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fuel pump relay

23K views 20 replies 9 participants last post by  brosamuel  
#1 ·
I've went throuh a couple threads on fuel pump problems but the problem I have on my 1997 astro is in the engine compartmant fuse block. When I remove the fuel pump relay, I have a 12v at the top left termanal which I think the wire is a solid orange but when I turn the key,I have no juice to any other termanal for that 2 second period. Which termanal and color wire is it that is supose to deliver that other 12v intermitted juice to activate the relay.
I was driving when all the sudden the engine kind of jerked/stalled then resumed fine for a second than just died ,nothing. The battery light was on in the dash so I that it was the altenator but I replaced that last year. While trying to restart the van I heard the fuel pump motor and it would start but last a few seconds. I was able to keep restarting the van and drive for 3 to 5 seconds till it would dye till I got the van off the freeway to a store parking lot.
Now I got a ride home and left the van for a few hrs and came back to get it thinking it was an altenator problem/dead battery so I jumped it but when I turned the motor over it would just turn and I didn't hear my fuel pump. So after getting it home I figured it was the fuel pump and bought an aftermarket one,you know,one of the ones were you have to change the connector plugs on the pump itself. After wiring it all up...nothing so after looking through some of your threads I seem to have no power from the ign.to the relay. Confused please help.
 
#3 ·
Deezer,

I did not know that you reposted. I answered your post over in "1998 Astro, no power to fuel pump". Check it out.

Bob
 
#4 ·
how do you know that its not ground thats switched to the relay when it needs to be activated

since the hot is all the time hence the orange wire

jump orange to gray and see if pump runs

put ground on the black wire and see if the relay activate and pump runs

alot of circuits are full time hot and have controlled ground

such as dome lamp circuits s for example,

also fuel level sender circuits

if theres a full time hot to a circuit then the odds are that ground is the activating controlling side of the circuit

of course
 
#5 ·
Sorry for posting twice,I got message from moderater when I posted on that other thread saying my post was disaproved for double post or something like that so I didn't know it went through. Also sorry for the delay in response,I clicked the box at the bottom of the post screen to" be notified when my thead got a reply"but I don't know what happened.
I'm only able to get access to the internet for now through my blackberry which makes viewing some of your guys info a little deficult for now.
Now back to the last respders response,I thought I read in the "1998 no power to the fuel pump"thread that the ign. sends an intermitted 12volt signal to the relay. There was a schematic in another thread that showed the fuel pump relay with a power,ing.pwr,ground,wire going to the pump. But in that schematic the wire going to the pump wasn't grey like mine but tan/org I believe.
 
#7 ·
RECox 286,I cleaned the connector and body groud wire and nothing. With the relay in and my test light hooked to the grey wire (I have the engine compartment fuse/relay box taken apart to gain access to the relay and wires from underneth)I turn the key and no power to the grey wire. What was the wire(location and color) that comes from my ingn. to the relay for that 2sec period of time? Also what is the pcm wire u guys talk of.
 
#8 ·
What was the wire(location and color) that comes from my ingn. to the relay for that 2sec period of time? Also what is the pcm wire u guys talk of.

http://www.chiltonlibrary.com/content/i ... 025282.pdf

The wire comes from the ign. switch to the PCM, not sure what color. The PCM wire to the fuel pump relay is Dk.Grn./Wht. That's where the 2 sec. power comes from. At this point I'd check all the fuses inside and out. Some seemingly unrelated power to the PCM may be the problem. Your owners manual is probably the best source for diagrams but here's a link to chilton's.

http://www.chiltonlibrary.com/ContentVi ... meset.aspx

If your still stuck in the parking lot and you are confident the oil is full and pressure good, you can drive it home by jumping the relay as you already said or take the dog house off and jump the wires at the oil pressure switch (Org. and Gry). You might discover other PCM stuff ain't working so this may be a bad idea but I've done worse things.
 
#9 ·
It won't hurt to shunt the pwr at the relay socket, as long as the engine is running. Don't put pwr to the pump with the engine not running for very long. This will at least let you get home. Sounds as if you may be having PCM problems at this point. ECM2 fuse powers the fuel pump thru the relay via the PCM, and also directly thru the oil pressure switch. If you have a constant 12v at the relay, which you say you do, then the fuse is OK. Something between the fuse and the control circuit to the relay apparently has failed.

Bob
 
#10 ·
I forgot to mention that I had to get her towed home after dying in the parking,that's when I droped and replaced the fuel pump. Jump the gun and when I hooked up the pump,that's when I discovered I had a problem whith my power to the pump. Checked all the fuses, both the ECM fuses and all looks good. I believe I checked the drk-grn/wht wire which is next to the grey wire,and no power. Will trace that wire to the pcm and see if the pcm is putting out anything. Is the pcm below the steering column next to the battery? Is the pcm the same as a vcm cause that is what a book I have is calling the thing below the sreering column next to the battery.
 
#12 ·
http://www.chiltonlibrary.com/ContentVi ... meset.aspx

Depending on who's book, it's called VCM, PCM, ECM etc. It's best to do this with two people, I'd back probe the Drk.Grn/Wht wire at the fuel pump relay again to check for the 2 sec. power from PCM. That wire should get hot for 2 sec. when key is turned on and should stay hot while cranking. The thin black wire should always be grounded. If your still not getting power at the Drk.Grn/Wht wire, check the other grounds. (thermostat housing, rear drivers side head, stud on radiator support,etc. Even if they look good take them apart and sandpaper them a bit, it's cheaper than the alternative.

Edit--Ok,took dog house off,unpluged oil pressure switch,jumped the org and grey wires and pump works!! So does this mean I nead a new pressure switch and problem solved?

No, that was a quick way to cheat the tow truck. It may end up being the final solution but power at Drk.Grn/Wht wire is the next step.

Somehow these posts got crossed, sorry.
 
#13 ·
Ahh crap...well I'll have to look at it next week being I have to work this weekend. I believe looking at my book,the grn/wht wire goes to the vcm through the C4 blk harness. I believe the vcm has 4 bulk wire connectors and the bulk wire connector with the grn/wht wire was labled C4.
Thank you guys for your help but since I'm on my blackberry I can't pull up anything that u guys posted that is in pdf form. I'll go to the library this week to look at some of the links you guys posted.
 
#14 ·
Traced back the grn/wht wire from relay to vcm/pcm and what do u know,there was a break in the wire. Seems the group of wires that plug in the C4 section black connector, were hanging down and rubbing against a metal surface that was directly below the vcm.
Grn/wht wire was completely worn through with no bare wire connecting and there was another green wire that just had bare wire showing so I spliced in another wire for each of them and now everything works.
Thank you guys for your help,I just wish I found this forum sooner before I dropped the tank and bought a new pump.
 
#17 ·
I Have a 1996 Astro Cargo Van only 80K Miles So Cal Runner , Im having Warm and/or Hot Restart Problems! This Vehicle at the Present Time will only start when it is Cold or signifcantly cooler, ambient or Engine cooler, or with Starting Fluid!

I had to Replace the Electrical High Voltage Coil about a 1 1/2 years ago,, was Leaking Power spark!

Had this problem Last Year, at this time, and then after running it down to Ensenada Mexico, , it went away , for a Year! Only after I added a quart, Coolant, the All Purpose for any Color Green , ( it seems these Astro Vans Drink Koolaid), Now the Hard Restart Problem is Back again .
I did have a Radiator, oil Problem where the Oil got into the Cooling system, so, I had a New Oil Cooler Installed,on the Side of the Radiator and then flushed, with Multiple water, refills of about 20,,, and I Installed Orange Prestone ..
Could the (ECTS) , be coated with some Residual Oil..?

On COLD Start, Im getting the Fuel Pump to Prime Pressure on the Cold Start, and can hear it stir, for 2-3 Seconds, for every 10 Seconds I delay the Key . Im getting about 49 PSI Fuel Pump Pressure at the Shrader Valve under the Dog House.

IM NOT GETTING ANY STIRRING, or any action out OF THE FUEL PUMP ON HOT OR WARM START, So I am not getting Fuel,

I Switched the Fuel pump relay with the Same similar one as the A/C Relay . No Change ,

When I measure Cold Voltages, on pulling the Fuel Pump Relay .. I get 12 Volts at 1 vs 2 and 1 vs 3 Inlet Recepticle Fuel Pump Relay terminals. when I turn on the Key to RUN ..

I get Continuinty from the Red Wire Subsidary Fuel Pump Wire Harness to Number 4 wire Inlet Recepticle Fuel Pump Relay .. when the Key is on run position .

I start the Van.....Starts and Runs Excellant Cold and stays Running , as long as I dont shut it off. ,, I let it warm as well as get to HOT operating Temps....
Run around the Block up and down some hills acclerate Rapidly,, and stop,, Full throttle Ok..Plenty and Full power get up and Go ,, Turn the Heater on ,,, blow some hot air, etc...

WHEN I pull the FUEL PUMP RELAY WHEN ITS RUNNING, THE ENGINE KILLS IMMEDIATLY,

Come back, Park, and go to Restart ........ NOTHING .... I also Hear NO stir from the Fuel PUMP
behind me as Well...
I still Measure 12 Volts at 1 vs 2 and 1 vs 3 inlet Recepticles,, on the Fuel Pump Relay when pulled.
I was going to try and Get behind the Fuse Box, is it Hard, to get at the Wires, remove that Plastic Tangs or what?

45 minutes Later,, I hear the Fuel Pump Stir, and it Starts..

QUESTION ? Does This Sound like the Engine Coolant Temperture Sensor (ECTS) problem or some other Temp Sensor , ?? ,

ECTS are about $10.99 at A-Zone, and it sits right next to the Thermostat Housing, with a Harness.. Little Tight, but looks like it can be Reached.

http://www.autozone.com/autozone/parts/ ... 46258_0_0_
 
#20 ·
My Solution to my Astro Van ....

1) Replaced the FUEL Pump.. with an AC Delco for 30 bucks on Ebay ....
you definitly Need a Certain Pressure , as mine was down to 48 ..
I also Replaced the Oil Pressure Sender Switch, as that was clogged.
and is in the Fuel Pump Relay Circuit .

2) I cut a Slight 4 inch Trap Door in my 1996 Astro Van... Using a Steel Grinding Cutter from Harbor Freight, being extremly carefull to not go below the Steel,, as you only have 3/4 inch clearance for the Fuel Lines below..

I have Pictures, and dimensions if anybody needs them .... Its Important to find your Center of your Tank where the Fuel Pump Assembly is .
THIS isthe way To go, to Get the Pump out quickly, check the Electrical Connections
and see if there are any Leaks in the Lines....

Now it starts with the very Touch of the Key .. Im a Happy Camper :wave:

Gary T
Del Mar California
 
#21 ·
I have a 99 astro and that won't start due to no power at the pump. I have power on the top left terminal of the fuel pump relay. I have no power at the other terminals. When I jump from the constant power terminal (ORANGE) to the wire that feeds the fuel pump, it blows the 20 amp ecb fuse. The van has a miss when its wet and sometimes I have had to jump the solenoid on the starter to start it. I swapped the fuel pump relay and it did nothing.