# JP's hugantic CIS-E write up (now complete)



## Longitudinal (Nov 13, 2004)

*JP's hugantic CIS-E write up*

Here it is, folks. CIS-E write-up extraordinaire!
*Cleaning:*
Keep stuff clean. I like to remove the metering head (which is actually called the fuel distributor) from the air plate assembly periodically. This allows complete scrubbing of the air plate assembly with household cleaners. 
Usually, at least for us non-west-coasters, the external part of the air plate housing is oxidized. I skim off the oxide with an open razer blade, just like shaving. Then I use a 3M Scotch Brite pad and household (Simple Green, Greased Lightning, etc.) cleaner to clean all external surfaces. 
DO NOT scour the air plate or bowl. These come clean easily with a little penetrating oil and a rag. I wipe down the external surfaces of the metering head with penetrating oil and a rag. 
I lubricate all pivot and friction points on the air plate arm with ATF--just a drop everywhere one part moves against another. I also clean where the o-ring seals between the air plate housing and the metering head, then put a little lithium grease on that o-ring. That o-ring hardly ever needs replaced.
DO NOT dismantle the metering head. Just don't do it. If you want to see what they look like on the inside, dismantle a junk or spare unit.
If I am storing a fuel distributor for a long time, I usually put a drop of ATF inside each hole where a fuel line connects.
*Maintenance and adjustments:*
Mixture rarely needs to be adjusted. If your idle mixture seems off, you should not make adjustments to the fuel system before checking thoroughly for intake vacuum leaks or bad sensors. Also, please note that idle mixture screw adjustment is very touchy. A little goes a long way. Inexperienced users should turn the screw only perhaps a 1/16 turn at a time, followed by a hardy blip of the throttle and waiting for current to stabilize and begin to search again.
Access to the idle mixture adjustment screw is blocked by a factory-installed plug. At this point, many of these factory plugs have been removed, some very crudely by a drill and brute force. If you have a great yawning chasm where there should be a small round hole, don't worry. The air admitted through that hole is unfiltered, but not unmetered. If the plug is still there, it must be removed in order to make any idle adjustments. You can drill it or extract it any way you please, but it must not be punched through. This plug is tapered, so it must come out the top.
To monitor changes in AFR, you will need to construct or purchase a test harness that connects between the DPR and its connector. I have used the heater connector from an O2 sensor and a pulsed fuel injector connector to make the test harness. Connect the two connectors so that the ground side is uninterrupted and the power side is broken. The two open ends of the test connector are to be connected to an ammeter set to a 20ma scale. 
Clockwise (henceforth "CW") is richer and Counterclockwise (henceforth "CCW") is leaner. Note also that turning the idle mixture screw CW causes a DROP in current and CCW an increase. Smaller numbers mean that the ECU is able to send a smaller current to the DPR in order to maintain a proper mixture at the O2 sensor. Higher current means the ECU is sending more current in order to maintain the mixture it wants, which indicates a leaner adjustment.
Idle DPR current will "search" or "hunt" on a warm engine and a working lambda circuit. Adjust the mixture screw to find a current that searches between 6 and 10 ma. Modified engines tend to prefer a richer idle mixture. I normally set modified and turbo engines to center on around 5 ma, never exceeding 6ma.
When adjusting idle current, remember: a high current means mixture is too LEAN, so the screw needs to go CW. A low current means mixture is too rich, so the screw needs to go CCW.
*Power Tuning:*
Power tuning CIS-E is fairly straight forward. I will cover the basic stuff that gets the results 99% of users want to see. Any power tune must start with ensuring that all ignition parts are in good repair, that basic ignition timing and idle mixture (DPR amperage) are set correctly, that injectors have a good spray pattern, that no intake leaks exist and that all sensors function as they should. Not paying attention to the details and trying to tune the car with anything else out of spec or leaking will not result in a good tune. Also, power tuning the CIS will likely result in a small loss in fuel economy and, in extreme cases, may result in difficulties passing e-checks. The effects of a power tune are proportional to state of engine repair and modification. On a stock engine, the gain will be small. On a modified and/or turbocharged engine, gains will be dramatic. A mixture meter is extremely helpful for dialing in full throttle mixture. They're pretty cheap, too. Narrow band will do just fine for the kind of power you can make with CIS-E.
For a Fox, the first step in a power tune is to wire up a full throttle circuit. This can be a simple procedure. It can be as simple as extracting ECU connecting pins from an old harness and inserting the pins into your car's ECU harness on pins 1 and 5. Pins 1 and 5 lead to the WOT switch. The WOT switch engages the full throttle open loop circuit and is definitely necessary for a power tune. Otherwise, the ECU never leaves closed loop, which means it will always try to pull the mixture back to stoich, which is not what you want for power. After this circuit is in place, you will require a KE-Jetronic ECU from a car with a full throttle circuit. Such cars include Audi 4KQ, QSW, KE-Jetronic A2 Golf and Jetta (including 16V GLI and GTI models) et al. I have not yet tried using a KE-Motronic ECU from a 16V Passat or Audi 80. The VAG PN will be 811906264A, B, C, or D. Any one will work. Connecting the full throttle switch should be self-explanatory, so I will skip that part. 
On boosted cars, I use a pressure switch instead of the WOT switch. Pressure switches are available from digikey, among others. These are nice becauce they are adjustable and permit the user to adjust the boost pressure at which open loop enrichment is desired.
Power tuning for 99% of the population will be accomplished by adjusting the differential pressure regulator. After checking that everything including idle mixture is good and correct, shut off the engine, disconnect the DPR connector, wrap a rag around the DPR and unscrew the DPR from the metering head. Fuel will spray. The rag is there to prevent fuel from spraying into the eyes, onto the skin, or onto a hot exhaust manifold. Keep track of the two green o-rings. They usually stay in the metering head, which is just fine.
Take the DPR from the car and place it in the palm of your hand in a folded-over shop rag. The rag is there to protect your skin in the event of flathead screwdriver slippage. Unscrew the brass flathead screw from the back of the DPR. The threads on this screw are amazingly fine. It is a marvel to me that such a screw could even be made. Remove the screw and KEEP TRACK OF THE COPPER WASHER. If you lose this washer, you will be looking for another DPR. 
Behind this screw is a small allen head (VERY rarely this screw is actually a very small flathead) setscrew. This screw is what you adjust to power tune CIS-E. Just as with the idle mixture screw, small adjustments are significant, and just as with the idle screw, CW enriches. A good initial adjustment is 1/4 turn CW. Turn the screw, then re-tighten the flathead screw and reassemble the DPR to the metering head and reconnect the DPR along with the test harness. Don't go nuts tightening the screws that hold the DPR onto the metering head. They don't require that much torque and they may well be coming right back off after a brief test drive.
Fire up the engine. The idle mixture that you just set a few minutes ago will now be way rich. As always, wait for the O2 sensor to heat up before making any adjustments. Once the O2 sensor is warmed up, the idle current will drop substantially, possibly to zero. Make small CCW tweaks on the idle mixture screw until current is back to spec. Continue running engine until cooling fan has cycled once. Once engine is fully warm and idle mixture is set, take the car for a test drive with the test harness connected and routed into the car for a passenger to read while under low-load cruising and acceleration conditions.
On the test drive, you are looking for a nice rich 12:1 if possible AFR under WOT/boost and a middle of the road amperage to the DPR under light cruising throttle. When the system is near the end of its range of adjustment, cruising amperage to the DPR will become very low. At the point that the cruising amperage touches zero, the ECU will no longer be able to make lean-out adjustments to correct light-load mixtures. Adjusting the system beyond this will cause poor economy with negligible (if any) power increases.
Repeat the above DPR adjustment procedure as necessary with this caveat: DPR adjustments from this point can be VERY touchy, so no more than a 1/8 turn increment per adjustment is advisable. Each time you adjust the DPR, you re-start the engine, warm it up and set idle mixture again as described above before driving. 
So far, I have found that 1/4 turn is all a stock engine needs to reach its full potential on CIS-E with a WOT switch. A 2L/big valve head/mild cam/good exhaust setup usually can take about 1/2 turn. A SUPER wild NA engine or turbo engine can use all the fuel it can get before the system can no longer adjust light load mixture--usually 3/4 turn. Beyond this, the system can usually no longer maintain a good stoich-ish mixture under light load.
When making these adjustments, remember: "Keep it real. Think slow. We should get through it just fine." Take your time and make small adjustments. Don't try to be a hero and jump to the final lesson. Each metering head, air plate and DPR will respond slightly differently based on their condition and pre-set internal adjustments. Don't rush. Use this information wisely and you will get some more useful power from your CIS-E. CIS-E is an excellent fuel system capable of excellent power and economy if properly tuned and capable of neither if jacked up and out of tram.


_Modified by Longitudinal at 5:07 PM 3-11-2007_


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## BlackFoxer (Aug 12, 2002)

*Re: JP's hugantic CIS-E write up (Longitudinal)*










The tuning procedure is what I'm really after.
I think the Bentley explain pretty well how the system is functioning and troubleshooting this system isn't that hard but still you can include it, the more you'll say the better it will be.


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## Slowturn (Nov 5, 2005)

*Re: JP's hugantic CIS-E write up (Longitudinal)*

I'll read any info you've got to offer, but I'm primarily interested in CIS-E turbo system fueling. Is there more beyond the "power module" (that just turns on the cold start injector)? 
Later!
SlowTurn


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## Longitudinal (Nov 13, 2004)

*Re: JP's hugantic CIS-E write up (Slowturn)*


_Quote, originally posted by *Slowturn* »_I'll read any info you've got to offer, but I'm primarily interested in CIS-E turbo system fueling. Is there more beyond the "power module" (that just turns on the cold start injector)? 
Later!
SlowTurn

There certainly is more fuel in the FD than the PM will allow out. The PM, sold by Autotech, which is a piece of junk in my experience, cranks up the DPR current when the FTS is closed. Before I learned how to tune the system, I bought a PM. The first didn't work at all and the second didn't work on the top two settings, which are the ones I needed. Plus, the PM does NOTHING to throttle response short of WOT. Tuning it does. 
So, power tuning. Any other stuff? Certainly somebody wants some diag procedures. The Bentley is not as succinct as it could be on this matter.


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## voxwagen88 (Dec 9, 2001)

*Re: JP's hugantic CIS-E write up (Longitudinal)*

Some diagnostics / trouble shooting would be great.
Maybe that would cut down on the number of Winter Cold Start / Summer Hot Start postings.
And, of course, some power tuning.


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## mike in SC (Apr 29, 2004)

I'd like to see some information on DPR tuning. I too am interested to read about power tuning.


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## Longitudinal (Nov 13, 2004)

*Re: (mike in SC)*

I have finally begun the write-up. It's far from finished yet, but I had to do something. Look at the OP on this page for the write-up.


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## WyMCoupe (Jul 12, 2006)

*Re: (Longitudinal)*

And I thought I was the only one who used words like "hugantic" and "ginormous". 
Thanks for the info and I can't wait to read the rest of your writeup!!
Now I just need a decend DMM since I fried the ammeter on my last one by trying to measure voltage through it


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## Longitudinal (Nov 13, 2004)

*Re: (sausagemit)*


_Quote, originally posted by *sausagemit* »_And I thought I was the only one who used words like "hugantic" and "ginormous".

I have used those for years. Also, "spectabular," "splendiferous," etc. I also like to respond to the question "how's it going?" with a simple "excrementatious."
Write up is tentatively finished. It is also FAQed as well, under motor and transmission.


_Modified by Longitudinal at 12:38 AM 3-11-2007_


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## BlackFoxer (Aug 12, 2002)

*Re: (Longitudinal)*

Simply awesome!!
http://****************.com/smile/emthup.gif


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## voxwagen88 (Dec 9, 2001)

*Re: (BlackFoxer)*

It is now very clear why you were reluctant to share this info. I hope not to become one of the ones posting up "I powered tuned my Fox and now I need a new FD."
How many "smart" ecu's do you have in stock? Too bad a wide band O2 meter isn't necessary, I'm looking for an excuse to get one.
Thanks.


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## Longitudinal (Nov 13, 2004)

*Re: (voxwagen88)*


_Quote, originally posted by *voxwagen88* »_It is now very clear why you were reluctant to share this info. I hope not to become one of the ones posting up "I powered tuned my Fox and now I need a new FD."
How many "smart" ecu's do you have in stock? Too bad a wide band O2 meter isn't necessary, I'm looking for an excuse to get one.
Thanks.

Heh, yeah, I'm sure you will use it wisely. I have at least three ECUs in stock.


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## 87FoxGL (Sep 29, 2006)

Very informative. I do have a question: how much of this info is relevant to just basic CIS, because that's what my Fox has.


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## Longitudinal (Nov 13, 2004)

*Re: (87FoxGL)*


_Quote, originally posted by *87FoxGL* »_Very informative. I do have a question: how much of this info is relevant to just basic CIS, because that's what my Fox has.

Virtually none of these data applies to K-basic. Idle mixture screw is used in the same way to set idle mixture, but since there is no DPR, you would read idle mixture with an AFR meter. In K-basic, power tuning is accomplished by adjusting system pressure to spec (using shims) and by lowering control pressure. Lower control pressure generates more air plate lift for a given air flow. More plate lift means taller slits and more fuel. It's a pretty simple procedure, but you'd need to hunt down shims for control pressure and a turbo control pressure regulator to have load correction for control pressure. 
However, on K-basic fueling is much richer from the factory compared to KE. 


_Modified by Longitudinal at 5:44 PM 3-11-2007_


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## jackfrost1031 (Oct 19, 2004)

*Re: (Longitudinal)*

I am certain I have a vacuum leak because my idle is sparatic, but I cannot find it. Is there a good way to check for leaks? I tried spraying starter fluid and seeing if the engine revved and nothing changed.


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## BlackFoxer (Aug 12, 2002)

*Re: (jackfrost1031)*

I have no secret to find them but this tool helped me knowing what was going on.








Turns out it was a couple of small things; injectors o-rings, tb gasket...


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## Longitudinal (Nov 13, 2004)

*Re: (jackfrost1031)*


_Quote, originally posted by *jackfrost1031* »_I am certain I have a vacuum leak because my idle is sparatic, but I cannot find it.

What do you mean by sporadic (AKA "sparatic")? What exactly is it doing?


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## jackfrost1031 (Oct 19, 2004)

*Re: (Longitudinal)*

It's doing the bouncy idle thing. I start the car and it'll be fine sometimes, sometimes it dips down around 500rpm then back to 1000rpm and keeps doing it. If I give it a touch of throttle it'll be fine, and sometimes it will stop it self. It sometimes olds even around 800, 1000, or anywhere inbetween. There is little consistency. I think I've adjusted the idle bypass screw in the past (around 2 years ago) and it did next to nothing.
I guess it could be the solenoid, but I know how CIS despises vacuum leaks.


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## highmile fox (Mar 2, 2007)

*Re: idle jumping*

my 88 fox did the same thing for years on and off drove me crazy, one day i jiggled the wires coming down from my coolent temperature sensor it helped alot ended up replaceing it idles just fine now 330,000 miles and still going strong


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## Longitudinal (Nov 13, 2004)

*Re: idle jumping (highmile fox)*

Looks like we're getting some high-mileage, worn engine and leaking seals kind of questions. Should I amend to include leak finding procedures?


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## jackfrost1031 (Oct 19, 2004)

*Re: idle jumping (Longitudinal)*

engine only has 110k on it.
but finding a leak procedure wouldn't be a bad addition at all


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## WyMCoupe (Jul 12, 2006)

*Re: idle jumping (jackfrost1031)*


_Quote, originally posted by *jackfrost1031* »_but finding a leak procedure wouldn't be a bad addition at all









x2
When my car only had 60k on it an AC hose rubbed a hole in the vac line on the bottom of the intake manifold. When it would reach operating temp it would die at idle unless you had your foot on the gas. It was a complete pain in the ass to find (2 days and every visible vacum line removed, labled and pressure tested). If I would have known ahead of time where to look it would have been extremely handy.


_Modified by sausagemit at 3:48 PM 3-14-2007_


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## Longitudinal (Nov 13, 2004)

*Re: idle jumping (sausagemit)*

CIS-E idles and runs remarkably well without any of the idle air control and idle stabilizer stuff in place. On performance cars, I normally delete all of this because the look is dramatically cleaner and many possible vacuum leaks are totally eliminated. AC cars should retain idle stabilization for good loaded idling. 
The only side-effect of removing all the idle control stuff is that the engine is grumpy on start-up. This lasts for usually less than 20 seconds. DBG's CIS-E turbo has zero idle control hardware and idles perfectly once it has reached closed loop--and that's with a turbo trying to confuse it. 
Anyway, the first step in diagnosing anything (including idle problems) with CIS-E is to build a test harness and check idle DPR current. This is my FIRST STEP in ANY CIS-E diagnostic.


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## Longitudinal (Nov 13, 2004)

*Re: idle jumping (Longitudinal)*

Has anybody tried using this information?


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## BlackFoxer (Aug 12, 2002)

*Re: idle jumping (Longitudinal)*

Me. I started cleaning the FD unit. I just wait 'til a certain jig is done so I can put my manifold back on and start working on tuning again!


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## Fox-N-It (Jul 23, 2003)

*Re: idle jumping (Longitudinal)*


_Quote, originally posted by *Longitudinal* »_Has anybody tried using this information?

I used a bit of it on a 16v the other day. Most of what you have written is confirmation on what i have read else where.
http://****************.com/smile/emthup.gif


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## BillLeBob (Aug 10, 2004)

*Re: idle jumping (Longitudinal)*


_Quote, originally posted by *Longitudinal* »_Has anybody tried using this information?

I've looked at an extra DPR, found a computer, and need to gather up the goodies for a WOT switch.

_Quote, originally posted by *JP* »_Take the DPR from the car and place it in the palm of your hand in a folded-over shop rag. The rag is there to protect your skin in the event of flathead screwdriver slippage

I did not heed your warning. My the bone in my thumb thankfully stopped the screwdriver.


_Modified by BillLeBob at 2:01 PM 3-23-2007_


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## Longitudinal (Nov 13, 2004)

*Re: idle jumping (BillLeBob)*


_Quote, originally posted by *BillLeBob* »_I did not heed your warning. My the bone in my thumb thankfully stopped the screwdriver.

Ha! Thank God for bones being there. A through-and-through would have been far worse. 
Dean, is the DPR information out there elsewhere?


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## Fox-N-It (Jul 23, 2003)

*Re: idle jumping (Longitudinal)*


_Quote, originally posted by *Longitudinal* »_Ha! Thank God for bones being there. A through-and-through would have been far worse. 
Dean, is the DPR information out there elsewhere?

Heh theres a good CIS-e guy here in richmond. 
I havent read it anywhere but he's shown me some of the tricks you've listed. http://****************.com/smile/emthup.gif


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## jackfrost1031 (Oct 19, 2004)

*Re: idle jumping (Fox-N-It)*

Next time I get to tinker with Foxey (2 weeks from now) I'll be checking all this stuff. I need to replace a few sensors.


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## tornadoredcabby (Feb 14, 2002)

*Re: idle jumping (jackfrost1031)*

Good stuff http://****************.com/smile/emthup.gif 
Thanks


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