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1Back to top Go down    Fuel Presure regulator problems on Sat Jul 13, 2013 10:37 pm

IDTWIKA

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91 k100, I replaced the fuel pump and it is working, lots of pressure, I replaced the fuel pressure regulator because the bike had been sitting for 8 years. I am not pushing anything past the regulator. Could it be bad off the shelf?

    

2Back to top Go down    so on Sat Jul 13, 2013 11:35 pm

ibjman

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Nothing out the return port of the reg. back to the hose returning to the tank?
Have you tested the return pipe in to the tank to see that the check ball isn't rusted up in there, preventing it from allowing fuel back through in to the tank?
if so:
Have to put a pressure gauge between the fuel injector rail and the inlet to the regulator. If the gauge reads like 50 - 60 then the regulator isn't opening.....it should "spill over into the return hose port at somewhere around 35. My guess? Maybe the hoses are reversed at the tank and your pumping the pressure into the exhaust port of the regulator?
Otherwise, put the old reg. back on & try again.
If you connect a short U shaped hose between the two tank pipes and cycle the pump you should be abkle to see the fuel exhausting back into the tank return port by looking in through the cap hole.
Regards, Ibj...

    

3Back to top Go down    Fuel Presure regulator problems on Sun Jul 14, 2013 1:11 am

IDTWIKA

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all great ideas, but no,
The fuel pump actually is sitting in a coffee can full of gasoline, fuel tank in not part of the picture. I took pictures of pre dissemble and the orientation is the same. the regulator is the same model as the old one. Fuel is getting to the regulator but not past the regulator. When I "relieved" the pressure I still got sprayed with gasoline when I separated the filter. so the de-pressurizing did not work. I have tossed (sadly) the old regulator. The new one was sill in the plastic bag. Everything I have read indicated a poor regulator will result in poor performance, nothing is noted about no performance.
Thanks for chiming in.
Stephen

    

4Back to top Go down    Re: Fuel Presure regulator problems on Sun Jul 14, 2013 2:47 am

RicK G

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Use a piece od 5/16 tube and bypass the regulator, if you get a flow back into the tank then the regulator is the bad item, if you get no flow then look elsewhere.
When sitting the rubber vibration damper in the tank and around the pump will virtualy disolve along with the internal lining of the lines and the goo gets into the pump, lines and injectors blocking them. Its a good idea to replace the lines when they have been sitting like yours has. Make sure you get the right stuff for permanent imersion in fuel.
TIP Put the model and year of the bike in your signature line that way you dont need to tell us every time and no mistakes get made.
I know yours is a 91 K100 but RS of that year is 16 valve and RT/LT is 8 valve which are very different.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

5Back to top Go down    still worth checking on Sun Jul 14, 2013 5:06 am

ibjman

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A _-_ BE VERY CAREFUL! You have a HUGE explosion/Fire/Injury HAZARD there in your Coffee can!!!


Still worth checking are 2 things.

#1 observe the orientation in the photo:


Be sure the fuel is going in the side & out the top as pictured.

#2 the regulator will not pass any fuel back out the exhaust side if the pump is not building sufficient pressure to overcome it's "MAX" setting. Even though you have a new pump in the coffee can it could be a problem???
Install a test gauge between the pump and the inlet side of the regulator.

#3 Apply about 28" Hg Vacuum to the line port at the bottom. This will begin to lessen the pressure needed to make the regulator bypass fuel. Down to say 35 PSIg.

#4 A new regulator may well hold a lot of pressure for a long time without bleeding off especially if the check valve in the fuel pump is also good. Not unusual for it to hold pressure for hours.

#5 If all that is proved good, verify the result by re-trying the old reg.

Regards, Ibj.



Last edited by ibjman on Sun Jul 14, 2013 5:08 am; edited 1 time in total (Reason for editing : omission)

    

6Back to top Go down    fuel pressure regulator on Sun Jul 14, 2013 3:13 pm

IDTWIKA

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Thanks,
You have been more than helpful, I see the error of my ways, I had the in/out on the regulator reversed. You comment about the open can is well taken. I have a assistant with fire extinguisher at the side.


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In theory, practice and theory are the same, in practice they are different.
Stephen 1991 K100LT
    

7Back to top Go down    It is on Sun Jul 14, 2013 3:21 pm

ibjman

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It is "solved" then?????

    

8Back to top Go down    fuel pressure regulator on Sun Jul 14, 2013 5:32 pm

IDTWIKA

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correctly installed I am now getting fuel back through the return port of the regulator. Engine still not running. I have spark and if I prime #1 it will fire. When I pull the plugs they are dry, I believe the next step is to clean/replace the injectors.
It may be next week when I get that part.
Thanks again for your help.


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In theory, practice and theory are the same, in practice they are different.
Stephen 1991 K100LT
    

9Back to top Go down    You might on Sun Jul 14, 2013 6:25 pm

ibjman

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You might just want to check to see that you have power to the injectors to fire them?
All injectors get 12V + power all the time through a Green/Red wire from the fuel injection relay which in turn is also fed on a Green/Red wire directly from fuse #6.

The injector coils are fired from the Fuel Injection Controller by sending momentary ground signals to all the injectors on a Yellow/Green wire from Pin #12 at the under tool box FIU connector.

All 4 injectors fire at the identical time. The fuel waits in the intake port until the selected inlet valve opens.

So......at 1 or all of the injector nozzle connectors, 1 wire should be 12V + when cranking or running.
The other wire should be cycling between open & ground at the same time.

The easiest way to test that is with a "Noid" light available at most auto parts stores or with a standard auto test light touch the point of the test light to any of the injector plug contacts that have the Green/Red wire. Connect the ground clamp on the end of the test lamp wire to the positive battery post and crank the engine. The test lamp should blink on and then back off (very quickly) if the FIU is cycling the injector grounds.


Conversely, If you remove the test light then move it to the negative battery post and then touch the injector contact with the Green/Red Wire & crank the engine, the light should be on steady during cranking.

Regards, Ibj....

    

10Back to top Go down    fuel pressure regulator on Sun Jul 14, 2013 7:06 pm

IDTWIKA

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Thanks again.
That was also on the list but I had to get the injectors plug off and I ended up pulling the fuel rail and injectors. The tips of the injectors look like the bottom of my sisters "Easy Bake Oven" after I had cooked GI Joe.
Will double check the voltage.


__________________________________________________
In theory, practice and theory are the same, in practice they are different.
Stephen 1991 K100LT
    

11Back to top Go down    yes on Sun Jul 14, 2013 8:10 pm

ibjman

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Those plugs are tricky to remove. You have to take a tiny little pick and pry the retainer wire out at each end of the plug to get the plug off over it's retainer shoulder.
Sorry, I omitted telling you that. Now that you have the injectors out......after you have made some attempt at cleaning them, you can reinsert them in the upper fuel rail & point them out over the edge of the valve cover at a sheet of brown carboard about 8 - 10 inches away & cycle the starter.......you should get 4 nice even round damp spots on the cardboard.
CAUTION: Extreme fire danger when doing this.....make sure you don't have a disconnected spark plug wire or other ignition source hanging nearby. A fire extinguisher is recommended also.

OBTW. Each injector has a tiny little strainer screen kind of pressed down into the inlet port....very difficult to see, even when you know it's there.

You may have to find someone with an ultrasonic cleaner to clear them. I was fortunate on mine......even though I had year of deteriorated gasoline & gooey rubber all over inside the tank, Once I got the new tank & pump, the bike finally stuttered to life after about 15 mnutes of intermittent cranking. I did have a new battery in it also. I never did have to clean the injectors......I did run 1 can of Chevron techron through the first complete tank of fuel.....no worries since.
"Regards, Ibj...
PS: I'll be offline for 10 days starting tonight.....headed for the BMW rally in Salem, OR

    

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