FAQs about Fuel Pumps

  • How to replace the in tank fuel pump.
  • Where is the fuel pump relay?
  • What causes my fuel pump to whine?
  • How can I check the check valve?
  • What are some symptoms of a dying fuel pump?

  • How to replace the in tank fuel pump.

    Date: Sat, 17 Aug 91 14:04:10 -0400
    From: jxs18@po.cwru.edu (Jerry Sy)
    To: mm@lectroid.sw.stratus.com
    Subject: Re: US$114 for the in-tank fuel pump?
    Cc: volvo-net@me.rochester.edu

    > You don't need to drop the tank to get to the in-tank fuel
    > pump. You can get to it from the trunk or, in the case
    > of a wagon, from the rear tailgate.
    > As for the $114, does this include the filter as well?
    > Did they order the main pump by mistake?

    > Micahel

    When I had my in tank fuel pump fixed, I paid $90 for parts labor and taxes. The mechanic returned to me the old pump and the filter. Could you tell me if this is indeed the in-tank fuel pump ?

    pump is cylindrical about 2.5" high and 1.5" diameter, it has 2 terminals sticking out on one end and a white plastic tube. on the other end, it is made of black plastic and the filter is attached to this. The filter looks like a small nylon tube (black color) about 5.5" long and 1" across.

    Somehow I think my problem has not been totally fixed because now my fuel is less that 1/2, I start hearing a buzzing sound again and I can still feel that the car will almost stall again also, the mechanic told me he had to take down the gas tank, is this correct ? or is the fuel pump he replaced the main fuel pump ?


    Cc: volvo-net@me.rochester.edu
    Subject: Re: US$114 for the in-tank fuel pump?
    Date: Sat, 17 Aug 91 12:48:18 PDT
    From: "John Abt" <johna@gold.gvg.tek.com>

    I did the in-the-tank pump job myself on my '80 264.

    It's easy except for the first step. You have to remove a large (about 3") twist-lock sort of cap at the top of the fuel tank (sedan, in the trunk). It's a little tight due to a rubber compression donut style washer. If you have the Volvo tool, I'm sure it's no problem. Without the tool. you have to improvise a little, or possibly fabricate your own tool.

    When you get this cap off, everything comes out with it. You have to be careful here because the fuel gauge sender is also in this assembly and it could be damaged if bumped.

    There's a couple of hoses associated with the pump which also should be replaced.

    I'd bet that more often than not, the problem is the filter. Volvo recommends replacement at 60k mi, but nobody does it.

    John Abt

    Date: Sat, 17 Aug 91 23:27:18 EDT
    From: mm@lectroid.sw.stratus.com
    To: jxs18@po.cwru.edu
    Cc: volvo-net@me.rochester.edu
    Subject: US$114 for the in-tank fuel pump?

    Yes, that's the intank pump. Even if it wasn't the in-tank pump, you don't have to remove tha gas tank to replace the main pump. In fact, the main pump is trivial to replace. Your gas tank could have alot of crud in it. Your fuel accumulator could be spent. The line between the accumulator and the main pump, or between the main pump and the fuel tank could be clogged, thanks partially to alcohol in the fuel (not your fault). Your main pump could be bad as well. I forget how many miles your car has, but my original pump went 148K. Think how many gallons of fuel it pumped in it's life...


    Date: Sun, 18 Aug 91 10:36:14 -0400
    From: jxs18@po.cwru.edu (Jerry Sy)
    To: mm@lectroid.sw.stratus.com
    Subject: Re: US$114 for the in-tank fuel pump?
    Cc: volvo-net@me.rochester.edu

    mine currently has 132k. is the main pump and the accumulator located under the car ? or in the engine compartment ?

    my car is now running <1/2 tank full. I can still feel a little stall once in a while, but then, yesterday was not a particularly hot day, it was raining here all day.



    It's 160 miles to Chicago, we have a full tank of gas, half a pack of cigarettes, its dark and we are wearing sunglasses. HIT IT !!

    --Joliet and Elwood Blues, The Blues Brothers

    Date: Wed, 21 Aug 91 21:10:46 -0400
    From: jxs18@po.cwru.edu (Jerry Sy)
    To: mm@lectroid.sw.stratus.com
    Subject: Re: US$114 for the in-tank fuel pump?
    Cc: volvo-net@me.rochester.edu

    > Did you check the fuel pump relay?

    > Michael

    I discovered that the 5th fuse (in-tank fuel pump) got busted, replaced it and the buzzing dissappeared.

    From: kaleb@thyme.jpl.nasa.gov (Kaleb Keithley)
    Subject: Fuel pump from hell (???)
    To: volvo-net@me.rochester.edu
    Date: Mon, 9 Sep 91 8:58:16 PDT

    Well, I tackled my in-tank fuel pump on my 760 wagon this weekend. I hope I never have to do that again. All I can say is it better have fixed my stalling problem.

    What went wrong you ask? Actually, the removal was a snap. Getting to the access door in the wagon was easy enough, fold the rear seats down, remove three nuts and the floor panel slides forward to reveal the access door. Remove the access panel and four hoses. (All the clamps were facing the wrong way.) Then a gentle tap with a wide screwdriver and a mallet to remove the "ring", and voila, out come the fuel gauge sending switch and pump assembly. Half an hour, max. I thought I was home free.

    When I'd picked up the new fuel pump from the dealer, I looked at it; if I'd noticed that there weren't nuts on the electrical terminals, I probably dismissed the fact, presuming that I'd use the old nuts from the old pump.

    At home, the first thing I noticed is that the new pump is about an inch longer than the old one. Hmmmmh. Doesn't seem to be a problem, I just took an inch out of the rubber fuel line which connects the pump to the steel fuel line. So I installed the new pump into the plastic "bucket", clamped the now one inch shorter fuel line down and went for the electrical hookup, only to discover that the nuts don't fit. Out came the tap and die set... Well, the old pump used 6-32 standard threads. The new one must be metric. Off to the hardware store with pump in hand... Only to find that 3mm nuts are too small, and 4mm nuts are too big. Back home. Compared the terminals to my 3mm tap. Yup, they're bigger, and smaller than the 4mm tap. Must be 3.5mm; don't have that one, chart shows there is one. Off to Sears; they don't have one. It's in the catalog, they'd be happy to order one. Well, my car's half apart in my driveway, I can't *wait* while they order one. Three hardware stores, two tool supplies, a hobby shop, and two hours later, I still have neither nuts nor tap in hand.

    So, I tried soldering the them on. I don't know what they coated those terminals with, but they sure didn't want to take rosin core solder at all. I finally had to resort to getting the terminals hot with the soldering iron and dabbing some acid flux on them. Only then would the solder take. Meanwhile I was praying that the heat didn't melt other solder joints or plastic inside the pump.

    After all that, closing up and cleaning up took another half hour, piece of cake. Started the car and let it idle while I put the interior back together. No apparent damage to the pump by soldering on it. The car runs fine. Now I have to wait and see if it stalls...

    The moral to the story is, if you haven't guessed it by now. Either let the dealer do this job, or don't let them give you a pump without the nuts on it.

    BTW, the old pump was an AC (as in AC/Delco), the new pump is also an AC part, and, unlike the old one, has an AC part number stamped on it (which I wrote down, but left at home, so I'll have to follow up with a post of the part number). Now, if I could find an AC dealer/jobber who could get this part, it makes sense to buy it on this side of the pond before it's been sent to Sweden, repackaged in a Volvo box, and sent back, right? And probably a lot less expensive too!

    Kaleb Keithley kaleb@thyme.jpl.nasa.gov

    Not authorized, in any way, shape, or form, to speak for anyone.

    Return to the top of the

    Where is the fuel pump relay?

    Date: Thu, 5 Sep 91 11:53:24 EDT
    From: wiegman@orion (Herman L. N. Wiegman)
    To: volvo-net@me.rochester.edu
    Subject: fuel pump woows

    well, the recent discussions of people having some trouble with their fuel pumps finally hit close to home. One of my co-workers called me and asked me for a ride because his car stalled dead in it's tracks. I didn't like the sound of it because he owns two Volvo's. I took a minute and didn't hear any buzzing from the rear. My first guess was the main fuel pump. Wrong. There also wasn't the slightly higher pitch, but softer noise from the intank pump. Reality was that no juice was ever sent to the fuel pumps.

    This led us to the fuse box, which checked out, and then to the Haynes manual. Now it looks like one of three things ...

    1)the fuel pump relay (which delivers power to both of the pumps)
    2)the key ign. switch (i've seen only one fail, but it was hard to diagnose)
    3)the ECU module (it also has a control signal which goes to the fuel pump relay probably to regulate the fuel pressure.)

    Questions 1) any guesses as to where the fuel pump relay is ?

    2) anybody with an old ECU? (1983), else i will call Strandurgs for a used one.



    p.s. in my initial phone calls, i asked about Main Fuel Pump prices.

    from the dealer -> $265 retail, but he was willing to cut some slack, so it would come to $225. from wrecking yard -> $45 used, with 30 day guarentee .. not bad.

    Cc: volvo-net@me.rochester.edu
    Subject: Re: fuel pump woows
    Date: Thu, 05 Sep 91 10:43:25 PDT
    From: "John Abt" <johna@gold.gvg.tek.com>

    The fuel pump relay is under the dash on the drivers side (or at least it is on my 3 200 series). It is a small green plastic box about 1x2x.75 inches with a black plastic conn on the end. It is attached with a spring-loaded clip usually to the lower-inside dash by the steering column, but easy to find if not there.

    I would recommend getting the number off the part to match at the dealer... there are several versions out there.

    When these things go, it's usually intermittent due to poor relay contact. As a temporary fix, you can take the plastic cover off and clean the relay contacts with some 400 sandpaper. (That won't last long though, you should definately replace the relay.)

    I believe the control from the ECU is actually just a switch controlled by the air-flow flap (sorry, I forgot the real term) in the fuel injection, i.e., no air flow, no fuel pump. Also, the pumps are engaged when the motor is being started (there might be a time-out on that).

    A good way to test if the pumps are getting juice is to just "pulse" the starter for an instant - then you can hear the pumps run for a second or two before the relay drops out.

    John Abt

    Date: Thu, 5 Sep 91 12:13:22 EDT
    From: mm@lectroid.sw.stratus.com
    To: wiegman@orion.crd.ge.com
    Cc: volvo-net@me.rochester.edu
    Subject: fuel pump woows

    > Questions 1) any guesses as to where the fuel pump relay is ?

    No guesses needed. It's under the dashboard, to the left of the steering wheel column (as you look at it while sitting int he seat). It's green and about 2" high and 1" wide.

    They run hot and cause the pc board that the relay sits on to overheat and burn the connections. Also, the contacts wear and don't make proper contact. You can check it out just by pushing the contacts closed with your fingers with the ign. key on. If it works then, you might be able to sandpaper lightly the contacts and get some more life out of it. Don't go for a used pump relay, unless it's out of a new car...

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    What causes my fuel pump to whine?

    From: southern@neit.cgd.ucar.edu (Lawrence Buja)
    Subject: Pre-Pump repair
    To: swedishbricks@me.rochester.edu (Volvo mailing list)
    Date: Sun, 4 Jul 93 7:53:51 MDT

    I just replaced my prepump to try to silence a noisy main pump. To see if the noise is coming from the main pump, stick your haid up under the car in front of the drivers side back wheel. At least that's where it's located on my '82 245. While the pump should make some noise, it shouldn't be an unpleasent whining or buzzing.

    As far as changing the prepump, it was not well documented in the manuals that I had. So, here's what I did and discovered:

    [go to the trunk and remove the carpet (or rear deck in a wagon).-hlnw ]

    1. Find the little square steel cover (attached with 2 screws) and disconnect the wires (1 ground and a small harness) coming out of it from their connections in the car.

    2. Remove the little cover. To get more room, detach the little cover from the grommet protecting the wires and slide it off the wires and out of the way.

    3. Below is the round hatch attached to the top of the gas tank. For me, there were three gas lines, one which was a capped off dummy, and the wires coming out of it. Don't detach the wires. The outgoing gas line (the middle of the three gas lines) detached without any problem, I plugged the rubber fuel line with a generic 3/8" socket extender to prevent contamination and spillage. The return fuel line was a bigger problem as there no connection to detach. I ended up jacking the rear of the car up and undoing the next connection upstream, over the axle with a 9/16" and a 5/8" wrench. There was some minor gas spillage here too.

    4. The hatch system consists of four pieces: The Hatch, The Ring, The Lip and a rubber seal. The Hatch itself is a plain round flat plate that has the wires and fuel lines running thru it. It is not threaded or anything, it's just a flat plate. The Ring is a strange crownlike affair. On the inner radius there are square castellations sticking up to apply the wrench to. On the outer radius are ramped castellations which engage The Lip (kinda like a reversed radiator cap). The Lip is a formed ring, welded to the gas tank, designed to engage the ramped portions of The Ring. When The Ring is rotated, the ramps engage The Lip, forcing The Hatch down tight against the rubber seal and the top of the gas tank. To loosen this system, The Ring is rotated counter-clockwise, the normal loosening direction. Since I didn't have the special wrench to remove The Ring, I carefully applied the old screwdriver+hammer method to the square castellations with great success.

    5. Once out, replacement of the prepump and in-tank filter is trivial. I did replace the rubber gas line connecting the prepump to the steel gas line attached to The Hatch, since the old one was deteriorated badly.

    6. Reverse the proceedure to replace it all.

    I applied penetrating fluid to The Ring for several days before since there seemed to be a fair amount of grunge collected in this area.

    The old prepump was as dead as a doornail. 12 volts to the new one sent it spinning, 12 volts to the old one did nothing.

    The new prepump stopped the main pump from buzzing. For 20 minutes :-( Then the buzzing returned. For my next trick I'll disable the main pump and run the feed from the prepump into a jar to see what kind of volume it's moving.

    /\ Lawrence Buja Climate and Global Dynamics Division

    \_][ southern@ncar.ucar.edu National Center for Atmospheric Research


    Date: Mon, 13 Apr 92 13:37:25 PDT
    From: u6946@craywr.cray.com (David Dannenberg)
    To: miken@apd.mentorg.com, swedishbricks@me.rochester.edu
    Subject: Re: Whine from the rear

    I have a 78 Volvo 262C and a 79 Volvo 245DL. In the past year, both have had the fuel pre-pump replaced (about $200 repair job at a Volvo dealer). I was told that if you hear unusual noises from the fuel pump area when you are below a 1/4 tank, be ready for some fuel pump problems. I should point out that I bought my 262C in 1988 with about 50,000 miles on it, and it lurched whenever I took off from a dead stop ONLY if the tank was less than a quarter full. I was able to drive it this way for almost 3 years (about another 30,000 miles) before the pre-pump died completely.

    As far as a high pitched whine from the rear, my 79 245 has been making sounds like that every since I bought the car new. I look at it as an aid to let me know the fuel pump is working. If I don't hear it, the fuse probably blew again. It appears to be normal for the fuses to blow every few months or maybe only a couple times per year, depending on the car I guess. I've owned 4 Volvos and I've noticed it with 3 of them. I've also been told by mechanics that it's not all unusual.

    Dave Dannenberg


    Date: Mon, 13 Apr 92 16:26 EST
    From: STEVE GINELL 201-932-2200 <GINELL@dnarna.rutgers.edu>
    Subject: FUEL LINE WHINE
    To: SWEDISHBRICKS@me.rochester.edu








    Date: Mon, 13 Apr 92 14:54:49 PDT
    From: senator@cco.caltech.edu (Bill Bradley (D NJ))
    To: swedishbricks@me.rochester.edu
    Subject: Whiny noise

    Check your gas cap. It sounds strange, but when Brian mentioned it only happening when the car is low on gas, it reminded me of when the vent on my gas cap when bad and the cap started making high pitched, surprisingly loud noises from venting. It also had the effect of making the car run really rough after having it at highway speed for a while.


    To: jxs18@po.cwru.edu (Jerry Sy)
    Cc: swedishbricks@me.rochester.edu
    Date: Thu, 28 Jan 1993 12:05:33 -0800
    From: Rick Farnbach <fsf@wv.mentorg.com>

    >>>>> On Thu, 28 Jan 93 11:33:41 -0500, jxs18@po.cwru.edu (Jerry Sy) said:

    Jerry> Great ! Now, how do I replace the in-tank pump ?

    Pop the access cover off in the trunk. Clean the area around the pump cover *now* so you don't knock any dirt into the tank or, worse, into the valley that seals against your O-ring. The whole cover unscrews by inserting about a four inch wide, two prong fork behind a couple of dogs in the cover and rotating. I've seen this operation performed by putting a screwdriver behind just one of the dogs and tapping with a hammer, but this could potentially damage the cover. If you're going to try this, work both dogs equally until the cover begins to turn. Either have a friend work on the other side or alternate between the two yourself. If the cover doesn't look like it's going to move, give up. You should be able to fashion a reasonable facsimile of the Volvo tool by welding a handle onto a bent piece of stock, like so (ASCII GRAPHICS ALERT!):

             Weld handle to bar, or drill and bolt



    \_______/_______ /\__________\/ <---- bar for handle

    //\_____// /

    // / // /

    // / // /

    // / // / <---- Bent piece of stock

    // / // / Make sure each leg is long

    // / // / enough to reach cover from trunk.

    \\/ \\/

    Measure opening to fit

    prepump cover

    Installation is the reversal of removal. (Haynes readers should know what that means.) Use a new O-ring. Clean the O-ring mating surface on the tank with a vacuum and possibly a tack rag. Take care not to drop dirt or rust into tank. Don't use compressed air since this will knock dirt into the tank. If this O-ring doesn't seal, when the tank pressurizes it will dump gas out the top of the tank where it will blow backwards onto the muffler and potentially ignite.

    Test the O-ring's seal by filling the tank as full as possible, making sure there is some gas in the filler pipe. Since the filler pipe is higher than the top of the tank, if the O-ring is not sealed gas will leak around the O-ring. Remove the access cover in the trunk and check around the seal. If there is gas, have the car towed back and try it again. If you clean the mating surface and use a new O-ring you should have no trouble getting a proper seal.


    From: "David E. Cox" <decox@vdoe386.vak12ed.edu>
    Subject: Re: Noisy Fuel Pump
    To: swedishbricks@me.rochester.edu
    Date: Mon, 25 Jan 93 11:55:24 EST

    Add my 75 245 to the noisy fuel pump group, especially with a fuel tank that is low. Been going on since I bought the car in '75. In fact, within days of picking up the car, I encountered random no-start conditions. I had the car towed back to the dealer on a couple of occasions. Turned out to be a loose ground wire on the fuel pump (or so I was told).

    you may want to carry along a cane or stick to give it a whack should the car not start and you suspect fuel pump problems. Usually that's all it takes to get it going so you can get it home or to your favorite repair shop. (Of course, you will also want to check the fuse.)

    David Cox (decox@vdoe386.vak12ed.edu)

    Date: Mon, 25 Jan 93 12:55:43 -0500
    From: jxs18@po.cwru.edu (Jerry Sy)
    To: swedishbricks@me.rochester.edu
    Subject: YABFP (yet another buzzing fuel pump)

    My 264 has experienced the buzzing fuel pump ever since I let a mechanic replace the in-tank filter (if he did replace it).

    But mine occurs only when the temperature outside is > 80 def F, and when the gasoline is less than half tank, and begins to buzz as soon as I hit my first bump. The buzzing stops (sometimes) if I hit another bump again, and so on.

    this has been going on for more than a year now.


    79 264 156k

    Date: Mon, 25 Jan 93 15:16:59 EST
    From: wiegman@orion (Herman L. N. Wiegman)
    To: memsthd@prism.gatech.edu
    Subject: Re: Noisy Fuel Pump
    Cc: swedishbricks@me.rochester.edu

    Mike, and netters (just about all of us besides the Diesel crowd)

    >Any idea what causes the buzzing?

    Well, I thought it was due to the Main Fuel Pump's rotors, but it seems that some people have noticed buzzing after a mechanical disturbance suggesting that a bracket may accentuate the noise.

    The Volvo manual on FI systems says...

    "Fault Symptoms: faulty fuel pump will cause low line pressure.

    The following symptoms may arrise.

    - engine difficult to start or does not start

    - engine misfires during driving, under heavy load

    - poor acceleration

    - poor engine performance

    - pump noise. NOTE! May also be due to a defective tank pump

    or vapor locks in the fuel system.

    Fuel Pump NON-return Valve, fuel accumulator: if these components are defective, the rest pressure will be below the specified value.


    - difficult to start warm engine. "

    I know that the post 1975 Main Fuel Pump is a centripital (sp?) pump which can not "suck" fuel. The job of the In-Tank pump is to feed the more costly Main Fuel Pump. If the In-Tank pump is marginal, one will experience more buzzing from the Main Fuel Pump.

    I hope this helps...


    p.s. I have found that GE-silicone goo on the mating surfaces of the plastic dash pieces help to attenuate squeeks.

    Herman L.N. Wiegman -> wiegman@orion.crd.ge.com
    General Electric - Corporate R&D, Schenectady NY
    the Flying Dutchman in the DSP Swedish Brick -

    Date: 28 Jan 1993 22:45:22 -0400 (EDT)
    From: "John W. Retallack" <JWRPPH@ritvax.isc.rit.edu>
    Subject: In-tank pump, etc.
    To: swedishbricks@me.rochester.edu

    Jerry> Great ! Now, how do I replace the in-tank pump ?

    RICK> Pop the access cover off in the trunk.......

    I agree with all that Rick said (an excellent description of how to). And I add the following:

    In my case ('76 244) I found the job much easier with the gas tank out of the car. Perhaps that has to do with my size. It also had to do with the general condition of the entire system in my car. Several of the hoses were rotten and needed replacement. My in tank pump was an add-on by a dealer. The pump was OK in my case. The filter was dirty, all the hoses were bad. (I was running out of gas at 1/4 tank.) There is a 1 inch rubber hose inside tank on the pre pump/fuel gauge assembly. Mine was deteriorated to the point that it let air in the system when exposed.

    Note that there are 2 sizes of "O" rings. I suggest that you buy both and return the one you don't use.

    It's not a bad job, really. Just be careful... no smoking, no sparks.

    JOHN W. RETALLACK '69 1800s in restoration

    Subject: Re: F.P. Relay- Is it possible..?
    Date: Sat, 16 Dec 1995 13:24:06 -0500
    From: volvor@you.wincom.net (martti delabarre)
    To: jfritsch@vt.edu (Jon Fritsch)
    CC: swedishbricks@me.rochester.edu

    >Fellow Netters,

    >1980 245 97,000

    >I have the "whining" main fuel pump problem. I have gone through the

    My check for the in tank pump operation is to have someone listen at the filler hole while you pull the in tank fuel pump fuse. it should give an obvious sound differance/

    Martti Volvo Recycle Windsor Ont

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    How can I check the check valve?

    Date: Mon, 02 Aug 1993 10:56:13 -0400 (EDT)
    From: DJE8577@ritvax.isc.rit.edu
    Subject: testing check valve
    To: swedishbricks@me.rochester.edu

    To check and see if the line pressure is being lost during the time between shutting down and the next restart; turn the key on......the pump will run briefly (several seconds on a timer) this is to give a brief pumpin up of the fuel pressure.

    turn the key off.

    repeat this several times.

    If you note a difference in the sound of the pump prior to it timing out this is an indication that the pressure has come up to snuff. ( the pump feels the resistance to flow of fuel when the pressure is up and no flow is going to the engine).

    now try to start the car.......if it starts first time this is an indication that you have manually built up the pressure in the line by the key on off routine..........problem the fuel pressure is bleeding off during periods of not running. check for one way valves in the fuel supply system...it may be leaking internally hence the loss of standby pressure.


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    What are some symptoms of a dying fuel pump?

    Date: Fri, 1 Dec 1995 14:24:41 -0600 (CST)
    To: swedishbricks@me.rochester.edu
    From: dwillson@airmail.net (Don Willson)
    Subject: Re: fuel pump

    >A basic question
    >What are some symptoms of a sick or dying fuel pump?

    The engine will not get sufficent gas and will have low power or not run. But...

    What are your sysmptoms?

    Check the fuel filter if you loose power with a heavy foot, enough fuel gets through to run the car but not enough for full throttle accelleration.More likely the problem is getting power to the fuel pump.

    If it is intermittent it is probably in the electrical system, relay, ignition switch, connectors or other electrical parts.

    For the fuel pump to run the engine must be turning over, and this is determined from the distributor. So take it systematically and analyze the symptons.

    If you only loose power when turning with a low tank, 1/4 full, check the intank pump. It feeds the intake of the high pressure pump when the gas tank is on the bottom half.

    Don Willson, Retired Engineer
    Richardon, Texas

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