# CIS-E problems Please tell me im right



## Dustindavisusmc (Apr 6, 2010)

I have an 87 golf 1.8l and am curious as to if the small round object mounted next to the fuel distributor??? i know it is a differential pressure regulator, but all the parts i look up screw to the side and dont appear to have any fuel connections. Also they are square... the VW part number is 027 906 267


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## turbinepowered (Mar 19, 2007)

The *D*ifferential *P*ressure *R*egulator is the small boxy thing bolted to the side of the fuel distributor. It has a two-wire electrical connector but no external plumbing connections.
You also have a _system_ pressure regulator. It has two plumbing connections, one to the return line and one to the fuel distributor. Also has a vacuum nipple, if I'm not mistaken. It's held to the fuel distributor by a small band clamp.


_Modified by turbinepowered at 3:13 PM 4-6-2010_


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## Dustindavisusmc (Apr 6, 2010)

*Re: (turbinepowered)*

the deal though is that it does have one line that goes to the bottom of the fuel distributor and one that goes to the top of it. ill take a picture and add it to the post... it also has a two prong electrcal connection..


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## ABA Scirocco (May 30, 2001)

*Re: CIS-E problems Please tell me im right (Dustindavisusmc)*

What you describe is NOT a differential pressure regulator (DPR) The dpr is a CIS-e part, the 87 Golf does NOT have CIS-e, unless it's a GTi. The fuel system you have is CIS-lambda and the part you describe is the frequency valve, it's shown here in red. ETKA calls the part "valve for lambda probe"











_Modified by ABA Scirocco at 7:08 PM 4-6-2010_


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## turbinepowered (Mar 19, 2007)

What he said ^
I've never owned an 80s A-platform car, so I didn't know what years got what system.


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## Dustindavisusmc (Apr 6, 2010)

*Re: CIS-E problems Please tell me im right (ABA Scirocco)*

thats it!!!! sorry trying to figure out how to load pic..... ok what does it do then.... im lost now


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## Dustindavisusmc (Apr 6, 2010)

*Re: CIS-E problems Please tell me im right (Dustindavisusmc)*

good call i looked it up... the part cost $375... curiosity now is it suppose to squeek ... and would the failure of it cause hesitation during excelleration? ok so maybe i better talk about whats happening.. when on a start it idles rough... not up and down ... that is steady... cleaned all parts potentiometer(i think that is how it is spelled) pulled distributor off and cleaned the plunger. All injectors have great spray pattern... but that rpm climb... you guys know what im talkin bout... wow.. wow.. just that quick response.. it takes me holding the rpm at 3000 and you can hear the hesitation dissapear.. good to go then unless you give her to much peddle then seams like she is starving.. i dont know .. i need help guys and thank you for everything that is a suggestion cause im out of um...


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## ABA Scirocco (May 30, 2001)

*Re: CIS-E problems Please tell me im right (Dustindavisusmc)*

It's supposed to make a noise, most people would describe it as a buzzing sound. 
The symptoms you describe don't give me any reason to suspect there's a problem with the frequency valve at least not it's basic operation. The frequency valve is what the ECU uses to fine tune the fuel mixture and the ECU drives the frequency valve in response to the input it receives from the O2 sensor so if the O2 sensor isn't working properly, the ECU may be responding to erroneous inputs and hence driving the frequency valve improperly, this could potentially cause rough idle or hesitation. Here are a couple websites with good info regarding CIS-Lambda systems. Start with The Bad Habit Rabbit, it has some simple to read but informative articles, move on to Cabby-info, which has more in depth info.


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## Dustindavisusmc (Apr 6, 2010)

*Re: CIS-E problems Please tell me im right (ABA Scirocco)*

thanks !!!!! i really enjoy input and hope to help someone else.... again thank you guys


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## ABA Scirocco (May 30, 2001)

*Re: CIS-E problems Please tell me im right (Dustindavisusmc)*

You're welcome and good luck.


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