Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Sponsored by:
Sponsored by: CARiD

Fuel Pump

Old Jul 3, 2013 | 02:41 PM
  #1  
1987--GTA-'s Avatar
Thread Starter
Junior Member
10 Year Member
 
Joined: Jun 2013
Posts: 10
Likes: 0
Fuel Pump

I suspect my fuel pump is going out on the 87 GTA 355 TPI - as after sitting it cranks excessively before it will start, if i turn the key on and let it sit awhile, it will start,, i did not have a pressure gauge but am picking one up tonight--
anyone have a procedure to replace the pump?
tell me the rear end really does not have to be dropped out?
any suggestions for a new pump? just the O'reilly or NAPA ok?
Reply
Old Jul 3, 2013 | 08:17 PM
  #2  
vetteoz's Avatar
Supreme Member
20 Year Member
iTrader: (13)
 
Joined: Apr 2005
Posts: 7,736
Likes: 14
From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: Fuel Pump

Originally Posted by 1987--GTA-
cranks excessively before it will start,?
Very common problem with age
Other things to consider 1st with extended crank start; most of which require a gauge to check

Fuel pump may not be running to prime the rail when key 1st turned on ( bad relay / wiring )
Faulty check valve may allow the prime pressure to bleed off before cranking
Faulty reg may allow prime pressure to bleed off to bleed off before cranking.
Lots to check before dropping the tank

Also if the engine runs fine after starting highly unlikely the pump is at fault
Reply
Old Jul 3, 2013 | 08:27 PM
  #3  
vetteoz's Avatar
Supreme Member
20 Year Member
iTrader: (13)
 
Joined: Apr 2005
Posts: 7,736
Likes: 14
From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: Fuel Pump

Need to understand how things are supposed to work.

When you turn the key on ,the pump relay runs the pump for 2 sec to build pressure ( prime ) in the fuel rails .
This pressure is supposed to hold.
Then when you start cranking , that retained pressure is supposed to supply the injectors which results is a "instant" fire up
When cranking as soon as oil pressure is over 4 psi , a pressure switch then runs the pump in parallel with the relay .
This serves as a backup pump supply should the relay fail ;giving engine start with extended cranking ; which is what you are describing .

If you loose the prime pressure or are waiting for the OP switch to run the pump then you will have long cranking until fuel pressure is available again
Reply
Old Jul 5, 2013 | 08:20 AM
  #4  
1987--GTA-'s Avatar
Thread Starter
Junior Member
10 Year Member
 
Joined: Jun 2013
Posts: 10
Likes: 0
Re: Fuel Pump

isn;t the check valve on this car in the tank with the pump?
also i was told there was no relay like this on this year car, i have a 1992 chev 1500 pick up where the relay was replaced due to long cranking which solved the problem, but again i was told the 1987 system was diffrent from this
Reply
Old Jul 8, 2013 | 11:48 AM
  #5  
1987--GTA-'s Avatar
Thread Starter
Junior Member
10 Year Member
 
Joined: Jun 2013
Posts: 10
Likes: 0
Re: Fuel Pump

i put a fuel pressure gauge on the GTA:

1. turned key went up to 30 psi right away

2. would not start though, after about 1/2 hr had dropped to about 25

3. let sit about 20 min with key on, started right up but stalled !! (never did that before) got running but ran rough, gauge was now at 45-50 psi while running, sort of was missing and gauge would drop off a few lbs while it did that

4. just recently installed one of those air foil pieces- could i have done something wrong with that to cause the miss?
Reply
Old Jul 8, 2013 | 07:35 PM
  #6  
mcrandrz's Avatar
Member
10 Year Member
 
Joined: Feb 2013
Posts: 226
Likes: 1
Car: 1991 camaro rs
Engine: 3.1 - looking to upgrade to 3400 hy
Transmission: 700r4
Axle/Gears: Stock? Lol
Originally Posted by 1987--GTA-
i put a fuel pressure gauge on the GTA:

1. turned key went up to 30 psi right away

2. would not start though, after about 1/2 hr had dropped to about 25

3. let sit about 20 min with key on, started right up but stalled !! (never did that before) got running but ran rough, gauge was now at 45-50 psi while running, sort of was missing and gauge would drop off a few lbs while it did that

4. just recently installed one of those air foil pieces- could i have done something wrong with that to cause the miss?
Pull the vacuum off the fuel pressure regulator when you start it. any spike in pressure? And any fuel coming out of the fpr its self


Posted from Thirdgen.org App for Android
Reply
Old Jul 9, 2013 | 11:25 AM
  #7  
tomsaddy's Avatar
Member
20 Year Member
iTrader: (4)
 
Joined: Apr 2002
Posts: 117
Likes: 54
From: Savannah, GA
Car: 1987 GTA
Engine: TT LC9
Transmission: T56
Axle/Gears: 3.50
Re: Fuel Pump

Are you sure the MAF sensor was reinstalled correctly after the airfoil was installed? A disconnected or backwards MAF sensor will cause it to run pretty bad, although I'm not sure if it would cause your starting problem.
Reply
Old Jul 9, 2013 | 11:34 AM
  #8  
1987--GTA-'s Avatar
Thread Starter
Junior Member
10 Year Member
 
Joined: Jun 2013
Posts: 10
Likes: 0
Re: Fuel Pump

i don;t think we disconnected the MAF when we did the conversion, just took off the bellows, but i will check, i had the hard starting for a couple years now, the the rough running is new and the stall, since we did the air foil, i am going to replace the gasket under the TPI embossed plate to be sure the gasket didn;t get in there funny or cracked.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Glowsock
Tech / General Engine
13
Jul 24, 2025 03:15 PM
92camaroJoe
TBI
32
Jul 29, 2023 07:57 PM
RazorN8
Tech / General Engine
4
Jan 7, 2022 11:44 AM
beachrodder
Tech / General Engine
7
Aug 25, 2015 08:05 AM
92camaroJoe
Tech / General Engine
6
Aug 13, 2015 06:07 AM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 03:40 PM.