SHOForum  


Go Back   SHOForum > Help and Maintenance - Gen 1 (89-91) & Gen 2 (92-95) > Gen 1 & 2 - Engine, Exhaust, Drive Line & AC systems

Reply
 
Thread Tools
  #1  
Old 09-24-2012, 01:59 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default How long should fuel pressure remain in rail after shut down?

Mine drops off almost immediately and if I press the valve at the rail in, the fuel coming out is not under a lot of pressure. Instead of shooting out, it flows out and I hear air bubbles along with it. Pump was replaced last year.

Trying to diagnose an intake backfire. Also when I replaced the fuel filter after 10 minutes of the car being off, there was no no pressure or gas in the line running after the filter at all.

Last edited by jimtash; 09-24-2012 at 02:06 PM.
Reply With Quote
  #2  
Old 09-24-2012, 02:13 PM
kevinspann's Avatar
kevinspann kevinspann is offline
87 Octane
 
Join Date: Sep 2007
Location: Richmond VA
Posts: 2,882
kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!kevinspann is brilliant!
Default

Days/months. Sounds like a bad check valve in the pump...
__________________
15s in 2015
Reply With Quote
  #3  
Old 09-24-2012, 03:28 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

Yeah something is amiss. It does prime but pressure and flow immediately drop off as well if it's not started.

Thanks.
Reply With Quote
  #4  
Old 09-24-2012, 03:56 PM
93markVIII 93markVIII is offline
Registered
 
Join Date: Jan 2011
Location: MO
Posts: 196
93markVIII will become famous soon enough
Default

yes. should hold pressure quite a long time.
bad check valve in the pump is a somewhat common issue.
__________________

1996 Lincoln Mark VIII LSC
195k miles, Cobra wheels and brakes.
1993 Lincoln Mark VIII
204k miles, still on air
1969 Mercury Cougar
Reply With Quote
  #5  
Old 09-24-2012, 04:43 PM
JRA2000TL's Avatar
JRA2000TL JRA2000TL is offline
The Complainer
 
Join Date: Dec 2006
Location: Daphne, AL
Posts: 1,661
JRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud of
Default

Did you put an airtex pump in there?
__________________
Quote:
Originally Posted by SuperHO View Post
Do yourself a favor-ball up your fist, punch yourself in the nuts, and then after you replace your timing chain tensioners, go back to that mechanic and smack him in the face with the used tensioners.

Stop being afraid of screwing something up, roll up your sleeves, grab your nuts and get dirty.
09 Corolla S (blk/blk)
95 SHO MTX (wht/tan)
89 SHO (red/gray) still leaks oil
06 Honda Aquatrax F-12X
90 SHO (slvr/blk) SOLD,crushed
93 SHO ATX (wht/tan) SOLD
Reply With Quote
  #6  
Old 09-24-2012, 04:49 PM
Ishodu's Avatar
Ishodu Ishodu is offline
Moderator
 
Join Date: Jun 2002
Location: Hanover Ontario Canada
Posts: 5,079
Ishodu is a splendid oneIshodu is a splendid oneIshodu is a splendid oneIshodu is a splendid oneIshodu is a splendid oneIshodu is a splendid oneIshodu is a splendid oneIshodu is a splendid one
Default

It won't be causing your issue. Those of us with after market regulators have no pressure after shut down every time.
The only thing you might get from low rail pressure after shutting car off is vapor in there from boiling fuel. This can cause a hard start.
__________________
95 MTX
3.2 High Comp forged pistons and Custom Cams plus more.
312hp 266tq
Drag Vid


Reply With Quote
  #7  
Old 09-24-2012, 08:27 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

Quote:
Originally Posted by JRA2000TL View Post
Did you put an airtex pump in there?
I think it's a Bosch pump. Got it at Rockauto on a closeout deal.

Quote:
Originally Posted by Ishodu View Post
It won't be causing your issue. Those of us with after market regulators have no pressure after shut down every time.
The only thing you might get from low rail pressure after shutting car off is vapor in there from boiling fuel. This can cause a hard start.
Haven't tested the pressure itself but would a low PSI cause a fuel starvation problem?

Have also experienced long cranking hard starts, a gas smell, and a low throttle tip in hesitation under load.

Last edited by jimtash; 09-24-2012 at 08:33 PM.
Reply With Quote
  #8  
Old 09-24-2012, 08:49 PM
SHOtime2511's Avatar
SHOtime2511 SHOtime2511 is offline
CGP
 
Join Date: Oct 2004
Location: Raeford,North Carolina
Posts: 4,967
SHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond reputeSHOtime2511 has a reputation beyond repute
Default

Any codes?
__________________
2009 Cheby Corvette ZR-1
2009 Honda Accord V6 MTX
1990 Ford Taurus SHO turbocharged 3.2L
________________________________________
Brian
Reply With Quote
  #9  
Old 09-24-2012, 10:24 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

This is all related to the intake popping at idle and I'm at my wits end with trying to figure it out. Swapping out between two PCMs, one a LOS and the other an X2J, the LOS shows nothing but the X2J will show a 157. Low throttle tip in hesitation has been present for a while now even before the intake popping noise started. Car seems to idle better with the MAF unplugged but the popping noise is still present.

Every time it pops now, I also get a slight ping or knock. That just started up recently When everything was running correct, the plugs had a nice tan color to them and now they look pure white which is a sure sign of running lean. No vacuum leaks and the only other thing left is fuel. I just know on my V-8 that in order to relieve the fuel pressure, I have to pull the fuse to pump in order to burn it all out of the rail. Pressing the valve down produces such a continuous spray of pressurized fuel that doesn't subside even after sitting for an hour. On the V-6, it'll just flow out like running out of a tap with hardly any pressure behind it.
Reply With Quote
  #10  
Old 09-24-2012, 11:43 PM
93markVIII 93markVIII is offline
Registered
 
Join Date: Jan 2011
Location: MO
Posts: 196
93markVIII will become famous soon enough
Default

so bad pump or clogged in-tank filter.

you need to test fuel pressure with the car running.

if you unplugged the MAF with the car running, that will give you a 157 code.
Reply With Quote
  #11  
Old 09-24-2012, 11:50 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

Code 157 seems to be legit. Verified by disconnecting battery to clear codes, reconnecting and letting the car idle til cooling fan comes on with MAF connected. Then do a KOEO test and it always pops up.
Reply With Quote
  #12  
Old 09-24-2012, 11:57 PM
93markVIII 93markVIII is offline
Registered
 
Join Date: Jan 2011
Location: MO
Posts: 196
93markVIII will become famous soon enough
Default

ok. tried another MAF?

when you reset the computer, does the car run ok and seem to get worse as it warms up? if so, then the maf is screwing with the fuel tables.
either bad maf, or bad wiring?

reset the computer and leave the maf unplugged. then it wont use the maf. see what it does.
Reply With Quote
  #13  
Old 09-25-2012, 12:54 AM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

Still pops with the MAF unplugged but it idles noticeably smoother. Does that with both PCMs even though the LOS doesn't throw a code (which would be a 66) and the X2J does. X2J also runs slightly different than the LOS due to the hotter tune. That's why I'm looking at the pump now. Everything else has been ruled out. MAF wiring is OK and checks out good with a volt meter. The signal to the PCM from it fluctuates even though it's just idling from .05 to .06 volts. The car is down on power as well. Definitely missing its pep.

One other thing is the engine blew out two plugs at the same time yesterday when diagnosing. And by that I mean the insulators spun freely inside the body causing a huge air leakage. Cylinders 1 and 5 to be exact.

Last edited by jimtash; 09-25-2012 at 12:58 AM.
Reply With Quote
  #14  
Old 09-25-2012, 01:14 AM
SHOtimer's Avatar
SHOtimer SHOtimer is offline
#2910
 
Join Date: Sep 2002
Location: Santa Clarita, Ca
Posts: 4,049
SHOtimer is a beacon of lightSHOtimer is a beacon of lightSHOtimer is a beacon of lightSHOtimer is a beacon of lightSHOtimer is a beacon of lightSHOtimer is a beacon of light
Default

What is your fuel psi when the car is running? You get an improvement when you pull the vacuum tube off of the fuel pressure regulator?

Doug
__________________
95 ATX - 261k
95 Lincoln Mark VIII - 144k
90 Dodge Dakota - 102k
99 MBZ 230 Kompressor - 149k
Reply With Quote
  #15  
Old 09-25-2012, 01:56 AM
93markVIII 93markVIII is offline
Registered
 
Join Date: Jan 2011
Location: MO
Posts: 196
93markVIII will become famous soon enough
Default

yeah, back to pump. check that pressure.
Reply With Quote
  #16  
Old 09-25-2012, 12:21 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

Definitely think it's the pump. Went to start car, turned the key on and checked to see if there was fuel in the rail. None. Cycled key on and off 3 times, pump sounds like it's priming but there's no gas in the rail. Did get a faint sound of air coming out of it.
Reply With Quote
  #17  
Old 09-25-2012, 05:57 PM
JRA2000TL's Avatar
JRA2000TL JRA2000TL is offline
The Complainer
 
Join Date: Dec 2006
Location: Daphne, AL
Posts: 1,661
JRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud ofJRA2000TL has much to be proud of
Default

You can't get a break with that car it seems. So, when you replace the pump, are you going to drop the tank or do the access hole modification under the seat? I'm leery to cut into the sheet metal of my car but I hear folks do it all the time. Takes alot less time to replace the pump that way---even watched frosho change his out in the parking lot at the Charlotte convention last year.
Reply With Quote
  #18  
Old 09-25-2012, 10:05 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

Man you ain't kidding. Hopefully this will be it.

I already modded mine last year when I installed the current pump in it. It's harder to pull the seat cushion out than it. No way in hell I'm dropping the tank. It's an easy mod and one that will not harm the structure of the car as far as I'm concerned. If you do yours too, go back and repaint where you cut and use 3M strip caulk this to seal the area.

Last edited by jimtash; 09-25-2012 at 10:10 PM.
Reply With Quote
  #19  
Old 09-29-2012, 02:18 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

Didn't put the pump in yet but the Delphi FEO155 pump at Rockauto is actually the Walbro 526 pump. $40.00 and you can't beat it.
Reply With Quote
  #20  
Old 10-03-2012, 07:40 PM
jimtash's Avatar
jimtash jimtash is offline
Registered
 
Join Date: Dec 2001
Location: nc
Posts: 1,180
jimtash is spectacular!jimtash is spectacular!
Default

OK pump is in. For some reason it wouldn't prime and had a horrible sound to it so back out it came. Put battery voltage to it while submerging it in water and now it works. Sounds normal and functions fine. The old pump BTW was missing the strainer and it was laying at the bottom of the tank. Car runs fine, doesn't miss out the back or backfire into the intake but fuel pressure is still not holding after shutdown.

Edited to add luckily the floor pan mod was done and the pump was easy to get to. Imagine having to go back and drop the tank again. Highly recommend it.

Last edited by jimtash; 10-03-2012 at 07:43 PM.
Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


If you wish to help keep SHOforum running please click the donation button below


All times are GMT -4. The time now is 08:59 PM.

Powered by vBulletin® Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.
Style Provided By: Wrestling Clique - Wrestling Forums

All content Copyright 2000 - 2014, SHOForum.com
This forum is not affiliated with Ford Motor Company