1998 Astro - No Power to Fuel Pump

[KenR]

1998 Astro 4.3L V6 code W 2WD 176k miles

Good Morning,
The van recently stalled and would not restart while driving in rainy conditions. I had previously had problems with it surging on take off and a vibrating fuel level needle. After much research I realize these are compounded problems that I can fix as I go. The most important issue is that there is no power to the fuel pump. I replaced the fuel pump, filter and relay. It ran well at first but then became harder and harder to start until now it refuses to start.

I verified wire continuity up to the pump with no grounds. When I turn the key the relay clicks but no power to the fuel pump connector. I've verified 12V at the relay and 12V at the oil pressure sensor.

I checked voltage across the oil pressure sensor and it was zero with the key turned, makes sense since the oil pump is not turning. I jumpered across the oil pressure relay and with the key turned I show 12V at the fuel pump.
According to the wiring diagram, these two provide redundant power to the fuel pump, but where do they meet? I'm thinking it might be an ECC problem but do not know enough about how that works. I don't want to swap the ECC only to find it is something else. I've read that there is a module behind the kick panel on the passenger side. I pulled it and found a circuit board but do not know what that is either.

I need to add that right after I finished replacing the fuel pump, I refilled the brake fluid. Then when I first started digging, I found that I had not reinstalled the gasket right and brake fluid had leaked from the reservoir onto the ECC cables. I pulled one and cleaned it, the plug looked clean on the inside. Now I'm trying to figure out if the fuel pump was the original problem that I fixed and then caused a new problem, or if the fuel pump was only a symptom of a bigger problem.

Any help here would be greatly appreciated.

Regards,
Ken

[astroturf]

Have you checked the coil for a good blue spark?

Jim

[KenR]

I haven't checked the coil because it doesn't seem to problem starting. There just isn't any power to the fuel pump when the key first turns. I'm not sure how the starting coil fits into this part of the circuit?

[astroturf]

It dosen't Ken

I am sorry

Jim

[KenR]

No worries. I'm very much a mechanical person but handy with a voltmeter so I'm way out of my comfort zone on this one.

[RECox286]

Hey Ken,

Not familiar with ECC. Are you referring to PCM (power train control module) or ECM (engine control module) ? ...In any event, the computer?

What I would do is remove the Fuel Pump Relay, and probe for 12v at one of the 4 terminals. The power comes from the ECM fuse, which is always hot.
If you have "pump" power to the relay, then probe the other terminals to see if the ECM is calling for the relay to switch ON. You should get a 2 second window as the key is turned to RUN. If you have joy so far: there should be a female terminal near the relay that you can plug 12v into. It is a straight shot to the Fuel Pump, so listen for the pump to run. If no joy, then check the ground connection to the truck right around the last connector before the fuel pump module. The ground is a separate wire attached to the truck, and provides the ground for both the pump, and the fuel gage sending unit. I have had problems with that ground wire becoming corroded, and also coming loose. Either way, no joy. If still no joy, I would suggest a long jumper wire to bypass all the rest of the truck, and put 12v directly to the grey wire, that goes to the pump, at that connector under the truck near the ground wire connection. If the pump still refuses to run, (don't laugh) whack the side of the tank with a Ford Repair Tool. (ie: heavy, blunt object)

After trying the above, and (possibly) mumbling vocabulary your mother didn't know you knew, get back to us with the gorey details.

Bob (ADR, ADJ, AD 1) USNR-R Ret.

[KenR]

Thanks for the tips. I've seen it called the ECM, ECC and in the Haynes manual drawings, Vehicle Control Module. I'm pretty sure I'm talking about the computer mounted under the underhood fuse center, next to the battery.

I definitely see 12v at the relay. With the relay plugged in, I can feel and hear it click when the key is turned but have not checked that voltage is getting across the relay. I can get voltage to the pump connector when I jumper across the oil pressure sensor. Just not for that 2 seconds when the key is first turned (without the jumper).

I can't find a ground wire around the underhood fuse center though. I've pulled the battery and moved the wiring harness around but do not see anything. I suspected a bad ground connection because of the fluttering fuel level needle. I just can't find it anywhere and have been assuming it is a common ground through the ECC/ECM/VCM.

I've also unwrapped all the wiring leading from the fuel pump connector under the van and tracked it into the engine compartment but do not see a ground connection anywhere. The black wires just keep going up the bundle.


At this point, the tank is dropped and the wiring is disconnected. The engine cover is out and the air intake box is pulled.

I'll try jumpering from the relay to the pump and check it again.

[astroturf]

Ken,

I have 4 drawings for you.

Hope it helps, Jim

98 Engine Controls drawing 1.pdf

(46.87 KiB) Downloaded 437 times

98 Engine Controls drawing 2.pdf

(47.9 KiB) Downloaded 296 times

98 Engine Controls drawing 3.pdf

(43.21 KiB) Downloaded 401 times

98 Engine Controls drawing 4.pdf

(48.35 KiB) Downloaded 235 times

[KenR]

Thanks again. I have similar drawings from the Haynes manual. One difference in yours though is the label S115 where the oil pressure and fuel relay power meet. Any idea what that S115 is?


On second look, these are much better than my Haynes manual. Thank you, these will be very useful in the future.

[astroturf]

Ken,

I would say a splice?

Well over my head at this point.

Jim

[chevy57bert]

1998 Astro 4.3L V6 code W 2WD 176k miles
I jumpered across the oil pressure relay and with the key turned I show 12V at the fuel pump.

Did you use a big bulb to see 12 v at the fuel pump for 2 sec. ??
Don`t use the multimeter for this.

[KenR]

Unfortunately, mine too.

[RECox286]

Ken,

I don't have access to the 98 schematic, but looking at what Jim pulled out of his hat, it definitely shows a body ground for the pump. The other black ground that continues is for other gizzies in the module. Have you gotten far enough to put 12v to the grey wire at the connector under the truck? I'm betting on a ground wire which almost surely had to be disconnected to change out the fuel module.

Bob


BTW, Thx Jim.

[KenR]

Ok so I'm the dork. I found the body ground. It's just above the fuel pump connector, so if you happen to be laying under it, you won't see it.

I checked that there is power coming out of the fuel pump relay. I'm thinking about just re-running wire from the downstream side of the fuel pump relay and splicing it in to the pump connector. The more I think about it, the more I'm convinced there is a wire break somewhere. I just don't like the fact that it happened after I switched out the pump, etc. and I can't find a real culprit.

[astroturf]

It is always more fun when you find the original fault.

Good Luck and Keep us posted.

Jim

[chevy57bert]

It is always more fun when you find the original fault.

Me to Jim. Me to....

Keep us posted Kenr.

[RECox286]

Ken,

There are no stupid questions. There are no such animals as stupid dorks. What there are: inexperienced personnel, who learn mostly by their own effort. I never did my first tune-up until I did my first tune-up, by golly! (Not everybody pops out of the womb ready to take the AAA mechanics test.)

OK, so we're making progress. Good.

Bob

[KenR]

Here's the latest. I went to rewire the fuel pump, and when testing for voltage, nothing. I thought I fried the week old relay in my attempt to jumper it. Back to Autozone for a new one, dropped it in and the fuel pump started.

Put it back together and the engine fired right up. Now I need to figure out why a new relay burned out after about three days of running. Maybe I need to start a new thread. I'll run it for a few days and update you guys on how it holds up.

Thanks for all the great info. Back to square one...maybe it's the ECM?


Ken.



Work so far:
Fuel pump. Aftermarket - too bad I didn't read the forums before buying that one. Hopefully it holds up.
Fuel pump relay
Fuel filter
Three days later new fuel pump relay


Just for kicks, rotor, cap, wires, plugs.


Background info:
Fuel pump has never been changed until now.
I'm pretty sure we had the fuel filter changed about 8-9 years ago.
--So not surprised it went or that its getting its revenge on me now.

[astroturf]

Hang in there Ken

Man put it together

And Man can fix it

Jim

[RECox286]

Glad to hear we're running again. If it's not one thing... I guess it's like being in the Navy: It's not a job, it's 3 or 4 jobs! So, now that things have settled down, what do you do for a living? Brown shoe, or black? Boats, or shore duty? (nag, nag, nag)

I did 23 years ASW in P-2, P-3's. I got to sit between the drivers for a long time.

Bob