have a digital volt meter. I tried to pull the codes today but its too hard to see what codes the digital meter is trying to show me. In my haynes it says to use one of those old style meters with the needle. I dont have one of those. Can I take it to jiffy lube and have them tell me? My car is supposed to be OBD-1 correct? its a 93 fox 5.0 BTW. Can I buy a OBD-1 scan tool and hook that sucker up to the harness under the engine bay where im supposed to hook up the volt meter to check codes. Again my haynes doesnt explain much. Thanks for any help. Ill let u guys know the codes when I get em pulled for some advice as to what the hell is going on with her.

GT347SC · April 24th, 2009, 10:53 PM

Did you pull the spout plug out when yo set the timeing? It doesnt say you did. If you didnt then your timing is off.

1slo5.0 · April 24th, 2009, 11:10 PM

Originally Posted by GT347SC

Did you pull the spout plug out when yo set the timeing? It doesnt say you did. If you didnt then your timing is off.

+1

Reducing fuel pressure to about 27lbs is worth about 4-5hp across the rpm range. You need an adjustable fuel pressure regulator to do this and you need to set the fuel pressure with the vacuum line disconnected.

5.0 street stanger · April 25th, 2009, 02:45 AM

Spout plug? lol, no. I just read about that connector actually. guess ill be pulling out the timing gun again. My fox isnt here right now tho. In the haynes it says this connector is directly above the main harness that plugs into the module. I thought there was only one main harness plug that plugs into the dist.? unless its somewhere else. Kinda hard to picture things when the car isnt here. Can you tell me where it is incase I dont find it tomorrow? My VECI label is missing from my car. What is base timing for my car set at BTW? and I am correct about 14degrees advanced is about as much as i can go being pretty much stock? Do I really need to run 93 octane after the advance? Oh and if i get an adj FPR for my stock rail will i be able to reuse the new adj FPR on upgraded rails?

5.0 street stanger · April 25th, 2009, 02:59 AM

I just looked on summit and all the regulators lowest psi setting was only as low as about 30-35psi. There was only one FPR from Paxton that allowed fuel pressure to be set at 27psi and of course it was the most expensive one. Does anybody know of a FPR that will allow me to set fuel pressure as low as 27psi that wont cost me an arm and a leg? or even an adjustable FPR off a car at the junk yard that will work on my stock fox fuel rails, or do most cars not have adj FPR's? Im poor what can I say. Thanks for the help.

1slo5.0 · April 25th, 2009, 11:54 AM

Get this one eBay Motors: Mustang 5.0 Adjustable Kirban Fuel Pressure Regulator (item 260397682275 end time Apr-28-09 14:44:46 PDT)

No it won't work on aftermarket fuel rails. Aftermarket fuel rails are a totally different design than the factory fuel rails.

April 24th, 2009, 12:35 AM	#1
5.0 street stanger Regular Join Date: Oct 2006 Posts: 171 iTrader: 0 reviews	What is going on with my fox Ok so I recently put my exhaust back on my car and it now runs like shit. It was straight header for a little while. I put the dual exhaust back on and it now runs like worse than it did open header. I did change the timing to 14degrees. i did run it after that open header like it was and it ran fine. didnt notice any gains with the timing but i figured i wouldnt really notice much to begin with. I have had the exhaust on it and it never had a problem like it does now. Its got long tube headers and dual 2 1/2 exhaust with an H pipe and flowmaster super 40's or 44's. Not sure exactly which. but now it runs like SHITS. it has nothing off the line. The car basically rolls. Im thinking that it doesnt like the timing. But like I said I did run it after the timing with open header like it was and it ran good. Any ideas as to whats going on? If I cant figure it out ill put a video up of it reving and u guys can tell me what u think. Im going to get out the volt meter tomorrow and check what codes are being thrown with the check engine light cause the light has always been on.

April 24th, 2009, 07:53 AM	#2
1slo5.0 MM Ninjas! 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: North Fond du Lac, Wisconsin Posts: 11,375 iTrader: 1 reviews	Check codes and did you set the timing correctly? __________________ My daily driver has 16 cylinders and 4400hp @ 1000 rpm.... ***1988 Mustang GT - Stock....almost

April 25th, 2009, 11:54 AM	#8
1slo5.0 MM Ninjas! 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: North Fond du Lac, Wisconsin Posts: 11,375 iTrader: 1 reviews	Get this one eBay Motors: Mustang 5.0 Adjustable Kirban Fuel Pressure Regulator (item 260397682275 end time Apr-28-09 14:44:46 PDT) No it won't work on aftermarket fuel rails. Aftermarket fuel rails are a totally different design than the factory fuel rails. __________________ My daily driver has 16 cylinders and 4400hp @ 1000 rpm.... ***1988 Mustang GT - Stock....almost

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April 24th, 2009, 10:15 PM	#3
5.0 street stanger Regular Join Date: Oct 2006 Posts: 171 iTrader: 0 reviews	well i set my timing gun on the number one cyl. and started it up and let it warm up and turned the dist. until i saw 14degrees advanced. Did i do it right? I have a haynes but it sucks! doesnt explain much. I would also like to drop some fuel pressure at idle for a little more power. Or so I have read. Can I do this on my stock fox? Is the regulator adjustable? and Im thinking its that chrome thing that sits on the fuel rail close to the fire wall. Correct? And I have a digital volt meter. I tried to pull the codes today but its too hard to see what codes the digital meter is trying to show me. In my haynes it says to use one of those old style meters with the needle. I dont have one of those. Can I take it to jiffy lube and have them tell me? My car is supposed to be OBD-1 correct? its a 93 fox 5.0 BTW. Can I buy a OBD-1 scan tool and hook that sucker up to the harness under the engine bay where im supposed to hook up the volt meter to check codes. Again my haynes doesnt explain much. Thanks for any help. Ill let u guys know the codes when I get em pulled for some advice as to what the hell is going on with her.

April 24th, 2009, 10:53 PM	#4
GT347SC Regular 89 GT, 92 LX Join Date: Nov 2008 Posts: 120 iTrader: 0 reviews	Did you pull the spout plug out when yo set the timeing? It doesnt say you did. If you didnt then your timing is off.

April 25th, 2009, 02:45 AM	#6
5.0 street stanger Regular Join Date: Oct 2006 Posts: 171 iTrader: 0 reviews	Spout plug? lol, no. I just read about that connector actually. guess ill be pulling out the timing gun again. My fox isnt here right now tho. In the haynes it says this connector is directly above the main harness that plugs into the module. I thought there was only one main harness plug that plugs into the dist.? unless its somewhere else. Kinda hard to picture things when the car isnt here. Can you tell me where it is incase I dont find it tomorrow? My VECI label is missing from my car. What is base timing for my car set at BTW? and I am correct about 14degrees advanced is about as much as i can go being pretty much stock? Do I really need to run 93 octane after the advance? Oh and if i get an adj FPR for my stock rail will i be able to reuse the new adj FPR on upgraded rails?

April 25th, 2009, 02:59 AM	#7
5.0 street stanger Regular Join Date: Oct 2006 Posts: 171 iTrader: 0 reviews	I just looked on summit and all the regulators lowest psi setting was only as low as about 30-35psi. There was only one FPR from Paxton that allowed fuel pressure to be set at 27psi and of course it was the most expensive one. Does anybody know of a FPR that will allow me to set fuel pressure as low as 27psi that wont cost me an arm and a leg? or even an adjustable FPR off a car at the junk yard that will work on my stock fox fuel rails, or do most cars not have adj FPR's? Im poor what can I say. Thanks for the help.

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