TPI Tuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
Sponsored by:
Sponsored by:

Fuel pressure bleeds off

Thread Tools
 
Search this Thread
 
Old May 14, 2012 | 05:23 PM
  #1  
Malderun's Avatar
Thread Starter
Junior Member
 
Joined: Jun 2008
Posts: 14
Likes: 0
From: Syracuse NY
Fuel pressure bleeds off

1991 TA with a 305 tpi this car is unmolested 69k miles driven by a granny in the summers.
I recently had it in my shop car when warm idles like ****. Long story short.
I put new injectors in they were bad 5-6ohms warm 8-14 cold and the iac sensor.
reset the idle and tps car idles mint wont stall out anymore drives great 600 rpm idle

My problem is now the fuel pressure drops off to zero with in 15 sec of shut off. Key on goes to 40 but drops same but pump is on so it makes pressure back up. This leads to hard starts
when cold because the system has no pressure and it should. Once it starts its fine but it
should crank right over. Which it will if its been shut for no more than 5 min.

Theres a smell of gas in rear bad now.. im thinking when i put air to the gas lines when
I installed the injectors to keep it from syphening the tank that i ****ed somthing up.

So im wondering whats back there on these old ****** that i botched

Last edited by Malderun; May 14, 2012 at 05:27 PM. Reason: Smart phones suck typos
Reply
Old May 16, 2012 | 06:54 PM
  #2  
Malderun's Avatar
Thread Starter
Junior Member
 
Joined: Jun 2008
Posts: 14
Likes: 0
From: Syracuse NY
Re: Fuel pressure bleeds off

if anyone cares. I pulled the tank today in about 45 min droped the read end everything pulled the tank and pump.

I did not hurt it by blowing back the return line just simply dumps in tank. it apears that the sock is desintigrating after 21 years and may be the cause of the problem.

Where is the check valve on these pumps? inside the pump or is it suppose to be that 2 way port orange insides that is between the pump and feed line? Cause theres no ball in it little too fancy to jsut be a connector tho.

Anyone have a diagram of these stock pumps? the pump works fine I figure if I can fix it w/o buying a new sending unit whole thing save this women some money.

-Thanks Jeff
Reply
Old May 16, 2012 | 11:51 PM
  #3  
antoine's Avatar
Senior Member
20 Year Member
 
Joined: Mar 2003
Posts: 851
Likes: 3
From: vacaville,ca
Car: 1988 camaro z28,1997 camaro lt1
Engine: 355 afr 195 heads,tpis big mouth
Transmission: 700r-4 built by me 3-4 z pack
Axle/Gears: 3.42
Re: Fuel pressure bleeds off

The one way check valve is in the pump,the only fix is to replace the pump
Reply
Old May 17, 2012 | 07:18 AM
  #4  
DrewsCam's Avatar
Supreme Member
iTrader: (2)
 
Joined: Mar 2002
Posts: 1,029
Likes: 1
From: West Houston, Tx.
Car: 1991 Z28
Engine: 355 TPI
Transmission: 700r4
Axle/Gears: 9 bolt disc / 3:27
Re: Fuel pressure bleeds off

Agreed the original was not designed to be disassembled..
Reply
Old May 18, 2012 | 11:43 AM
  #5  
Russ-So Cal's Avatar
Supreme Member
 
Joined: Dec 1999
Posts: 2,430
Likes: 0
From: Lakewood, ca. USA
Re: Fuel pressure bleeds off

With the tank out, replace the pump whether it is bad or not. It is too much work to remove the tank, not to replace the pump. Since the strainer sock is disintegrating, be sure to replace the external fuel filter as well.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
92camaroJoe
TBI
32
Jul 29, 2023 07:57 PM
R3500
Engine/Drivetrain/Suspension Wanted
1
Aug 17, 2015 12:16 PM
wayshegoes
Tech / General Engine
8
Aug 17, 2015 12:00 PM
92camaroJoe
Tech / General Engine
6
Aug 13, 2015 06:07 AM
Kaweh
TBI
3
Aug 9, 2015 02:54 PM




All times are GMT -5. The time now is 04:33 PM.