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1989 780 with B230FT. 170,300+ miles and has been sitting for ~5 years.
I got it cleaned out, cleaned up, and my fluids topped up (except Gasoline, which is at only 3 gallons). Oil is nice a clean. It cranks just fine, all electrics (except the power seats) are also working fine. All fuses have been checked and are intact.
So here's the issue. No fuel. Nothing is getting up to the rail. I've cranked and cranked, opened the line, diverted it into a container. No fuel is getting to the rail. That usually means relay, or pump(s), or a busted pickup hose in the tank.
I've checked the pump relay, feeling and hearing the click as it is activated with the ignition switch.
I hear nothing from the main pump, and nothing from the pre-pump when I crank or when I click the ignition.
I've located the pre-pump/sender wiring plug and here's where my past knowledge starts to fail me. My 940 has four wires, two are the loop for the resistor/gauge, the other two are hot and ground for the main pump. It's easy to test pump function on the 940 by applying current to the red/black wires. On the 780, I'm not so sure. Nothing happens...
The 780 has three wires: Red, Brown, Grey. Is one of these even ground? I've tried applying 12v to a combination of the wires, but I get nothing at all from the pre-pump. Shouldn't I hear something? I'm guessing that Red is pump hot, brown is pump ground and grey is the sender wire, but maybe not, maybe I just fried something...
Is there another way to test the pre-pump w/o the engine actually running? The FAQ doesn't suggest much here.
What should I be hearing?
What do the three wires to the in-tank assembly do? Where is the "ground" I have read about?
Should I be hearing the pre-pump running?
I'm not afraid to, but I'd rather not pull the in-tank assembly.
And of course there's the main pump...
Some (Maybe) Relevant Background
For the last 7 years I've owned a 1995 NA 945 with a single in-tank pump. I've had to replace it, and open it up three other times to repair the resistor wiring, and replace the pickup hose when it popped off. I used to own a two-pump 86 745 GLE, but that was before I got back into Mechanics. Back then, I never messed with the fuel system aside from replacing the filter and doing tune-ups.
The 780's previous owner was actually a Volvo mechanic. He assumed that it was a failed relay, pre-pump hose, or similar. However, aside from opening the access panel and pulling some fuses, he never tried to diagnose it. The guy hurt his back and gave up on the car. It's been sitting since early 2007.
The 780 had a hand-free cell phone setup. It also appears to have an alarm system. I have no idea if either could be screwing with the pump... The non-functional seats might be related... probably not.
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After discovering the main pump would only go "thunk" when powered, I picked up a pump and filter assembly from a local Pull-A-Part. I tested and installed it.
Cranked for a good 30-45 seconds before I was rewarded with a startup and rough idle.
Probably needs a tune maybe a new intake gasket.
I quickly learned that the turbo oil cooler line was broken and oil was spraying all over the front of the motor.
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You are going to have to pull the pump at this point. With only 3 gallons in the tank and sitting for 4-5 years, the pump has probably dried out and the pick up hose fallen off. Besides, the gasoline in the tank is probably made up of 1 gallon of water.
My second Volvo was a 780, 1998 with a PV6. The interior is unique to this model. Do not try to take the buttons/switches off the side of the front seats, the ones that make the seat backs fold forward, if you do they will break.
The power seat buttons can be lifted off to clean the contacts, but watch out for the micro springs and ball bearing!! Same as the 700/900.
Klaus
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My name is Klaus and I am a V ♂ lv ♂ holic
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Err.. thanks for the bad news, I guess. Don't pull your punches. I want to get this car running again. Mainly so I can get it out of my Carport.
Did I mention that I'm not afraid to do it but I actually *hate* pulling the in-tank pump?
I added another 5 gallons, so I'm up to ~1/4-1/3, but you may be right, problems down in there... I have reason to believe that the tank was empty when I got it home.
Resurrecting cars is usually a PITA.
I'd really like to confirm pump function. I can't hear anything from either with fuses in. Is this normal? How do I test this? FAQ is fully of fiery horror stories.
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I know your read this already: From the FAQ - If you have an old relay, you can remove the electricals and solder a large wire between terminals 30 and 87/2. As soon as you put it in (even without the ignition on) the main fuel pump should start to run and keep running and car should start. If nothing happens, then your main pump is well dead. Don't forget to remove the relay and chuck it, or mark on it what you did to it as it would be really dangerous to use otherwise. It is a strictly 'get you home' or diagnostic.
Sooo, just jumper 30 and 87/2 and see if the pump runs. A paper clip will get hot fast, but you are just verifying the pump working.
Did you try the pump to a bucket after you added gasoline to the tank?
BTW, there is a guy selling a 780 up here with the same problem, but for $1000.
http://minneapolis.craigslist.org/hnp/cto/3033676556.html
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My name is Klaus and I am a V ♂ lv ♂ holic
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Thank for the suggestion Klaus. I took a piece of 12 gauge wire and put a couple male spades on the ends. Then I jumpered 30 to 87/2 (I marked the ends of the relay to be sure I got the right connections), switched on the key...
And nothing happened. Tried cranking. Nothing. The wire warmed up but I got nothing at all from the pump. To me a warm wire says current. Maybe I should probably grab my multimeter to measure it.
To me, this suggests that the pump is dead as a doornail or the wiring to the pump is fsckd.
Seems that the next most logical move would be the drop the main pump/filter assembly and bench test the pump.
If the pump is good I can guess that it's wiring or the relay. If the pump is bad, well.. I probably shouldn't be shocked.
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Main pump is $89 at FCP and in tank is $50. IIRC, the main pump is under the rear seat area, next to the filter?
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My name is Klaus and I am a V ♂ lv ♂ holic
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Yeah, it's under the seat. 'Though I'm still actively avoiding giving my money to FCP. Tasca Volvo can get me OEM for the same price.
I still find it strange that both pumps are inop at the same time. I'll bench test before I order anything.
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posted by
someone claiming to be mmal231294
on
Tue May 29 06:51 CST 2012 [ RELATED]
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With the fuse jumpered have you checked for +12volts at the connector to the A)The main pump and B)The In-Tank Pump? If you have 12 volts at the connector and pump doesn't run then you KNOW the pump(either) is bad. Without confirming 12 volts at connector you arent eliminating the possibility of a wiring issue(etc) prior to connector.....
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Okay, did some testing.
Key at KPII
Jumpered 30 and 87/2 and checked for voltage across #1 fuse (Main Pump). Got 11.89v. Tested across #11 and got the same.
Something a bit funky here... tested with the relay in, was able to get voltage across #1 on the second try, but not the first... Maybe was doing test wrong.
Raised car on jackstands. Key at KPII with Relay - pulled main pump connectors checked for voltage - NOTHING.
Pulled relay, jumpered 30 to 87/2, measure 11.89 across connectors.
Need to test a bit more to figure out what's going on. The relay seems to be intermittent.
--edit--
a bit more reading and a bit more testing suggests that my main pump, and probably in-tank pump are dead. Weird that they'd both go, but it's been sitting a while.
I'll pull the main pump and do a bench test before I get a replacement - just to be sure.
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When I jumpered my 85 across 30-87/2 with the key off, I get both pumps running. As far as wiring, I discovered mine is different than most(and what is in the FAQs) Three wires lead out the tank, black to direct ground near filler tube. Purple is for the fuel gauge and white/black for power to intank pump. The fuel pump relay has been know to have bad solder joints(FAQs) and the seating base sometimes doesn't make a good connection. My guess if it sat for 5yrs with fuel in the tank, both pumps probably are full of varnish and won't run. To check voltage at the intank. I would remove fuse #1(main pump), the connector in the trunk disconnect. Then jumper 30-87/2, and check for voltage. My guess would be red would be hot. The FAQs covers testing fuel injection, pumps, relays etc in great detail. I have read different statements on whether the pumps prime in KII. Mine doesn't. If I bump the KIII for a second, (not long enough to start) when I release the to KII, I'll hear the pumps for about a sec.
Here's wiring info: http://www.nuceng.ca/bill/volvo/Volvo740wiring.pdf
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Post Back. That's whats makes this forum work.
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I'm guessing that the brown and red are the pump wires?
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Told you all I know.
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Post Back. That's whats makes this forum work.
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Not sure I follow all of this, but does the main pump run. You can jump it by hot wiring between 2 fuses (can't recall which 2 to see if pump will run). Car will usually run without the in tank pump working. Mike
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I'm not quite sure I follow either. Jumr the main pump fuse in the fuse panel? How would that complete the circuit?
Maybe to put it less narrative.
Symptoms:
-No Fuel at Rail
Possible Causes:
1) Pump Relay
2) Pre-Pump Failure
3) Main-Pump Failure
4) Broken Fuel Pickup Hose
5) Electrical fault at one or both pumps
6) Alarm system?
7) Other?
Pump Relay
-Test: check for click when ignition is switched
-Result: "clicks" with ignition - usually indicates proper function
Pre-Pump Failure/Pickup Hose
-Test: apply external power, listed for pump to run, "waterfall" noise inside tank indicates broken hose
-Result: No function, but I'm not sure I am applying the power correctly. Unsure which wires do what.
Main Pump Failure
-Test: ??
Electrical Fault
-Test: ??
Alarm System
-Test: ??
Other
-Test: ??
Questions
On my 940, switching the ignition energizes the pump briefly. It is audible, even though it's a single in-tank pump. I get nothing like that on the 780. Is that normal?
How do I "hot wire" the in-tank pump to confirm proper mechanical function?
How do I "hot wire" the main pump to confirm proper mechanical function?
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this happened to my 940 se.
it was the ECU.
When i jumped the relay (via 87 and 30 per FAQ) both pumps ran and fuel came from the return line.
but the car wouldn't start because the ecu was not grounding the relay to activate the fuel injectors.
one of the two switches clicked everytime i turned the key. Finally i pulled the top off the relay and pressed them both with my finger. the car started! diagnosis... bad ECU.
ref: http://www.brickboard.com/RWD/index.htm?id=1344111&show_all=1
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I removed the top of the pump relay and confirmed that the first relay was closing when I put it at KPII. I then closed the other (closer) relay contact with my finger and heard a distant "thunk" noise.
It sounds like someone give the side of a cardboard box a tap. I tried it a couple times. Pretty sure it's the main pump. This relay looks brand new.
I wonder if I pull the main pump and pour some fresh fuel into it, if it might clear out any accumulated varnish and save the pump. Maybe
Since I found fuel in the main line at the rail, I assume it had fuel all the way back to the pump and did not dry out.
Then again, maybe it's dead.
Thoughts?
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FAQs. Covers jumpering the fuel pump relay. If you pull the intake pump fuse, then only the main will run. If you pull the main pump fuse, only the intake will run. Only do this for a few seconds.
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Post Back. That's whats makes this forum work.
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