Article 20844 of rec.autos.vw: Newsgroups: rec.autos.vw Path: lynx.unm.edu!umn.edu!The-Star.honeywell.com!scornelius From: scornelius@ws11.iac.honeywell.com (Steve Cornelius) Subject: Re: [W] GTI runs rough when cold Message-ID: Sender: news@The-Star.honeywell.com Nntp-Posting-Host: ws11.iac.honeywell.com Organization: Honeywell Industrial Automation & Control References: <1993Sep22.134120.6162@nntpd2.cxo.dec.com> <28c91v$f0n@usenet.rpi.edu> Distribution: na Date: Thu, 30 Sep 1993 20:28:29 GMT Lines: 89 In article <28c91v$f0n@usenet.rpi.edu>, kokerj@jec324.its.rpi.edu (James Matthew Kokernak) writes: |> Most A2 cars have the one wire Bosche sensor as well. The change |> interval is 30K miles for my '87 Jetta GL. Is it possible that |> the 3-wire sensors are on the 16V engines? The three-wire OXS is used with the 8V big-valve (102hp high-compression) motor also, these are knock-sensor equipped. Although you can often get them to last 60K miles or more, they're also twice as expensive as the one wire OXS (usually $70 to $90). I missed the original post, but here's an additional idea if you're following: The 102HP RD series motor used in the GTI/GLI has an odd little idle stabilizer valve that, if defective, can give you some nasty idle speed problems when cold. The valve ain't cheap at all ($245 from a Mesa, AZ VW dealer, usually my cheapest parts dealer). It has a Bosch sticker showing a part number 0.280.140.505, and I haven't tried Bosch directly yet. The assembly is a brass colored tube about 10cm long by 4cm in diameter. It mounts on a bracket directly over the middle of the valve cover, with small hoses that bypass the throttle valve, and a 3 wire connection on the other end. This isn't so much a valve as it is a quaint little servomotor that acts as a slaved subthrottle controlled by the smog computer. It has a small valve on one end that bypasses the throttle, and is centered by a coil spring. The valve is operated by a basic DC motor shaft that has a 3-way commutator on the end, with point contact brushes. There is a 3-pin connector on the end that connects to the computer. Total opening area of the valve is about 1 sq cm, and the spring holds it about 80% closed when unpowered. The center connector goes right to +12V. The other two pins are pulse switched to ground at the computers discretion. Duty cycle of the pulse opens or closes the valve as necessary. The basic purpose of this device is to regulate idle speed until the motor comes up to temperature. It also serves as a kickup valve for the air conditioner, and compensates for compressor load even when cruising (I like this, speed doesn't change when it kicks in....). In my car (an '86 GLI), the "common" (actually +12V) point on the commutator started to arc until the contact point was completely burned away, opening the circuit. Occasionally it would make contact, and the idle would "jump" for a second or two. The engine should idle at 900rpm warm, but with a dead valve Since I'm to cheap and lazy to buy a new valve, I took the old one apart and "fixed" it by making hardwired contacts using braided wire out of some small coax (This stuff has already broken once, what I really need to find is some fine braid like that used in speakers....). This works only because the motor shaft can only make a partial turn. I also added a 1A fuse in the +12V line to try and protect the transistors in the computer from a dead short. And if anyone tries this, I still wouldn't guarantee that the fuse is fast enough to protect those transistors (normal current was measured at 850mA, motor coils are 12.5 ohms). So if you try this, proceed at your own risk.... Troubleshooting: Start the engine cold. If the tach shows 700rpm or less, the idle stabilizer valve is suspect. Disconnect the valve while idling, if the speed changes, then the idle stabilizer is not the problem. I'd go for the OXS next. Check pins 1 - 2 and 2 - 3 on the stabilizer valve (engine off now) with an ohmmeter, you should see about 12.5 ohms on both. Pins 1 to 3 should show 25 ohms (both windings at once). If you see an open connection here, you have a bad idle stabilizer. My condolences.... If it checks out OK, look for two microswitches on the throttle assembly, one for idle, one for wide-open. The idle switch should be closed when the throttle is closed, wiggle the throttle to check it. (In fact, even if your motor has a different idle setup, this is a good thing to check. If the computer can't see an idle state, it can't compensate for it.). Do NOT mess with the idle bypass screw on the throttle unless you know how to do a dwell meter. If someone's mucked with it anyway, set it for 825-850rpm engine *warm* and idle valve disconnected. Reconnect the idle valve and tweak it until the speed "two-steps" slightly from cruise to idle. That makes for a reasonable adjustment. Good luck, I hope this helps..... -- ------------------------------------------------------------------------- Steve Cornelius - AA7XV | If you *don't* like airplane noise, Phoenix, AZ, USA | then why in the #*!! did you buy a scornelius@ws11.iac.honeywell.com | house next to an airport !! ------------------------------------------------------------------------- Nope, not an official Honeywell opinion. Article 21757 of rec.autos.vw: Path: lynx.unm.edu!mimbres.cs.unm.edu!ogicse!uwm.edu!math.ohio-state.edu!sol.ctr.columbia.edu!jdonsbac From: jdonsbac@msi.com (Jeff Donsbach) Newsgroups: rec.autos.vw Subject: Re: [W] Passat GLX emissions computer Message-ID: <2a19d9$in4@sol.ctr.columbia.edu> Date: 19 Oct 93 17:50:33 GMT Article-I.D.: sol.2a19d9$in4 References: Distribution: world Organization: Molecular Simulations, Inc., Burlington, MA Lines: 25 NNTP-Posting-Host: thyroid.msi.com X-Newsreader: TIN [version 1.2 PL1] Josh Sirota (jss@greeble.Eng.Sun.COM) wrote: : Yesterday morning when I started my car ('93 Passat GLX wagon, 5-speed), it : was idling *very* roughly, at about 500-1000 rpm. It seemed to drive okay : though, and calmed down somewhat after it warmed up. Another thing it could be is a bad idle stabilizer valve. My mechanic showed me an easy way to check it when mine was going bad on my Corrado ('90, 96k miles). The idle stabilizer is a cylindrical thing on top of the valve cover (you probably already know that). Next time your car starts idling low, open the hood and tap on the idle stablizer with a hammer or something. If the idle goes back to normal, that's your problem. It's easy to fix (about 10 minutes) as long as the dealer has the part in stock (which he should since the VR6 uses the Motronic injection like in some other models). hope this helps.... -Jeff -- ========================= Jeff Donsbach Molecular Simulations,Inc., 16 New England Executive Park, Burlington, MA 01803 Internet Email: jdonsbac@MSI.Com "10 bucks is 10 bucks" - Geddy Lee From usc!cs.utexas.edu!uunet!destroyer!gumby!calvin!ursa!ptong12 Fri Oct 1 14:10:30 PDT 1993 Article: 20292 of rec.autos.vw Newsgroups: rec.autos.vw Path: usc!cs.utexas.edu!uunet!destroyer!gumby!calvin!ursa!ptong12 From: ptong12@ursa.calvin.edu (Peter Tong) Subject: Re: (w) "Frequency" valve Message-ID: Sender: news@calvin.edu (Netnews Punk) Nntp-Posting-Host: ursa Organization: Calvin College References: Date: Sat, 25 Sep 1993 16:53:22 GMT Lines: 37 In article aa224@Freenet.carleton.ca (Ken Lawton) writes: > >My 84 GTI recently developed an idle problem. The idle would hunt up and >down from 600 through 1200 rpm. > >A local VW specialist cured the problem by (here's a quote from the workorder) >"..adjusting duty cycle of frequency valve." > >There is no mention of a frequency valve in my Bentley manual. >Does anybody out there know what and where the frequency valve is? And >how does one go about adjusting the "duty cycle"?? > >Cheers... >Ken > Check frequency valve duty cycle is a 1 minute thing. Its in Ravens book. Finding the female duty cycle test connector near the passengers side of the intake manifold. Take the plastic connector off of it. Stick mini jeweler's screw driver that fits snugly into the blue connector wire (not the brown ground wire). Hook this to the red lead on your dwell meter, ground the other dwell lead to the engine block. Switch dwell meter to 4 cylinder. Start your car up and watch the gauge fluctuate as the Oxygen sensor system varies the fuel pressure via the frequency valve (the humming thing on the side of the fuel distributor). Should be right around 40 degrees +- 5 degrees of fluctuation. With the throttle enrichment switch engaged it will jump to about 70 degrees. With the oxygen sensor disconnected it should be on 45 degrees with no fluctuation. All the mechanic did was to set your fuel mixture back where it should be using a 3mm long allen wrench on the idle CO mixture hole in your fuel distributor. Peter Tong From lynx.unm.edu!jobone!newsxfer.itd.umich.edu!zip.eecs.umich.edu!yeshua.marcam.com!charnel!olivea!koriel!male.EBay.Sun.COM!stoner!jimmy Wed Apr 20 19:43:50 PDT 1994 Article: 30663 of rec.autos.vw Path: lynx.unm.edu!jobone!newsxfer.itd.umich.edu!zip.eecs.umich.edu!yeshua.marcam.com!charnel!olivea!koriel!male.EBay.Sun.COM!stoner!jimmy From: jimmy@stoner.EBay.Sun.COM (Jimmy Stoner) Newsgroups: rec.autos.vw Subject: Re: Idle still stinks! 87 GTI Date: 20 Apr 1994 16:50:12 GMT Organization: Sun Microsystems, Inc. Lines: 40 Distribution: world Message-ID: <2p3mg4$eu6@male.EBay.Sun.COM> References: <2p1nff$fb1@Tandem.CAM.ORG> Reply-To: jimmy@stoner.EBay.Sun.COM NNTP-Posting-Host: stoner.ebay.sun.com Mike, The symptoms you're describing were very similar to what I was experiencing. My problem was rough starting and rough idle, very low power/torque until over 2500 RPM's, and when you stopped for a light the engine RPM would drop very low and nearly die then go back up to about 800 RPM. It would then idle OK when warm with a slight surge but no low end power. Symptom would come and go at first. No problem for a few days then happen again for a few day. This happened to my son a couple of years ago. After several trips to VW they finally cured it by fixing the vacumn line going to the Knock Sensor Control Unit (KSCU). This time the vacumn line was good. I found a slightly correded connector going to the knock sensor. Someone suggested getting a can of contact cleaner to get the connectors really clean. After cleaning the connector for good contact the problem went away. I still have a slight surge but am hoping when I replace the injector seals I'll get a smooth idle. The knock sensor on my 87 16V is located on the grill side of the engine. Left and right refer to the engine as you face it from the front of the car. The sensor is bolted to the block just to the right of the engine mount on the lower left side of the engine. It looks like a thick washer with a heavy wire oming out of it. This wire harness then goes across the grille side of the engine to the lower right side and mates with a connecter on the right end of the engine. This was the connector that was slightly corroded and fixed my problem. The Knock Sensor Control Unit (KSCU)for my 87 GTI 16V is located on the passenger side of the car just below the windshield wiper. You must remove the plastic tray in the engine compartment between the windshield and the firewall. KSCU is a fairly big unit with a large connector plugged into it and a vacumn hose. Check your electrical connections and vacumn for the system. The Bently manual describes how to test the system. Raise hell with your VW shop and make them follow the proceedure. Let us know what fixed your problem. --- Jimmy Stoner | ARPA/Internet: jimmy.stoner@EBay.Sun.COM Sun Federal Program Manager | UUCP: ...!sun!stoner -------------------------------------------------------------------------- X-NEWS: dev7d.mdcbbs.com rec.autos.vw: 2094 Relay-Version: M&E Bulletin Board System 10/13/90 VAX/VMS V5.3; site mdcbbs.com Path: mdcbbs.com!uunet!uunet!wupost!uwm.edu!uwvax!astroatc!ludeman Newsgroups: rec.autos.vw Subject: Re: idle stabilizers Message-ID: <3904@astroatc.UUCP> From: ludeman@astroatc.UUCP (Zulu Monster) Date: 7 Oct 91 17:27:36 GMT Reply-To: ludeman@astroatc.UUCP (Zulu Monster) Distribution: na Organization: Astronautics Technology Cntr, Madison, WI Lines: 48 > >Does anyone know what the idle stabilizer and idle bypass valve do on >'85 and later Jetta and Golf? What are some of the symptoms of these >going bad? Well, all I know is what I read in the Bentley Manual, which wasn't all that much. Seems that 1) idle speed is controlled electronically by (rapidly) opening and closing the idle air stabilizer valve and 2) the duty cylcle of the valve is controlled by the bypass valve. i.e. bypass valve and stabilizer valve are in parallel. The Bentley Manual talks about adjusting the bypass valve to produce a certain duty cycle under certain specified conditions, blah, blah, etc. (It's been a while, anyhow, this is just background) What I _observed_ was that I had the same rough starting, hesitation problem as everyone else, and the dealer kindly gave me a photocopy of a service bulletin saying that this was unfixable when I had the car in for dealer service at 30K miles. The following morning on the way to work the car quit at two or three stop signs before warming up and was really balky. I drove the car for a week that way, then decided to fix it myself... What I did was adjust the bypass valve to give the smoothest transition from idle to throttle and vice versa -- you can do this very easily in the drive way by blipping the throttle by hand while adjusting the bypass valve. Open it too much and the engine falls to normal idle rather slowly, close it too much and the engine falls below normal idle and stumbles. Just right and it runs great ('86 GTI). For the last 40K miles (since I made this fix) I have had no starting difficulties at all and have only the slightest hesitation that occurs after I back out of the drive and put the car in first. The first stop I come to is two blocks away and it always accelerates smoothly there and thereafter (assuming everything else -- plugs, cap and rotor especially) are in good shape. If you decide to try this, I recommend that you first note the position of the bypass adjusting screw, and then make 1/2 turn adjustments and _keep_track_ of where you are. As I recall (dimmly at this point) it required ~2 turns (out) or so of adjustment from where the dealer had it and that "fine tuning" required getting it right to +/- 1/8 turn. Your hesitation may vary. Have fun. -- Evan Ludeman "I'll tell you why we do this, ludeman%astroatc.uucp@cs.wisc.edu we do it so we can say 'Sierra Mike, {...}!uwvax!astroatc!ludeman two minutes'". -- John Seymour "SM" X-NEWS: dev7d.mdcbbs.com rec.autos.vw: 1644 Relay-Version: M&E Bulletin Board System 10/13/90 VAX/VMS V5.3; site mdcbbs.com Path: mdcbbs.com!uunet!uunet!airs!andrew Newsgroups: rec.autos.vw Subject: Re: Still hesitatin' after all these weeks.... Message-ID: <2427@airs.com> From: andrew@airs.com (Andrew Evans) Date: 23 Aug 91 19:03:15 GMT Sender: news@airs.com References: <1991Aug22.141852.11398@athena.cs.uga.edu> Lines: 43 steele@athena.cs.uga.edu (Frank Steele) writes: >The problem is that the car runs smoothly as long as there's fuel injector >cleaner in the tank, and rough when it's not. I've run ~3 bottles of the stuff >through the system and it seems like there would be some improvement after I >quit using it if it were actually cleaning the injectors. Am I doomed to forever >run a bottle of injector cleaner through the car with every fill-up? >If you're still reading, I've been using STP's cleaner, and have been running >mostly either Plus or Premium grade gas. The 16V cars, I'm told, are very susceptble to intake valve deposit buildup. This could cause poor idling and loss of power as well. You might be able to inpect the back of the valve by pulling the fuel injectors out of their seats and looking in there with a flashlight. The best way to fix this is to pull the head and have a valve job done, but VW's also got a valve deposit cleaner that comes in a can and attaches where the fuel line goes on the fuel distributor. You run the engine through a couple cans and it supposedly makes a BIG difference (so said VW & Porsche mag.). Possibly a good independent VW garage can do this (the adapter to fit the can to your fuel distributor is like $70), if not the dealer. It could also be that bad fuel has contaminated part of the fuel injection system. Bosch CIS is VERY sensitive to bad fuel. What brand of fuel have you been running? This makes more of a difference than which grade of fuel. I highly recommend all grades of Mobil, though Super will get you the best performance with your car. I've also done well by Shell and Sunoco. I've used Texaco a couple times, and it seems ok. You might have gotten a bad tank of gas, contaminated with water or some sort of particles. Draining the tank and replacing the fuel filter is a good place to start, and it certainly won't hurt. There are also tests that can be performed (if you have the tools and the Bentley manual) to observe the spray pattern of the fuel injectors and the amount of fuel they deliver. If you've got a problem after doing the filter, you're going to have to find out what fuel system component has been damaged. Try draining the tank and changing the filter first, and see if that doesn't help. If not, you could be in for a bigger ordeal. andrew Article 54821 of rec.autos.vw: Path: usenet.eel.ufl.edu!hookup!uwm.edu!cs.utexas.edu!swrinde!pipex!sunic!sunic.sunet.se!news.uni-c.dk!dkuug!usenet From: nez@login.dknet.dk (Niels Ezerman) Newsgroups: rec.autos.tech,rec.autos.vw Subject: Re: 85 VW Golf Fuel Injection Problem Date: Sun, 26 Mar 1995 10:03:02 -0100 Organization: DKnet / EUnet Denmark - Login Tjenesten Lines: 47 Message-ID: References: <95Mar21.190512est.6212@neat.cs.toronto.edu> NNTP-Posting-Host: login.dknet.dk Xref: usenet.eel.ufl.edu rec.autos.tech:118916 rec.autos.vw:54821 In article <95Mar21.190512est.6212@neat.cs.toronto.edu>, enenkel@cs.toronto.edu ("Robert F. Enenkel") wrote: > Can anyone familiar with the CIS fuel injection system on an 85 VW Golf > help me with some diagnosis? > 2) If it is hot as before, but I shut it off for 2-3 hours before > restarting, the starter must crank it for about 5 seconds before > it suddenly starts. > If I then stop and restart it, it starts immediately. > I thought perhaps that the residual fuel pressure kept in the system by > the accumulator might be being lost through a faulty check valve in the > fuel pump, so I tried an experiment. > I stopped the hot engine, then immediately clamped shut the hose from the > fuel tank to the pump, so no pressure could escape even if the check valve > was leaking. > After waiting 2 hours, I unclamped the hose and started the engine. > It took 5 seconds of cranking anyway, so I guess the check valve is not > the problem. What is? Excellent try. Then you can check if there is a leak from the system pressure regulator valve. - Stop the hot engine, unscrew the return line from the fuel controling unit to the tank. - Check if there is a leak from the fuel controlling unit, if so, get a repair kit for the system pressure valve (o-ring etc.) Else check that the injectors dont leak, there are different pressure values (newer with higher opening pressure). Check that the air plate in the cone is not placed too high, after stopping hot engine. / / / __ | <-- i can't remember the exact mm, 0-1 mm below -----__--------| the edge to the cone/taper. Check that the coldstart valve is not leaking. BTW. it is a common problem for this system. -By Niels Ezerman.