Riddle me this GURU's... that means you Dee, Mad, Ryan etc! =)

[MeanGreenS13]

Okay, here's the deal ladies. Buddy mark lent me a SARD Adjustable FPR with gauge for temporary use until I can afford a new one (thank god for good friends) Anyway, we put it on, set fuel pressure to 36psi...

But here is the part that neither he, nor I have EVER seen before. We discovered, that when the fuel pump is on and running, the gauge will read said 36psi, and the car will idle slightly rough (tune is WAY OFF right now but doesnt matter for this issue) around 650rpm.

if you pull the fuel pump fuse OUT of the car, pressure drops to 0 but the car will sit and idle for 10 minutes +... the pump IS not on, you cannot hear it or feel it running in the trunk, wideband stayes PEGGED on 10.0 as it does at all times because of the tune...

Does anyone have any ideas on this? I am baffled by this one... I'm wondering if I may have a pump issue...

this is how my fuel system is run

THANKS GUYS!

[CakeEater]

I've seen this before...there is enough fuel getting into the engine to keep it running even without pressure.

I had this happen to my CA once when the pump died and it just kept on running (idleing). It will die if you give it throttle.

I liked having it powered by my own sense of self satisfaction.

[MeanGreenS13]

yeah, as soon as you give it throttle, it dies... Its farkin weird!!!!! I assume you never tried pulling the pump fuse? if you did, did your idle raise up? or could that just be associated to how rich my car is running right now due to the shady tune thats in there? I'm gonna dump the new tune in tomorrow, i just re registered and insured the car today... IM SUPER EXCITED! I just have never seen this before...

[boost_boy]

It's not a bad thing. It means your FPR is doing it's job and your pump was somewhat doing it's job by getting the fuel supplied to the rail. Since you're not demanding any extra fuel through the injectors, it should idle for a bit. Diagnoses:NORMAL

Dee

[MeanGreenS13]

wow. it just seems like it will run forever, i stood on the phone for 12 minutes while it sat there and idled with the fuse out.

i have honestly never heard of that. good to know its normal or somewhat normal! THANKS DEE!

[ca18detgabby]

isnt that what they call desieling?

[zombieslider]

ya it is

[RS12Turbo]

I have a hidden kill switch that is hooked up to my fuel pump that I turn off when I leave my car parked somewhere....if I shut the switch off while the car is idling, it will idle perfect for about 30 secs before the engine shuts off. I'll have to look at the af gauge and see what it says during this

[MeanGreenS13]

30 seconds is perfectly normal.. that's about the time it takes to get all the fuel out of all of the lines.

also dieseling, is USUALLY just when you turn the key off, the car will continue to run for a few more seconds. That is not what is going on here.

Either way, CakeEater and Dee both said they have seen it before and it can be normal. I'm pretty much guessing that there is a small siphon being created and just enough of a dribble of fuel is getting up to the rail to keep it running at idle. I think the higher idle can be attributed to leaner mixture because there is no system pressure. Tune goes in either tonight or tomorrow, then i'm going to clean my wide band sensor with electric parts cleaner and recalibrate it, and go for a ride.
Modified by MeanGreenS13 at 6:55 AM 10/8/2009

[XTCshri2222]

mine always takes about 10seconds to shut down

[MeanGreenS13]

someone lock this. dee answered my question and everone else is posting nonsense... probably not even reading the OP completely.

[r34 gtr]

That is awesome? Honestly I would be trying everything in my power to keep it from doing that. I don't like the idea of idling an engine for that long. Might just be me, but whatevs.

Side note, you need to update your avatar. Your car is also no longer green, so maybe a username change to "MeanWhiteS13" ??

[MeanGreenS13]

i keep that avatar cause that is the car that started it all for me... and it still exists for me... its in my dads garage in massachusetts... I just dont talk about it cause its brokedided

on a side note... entered the tune into the 240... runs way better... going to change the oil and take her for a spin =)

there is no reason for me to ever let the car idle that long. But when i kill the key on the car, it shuts off, doesnt even hesitate. so i really have no worry about the fuel pump fuse being pulled and it idling for 20 minutes lol

oh yeah and TIM... watch this! http://www.youtube.com/watch?v=4-PGy6FTWPM

[Seishuku]

I would think that it's caused by vacuum drawing the fuel through the injectors

[MeanGreenS13]

pretty much what i was assuming at first. just enough of a tiny siphon created to put just enough fuel in to keep the car running.

bigger fish to fry now, LOCK THIS UP! go migrate to my new thread =)

[float_6969]

Just one quick thing. If you set the fuel pressure to 36psi @ idle, you did it wrong. Read my FPR post in the stickies again.