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    Thread: Brand new fuel pump test pressure fail! Why?

    1. 09-08-2012 12:15 PM #1
      Hi, for five years now my Corrado was sleeping in the garage. Last year I had time to work on it and tried to put it back on the road.

      When I tried to start for the first time my engine, it was cranking, but wont start.

      Finally I found that it was the fuel pump that was dead.

      I went in a speed shop to order a brand new one and tried a second time my engine. It was runnig good at iddle, but had trouble at WOT.

      So I read the FAQ's and tried to find why I had this trouble.

      After all, I did a big tune up, change the rotor and cap, blue, black sensor, plugs, all vaccum and the one to the ECU 1m long, fuel filter, and spark plus wire and the air filter and some other things.

      I checked to make sure that all wires in the engine bay was in good shape.

      After all, the trouble was always there, runnig find at iddle, but no power at WOT.

      Finnally, I did a fuel pressure test and had 3 bar of fuel pressure, so my FPR is a 3.5bar

      I called the guy who sold me this fuel pump to have another one and now with this new pump I have 3 bar fuel output at the fuel pump.

      I did the test putting the gauge at the output of the fuel pump, so I dont understand why nthe pressure is so low with those fuel pump.

      I dont know the brand of the fuel pump, but when I read in the bentley it's look like it was two models of fuel pump for the corrado, one with two fuel pump and another one with one fuel pump in the tank!

      The one with two fuel pump is supposed to give 3 bar and the model that I have with one fuel pump in the tank is supposed to give me 4 bar at the output of the pump!

      I'm not a mecanic, and the speed shop tell me that the fuel pump is supposed to gave me 3 bar of fuel pressure at the iddle and the pressure was supposed to be higher at WOT. I asked the guy how the fuel pump was supposed to gave me more pressure at WOT if the voltage at the pump is always in between 13-14V and he did'nt gave me any reasons.

      So I want to know if it's the good way to do the fuel pressure test, my fuel tank was open and I put the gauge at the output of the fuel pump with a T fitting.

      Help me please, I want to put this bitch back ont the road as soon as possible!



    2. 09-08-2012 12:27 PM #2
      This is how I did the test:

    3. Member sdezego's Avatar
      Join Date
      Apr 23rd, 2004
      Hurricane Central FL
      '90 Corrado | '62 Harley Panhead
      09-08-2012 04:56 PM #3
      if you are checking the pump output, then you need to have that line to the left of gauge T pinched off completely. You should see about 70-80 PSi

      The way you have it, you are essentially checking the Rail pressure. which should be 3 Bar with the car not running (3.5 if someone changed it to a 3.5 FPR).

      When you changed the pump, did you clean the tank. When the pumps go bad, they leave a ton of goop and stuff at the bot of the tank from the rubbers and isolators. This will clog up the intake screen of the new pump and cause issues.

    4. 09-08-2012 06:43 PM #4
      Yes I know that the other side of the T fitting is supposed to be off, it is but you just dont see it in this picture!

      I know that the old fuel pump let some **** in the tank, that why I drain my fuel tank and clean it all before installing my new pump.

      Today I went to a scrap yard and find a OEM fuel pump from a MKIV jetta, I dind'nt know if it was a V6, 1.8T ou 2.0, but I removed the fuel pump and I tried it in my fuel tank!

      I had 70 psi of fuel pressure and my engine was runnig better than the brand new pump that I had from the speed shop!

      Where can I buy a new pump, a good one?

      If y someone know where I can buy one!

      Looks like my speed shop are unable to find the goog pump for my Corrado!

    5. Member sdezego's Avatar
      Join Date
      Apr 23rd, 2004
      Hurricane Central FL
      '90 Corrado | '62 Harley Panhead
      09-08-2012 07:20 PM #5
      Even the Cheapest pumps, I have rarely seen them bad right off. It happens though so, maybe you got one. IDK, but seems odd. It a pump runs dry for even a brief period, it can ruin. Did not see where you said you cleaned out the tank, but I could have missed it. Some skip this step and the crap in the bottom clogs up the intake screen in short order and causes the pump to cavitate and starve and will never make proper pressure. ..and ruin the pump

      If you pulled the new pump out and the screen was clean, then you must have gotten a bad one. See if the Shop you got it from will warranty it. Even the cheap pumps usually have a min warranty.

      The problem is that the factory pump replacements do not accept the stock Fuel gauge sender from the Orig (since VW changed from Pierburg to VDO). So, unless you have a VDO sender (99.9% you do not), you will need to buy a pump and a sender. It is $$$ to do it proper. TRE Performance sells an aftermarket unit $89 that comes with everything (pump and sender) but on the G60 it is not a direct replacement plug and play even though it says so The VEMO that some places sell is cheaper than VDO, but require the new sender as mentioned just like the VDO. And it's not that much cheaper. So, for me, I am not paying an arm and a leg for a FP to get some off brand.

      Best bet and never have to deal with it again is to go with a name Brand VDO replacement and Sender (germanautoparts.com). However, it is not cheap. -> http://www.germanautoparts.com/Volks...rado/Fuel/97/2 However, it is one thing you will never have to deal with again!

      There are other alternatives, but they require you to get very creative and there are caveats with all of them.

      The MkIV itself should work fine, however, I think the sender will cause your gauge to read backward

    6. 09-09-2012 09:18 PM #6
      When I take off the pump I*looked under and it was very clean, I had no clogs in the tank.

      To be sure that the pump was not damage, I put 20L of fuel in the tank!

      I know that my new fuel pump was not a VDO, but I paid 260$ for this fuel pump!

      I just buy this MKIV VDO fuel pump to do a test, and for 18$ to know where is the real trouble, it's cheap and now I know that my car is running good with the MKIV VDO and lean with the new no name fuel pump.

      I dont care about if it's cheap or not, I just want to drive it as soon as possible.

      If I have to pay to play, I will do it!

      I will check with the speed shop if they can give back my money or not and see after for german auto parts!



    7. 09-23-2012 09:57 PM #7
      I tried a brand new VDO fuel pump and now tha car is running good!



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