# HELP low voltage to fuel solenoid



## Greasemonkey91 (Aug 3, 2010)

im getting low voltage from the computer to the fuel solenoid. i have tested rhe solenoid changed the computer twice and cleaned and tightened all connections but still same problem. any ideas?


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## WaterWheels (Aug 14, 2005)

I think you are going to have to explain just what it is you're calling a "fuel solenoid". You don't say what car you are dealing with, whats listed to the left is often usless, so that information would be great too.


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## Greasemonkey91 (Aug 3, 2010)

im working on an 86 gti and its the solenoid on the side of the fuel distributor that lets the fuel flow to the injector lines. sorry if i dont know the actual names of the parts this is my first cis car


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## WaterWheels (Aug 14, 2005)

OK, most times called a diferential pressure regulator (DPR for short) but I believe VW calls it something else having to do with hydraulic this or that. Why are you testing for VOLTAGE there? The voltage is very low and what you should be testing for is milliamperes (mA) and then only if you have a reason, like setting the idle fuel mixture. What manual are you using which tells you to test for voltage?


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## Greasemonkey91 (Aug 3, 2010)

not using a manual i know the dpr is suposed to click when you turn the key on and its not. if i jump a wire from the battery to the dpr it clicks and work like its suposed to. and im just doing what testing i can with what tolls i have


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## cuppie (May 4, 2005)

OK. That's not a solenoid, and it most definitely is not supposed to click. 
Like WW said, it's called a Differential Pressure Regulator (DPR for short); also known as an Electro-Hydraulic Actuator (or EHA.)
And, it does not "allow fuel to the injector lines", either - the metering rods in the fuel distributor do that.
What it does is regulate the pressure differential (hence the name) between the lower (supply) and upper (control) chambers in the fuel dist, thereby controlling fuel mixture.

Respectfully, it seems that you aren't familiar with how it's supposed to work. So, I'd suggest this: *stop now*, before you do something to break it. Find information. Read. Study. 
Best thing to do: buy the Bentley manual for your car. It's well worth the ~$45 that it costs. We call it "the Bible" for a reason.  

No cash? Then to the internet with you!
Bosch official CIS operational theory (applies to CIS-Basic and CIS-Lambda; but, most of what you learn also applies to how CIS-E (KE-Jetronic/KE-Motronic) also work.)
KE-Jetronic power tuning. Also explains a lot of what's 'normal' operation.


Now, the $25,000 question:
what, exactly, is the problem that you're having with the car? 
We can help you figure it out; but, it would help if we knew what was wrong with it...


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## Greasemonkey91 (Aug 3, 2010)

getting fuel into the fuel distributor but not to the injector lines


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## ziddey (Apr 16, 2006)

none into the lines, or not enough pressure to pop open the injectors? your problem is well before the dpr comes into play at all.

are you using a horn relay in place of the fuel pump relay, or similarly jumping the pumps to run?

are you lifting up on the air plate? are you getting fuel to and from the distributor? I'm assuming you have no way of checking pressure.


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## Greasemonkey91 (Aug 3, 2010)

l put another fuel distributor on and im definately getting fuel to and from it. the car will start and run for about 5 seconds and shuts off.and i tried lifting the air plate and it doesnt seem to change anything. fuel pums are working off factory relay.


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## cuppie (May 4, 2005)

@ ziddey:
remember, he's got a KE-Jetronic (CIS-E) car. These use a simple 4-pin fuel pump relay, controlled by the knock control, as opposed to -Basic or -Lambda's 5-pin 'smart' relay. So, a jumper is required for fuel system dianosis.

@ greasemonkey:
first off, you have got to check the fuel pressure on this thing. No further diagnosis makes sense, until you're sure the fuel pressure is correct. CIS is _extremely_ sensitive to incorrect fuel pressure.

Once you're sure that the fuel pressure is correct...
remove all four injectors, place each into its own glass container (say, a clear beer bottle.) Remove fuel pump relay, and jumper pins 15 and 87 in the relay socket. Turn key on - pumps should now run continuously. No fuel should be coming out of the injectors.
All OK so far? Start lifting the airflow meter plate, and watch the injectors. When they start spraying, note the pattern - should be a nice, even cone shape, and all four should spray an equal volume (check volume after you drop the meter plate.)

Injectors check OK? Recheck for intake leaks - notably, something blatantly disconnected or broken. It doesn't take a particularly large intake leak to make the engine do the start-n-stall that you describe - it's quite possibly running solely off of the cold-start valve's injected fuel, and is suffering from a large-enough intake leak that it can't lift the metering plate plate enough to fuel itself.


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