Pontiac When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made.

Fuel Pump Circuit Problem

Thread Tools
 
Search this Thread
 
Old 01-20-2020, 09:25 PM
  #1  
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Old DD's Avatar
 
Join Date: Jan 2020
Location: SoCal mountains
Posts: 16
Received 0 Likes on 0 Posts
Old DD is on a distinguished road
Question Fuel Pump Circuit Problem

95 Pont, GA, (3100 '96)
Major tranny work done.

Can't get power to the fuel pump past the relay, save a quick flash of the test light when key is turned to start.

Fuse(new)20amp, relay Napa(new).

Relay plug checked for power, have power to 30 and 86 (steady light) , 85 ground(good) reversed test light poles, outgoing side (pierced wire insulation) 87 pump(nothing), 87a primer(flash),same flash I get under the rear sear connection. No pump spin.

Engine wants to fire up with starting fluid.


Old 01-20-2020, 09:27 PM
  #2  
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Old DD's Avatar
 
Join Date: Jan 2020
Location: SoCal mountains
Posts: 16
Received 0 Likes on 0 Posts
Old DD is on a distinguished road
Default

Tested new relay, all in spec.
Old 01-20-2020, 10:07 PM
  #3  
Senior Member


True Car Nut
 
CathedralCub's Avatar
 
Join Date: Feb 2015
Location: Earth
Posts: 5,582
Received 876 Likes on 805 Posts
CathedralCub is a splendid one to beholdCathedralCub is a splendid one to beholdCathedralCub is a splendid one to beholdCathedralCub is a splendid one to beholdCathedralCub is a splendid one to beholdCathedralCub is a splendid one to beholdCathedralCub is a splendid one to behold
Default

Originally Posted by Old DD
Major tranny work done.
Did the car start before the major transmission work was done?

Originally Posted by Old DD
Can't get power to the fuel pump past the relay, save a quick flash of the test light when key is turned to start.
How long of a quick flash?
Old 01-20-2020, 11:36 PM
  #4  
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Old DD's Avatar
 
Join Date: Jan 2020
Location: SoCal mountains
Posts: 16
Received 0 Likes on 0 Posts
Old DD is on a distinguished road
Default

Originally Posted by CathedralCub
Did the car start before the major transmission work was done?



How long of a quick flash?
Yes, the car ran before the tranny was replaced, it has a '94 4T60E updated with '95 final drive fine pitch gears.
It has 20,000 miles since a valve grind head job. Always starts ! unless it has no fuel.

Half second, tops..Test light lights bright though.

Cheapie RockAuto ignition switch installed 4 years ago.

Strange it has power on the low and high side and a good ground, but.....


Old 01-20-2020, 11:38 PM
  #5  
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Old DD's Avatar
 
Join Date: Jan 2020
Location: SoCal mountains
Posts: 16
Received 0 Likes on 0 Posts
Old DD is on a distinguished road
Default

Fuel pump is 2 years old. Not that it makes much difference, problem is in front of the pump.
Old 01-20-2020, 11:47 PM
  #6  
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Old DD's Avatar
 
Join Date: Jan 2020
Location: SoCal mountains
Posts: 16
Received 0 Likes on 0 Posts
Old DD is on a distinguished road
Default

Fuel pump switch/oil pressure sensor, is on the circuit and should be suspect since it has not been eliminated.
Old 01-21-2020, 08:44 AM
  #7  
Retired



Certified Car Nut
 
Mike's Avatar
 
Join Date: Jul 2003
Location: Dark Side, AZ
Posts: 17,921
Received 1,781 Likes on 1,305 Posts
Mike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond repute
Default

If your relay is turning on, then the OP is sending the signal.

Smack the bottom of the tank where the sending unit is located while someone is attempting to start the engine.

BTW, you can have good continuity in a circuit, but the circuit could not be capable of carrying a high amp load such as a fuel pump.
__________________
Retired Administrator
2002 *-10 5.7 V8
2023 Jeep Rubicon Diesel

Old 01-21-2020, 09:02 AM
  #8  
Senior Member


True Car Nut
 
carfixer007's Avatar
 
Join Date: Dec 2018
Location: Flint, MI USA
Posts: 2,790
Received 1,127 Likes on 995 Posts
carfixer007 is on a distinguished road
Default

Do a isolated test of the pump.
Old 01-21-2020, 09:49 AM
  #9  
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Old DD's Avatar
 
Join Date: Jan 2020
Location: SoCal mountains
Posts: 16
Received 0 Likes on 0 Posts
Old DD is on a distinguished road
Default

Direct power to the pump via jumpers after work. That should get her to fire up if the pump is ok.

Had this car for 10 years now, lost the first motor to the intake gasket meltdown.
Got this used motor did the intake manifold gasket and had a valve grind done at the same time.
Rebuilt my 3VZE too, nothing EZ about that motor. If you thought the 3100 was a PITA try that Toy engine.
I can spin a wrench
Old 01-21-2020, 01:42 PM
  #10  
Senior Member


True Car Nut
 
carfixer007's Avatar
 
Join Date: Dec 2018
Location: Flint, MI USA
Posts: 2,790
Received 1,127 Likes on 995 Posts
carfixer007 is on a distinguished road
Default

I have the service literature for your Pontiac if you need anything.


Quick Reply: Fuel Pump Circuit Problem



All times are GMT -4. The time now is 01:04 PM.