No power to grey wire at Fuel pump relay

No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » February 21st 2017, 8:18pm

Ok... Ive jumped the hot from the blower motor to the grey wire in the fyel pump relay and it starts but will not drive properly under load. Without the jumper, the engine will not start. I thought originaly it was a fuel pump but the pump works after testing. All fuses are good. Im lost, you guys......... Please help im stuck in the rain. Im a surfer whom lives in his van.
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

  • Similar topics
    Replies
    Views
    Author
  • power window failure NOT the switch nor relay.
    by AstroNuts » October 22nd 2016, 8:21pm in Electrical
    13 Replies
    443 Views
    Last post by sixsix View the latest post
    October 29th 2016, 12:01am
  • Fuel pump
    by DRZ » October 22nd 2016, 2:29am in Electrical
    10 Replies
    425 Views
    Last post by DRZ View the latest post
    November 16th 2016, 7:12pm
  •  
    7
    80
    Last post by AstroSafari.com View the latest post
    March 28th 2017, 5:20am

Re: No power to grey wire at Fuel pump relay

Postby Lumpy » February 21st 2017, 9:25pm

What's the history of your -

- Fuel Filter?
- Fuel Pump?

If I understand correctly, you power up the FP relay on the firewall and the van starts but does not continue to run. Is that correct? And therefore is it also correct that you're not getting power to the FP relay via it's normal route?

Please verify what style intake you have - TBI or other? To know what your fuel pressure should be.

And where are you surfing? SoCal, my old breaks?


Lump
Image
User avatar
Lumpy
250k+ Miles
250k+ Miles
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: Lumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full years
Posts: 11000
Topics: 261
Joined: April 2010
Location: Phoenix AZ USA
Gender: Male
Year: 1989
Van Make/Model: Chevrolet Astro
Extra Info: 11 in. lift Camo

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » February 21st 2017, 9:49pm

Lump, i feel i may have met you in Topanga?... I live 4hrs north of san fran and surf mostly the humboldt coast. Its a 94 and T.B.I. The van suddenly died two weeks ago and i assumed that the fuel pump was not working and cut a hole in the floor and replaced it. Nothing. I had already replaced the relays but checked the orange wires at the fuel pump relay and they have power. The grey wire, powering the fuel pump, does not have power so i ran power from the bkower motor over to it and the van started running. Confused, i check the green/white (pcm wire) and get no two second pulsetio close the relay. I chased the continuity back to the pcm and its all good. Ive also jumped the oil pressure switch orange to grey to rule it out and nothing changes.
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » February 21st 2017, 9:53pm

Also....the van runs as long as the power is fed to the grey wire on the FP relay but does not stay running once i shift into drive or reverse ect.
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby AstroWill » February 21st 2017, 10:49pm

I would focus on 1 problem at a time. Lets get the fuel pump circuit working first. You will want to look at the orange wire at the fuel pump relay. It should have power all of the time(if I'm looking at a similar diagram, if not all of the time, it should definitely be switched on with the ignition).

Also, check at your oil pressure sender, the orange wire there should also have power.

The dark green and white wire should have power when cranking, that is the signal from the PCM.


If anyone has a factory diagram for the 94 oil pressure switch/fuel pump relay/pcm please post.
User avatar
AstroWill
Team Leader
Team Leader
Firing on 8 Cylinders (L5)
Firing on 8 Cylinders (L5)
Years of Membership: AstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full years
Posts: 4974
Topics: 60
Images: 87
Joined: February 2009
Location: Between Chair & Keyboard
Alias (AKA): Richard C., Advocatus Diaboli
Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: 90TigerGTv8 03AWD

Re: No power to grey wire at Fuel pump relay

Postby Lumpy » February 21st 2017, 11:19pm

If you'd met me in Topanga it would have been in the 60s or 70s. Zuma to K181, mostly S. Orange Co, Trestles, Salt Creek. Not the gang warfare (even back then) of Huntington, Newport, Laguna.


Here's our schematic -

Image

How about fuel filter? That replaced with the pump earlier?

Can you safely disconnect the fuel line from the filter and measure the output with FP activated? Let gas run into something that will measure. I'm trying to find the numbers now in my notes - You let it run for XX seconds and should have YY oz or cups or something of fuel. It's ghetto (Desert, Redneck, Hillbilly, Martian - Pick your coloquilis) fuel pressure measurement when you don't have a gauge and adaptors.

Anyone else have that formula handy? It's in my Haynes and Chiltons that I can't get to right now.

Other than what you're looking at, everything else obvious in place? Air cleaner goobered up? getting spark for sure? Take air cleaner off and watch injectors while you move the linkage...See both fuel streams?

I suggest keeping an open mind about the fuel flowing vs the apparent relay thing. They may or may not be related.

I also suggest revisiting any new work. Esp since you have an access, verify the electrical and fuel connections at the top of the tank.

Assume Stupid. ie, it's likely to be the stupidist thing like a connector loose or pinched hose or clogged filter, rather than a Sheldon valve lubricator nozzle eeprom failure.


Lump
Image
User avatar
Lumpy
250k+ Miles
250k+ Miles
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: Lumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full yearsLumpy has been a member for 6 full years
Posts: 11000
Topics: 261
Joined: April 2010
Location: Phoenix AZ USA
Gender: Male
Year: 1989
Van Make/Model: Chevrolet Astro
Extra Info: 11 in. lift Camo

Re: No power to grey wire at Fuel pump relay

Postby AstroWill » February 21st 2017, 11:24pm

Thanks Lump, I was looking at a similar diagram, just wasn't 100% positive it was the same on the 94. 1/2 pint in 15seconds is what Chilton's says.
User avatar
AstroWill
Team Leader
Team Leader
Firing on 8 Cylinders (L5)
Firing on 8 Cylinders (L5)
Years of Membership: AstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full years
Posts: 4974
Topics: 60
Images: 87
Joined: February 2009
Location: Between Chair & Keyboard
Alias (AKA): Richard C., Advocatus Diaboli
Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: 90TigerGTv8 03AWD

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » March 18th 2017, 2:24am

Thanks everyone who chimed in. Ok, so i do have power to the orange wire. I DO NOT get power to the green/white wire for the 2-sec. I have run a lead from the battery to the grey and it will run and drive. I was stuck in a very undesirable spot so i installed a toggle switch to turn on the fuel pump to get out. Napa only had the pump but not the sending unit so i only replaced the pump. Could the sending unit itself have anything to do with this? Like maybe the connectors? The gas gauge also is not working now so maybe? Idk. Thanks for everyones patience.
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby RECox286 » March 18th 2017, 4:43am

Swap the relays at the upper right hand (pax) side of the truck. They are both the same part number.

If the problem goes away, then the fuel pump relay went bad, and you need a new one. IF the problem

persists, then have another person work the key... There should be power from the battery all the times at

one terminal,there should be one terminal that is powered for 2 to 5 seconds (prime mode). If you don't get

voltage during prime mode, there is a problem with the wire from the pcm to the relay. After the

engine starts, the oil pressure sender keeps the fuel pump powered, until oil pressure drops below 5 psi.

Uncle Bob
Start a fire for a man and he will be warm for a day.
Set a man on fire and he will be warm the rest of his life.

Sent using two Progresso soup cans and a string
User avatar
RECox286
U.S. Armed Forces
U.S. Armed Forces
Firing on 8 Cylinders (L5)
Firing on 8 Cylinders (L5)
Years of Membership: RECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full years
Posts: 4930
Topics: 38
Images: 0
Joined: July 2010
Location: South Jersey
Gender: Male
Alias (AKA): Uncle Bob
Year: 1993
Van Make/Model: Chevrolet Astro
Extra Info: RWD V6 [325K mi]

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » March 18th 2017, 6:01am

I did swap the relays to no avail. I am missing the 2 second prime power from PCM. If the oil pressure switch is bad, will it stop the 2 second power from the PCM?
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby chevymaherchevymaher is online! » March 18th 2017, 12:50pm

Johnnybluesky wrote:I did swap the relays to no avail. I am missing the 2 second prime power from PCM. If the oil pressure switch is bad, will it stop the 2 second power from the PCM?

No it wouldn't.
User avatar
chevymaherchevymaher is online!
Team Leader
Team Leader
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: chevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full years
Posts: 13123
Topics: 82
Images: 94
Joined: November 2010
Gender: Male
Alias (AKA): chevymaher
Year: 1994
Van Make/Model: GMC Safari
Extra Info: SLE RWD Mercruiser

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » March 19th 2017, 7:13pm

Ok. Another dumb question. If i replaced the pumo only and not the entire sending unit as well, could that have anything to do with this?
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby RECox286 » March 19th 2017, 11:24pm

The fan circuit may not be the best 12v source. I always jump the test connector straight from the battery.

(?) eh (?). IF you aren't getting prime mode voltage, it would seem to me to be a wire, a connector, or a

pcm problem, any of which would give you no voltage on the green/white wire.

Uncle Bob
Start a fire for a man and he will be warm for a day.
Set a man on fire and he will be warm the rest of his life.

Sent using two Progresso soup cans and a string
User avatar
RECox286
U.S. Armed Forces
U.S. Armed Forces
Firing on 8 Cylinders (L5)
Firing on 8 Cylinders (L5)
Years of Membership: RECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full years
Posts: 4930
Topics: 38
Images: 0
Joined: July 2010
Location: South Jersey
Gender: Male
Alias (AKA): Uncle Bob
Year: 1993
Van Make/Model: Chevrolet Astro
Extra Info: RWD V6 [325K mi]

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » March 20th 2017, 11:53pm

Thanks bob. Ya, i have a jumper running from the battery with a fuse and a toggle switch in between amd it will drive that way. Since i only replaced the pump and not the sending unit, could the sending have anything to do with this or is it stricly for the gage?
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby AstroWill » March 21st 2017, 1:59am

Johnnybluesky wrote:I DO NOT get power to the green/white wire for the 2-sec.

Do you get power there while cranking?
User avatar
AstroWill
Team Leader
Team Leader
Firing on 8 Cylinders (L5)
Firing on 8 Cylinders (L5)
Years of Membership: AstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full years
Posts: 4974
Topics: 60
Images: 87
Joined: February 2009
Location: Between Chair & Keyboard
Alias (AKA): Richard C., Advocatus Diaboli
Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: 90TigerGTv8 03AWD

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » March 21st 2017, 3:09am

Nope. I have yet to see the power for the 2 sec on the green/w while cranking. The reason i want to know about the sendinf unit is i noticed the gas gage does not work even though the pump was replaced but did not replace the sender. I get that a bad sender would stop the gage but could it ALSO stop the priming? Thanks for everyones patience, im ready to park this thing in the ocean, grrrrrr...
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby AstroWill » March 21st 2017, 3:16am

The fuel sending unit and pump have no effect on that wire or that part of the circuit at all.

The PCM should be applying power to the grn/white the entire time it's cranking. If not, there is a fault there, either in the wiring/connector/pcm/or testing methods.

Regardless of that, once you get oil pressure, that will cause the grey wire to be energized through the oil pressure switch. If that isn't happening there is a fault there as well. Either the switch/connector/wiring/or testing methods :)
User avatar
AstroWill
Team Leader
Team Leader
Firing on 8 Cylinders (L5)
Firing on 8 Cylinders (L5)
Years of Membership: AstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full years
Posts: 4974
Topics: 60
Images: 87
Joined: February 2009
Location: Between Chair & Keyboard
Alias (AKA): Richard C., Advocatus Diaboli
Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: 90TigerGTv8 03AWD

Re: No power to grey wire at Fuel pump relay

Postby Johnnybluesky [OP] » March 21st 2017, 3:33am

I replaced the oil pressure switch since it was easy amd cheapish.
Im thinking about taking it to an auto electrician but thats $95/hr. Waste of time and money?
I even opened the pcm to inspect for burnt or strangeness but nothing. Connectors look clean.
Original Poster [OP]
Johnnybluesky
Fueling (Empty tank)
Fueling (Empty tank)
Posts: 11
Topics: 1
Joined: February 2017
Gender: Male
Year: 1994
Van Make/Model: Chevrolet Astro
Extra Info: Awd 4.3l

Re: No power to grey wire at Fuel pump relay

Postby Mmusicman » March 21st 2017, 3:39am

A better "temporary" solution: you could just run an "ignition" source of power to the fuel pump from a switched source. This is actually how I've wired my 92 (with V8) permanently (same pump) now that I no longer have a controller. Works fine.. and no toggle switch to forget to turn on or off. Key on... pump on... simple! :mrgreen: (make sure ign source sends power while cranking)

BTW... have you looked at the ground connections?
Probably not the problem since you can give it 12v and it works... but could still be related to the fuel gauge sender?
Image
2000 Chevy Astro LS AWD | 31" LT265/70R17 Tires | 8" LIFT | 10" TOTAL
92 Chevy Astro Shorty | V8-350
http://www.CruisinSouthFlorida.com
User avatar
Mmusicman
V8 Swap Achievement
V8 Swap Achievement
Firing on 6 Cylinders (L2)
Firing on 6 Cylinders (L2)
Years of Membership: Mmusicman has been a member for 3 full yearsMmusicman has been a member for 3 full yearsMmusicman has been a member for 3 full years
Posts: 1681
Topics: 33
Images: 1
Joined: June 2013
Location: Ft. Lauderdale, Florida
Gender: Male
Year: 2000
Van Make/Model: Chevrolet Astro
Extra Info: 2000 AWD 92 V8-350

Re: No power to grey wire at Fuel pump relay

Postby RECox286 » March 21st 2017, 3:42pm

I know it may be a PITA, but you should be looking at the Green/wht wire as your source of

grief. The trouble shooting section of the Astro Bible makes it very clear and in no uncertain

terms that if the G/w wire terminal at the relay shows no voltage for 2 seconds when the key

is turned to RUN then there is a problem with the wire.. The best fix is to run a new

wire parallel to the original wire.

I would "back-stab" the G/w wire at the pcm connector and check for a 2 second signal to

verify that the pcm is doing it's job, and the wire isn't. If when you back-stab and get no

signal, then replace the pcm. The G/w wire can be checked with a Multi-meter on the

Ohms setting by back-stabbing at the G/w wire connector at the pcm, and stabbing at the

relay connector

Back-stab: use a straight pin ("borrow" one from your wife's sewing supplies) and insert the

pointy end into the connector where the proper wire also enters the connector, then use the

pin as the source for testing by test light or multi-meter.

I"m sorry but that is as clear as I can make the process. I haven't the capability to make or

send graphics...I know, I know, get a new(er) machine. Well it's always between that

or some other more necessary doo-dad ! (Currant machine found at curb side before pickup.)

Uncle Bob
Start a fire for a man and he will be warm for a day.
Set a man on fire and he will be warm the rest of his life.

Sent using two Progresso soup cans and a string
User avatar
RECox286
U.S. Armed Forces
U.S. Armed Forces
Firing on 8 Cylinders (L5)
Firing on 8 Cylinders (L5)
Years of Membership: RECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full yearsRECox286 has been a member for 6 full years
Posts: 4930
Topics: 38
Images: 0
Joined: July 2010
Location: South Jersey
Gender: Male
Alias (AKA): Uncle Bob
Year: 1993
Van Make/Model: Chevrolet Astro
Extra Info: RWD V6 [325K mi]

Next

 
  • Related topics
    Replies
    Views
    Last post

Return to Electrical

It is currently March 28th 2017, 5:20am

Electrical Forum
ElectricalDiscussion specific to electric components of vans. Category for alternators or batteries, starters and ignition parts, anything 12v and electrical issue like fuses, circuitry, wire, terminals, switches, connectors, bulbs, relays, and wiring. Voltage and amperage diagnosis.
Moderator: tedanderson
To create a new topic in Electrical, click this button:
Previous topic Next topic
Recent Image Attachments
Attached by:
hotpsca
in Electrical
Views: 2900
Comments: 14
Date: Mar 25 '17
Time: 4:47pm
» Read last comment
Attached by:
Attached by: chevy57bert
chevy57bert
in Electrical
Views: 2900
Comments: 14
Date: Mar 24 '17
Time: 12:04am
» Read last comment
Attached by:
Attached by: markmitch
markmitchmarkmitch is online!
in Electrical
Views: 1057
Comments: 15
Date: Mar 09 '17
Time: 6:33pm
» Read last comment
Attached by:
theFlyingDutchman
in Electrical
Views: 62
Comments: 1
Date: Mar 02 '17
Time: 2:46am
» Read last comment
Attached by:
Attached by: markmitch
markmitchmarkmitch is online!
in Electrical
Views: 294
Comments: 15
Date: Feb 18 '17
Time: 1:11am
» Read last comment
Sponsors
 

Who is online

Users browsing this forum: Yahoo [Bot] and 5 guests