shortcut for priming injection pumps - General - VWDiesel.net The IDI, TDI, and mTDI source.

• shortcut for priming injection pumps by Dr. Diesel on 05 Sep, 2004 18:32
• Here's a quick way to get an engine going that's been replaced or sitting long enough for the fuel to drain back into the tank. Fill a clean container (like an oil quart bottle) with fresh fuel. Remove the pump's supply hose from the fuel filter and stick it in the bottle. Crank engine, and observe fuel being pulled from the bottle. (you might first pour a little in the line to wet the pump if it's been sitting) When the engine starts and settles into a smooth idle (relatively speaking, of course) quickly pull the hose from the bottle and slip it back over the fuel filter outlet. Grab the throttle and rev the engine up. It'll probably slow down, cough and buck a bit,  but should draw fuel from the tank before the pump uses up it's internal fuel.
  Voila! No more cranking the starter for minutes at a time!
• #1 by VWRacer on 06 Sep, 2004 06:47
• Dr Diesel, I once ran my NA Rabbit out of diesel, but got it running right away by using the following trick. I loosened the nut on each injector, then had my wife hit the starter while I watched for fuel. Within 5 to 10 seconds I could see fuel beginning to ooze out from around the nuts, asked her to stop cranking, then tightened the line nuts back up and had her hit the starter again. The engine fired right up. It ran rough for a few seconds, but as soon as what little air was in the system was purged, there was no problem.
  
  I think the key thing is to purge the air as much as possible before trying to start the engine. If the injector pump has to "inject" a pint or so of air before it can start injecting fuel, as you say, it's gonna take a while! By cracking the line nuts, though, you give the air an easy escape route and the pump can start injecting fuel within seconds.
  
  Stan
  
  OTOH, I once ran the Cat 3208 in my motor home out of fuel, too!  :?  :roll:  :cry:
• #2 by fspGTD on 06 Sep, 2004 13:57
• The only problems I've ran into with getting a pump back up and running is after it's been removed from the car, when the fuel is drained out of it's housing...  if you merely run the fuel tank dry, there still seems to be an adequate volume of fuel inside the pump housing that is is "self priming" - IE: you can get it going by just cranking over the engine (long enough.)
  
  If the pump housing is totally dry though, say after you've had the pump removed and it's been laid on it's side so all the fuel has drained out, then in that state, it seems that even with fuel at the fuel supply union, and no matter how much cranking with or without the injectors cracked, the pump just can't prime itself.
  
  What I've been doing most recently is hooking up one of those outboard motor fuel line hand-squeeze bulbs into to the fuel supply line, and squeezeing on that bulb hard to get fuel forced though the pump.
  
  A method that works easily on only an NA diesel is to use a turkey baster to squeeze clean diesel fuel directly into the pump housing through the fuel outlet port (remove the banjo fitting on top of the pump there.)  Getting it into the fuel stop solenoid port works also as it's also connected directly to the main, high-pressure cavity inside the pump.  When primed this way, the pump will start firing the engine virtually immediately.  However, this method is hard on a turbo pump, because the LDA device is in the way of easy access to the fuel outlet hole.
• #3 by Giles@PerformanceDiesel on 07 Sep, 2004 17:34
• what i do in my shop is to blow compressed air into the return line
  of the vehicle (take off the filter) and watch the fuel flow into and out
  of the pump.... don't blow too hard or you'll blow the tank up.
  
  Giles
• #4 by Dr. Diesel on 07 Sep, 2004 20:11
• Quote from: "Giles@superiorFuelInj"

  don't blow too hard or you'll blow the tank up.
  
  Giles

  
  
  geez. I should have read the whole post. oops!
• #5 by caddywompus on 18 Sep, 2004 13:14
• I've had great success priming the IP by removing the return line from the pump (the line that goes back to the tank), and pulling a vacuum on the IP OUT fitting with a hand-operated vacuum pump.  Of course, this will also uncover any air leaks in your injector return hoses, but as long as these are all tight, this method is very easy and relatively clean.
  
  Justin
  81 Caddy 1.6TD
• #6 by ejust on 07 Nov, 2004 12:43
• Hers my $.02 worth. I did this to see how the injectors sprayed and how well the pump worked. Youll need a battery charger, fairly powerful drill, 19mm socket (1/2" drive), 19mm bolt and 19mm nut for bolt. Slip the bolt into the socket backwards(threads thru the square hole), install nut (spacers may be needed depending on bolt if threaded all the way). and grind the end of the bolt down so you can chuck it up on the drill (to about 5/16 or 8mm). The 19mm nut clamps the socket in in place to bolthead. Use the drill to spin the pump over. Use the charger on low 12V setting (2A or less) and hook red to solenoid lead and black to pump housing. Insert infeed line into fresh clean fuel and have an outfeed line and catch jar for return. Chuck up the homemade 19mm socket bit into drill, turn on charger, and spin away!!! <- make sure your lines and injectors are connected firmly AND YOU WEAR SAFETY GOGGLES!! You can watch the injectors at different rpms (my drill goes up to 1200rpm) and opening and closing the throttle.  You can use this trick to prime the pump if IP was removed. Reinstall IP on car inc lines and injectors but leave the lines loose at the injectors. Hook infeed and return lines all up. Spin the pump over till you get fuel leaking out. Torque lines to spec. Spin IP over for only a couple more seconds with throttle open.  Most if not all air will be gone and you should get instant start up.  Sorry it was long winded but hope it helps!
• #7 by Fisher on 15 Oct, 2005 14:18
• I just remove the return line from the pump and push on a piece of clear hose and suck on it till you see fuel in the clear line.  Easy, remove clear line and replace with return hose, You're done.
• #8 by fatmobile on 16 Oct, 2005 18:02
• Only thing I can think to add is if the pump has been sitting for a long time, it's a good idea to replace the "OUT" bolt with a normal banjo bolt that doesen't have a restrictor and screen.
   Disconnect the power so the injectors don't get fuel and use one of the many good ideas above to get fuel coming out the return line.
   Plug in power and crank it over. Let fuel flow through the injection pump for awhile and flush any bacteria colonies, rust or chunks from the pump body.
   Then swap the "OUT" bolt back in.
• #9 by VW Scully on 18 Oct, 2005 18:10
• These are good ideas I am going to be storing my Rabbit this Winter and will be replacing all the fuel lines with Viton (since I run BioDiesel), so this is good to know, should I need to remove the pump.
  Thanks guys!  
• #10 by Master ACiD on 18 Oct, 2005 21:42
• where do you get this urethane that is 12 times cheaper?
  
  thanks.
• #11 by VW Scully on 19 Oct, 2005 18:14
• I have a friend who works at a motorcycle supply company so I will ask him about it . I also bought all my hoses/clamps etc. for my BioDiesel processor at a local hose/tubing place so will check there too.
  I was going to get the Viton through my local VW shop and yes, it is expensive!  :shock:
• #12 by mortskeg on 10 Nov, 2005 23:13
• I've been running the urethane fuel line for about a week now and from my local powersports store it only cost me just over $8 for the 4' of 1/4" and 5' of 5/16".  Hopefully the fact that I feed the squirlles peanuts and the garage will keep my new fuel lines safe for some time.
  
  I just need to figure out something for the large diameter filler-tank rubber and pump seals and I will be 100% ready for B100.  Thanks again.
• #13 by mortskeg on 11 Nov, 2005 11:26
• I was wondering why the squirrels started running down the trees tail end first.   Good to know info for the squirrel lover/hater.  Sorry about the thread jack.
• #14 by hillfolk'r on 11 Dec, 2005 09:23
• as far as priming up a pump,,a few of these methods have worked for me,,,cracking lines loose works good,,,,,,ive aired up the tank too,,thats ok,,just dont blow the tank,,,im using a lift pump currently,,so priming isnt bad,,,,for the "pump that has beenlayin on its side",,ive taken a syringe+put in a few oz of atf,,its thicker than diesel fuel,and coats inside of pump for prime,,,,,,at work,on big old detroit 2 strokes,,ive added motor oil in the fuel inlet,,cause the gear pump(liftpump) can be fussy at pulling fuel,,,,,the fuel priming bulb works good too,,,,,,,,,