I have a 1999 saturn SL, and have an intermittent problem usually when its cool or cold out. For some reason the fuel pump will randomly stop working and fuel gauge goes to empty. I have checked the interior fuse panel for the F5 problem, and have power to the fuel pump relay. Although when it exhibits the behavior, and I turn the key on, I get no power to the fuel pump relay trigger connection. I've tested at the backside of the interior fuse panel for the DKGRN/WHT wire that feeds the trigger, and when its exhibiting the behavior I get no power there, but when the key is on I get 12v at the PCM connector on what I believe is the correct DKGRN/WHT wire.

This isn't only a cold start condition, as it can happen when driving, and will cut out and back on, sometimes immediately, and other times after a wait.

I have searched and searched everywhere I could find for answers, but have come up completely baffled.

Has anyone else had this issue, or know where else I can look?

I had another account on here a couple years ago and asked, but got banned after 2 hours for what it says is "inactivity" even though my account was only a couple hours old. How active do I have to be to not be banned permanently for "inactivity"?

 

Also, sometimes I can leave the key on with park lights on and it will work, other times it will not. But it will also just cut off when running like that as well, so I'm not sure if that helps or not.

 

Does it have power locks/key fob? Maybe a problem with immobilizer but just guessing that if it's a regular sl it probably wouldn't have that. Sounds like the connection is being interrupted at the pcm if you have power to relay but lose trigger. Either that or there is a bad/frayed wire en route to tank. I'll have to pull out the old fsms and see if I can scan in a wiring diagram.
Does this wire that your testing go/come from a fuse to the relay and how are you testing it. It's been awhile since I've been behind one of those panels

 

It doesnt have a fob, just the key. As far as I know the wire on the back of the fuse panel that isn't getting power does not have a fuse before it, and where I'm testing at the pcm is through the back of the plug. From what I have found, the wire from PCM is DRKGRN/WHT, but there are actually 2 different DRKGRN/WHT wires on 2 different plugs coming from the PCM, and I'm not 100% certain I'm testing the correct one.

I thought maybe something with wiring back to tank, but if its not even getting power to trigger it would rule that idea out I would think.

I'm testing with multimeter and probing the connector.

 

Definitley sounds like a shortage somewhere. Trace the wires back as much as you can.
I would assume the bundle of wires runs through the car as it does with the Ions.
Any rips/tears/leaks in the car?

 

The wiring harness between the PCM and fuse block inside basically goes up and over steering column and behind the instrument panel :/

Of course, unless I can find an actual pinout of what plug on the PCM and which DRKGRN/WHT wire is the correct one, I'm still not certain I'm testing the right place.

 

There isn't a fuse on the fuse box under the hood?

 

I've checked the power to/from the PCM1, PCM2, and IGN fuses in the underhood fuse box and all checks out fine.

Also, as curiosity, I tried jumpering the relay to power fuel pump, and the car still does not start when manually powering it. Tomorrow after work I'll check for power at the ignition module also. I'm curious if its just PCM failure, or maybe ignition switch power?

 

OK, I can only find the generalized schematic for 91-95, but Saturn tended not to change alot wiring wise b c it was too expensive to do so until they added the BCM iin 3rd Gens.

That being said:

The IPJB DRKGRN/WHT at F4 (F5 in later models I believe) is the input to the high side of the fuel pump relay coil; the other end of the coil comes out from the relay on pin A5 of the IPJB, on a BLK wire which goes into a splice pack --presumably to ground.

However, the FUEL PUMP AND PARK 10A fuses are upstream from the fuel pump relay and operating current for them comes from the RED/WHT wire that leads from the IPJB to the UHJB IP BATT fuse (UHJB Pin A, Connector 2239)


The fuel pump switch is of course normally open, but when the coil is energized, that part of the relay closes, and he current exits the IPJB through a GRY wire at IPJB D4 to the fuel pump.


Based on your description of events, I'm thinking one or some of the following

• the RED/WHT connection is intermittent at either the IPJB or underside of UHJB. I've read of many overheated torched connections under the fuse box.
• the IP BATT fuse, PARK fuse, F PUMP fuses are making poor electrical connection
• The fuel pump relay is bad.

My best guess is the IP BATT feed and connection on one end or the other (IPJB, UPJB) or dirty fuse contacts).

This scenario ties the two events (lights and fuel pump) together.

Most interested to see how this plays out.
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w/r/t being banned while online, it was done by neither Goalie nor I. Previous moderators of this forum were not fond of members joining without posting immediately thereafter (same session). I doubt the moderator had any clue you were online; probably just banning accts w 0 posts. For the record, new members are now sent a PM explaining they have 10 days to make 10 posts, etc.

No more grey area.

I don't apologize for other people's behavior, but I am sorry that this happened to you. Goalie and I have our email addresses in our signatures so you can badger us any time it becomes necessary.

 

The parking lights work all the time when they're supposed to though. It just seemed like having them on affected the process, but I'm thinking I was wrong with that assumption.

This morning before work the car cooperated enough to let me test during working conditions, and I was able to get the 2 second 12v feed at the PCM connection and the connection on backside of the interior fuse panel. So, at least I know its the correct wire and connections I've been looking at.

When the car is acting up I get constant 12v at the PCM connector, and nothing at the fuse panel. This leads me to believe its somewhere between the PCM and connection to interior fuse panel, but where is the question. Does the DRKGREEN/WHT wire for the fuel pump relay trigger go straight from one point to another, or does it connect somewhere else midway? I wonder this because even when its acting up and I manually jumper the relay to run the pump, the car still will not start.