What Fuel Presure For 24lb Injectors

chadjones99 · September 4th, 2006, 02:30 AM

what fuel presure should i run.. i have a 86 block converted to MAF and e303 cam / heads / intake ,etc I put 24 lb injectors. it ran a little stronger on the bottom end with my 19 lb injectors in, but fuel presure was set at 42 ish.
what should i set my 24's too ?
i also have a 65 MM throttle body on but i have a 70 MM, thinking about putting it on

dcraig8 · September 4th, 2006, 02:33 AM

i wouldnt go any higher than 44-45

chadjones99 · September 4th, 2006, 10:54 PM

well I am still trying to dial in this motor. it runs strong but feels like it has a real slight miss while driving but not under hard acceleration.
I had the fuel set at 42 lbs, but backed it off to 38 seem to pull a little stronger. I am still also playing with the timing
now when i had my 19 lb injectors in i set at 42-44 and it ran great, but these 24 flow to much fuel at that pressure.

Zak · September 5th, 2006, 04:54 PM

38 psi while the vacuum line's disconnected.. if it does have any.

chadjones99 · September 5th, 2006, 08:19 PM

oh, ok . i set it with the vacuum line on and running. set it with no vacuum on ?
thanks

chadjones99 · September 5th, 2006, 09:44 PM

ok adjusted it was like 42 ish when i pulled off vac line..adjusted to 38 and it helped alot !

Zak · September 6th, 2006, 12:20 AM

Thanks to Mr. Jim Roal, you don't know what you're missing if you haven't read his tech articles & Q&As:

http://jroal.home.mchsi.com/

Zak · September 6th, 2006, 12:24 AM

By the way, increasing the pressue of the rails affects the injectors negatively.. as you keep increaing that, your electronic injectors will need more force to lift up it's internal plunger in order to spray the fuel mist.. that would lead to premature failures.

chadjones99 · September 6th, 2006, 08:59 AM

ok thanks 38 lb's set correct now. and runs a lot better

chadjones99 · September 8th, 2006, 12:00 AM

ok, i set fuel to 38 lbs like my last post say's...its running better but when i dont have my foot in it and am just trying to cruise.. it feels like it has a small mis...so i have too issue's i checked fuel pressure again. here is whats going on..when i have the vac line on and the car is at idle (800-950 rpm's) it show 30-31lbs wheni rev it it spikes to 35 then drops to 25 and floats betteen 24-26 lbs. does that sound right ? vac line off it set at 38 lbs at idle. , i also have the vac line hooked right behind intake ..is it getting to much vac ? should i move vac line to vac header ?>
i am also playing with the timing. another issue there.. when i pull the plug (chip) to set the timing nothing happens. i thought the idle would change...its like the dam thing is not hooked up or something?
timimg i know should be 10-14 with chip pulled but i have it like 30-40 because the chip is not doing anything, car run pretty good, just that little bit of mis when i am not puring the gas too it. is there some were i can jumpper that wire the chip goes to to make it work ?
thanks

Zak · September 8th, 2006, 01:56 AM

Nope.. That doesn't sound right, Chad.. why's your idle at 950 rpm to begin with? that, plus saying that the engine misses at idle speed or low speeds.. and your fuel pressure regulator symptom.. they lead to one conclusion to me: vacuum leak!!

try tightening all those clamp screw but not too tight or will break that plastic tree.. check the hoses for cracks & listen for hissing noise.. some books say use soapy water but I cant see how! its a vacuum line not a boost line... if you have a cracked intake manifold gasket, carefully spray a can of carb cleaner or CRC around the manifold & see if the engine revs up..

About timing & your spark-out or "spout" connector.. you just CANT have 30-40* of ignition advance at idle - not talking about total timing here.. how did you check for that?!

chadjones99 · September 8th, 2006, 03:47 AM

with a timing light. it goes to 30 deg. and its a ways above that !. i can turn it back to 10-12 but it does not want to run. and the spout seems to have no effect on it.

Zak · September 8th, 2006, 06:53 AM

Anybody?

Autotech · September 8th, 2006, 08:48 AM

Are you shuting the engine off...pulling the chip...then starting engine to set the timing??? you can not pull the chip while it is running and get an accurate reading...

Other thing it may be ( seen this often) is if your balancer has spun.. I went through 3 myself before I bought a non rubber insert style.

Zak · September 8th, 2006, 09:46 AM

Originally Posted by Autotech

Other thing it may be ( seen this often) is if your balancer has spun.. I went through 3 myself before I bought a non rubber insert style.

I try to imagine that but I can't.. the balancer center has a keyway.. unless if the key is sheared, or the outer shell -the graded one- that is attached to the rubber damper is detached from it?

chadjones99 · September 8th, 2006, 07:14 PM

no i am not pulling chip before i set timing...but in the past when you pull the chip(timing plug) the engine RPM changes (alot) right now no change like it is not hooked up ?
i checked the yellow wire going to the chip and not voltage there while car is running. i would think that it should be hot.

chadjones99 · September 9th, 2006, 04:01 AM

ok its working now ? must have been a loose wire on the EEC
here is another question

n a fresh rebuilt motor(302 now 306), does it have more compression before or after break in ?
I have been playing with my timing and at one point had it way over 14 deg with no pinging, ran great just did not want to cruise very well, so how did I get away with that unless my compression is low do to engine only has like 30 miles on it ?also when i rev ny motor my fuel pressure drops from 31 to 25 ish with vac line on ? does that sound like a cloged pump screen ? and do these car have a fuel filter on them other than that ?

Zak · September 9th, 2006, 06:33 AM

your compression is optimum soon after the break-in cuz all those microscopic peaks & valleys are ground and the piston rings are well seated

you have to inspect your vacuum lines.. troubleshoot with EVTM

there are only 2 replaceable fuel filters: one screen mesh at the intank fuel pump suction, and one on the discharge line (the Bosch one which you usually change everything 50,000 miles) - of course, each injector has a built-in mini filter of its own.

chadjones99 · September 9th, 2006, 02:28 PM

were is the one on the return line ?
also on the 2 line were they come up into the engine compartment one is a little small around and the other that looks bigger is in a sleave of some type which on it the return ? because the small one got kinked over when i pulled the motor but it looks ok now

Autotech · September 10th, 2006, 06:04 PM

Yes Zak I ment the balancer came apart at the rubber part...Mostly due to NOS... When this happened I could set the timing at 36 Degrees at idle , cause it was reading wrong due to its new location. There is a fuel filter below the trunk infront of the gas tank. If your fuel pressure is decreasing when you rev it ...I would look at vaccum lines as suggested by Zak

September 4th, 2006, 02:30 AM	#1
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	What Fuel Presure For 24lb Injectors what fuel presure should i run.. i have a 86 block converted to MAF and e303 cam / heads / intake ,etc I put 24 lb injectors. it ran a little stronger on the bottom end with my 19 lb injectors in, but fuel presure was set at 42 ish. what should i set my 24's too ? i also have a 65 MM throttle body on but i have a 70 MM, thinking about putting it on __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 4th, 2006, 10:54 PM	#3
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	38 lbs right now well I am still trying to dial in this motor. it runs strong but feels like it has a real slight miss while driving but not under hard acceleration. I had the fuel set at 42 lbs, but backed it off to 38 seem to pull a little stronger. I am still also playing with the timing now when i had my 19 lb injectors in i set at 42-44 and it ran great, but these 24 flow to much fuel at that pressure. __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 5th, 2006, 08:19 PM	#5
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	oh, ok . i set it with the vacuum line on and running. set it with no vacuum on ? thanks __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 5th, 2006, 09:44 PM	#6
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	ok adjusted it was like 42 ish when i pulled off vac line..adjusted to 38 and it helped alot ! __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 6th, 2006, 08:59 AM	#9
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	ok thanks 38 lb's set correct now. and runs a lot better __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 4th, 2006, 02:33 AM	#2
dcraig8 Regular Join Date: Jun 2006 Location: san antonio texas Posts: 124 iTrader: 0 reviews	i wouldnt go any higher than 44-45

September 5th, 2006, 04:54 PM	#4
Zak Regular Join Date: May 2006 Posts: 254 iTrader: 0 reviews	38 psi while the vacuum line's disconnected.. if it does have any.

September 6th, 2006, 12:20 AM	#7
Zak Regular Join Date: May 2006 Posts: 254 iTrader: 0 reviews	Thanks to Mr. Jim Roal, you don't know what you're missing if you haven't read his tech articles & Q&As: http://jroal.home.mchsi.com/

September 6th, 2006, 12:24 AM	#8
Zak Regular Join Date: May 2006 Posts: 254 iTrader: 0 reviews	By the way, increasing the pressue of the rails affects the injectors negatively.. as you keep increaing that, your electronic injectors will need more force to lift up it's internal plunger in order to spray the fuel mist.. that would lead to premature failures.

September 8th, 2006, 12:00 AM	#10
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	question timing/fuel pressure ok, i set fuel to 38 lbs like my last post say's...its running better but when i dont have my foot in it and am just trying to cruise.. it feels like it has a small mis...so i have too issue's i checked fuel pressure again. here is whats going on..when i have the vac line on and the car is at idle (800-950 rpm's) it show 30-31lbs wheni rev it it spikes to 35 then drops to 25 and floats betteen 24-26 lbs. does that sound right ? vac line off it set at 38 lbs at idle. , i also have the vac line hooked right behind intake ..is it getting to much vac ? should i move vac line to vac header ?> i am also playing with the timing. another issue there.. when i pull the plug (chip) to set the timing nothing happens. i thought the idle would change...its like the dam thing is not hooked up or something? timimg i know should be 10-14 with chip pulled but i have it like 30-40 because the chip is not doing anything, car run pretty good, just that little bit of mis when i am not puring the gas too it. is there some were i can jumpper that wire the chip goes to to make it work ? thanks __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 8th, 2006, 01:56 AM	#11
Zak Regular Join Date: May 2006 Posts: 254 iTrader: 0 reviews	Nope.. That doesn't sound right, Chad.. why's your idle at 950 rpm to begin with? that, plus saying that the engine misses at idle speed or low speeds.. and your fuel pressure regulator symptom.. they lead to one conclusion to me: vacuum leak!! try tightening all those clamp screw but not too tight or will break that plastic tree.. check the hoses for cracks & listen for hissing noise.. some books say use soapy water but I cant see how! its a vacuum line not a boost line... if you have a cracked intake manifold gasket, carefully spray a can of carb cleaner or CRC around the manifold & see if the engine revs up.. About timing & your spark-out or "spout" connector.. you just CANT have 30-40* of ignition advance at idle - not talking about total timing here.. how did you check for that?!

September 8th, 2006, 03:47 AM	#12
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	with a timing light. it goes to 30 deg. and its a ways above that !. i can turn it back to 10-12 but it does not want to run. and the spout seems to have no effect on it. __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 8th, 2006, 06:53 AM	#13
Zak Regular Join Date: May 2006 Posts: 254 iTrader: 0 reviews	Anybody?

September 8th, 2006, 08:48 AM	#14
Autotech Regular Join Date: Aug 2006 Posts: 79 iTrader: 0 reviews	Are you shuting the engine off...pulling the chip...then starting engine to set the timing??? you can not pull the chip while it is running and get an accurate reading... Other thing it may be ( seen this often) is if your balancer has spun.. I went through 3 myself before I bought a non rubber insert style. __________________ www.freeautomechanic.com

September 8th, 2006, 07:14 PM	#16
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	no i am not pulling chip before i set timing...but in the past when you pull the chip(timing plug) the engine RPM changes (alot) right now no change like it is not hooked up ? i checked the yellow wire going to the chip and not voltage there while car is running. i would think that it should be hot. __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

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September 9th, 2006, 04:01 AM	#17
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	ok its working now ? must have been a loose wire on the EEC here is another question n a fresh rebuilt motor(302 now 306), does it have more compression before or after break in ? I have been playing with my timing and at one point had it way over 14 deg with no pinging, ran great just did not want to cruise very well, so how did I get away with that unless my compression is low do to engine only has like 30 miles on it ?also when i rev ny motor my fuel pressure drops from 31 to 25 ish with vac line on ? does that sound like a cloged pump screen ? and do these car have a fuel filter on them other than that ? __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 9th, 2006, 06:33 AM	#18
Zak Regular Join Date: May 2006 Posts: 254 iTrader: 0 reviews	your compression is optimum soon after the break-in cuz all those microscopic peaks & valleys are ground and the piston rings are well seated you have to inspect your vacuum lines.. troubleshoot with EVTM there are only 2 replaceable fuel filters: one screen mesh at the intank fuel pump suction, and one on the discharge line (the Bosch one which you usually change everything 50,000 miles) - of course, each injector has a built-in mini filter of its own.

September 9th, 2006, 02:28 PM	#19
chadjones99 Regular Join Date: Aug 2006 Location: Tonopah,az Posts: 86 iTrader: 0 reviews	were is the one on the return line ? also on the 2 line were they come up into the engine compartment one is a little small around and the other that looks bigger is in a sleave of some type which on it the return ? because the small one got kinked over when i pulled the motor but it looks ok now __________________ 1986 stang ,Edelbrook intake, aluminum heads, E303 cam ,70 MM throttle body ,24lb injectors ,373 gears , 10:1 pistons set up,no cats , flowmaster mufflers , short shifter , 255 fuel pump , smog pump delete , A/C delete , Aluminum Radiator , MAF convertion

September 10th, 2006, 06:04 PM	#20
Autotech Regular Join Date: Aug 2006 Posts: 79 iTrader: 0 reviews	Yes Zak I ment the balancer came apart at the rubber part...Mostly due to NOS... When this happened I could set the timing at 36 Degrees at idle , cause it was reading wrong due to its new location. There is a fuel filter below the trunk infront of the gas tank. If your fuel pressure is decreasing when you rev it ...I would look at vaccum lines as suggested by Zak __________________ www.freeautomechanic.com

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What Fuel Presure For 24lb Injectors

What Fuel Presure For 24lb Injectors

38 lbs right now

question timing/fuel pressure