FPR settings

S

Spicoli v3.0

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#1

• Apr 10, 2006

• #1

Just picked up an 88 lx 5.0 and it seems to be running rich, like the exhaust reeks of gas. I have a FPR on it already, mild cams headers etc. nothing crazy, but the fpr is set to about 48, i heard 45 should be better, any input would be great, and try to take it easy on me i'm new and stupid

 

5spd GT

"the 5.0 owns all"

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#2

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• #2

Can you give us your exact mods?

If you still have stock heads and intake...set it back down to 38-40psi with the vacuum line off and plugged with your finger...

Good Luck!

 

S

Spicoli v3.0

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#3

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• #3

mild comp cams, mac headers, stock heads, so i;m pretty stock. How do you adjust a fpr anyhow, never used one before, but i get a terrible gas smell from the exhaust, so i know it's running rich. If you cuold help me to adjust it that would be the best option.

 

vristang

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#4

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• #4

Since you don't mention any other mods, I will assume the car is otherwise stock.

Set the fuel press to stock, 38-40psi. 38 may be better to start with .

If you experience issues then start to bump the pressure up slowly. 1-2psi at a time.

That is way too much pressure for most systems.

jason

 

S

Spicoli v3.0

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#5

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I take it that's the reason for the gas smell? How do you adjust them? i have no clue.

 

5spd GT

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#6

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If it is an adjustable fpr...it should have some sort of stud that you twist or adjusting nut.

Clockwise turns up the fuel pressure and counterclockwise turns down the fuel pressure.

Before adjusting, turn the car on and let it warm up a bit, pull the vaccum line off the FPR and plug it with your finger or tape while turning the "adjuster" to the desired fuel pressure. Plug it back up and your done...and go drive it!

 

S

Spicoli v3.0

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#7

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it is adjustable, it has the little pressure gauge in the engine bay, now to find the actual fpr, and i'll be gold, what does unplugging the fpr vac hose do? is it necessary?

 

5spd GT

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#8

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It isn't necessary, but it is right there by your "adjuster" on the fuel pressure.

I tried it both ways, (vac. line on and off) and got a variance of 1psi. So it really isn't going to hurt anything if you keep it on or off, I just pull mine off and "plug" it to not have a vac. leak...

 

S

Spicoli v3.0

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#9

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ok last post, should it be easy to access? I dont' have a hoist so if i can get at it from the top it makes life easier. Sorry about the "dumb" q's i've owned the car for about 20 hours now so i'm way too excited and trying to figure everything right away. PS You're making my life much easier. thanks

 

J

jt1989

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#10

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I would unplug fpr mine veries quite a bit . The fpr is on your fuel rail on the passager side behind the intake on top of engine. If you don't know where it is how do you know its adjustable?

 

S

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#11

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I was told by the guy i bought it off of, it's adjustable as far as he said, it's got the pressure gauge in the bay and it should be attached to that somewhere right?

would anyone put an aftermarket fpr in that wasn't adjustable?

 

J

jt1989

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#12

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Gauge is most likely in front of engine on passanger side on fuel rail.Follow fuel rail to back of engine right behind intake. Its round with a vaccum hose attached.

 

HISSIN50

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#13

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• #13

If you run without cats, the exhaust can smell a bit rich. Our noses arent air fuel meters anyhow.

Good luck.

 

vristang

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#14

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The regulator is not attached to the psi gauge.

As mentioned above the regulator is to the aft of the throttle body, and should be fairly close to the egr valve.

You MUST disconnect the vac line to the regulator when adjusting the fuel psi. Otherwise the vac signal will be affecting the fuel pressure setting. You don't want this at idle, as the computer needs to have a set reference point for knowing how fuel pressure will change under specific engine conditions.
I take it then that when you read the fuel pressure at 48psi, the vac line was still attached?

jason

 

L

luckythirteen13

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#15

• Apr 10, 2006

• #15

if you smell gas when your just cruzing around town or idling, adjusting the fuel pressure wont do anything at all. if your not at wot, the fuel pressure is irrelivant (within reason). if not at wot (0 vacuum) the ecu will control the afr with injector pulse width. if you turn the fuel pressure down, the ecu will compensate by increasing the pulse width (time the injector sprays fuel).

if you smell fuel at wot, then turn the fpr down. if the smell is coming at idle, you can adjust the fpr down, but dont expect the smell to go away.

 

5spd GT

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#16

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vristang - I'm sure it is still attached because he hasn't found it yet...so he could not have taken it off.

No problem spicoli, Look at your upper intake, it will be on the left of your upper intake (if looking from the front) near the firewall. It will have vac. line coming off of it and the line will go into the back of the intake...

My stock fuel pressure line was red...

 

vristang

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#17

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5spd GT said:

vristang - I'm sure it is still attached because he hasn't found it yet...so he could not have taken it off.
...

Click to expand...

I was just saying that the fpr is not attached to the schader valve (where most in engine bay gauges are mounted). Maybe I shouldn't have assumed that was where his gauge was mounted.

Now that I think about it though the gauge could be plumbed into the afpr (and not the schrader valve) and be mounted anywhere.