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3 sets of fuel pumps failed

Before I go much further will you all correct me if I'm wrong? Didn't I just test the grounds for both pumps by jumping power at the fuse panel to each one and make them spin? If ground wasn't present at either site they wouldn't have turned on right? R.
 

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Ground may be present, but is it a GOOD ground? That is the question you answer with the resistance tests... Sometimes you could have a marginal ground, you can test and find 12 volts, but then find out later that it wasn't quite good enough to carry the amps needed. Think of it like a water pipe... it could be blocked by 80% and you would still see some flow out the other side. If you don't measure the volume and just check that there is some flow you aren't really seeing the whole picture.
 
A quick and dirty way to see that you do indeed have enough real current able to flow is to use a brake light or similar incandescent bulb wired up as a test light. They pull a good amount of amps, so if it lights up as bright as it should you can be pretty sure you are getting not only voltage, but also enough current...
 
That relay clicking on and off has got to be the root of the problem. It is either the relay itself, or the wiring.... have you re-flowed the solder on all the connections inside the relay yet?
 
That relay clicking on and off has got to be the root of the problem. It is either the relay itself, or the wiring.... have you re-flowed the solder on all the connections inside the relay yet?

/\ /\ /\ I'm not quite sure what the clicking relay is doing to the current flow to the pump, but it can't be good.

I know sometimes people run a varying duty cycle to a fuel pump so it's not pumping LOADS OF FUEL when it doesn't need to, but that's usually at a much higher frequency. If the relay clicking is at a much lower frequency where the pump mechanically speeds up and slows down constantly it could be overstressing it.

Clicking relay would seem to be an issue with the circuit that powers the relay, not as much to do with what the relay itself is turning on and off (the fuel pumps).

Last page of this PDF: http://www.volvowiringdiagrams.com/volvo/240 Wiring Diagrams/Volvo 240 1984.pdf

Shows the relay getting switched 12V+ on one side of the relay (terminal 86) from the ignition switch, and the ECU grounding the other side to turn on the relay (terminal 85 on the relay, goes to terminal 17on the ECU). That is the circuit that turns the relay on and off, if it's buzzing, it's either issues with the switched 12V coming to #86, or the ground to the ECU from #85, or an internal fault in the relay itself.

As a quick and dirty test, I'd use a jumper wire and ground #85 when the car is running, and the relay is buzzing. See if the buzzing stops. If so, there's some sort of issue either in the ECU, or in the wire between relay terminal 85 and ecu 17.
 
That's excellent advice (and exactly what I was looking for with the ground), thank you. I'll try that this afternoon. The relay is not buzzing so loud as to make a noise but I can feel it vibrating with a touch. R. We're talking about the ECU in the passenger foot well correct?
 
As far as I know this relay just runs the pumps constantly when the car is running. Any excess fuel is just recirculated back to the tank... If the relay is clicking it is turning the power on and off to the pumps...
 
I wasn't trying to say that Volvo is using a duty cycle to reduce the pump output, just that sometimes on high-performance cars with huge pumps they run the pump on a reduced duty cycle without harming the pump. But in this case, the problem with the relay may be doing it at a low enough frequency to damage the pump. It was a pointless sidebar.
 
Update. Before I attempted to ground term 85 of the pump relay I lightly sanded the fuse ends of #5 and #7. Started the car, applied the ground but it didn't do anything and that's when I noticed the whine of the pump was gone and replaced by the normal hum(s). I let him run/idle for about 1/2 hour while I washed it off and then pulled it into the garage. All that time it acted normal, so Friday is the earliest I can test drive it and will report back later. R.
 
We'll see, I'm so paranoid now of driving this guy any distance. I'll post ongoing test results starting Friday morning... Ralph
 
Gt him out and about running errands this morning with no issues other than the normal humming of both pumps which I'm so attuned to now; 35 mile 4 starts and stops. So far so good, going to buy a set of new fuses... R.
 
Let's continue shall we? I'm on the 4th pump set now and the main pump has started to get a little louder and pulsing a bit after the 3rd test trip around town, this one was a bit longer 1/2 hour to be exact. I cleaned every ground connection underhood including the battery and 25 amp fuse and junction box mounted on the side of the fender by the coil (even his terminal were burnished clean. Replaced the Pressure Regulator, took all fuses out of the panel and burnished every connection and replaced with IPDs kit of fuses. I took special care to clean the input/output connection to fuses 5 and 7. Both relays behind the glove box replaced. The only thing I haven't replaced is the in tank sending unit and looked under the rear seat to see how those connections look. looking at the fuse panel, car running I read 12.8 volts on the right side of fuse 5 and 13.6 volts on the right of fuse 7. Incredibly frustrated...
 
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Are you sure that you don't have some rust in the tank? Rust destroyed a brand new pump before I could even get through testing other fuel issues.

PB101370.jpg
 
If you got water in the tank, and didn't drain the tank FULLY, there will still be water there. Water sinks to the bottom of the tank, and won't mix with the gasoline. If your pump pickup is where it should be...you might be drawing water as well as gas into the pump. As a young guy, I worked at a bunch of gas stations and when we had to check the water level of the inground tanks, we'd smear some marking gunk on the end of the long stick we used, and submerge it into the tank. When it touched water, it turned from green to red, so we could tell how much water was there.

HEET (alcohol) will eventually separate from the water too, so it probably didn't work well enough as a 'drying' agent.
 
No, not absolutely sure. It's been a few months we've been fighting this with many fill ups in between. Do you think rust could still be an issue even after all this time? The whining only starts about 1/2 hour into a drive.
 
This many pump failures is beyond unlucky chance.

The pictured rust took out a claimed new pump when I bought the car and both a new lift and pressure pump that I installed. A significant contributing factor was that the PO had bent the in-tank pick up tube about 30 degrees off vertical. I assume trying to get the pump/float assembly back in. That permitted an inch or more of very old gas to remain at the bottom of the tank. No matter how much I added and pumped out, which I did several times, there was always that 2 gallons of old rusty gas at the bottom of the tank.

Your call on a new tank. Good price shipped. Be sure to under coat a new tank before installation.

I bought a lighted fiber optic camera with a 5 foot tube for less than $15 that connects to my Android phone. Might be an option in diagnostics before firing the parts cannon.

Just in case:

http://forums.turbobricks.com/showthread.php?t=269630
 
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