|
Post by smoren1 on Aug 24, 2014 9:39:48 GMT -6
My fuel pump relay has no power to its coil when cold starting. I spray a shot of starting ether into the air intake and it starts right up and runs perfectly after it starts. Where does the relay's coil get its power from? Help! PS. I ain't no newbe. I have kept this car going strong for five years.
|
|
tigger
Administrator
Posts: 2,844
Staff Member
|
Post by tigger on Aug 24, 2014 17:11:20 GMT -6
What year? I might be able to pull up a wiring diagram.
|
|
Randy T.
Administrator
☯ AURORA GXP ☯
Posts: 3,758
Staff Member
|
Post by Randy T. on Aug 25, 2014 6:27:45 GMT -6
Check your power from the ignition switch.
|
|
|
Post by smoren1 on Aug 25, 2014 9:28:16 GMT -6
It is a 1997 4.0. Wouldn't the fuel pump not come on ever if it was a faulty wire or ignition switch failure? It runs perfectly well after the initial start. There has got to be a pressure sensor in between the ignition and the pump as the pump is suppose to cycle for a few seconds then shut off when the fuel pressure is right for a start. Am I wrong on this?
|
|
|
Post by sall on Aug 25, 2014 12:25:03 GMT -6
Pump should prime in the run/on position. I don't have a wre diagram handy but will look later this evening if someone else doesn't post one.
|
|
|
Post by smoren1 on Aug 25, 2014 13:39:34 GMT -6
That's what I thought. Meanwhile I will wait for an answer. There has to be a switch other than the ignition that controls the fuel pump relay.
|
|
|
Post by smoren1 on Aug 25, 2014 23:05:44 GMT -6
I jumped the fuel pump relay and it started up normally. WTF! Something is in the way. Help!!!!
|
|
Randy T.
Administrator
☯ AURORA GXP ☯
Posts: 3,758
Staff Member
|
Post by Randy T. on Aug 26, 2014 6:09:56 GMT -6
It is a 1997 4.0. Wouldn't the fuel pump not come on ever if it was a faulty wire or ignition switch failure? It runs perfectly well after the initial start. There has got to be a pressure sensor in between the ignition and the pump as the pump is suppose to cycle for a few seconds then shut off when the fuel pressure is right for a start. Am I wrong on this? Yeah, I that read wrong, sometimes your brain only hears what it wants or knows, in writing and speaking. lol
|
|
|
Post by smoren1 on Aug 26, 2014 9:52:29 GMT -6
Well I never got an answer. I must have stumped everybody, ha ha! I guess I am asking the wrong people.
|
|
Randy T.
Administrator
☯ AURORA GXP ☯
Posts: 3,758
Staff Member
|
Post by Randy T. on Aug 27, 2014 6:23:52 GMT -6
Sometimes you have to be patient, people do not sit at the computer waiting to answer questions. I vote you should move along and find some better people to ask. We aint don't no nuttin roun here.
|
|
RCA1186
Administrator
Rob
Go Pack Go!
Posts: 4,837
Staff Member
|
Post by RCA1186 on Aug 27, 2014 11:34:34 GMT -6
Unfortunately there aren't nearly as many members of this forum as some of the other forums for what you would call more "popular" and "abundant" cars and thus it is going to take a bit for someone to answer your question. But also, not everyone on here knows everything there is to know. Heck, most of us ended up on here looking for an answer to a question of our own. Nobody knows everything there is to know about these cars. I know A LOT but I'm not sure on this one. So I keep silent and wait for someone more educated on the subject to give an answer. Just have to be patient
|
|
|
Post by sempar on Aug 27, 2014 17:41:39 GMT -6
I know that many GM cars used an oil pressure sensor inline with the pump relay in the 80's and 90's cars. If the sensor was bad, hard starting was the result. Unfortunately, I don't have a wiring diagram for your year. I can say that the 2001-03 cars didn't use this sensor, the pump was controlled directly bu the ECU. You could try swaping a known good relay from some other position on the fuse box. Personally I would suspect a poor connection at the fuel pump relay, or possibly a defective relay going by the symptoms you mentioned. Sorry I can't be of further help.
John
|
|
|
Post by smoren1 on Aug 27, 2014 18:32:12 GMT -6
Thank everyone! I will try it.
|
|
randnon
Aurora Passenger
Posts: 246
|
Post by randnon on Aug 27, 2014 19:20:07 GMT -6
I remember reading that their is a dual path for the fuel pump . Voltage can be supplied by the oil pressure sending unit or the PCM ignition relay. I think once it is cranked and runs for a few seconds on the starting fluid the pump kicks in on the secondary feed. You should be able to hear if the pump primes the engine on the primary circuit by turning the key only to the run position. The pump should run for 3 to 5 seconds and then turn off as the pressure reaches the proper limit. The relay itself is the likely failure. Good luck RICH
|
|
randnon
Aurora Passenger
Posts: 246
|
Post by randnon on Aug 27, 2014 19:31:19 GMT -6
After rereading the post ,I have another possibility. Your pump ect. may be OK and you are experiancing fuel pressure bleed down after a cool down. A leaky fuel injector or check valve on the pump allowing the pressure to drop way off over time. See if the pump comes on when turning the key just to the run position and If so, it is time to put a pressure meter on the fuel rail and observe what happens over night. RICH
|
|