# CIS guru needed



## iamdagerman (Feb 19, 2006)

My car has had rough idle since I've owned the car (89 cabby) I started checking the vacuum and it shows only 16 hg. my question is about the injector air shroud at head. It pulls vacuum I pinched off the hose and the engine idles down a lot and eventually stalls. Is this normal? People have told me it makes no difference when they pinch off this hose on their car!:banghead::banghead: please someone help


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## ziddey (Apr 16, 2006)

You should be able to block off both ends of the air shroud port and not notice a difference. It sounds like that hose may actually be cracked and ripped somewhere you're not seeing? Go over all the vacuum lines and replace as necessary. Check for leaks with starter fluid. 

What is your ignition timing set at? 

Does it behave the same cold and warm? How old is the oxygen sensor? 

When the car is hot, unplug the o2 sensor and measure its output with a voltmeter (black wire and a ground of your choice). Do the same with it plugged in.


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## iamdagerman (Feb 19, 2006)

timing is set to 6 degrees BTDC, O2 sensor is new maybe has about 5k. I pulled the hose off the air shroud pipe on head and it pulls lots of vacuum! Not normal right? Has new injectors, injector insulators and orings. I fixed all other vacuum leaks and only pulls 16hg. Also reset air/fuel ratio. Runs real bad at cold start but perfect when warm


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## ziddey (Apr 16, 2006)

Yes, it should pull vacuum since it leads to the intake ports. How much, I'm not sure. The lower plastic inserts have small holes in them, so maybe not that much? Maybe the lower inserts broke or fell off or otherwise aren't sealing well? Or it's just normal. Either way, you can cap that port for the time being to help with your diagnostics and reintroduce it later once everything is working properly. Of course, cap the other end of the hose as well if you're going to do this. 

What rpm are you idling at that you're drawing 16" of vacuum? I'm assuming 800-1000rpm? You are running the stock cam I'm assuming? Driveability is fine right? So cam shouldn't be off a tooth or anything. 

And you're positive your ignition timing at 800-1000rpm is 6*BTDC? 

Then it sounds like a mixture issue. How does the exhaust smell? Unplug the new o2 sensor and play with the mixture leaner/richer and see how it affects your idle/vacuum. 

Is it a stable 16"?


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## kamzcab86 (Feb 14, 2002)

iamdagerman said:


> Runs real bad at cold start but perfect when warm


 Did you check/test the AAR (aux air regulator)? When cold, it should open; when warm, it should close. If it's stuck closed, you'll have cold-running issues.


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## iamdagerman (Feb 19, 2006)

thats another thing I had to open the aux air reg a lot farther or it wouldnt help at all. Now it idles around 1200 when cold. Also when I first start in the morning it start, the needle suddenly goes down to almost stalling and jumps back up to 1100-1200 rpm until maybe 30secs. The timing is set at idle to the little notch on the flywheel (pretty sure thats 6 BTDC) and I set mixture 2 days ago. Vacuum reading is steady 16hg at idle


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## kamzcab86 (Feb 14, 2002)

iamdagerman said:


> thats another thing I had to open the aux air reg a lot farther or it wouldnt help at all.


 Explain in more detail, please? 



iamdagerman said:


> Also when I first start in the morning it start, the needle suddenly goes down to almost stalling and jumps back up to 1100-1200 rpm until maybe 30secs.


 Have you checked/tested the idle boost valve(s)? If stuck open, major air leak. Have you tested all of the Lambda components? Have you tested the OXS controller? Have you tested control pressure? 

Also, where are you reading the 16"?


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## iamdagerman (Feb 19, 2006)

the aux air reg has a adjustment on the side, when I first got the car it idled very low on cold start so I adjusted it more open. The control pressure is fine. By oxs controller you mean the ecu? 
to my knowledge the idle boost valves are fine, it makes no difference when you pinch the hose 

oh and for the 16" vacuum reading I put a t fitting in between the cold start enrichment vacuum switch and the tube going to vacuum booster


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## Glegor (Mar 31, 2008)

iamdagerman said:


> the aux air reg has a adjustment on the side, when I first got the car it idled very low on cold start so I adjusted it more open. The control pressure is fine. By oxs controller you mean the ecu?
> to my knowledge the idle boost valves are fine, it makes no difference when you pinch the hose
> 
> oh and for the 16" vacuum reading I put a t fitting in between the cold start enrichment vacuum switch and the tube going to vacuum booster


 aux air regulator has no adjustment.. the throttle body has an adjustment on the side of it tho.. 

and there is a difference between the ECU, and the OXS controller.. the OXS controller is small, and has 8 or so wires going to it. the ECU is considerably bigger than the OXS controller.


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## iamdagerman (Feb 19, 2006)

It doesn't have a oxs controller thats on the older cars and the aux air reg does have an adjustment


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## ziddey (Apr 16, 2006)

Vacuum booster? You referring to the brake booster? 

And I have never read about the AAR being adjustable and don't recall any screw on the side. If that's true, then I'll be damned. I've gotten a bunch of units from the junkyard before I finally got one that opened enough when cold. 

How did you set the mixture? 

How long do you have to crank for the car to cold start? How cold is it? Georgia? Probably not that cold then, so CSV is probably not active. 

And I misspoke (miswrote I guess..) earlier when I said the hole was in the lower insert. I believe it's actually on the brass piece that threads into the head. Like Glegor mentioned (in a different thread?), that hole is often gunked up. If you just redid the injector holders / seals and you're seeing that much vacuum, maybe one or more of the lower inserts fell off? 

Either way, you can most definitely cap off the air shrouding either permanently or for the time being to help diagnose the issue. 

Yes, the little dimple on the flywheel should be TDC, with the big notch next to it 6*BTDC. 

16" is still considered "normal." Have you done a compression test? 

With the car warmed up and running well, unplug the o2 sensor and report back with the voltage. Does anything happen to the idle / vacuum then? 

How much does the idle change if you spray starting fluid into the intake snorkle?


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## WaterWheels (Aug 14, 2005)

I know it is not discussed much if at all in Volkswagen circles, but Porsche and BMW people do sometimes talk about his. The AAV is in fact adjustable even if most people do not tinker with them. Due to their being "set" for a particular engine there are trade offs with adjusting them, but you can do it. Here is a stolen picture pointing to the adjustment nut, you have all seen it I'm sure.


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## iamdagerman (Feb 19, 2006)

I set the mixture using a duty cycle meter. Even on the coldest morning it will start right away, instanstly the idle drops to almost stalling and instantly ups back up to idle, happens all in about 1/2 second. also I cant block off the air shroud at head it makes the engine stall!! 

O2 is new and engine only has about 15k on it


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## kamzcab86 (Feb 14, 2002)

iamdagerman said:


> the aux air reg has a adjustment on the side, when I first got the car it idled very low on cold start so I adjusted it more open.


 Was that the only adjustment you did at the time to "fix" the low cold idle? Did you test the AAR back then, or just adjust it open? 

You've since done work to the car, in addition to adjusting the air-fuel; I'm wondering if ^that initial "fix" is now causing the current issue, not to mention the AAR being possibly faulty to being with. 

The idle boost valve: It sounds like it's doing its job (idle drops then picks back up), but I'd do the electrical tests outlined in Bentley on page 5-28 to verify the valve and relay are functioning properly. 

Don't recall, but have you tested the cold-start valve? 



iamdagerman said:


> By oxs controller you mean the ecu?


 Yes, sorry; the Jetronic ECU. I linked to the tests in my previous post, but here they are again: 
Testing the Lambda Components 
Testing the Jetronic ECU and OXS


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## iamdagerman (Feb 19, 2006)

Yes thats the only thing I did back then but after adjusting the air/fuel ratio I tested and installed another aux air reg w/ opening it up more and the cold idle was real low again so I installed the modded one again. I have checked the cold start valve and everything there is working. 
I also checked control pressure and cleaned the WUR so I know that fine. also had problem with fuel pump not priming on key position acc and after buying several new fuel pump relays with no luck I grabbed one off a rocco at yard and it primed finally(I used to have to hold pedal to floor before the rocco relay. 

To my knowledge the aux closes all the way or almost all the way because I opened it so far Could this be a problem?


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