# Fuel enrichment module help



## johnnyGO (Feb 23, 2009)

While I wait for the parts to come in for my vintagewatercooled module I want to put together the other version:








So I need to know if this relay will work:
























And I also need to know what terminals I should use on the potentiometer (IE: left & Right , middle & left, ect.. )


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## wclark (Mar 28, 2001)

*Re: Fuel enrichment module help (johnnyGO)*

That is a normally open (NO) single pole / single throw relay (SPST or ON-OFF), versus the single pole double throw relay (SPDT or ON-ON) in the drawing where the normally closed (NC) is the one used. That means your relay has no contact path (no pin 87a) when de-energized which is what the circuit shown needs and hooking up the pins 30-87 would result in the circuit operating in reverse of what you want - enrichment when NOT at WOT.
You would connect the center and one end of the pot. Since what you probably want is increasing richness as you turn the pot CW and to get that you need an increasing resistance CW, you would want to use the left and center terminals - as shown in your photo. It doesnt matter which pot terminal is connected to which of the pins 30 and 87a on the relay .


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## johnnyGO (Feb 23, 2009)

As always, thanks wclark.
Ill find anothe relay then, any suggestions as to what one I should look for (IE light relay, ect...)? I have a donor car with all its relays to pick from. 
Ok so here is something that Im confused about also. In this pic he shows the #3 wire going to ground:








But in the diagram it shows it going to switchable power:








So which one is the right one?


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## antichristonwheels (Jun 14, 2001)

*Re: Fuel enrichment module help (johnnyGO)*

you need a changeover relay 5 terminals. go to NAPA


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## wclark (Mar 28, 2001)

*Re: (johnnyGO)*

I dont know of any relays in the A2 that will work - they are all either SPST or DPST with NO (normaly open) contacts. You need either SPST NC (normally closed) or SPDT.
Virtually any SPDT 12VDC relay will do for this because the current needs are very small, but if you want to keep within the "Bosch" style automotive relay family (the terminals labeled 85, 86, 87, 30, etc.) to limit confusion, you want to look for something like this: http://www.parts-express.com/p...0-070 . The amperage rating is not important but the 12V DC operation and SPDT are because you need the coil operating voltage and one set of NC contacts (e.g. 30 and 87a).
Both the photo and the diagram accomplish the same thing but do it differently. In the photo, the author is using the 12V from the WOT switch output to power the relay and so the other side needs to be grounded to complete the circuit. In the diagram, the author has rewired the WOT switch so its input is ground instead of +12V and the ground is then passed to the relay when at WOT. So the relay needs a switched +12V on the other lead to operate. The CIS-E already uses the first scheme and it needs to retain the +12V at WOT to the ECU, I would opt for the photo's approach with CIS-E.


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## johnnyGO (Feb 23, 2009)

I went to napa and got a relay, I was told that you can hook the relay up 2 ways: closed or open.
But he did not know what terminal was which.
















I have everything hooked up but its doing weird things, it will start and idle just fine but when I give it gas it almost drops to its face then comes back up. But If I turn the potentiometer all the way down it will not do that.
Now I dont know if this makes any differance but I have the ground from the temp sensor split and going to the relay, should it be the sending wire going to the relay or does it not matter?


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## wclark (Mar 28, 2001)

*Re: (johnnyGO)*

Well if the diagram on the relay is accurate it does not have a normally closed set of contacts, but it has 2 normally open ones for some reason. That makes it electrically the same as your other one. To check its operation, check to see if you have a conductive path from terminal 30 to either of the ones labeled 87 when the relay is turned off. If you do then that terminal is more correctly 87a and is the one you want along with 30. If not then this relay wont work.
Checkout...Does the relay turn on when you press the WOT switch? The engine should not be running but the ignition should be on for this. The wire between theCTS and ECU should be split and wired to the relay teminals 30 and 87a. The pot should be wired to relay terminals 30 and 87a.


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## johnnyGO (Feb 23, 2009)

*Re: (wclark)*

Ill test the relay then, I thought it was weird that both terminals where 87 and not 87 & 87a but the guy went on saying " ahh ya I used the same one for a project and need a closed relay " so we will see.
The relay does turn on when the WOT switch is engaged, I ended up swapping the the wires ( so now the signal wire is split and going to the relay instead of the ground) and it fixed the falling rpm issue. But I noticed at idle (with the module hooked up) its running lean and the ecu isint doing its normal a/f adjusting... so Im guessing thats a big sign saying that the relay is the wrong one, I hope.


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## johnnyGO (Feb 23, 2009)

A little FYI for the Audi guys, the temp sensor is a dual sending unit ( BLK-RED = Fuel Injection Control Unit & BRN-RED = Ignition Control Unit ) so make sure you hook the right one up.


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## johnnyGO (Feb 23, 2009)

I got everything hooked up, woohoo








There is lag time between WOT and when the module does its thing, is there anyway to shorten that lag?
Also, I have the relay in the car so with the radio down I can hear it click, it will click once when the WOT switch is engaged then it does a double click right before the car gets up and goes, is that normal?


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## wclark (Mar 28, 2001)

*Re: (johnnyGO)*

Your relay should energize and de-energize with the WOT switch and nothing else.
If it is dropping out momentarily then look for the cause to be power or ground to the relay coil being interrupted at the time you hear the clicking. IF you have a test LED (like the thing most people make to "read" the KSCU "fault code") then you can observe each one independently. To observe the WOT signal connect the + to the WOT signal at the relay coil and - to a ground. It should be ON whenever the WOT switch is ON and it will turn off and back on if the drop is from the WOT switch. To check the ground side of the relay coil connect the test LED + to a +12V battery source and the - to the grounded side of the coil. This should stay ON all the time. If you notice it going off at all (when the relay double clicks), then it means ground is being lifted from the coil, so whatever you are using for ground must be going thru something that is acting like a switch.
The lag you feel may be the way your OXY CU reacts to the change in CTS input or it may just be related to the double clicking you hear. I am not familiar with the Audi implementation but I know that according to Probst, some of the Bosch implementations respond slower than others to sudden changes in this input. He did not list which ones were set up to be slow.


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## johnnyGO (Feb 23, 2009)

*Re: (wclark)*

I checked the power & grounds and everything is GTG.
With the ignition on and the car not running I dont get the double click, just the one when the WOT switch is engaged. I wondering if the double click right before the enrichment is made is the ECU going from closed loop to open, IE so the circut is broke for a split second as the ecu changes?


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## wclark (Mar 28, 2001)

*Re: (johnnyGO)*

The ECU should go to open loop when the WOT switch is tripped but it doesnt HAVE to. I dont have the wiring diagrams for the Audi 80 CIS-E and dont have first hand experience with Audi's implementation of JE-Jet (I do know the control units have different Bosch numbers) so I dont know for sure what else may be going on at WOT.
If you are not having a momentary drop in voltage from the WOT switch, or the ground is not momentarily going open, then your relay cannot be doing this. Are you sure its your relay that is double clicking?


_Modified by wclark at 3:31 PM 7-7-2009_


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## johnnyGO (Feb 23, 2009)

*Re: (wclark)*

here is the diagram : http://www.autolib.diakom.ru/C...2.pdf
I just dont get it, if you want I can take a video of what its doing if you would like.
-Paul


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## wclark (Mar 28, 2001)

*Re: (johnnyGO)*

The diagram (as far as the WOT wiring) looks like the VW with nothing on the supply side but the WOT switch, a fuse and ignition switch. I assume the ground side of the relay coil is tied to a chassis ground point...right?
Besides, you said you checked both the WOT and ground side of the relay coil the way I suggested (LED test light) and there was no matching glitch from either, right?


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## johnnyGO (Feb 23, 2009)

*Re: (wclark)*

Ya the ground is bolted right to the body. I took my led test light and check everything like you said, ohh and another note I noticed the lag and double clicking of the relay is much worse with the pot adjusted/turned from one side to the other. So Im wondering if I should swap the 10k pot with a 5k.


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## wclark (Mar 28, 2001)

*Re: (johnnyGO)*

The double clicking thing has me stumped. I would have to put my hands on the car to tell more. 
The value of the pot shouldnt matter. You should be setting it between 1k and 4k wither way, and you should be observing the AFR with a wideband since you probably want around 13:1 AFR.


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## johnnyGO (Feb 23, 2009)

I decided to just make a video so you can see & hear what Im talking about.
http://www.youtube.com/watch?v=8CAfcxxt-aI


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## wclark (Mar 28, 2001)

*Re: (johnnyGO)*

Good video. This is what I think I saw. When you went to WOT the visible pair of contacts opened (putting the pot in series with the CTS as intended), then at some point later as the RPM built to a higher number they closed and seemed to remain that way and that is when I heard the multiple clicks.
When a relay de-energizes it creates a fairly large back emf that can re-energize the coil for a moment and this can go on for 2-3 cycles. I think that is what I heard. The fix is easy as the beck emf is always reversed polarity. To fix it, put a 1A rectifier diode across the relay coil terminals with the banded end to the +12V (WOT switch) side. A good diode to use is the very common 1N400x family (1N4001 thru1N4007). This diode will do nothing unless the voltage across the coil reverses, which it will when the supply voltage from the WOT switch is removed, so it wont hurt anything.
The relay shouldnt de-energize until the WOT switch opens and as far as I could see it just de-energized (and bounced), it did not re-energize after that. I would say the WOT switch opened.


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## johnnyGO (Feb 23, 2009)

*Re: (wclark)*

Thanks again http://****************.com/smile/emthup.gif


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## johnnyGO (Feb 23, 2009)

Ok so I thought I was stumped before, I added the diode = no change ... Swaped the pot from a 10k to a 5k = no change ... I looked over my wot switch and noticed it was making a second click itself so I put another one on = no change.
Ive gone over the wireing of the module like a good 10 times and everything is how it should be.... maybe its just an Audi thing


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