How to check fuel pressure - B15sentra.net - Nissan Sentra Forum
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#1 Old 09-28-2010, 03:01 PM
Jugo Driver#1
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How to check fuel pressure

Hey everybody, does anyone know how to check fuel pressure on a 2002 spec v? I noticed there is no schrader valve, which fuel pressure gauge do you use that can mate to our fuel line? Thanks in advance!

02 Molten Silver Spec V
15.2xx@90.xx
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#2 Old 09-28-2010, 03:41 PM
timeattack85
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You'll most likely have to disconnect the fuel line from the rail and install a T-fitting to get a reading. I'm sorry, but I do not know what the O.E. specs are for the fuel pressure.
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#3 Old 09-28-2010, 05:05 PM
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^^^
What he said. Though I recall it being 50-51 PSI ?
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#4 Old 09-28-2010, 08:44 PM
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May I ask why you are checking fuel pressure?
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#5 Old 09-28-2010, 09:06 PM
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fuel pump may be going out, lean condition...many reasons to check it. iirc 52# is stock.

if its jammed-force it, if it breaksin the process- it needed to be fixed anyway
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#6 Old 09-29-2010, 06:29 AM
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Thanks for the input guys. Yea i think my pump may be on its way out and i just want to verify before i spend 270 bucks on a pump. I have a miss under heavy loads thats reproducable if I up shift early and am at 1000 rpm in any gear at WOT. Also only while in second do i notice the car hickup at around 5300 rpm for a split second.

I would like to know which fuel pressure gauge is compatible with our fuel line, I have not seen any that mention being for a Nissan application so I want to avoid buying the wrong gauge and having to return it. Any help is much appreciated thanks!

P.S. BTW the car and pump have 132,800 miles on them so that is why i suspect the pump.

02 Molten Silver Spec V
15.2xx@90.xx

Last edited by Jugo Driver#1; 09-29-2010 at 06:29 AM. Reason: additional comment
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#7 Old 09-29-2010, 08:08 AM
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As for the gauge, you should be able to use any fuel pressure gauge with a T-fitting. Also, even if a pump is getting weak it is better to do a fuel flow test by seeing how much fuel the system puts out per liter. If you check the fuel pressure, perform three tests. One with the key on and engine off, one while it's running, and one after the ignition is shut off and allow it to drop pressure for one minute. Match to O.E. Specs and let me know which one fails and maybe we can find the culprit.
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#8 Old 09-29-2010, 01:45 PM
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there is no reason to pay that much for a pump. a walbro 190 is about 100 bux and requires maybe 45 min to uninstall, trim the canister and reinstall.

if its jammed-force it, if it breaksin the process- it needed to be fixed anyway
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#9 Old 09-29-2010, 02:08 PM
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Quote:
Originally Posted by superspec View Post
there is no reason to pay that much for a pump. a walbro 190 is about 100 bux and requires maybe 45 min to uninstall, trim the canister and reinstall.
I happened to get my 255 used for $80 which I considered a pretty good deal. As I understand it, the thing is WAY overkill, but 30K miles, so far so good. As for the trim, I think you mean the pump itself. The only canister mod I recall doing was ditching that black rubber gromet/spacer thing.
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#10 Old 09-29-2010, 02:12 PM
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Quote:
Originally Posted by MarcAtArkon View Post
I happened to get my 255 used for $80 which I considered a pretty good deal. As I understand it, the thing is WAY overkill, but 30K miles, so far so good. As for the trim, I think you mean the pump itself. The only canister mod I recall doing was ditching that black rubber gromet/spacer thing.


the reason i suggest the 190 is because it doesnt need a return line. the 255 "should" have a return line. its been so long since ive done the pump that i cant remember if i trimmed the pump or the canister.

if its jammed-force it, if it breaksin the process- it needed to be fixed anyway
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#11 Old 09-29-2010, 02:29 PM
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No return line on my 255, lol. I was under the impression that the tank had a regulator, and the return line was only for adding a FPR (considered buying a Nismo) to the engine bay. There are spaces in the guides under the car for them, just never got around to it. 100% sure it was the fuel pump that required the modification. The end with a white plastic cap (top IIRC) has ridges like castle parapets that make it too tall. A few minutes with a dremmel and they're gone.
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#12 Old 09-29-2010, 02:37 PM
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thats it, the little things sticking up had to be taken off.

if its jammed-force it, if it breaksin the process- it needed to be fixed anyway
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#13 Old 09-29-2010, 11:19 PM
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Ok here are the test results

Key on engine off approx 20psi while priming once priming is done it drops like a rock to 0 in about 5 seconds

If I keep the key on without stepping on the clutch (pump runs continuously) i get 52 psi in about a second and it stays there until i stop priming and then it drops to zero once i stop priming also in about 5 seconds.

Engine running it stays at 52 psi at idle i couldnt rev it too much but if i blipped the throttle the pressure would drop to about 51psi.

02 Molten Silver Spec V
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#14 Old 09-30-2010, 04:24 AM
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sounds right to me

if its jammed-force it, if it breaksin the process- it needed to be fixed anyway
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#15 Old 09-30-2010, 06:52 AM
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Ok, so our cars are not supposed to hold any pressure in the fuel system after the car is shut off?

02 Molten Silver Spec V
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