ELECTRICAL SYSTEM # 6 Date: 04-03-94, 14:54 Left by: TURBOTIM Sent to: ALL Status: Public Topic: DIS The DIS (digital idle stabilizer) is common problem for 80-83 models for causing cutting out and dying problems. Locate a small black box with 2 round connectors and harnesses coming out of them. This is located in the vent tray under the hood on the left (driver) side. While you VW is running wiggle the 2 harnesses at the plug area, If the car sputters or dies then you have 2 choices on how to fix the bad pins and DIS unit. 1Install a new unit and new gold pins and coat with di-electric grease 2- Wire the wires together bypassing the unit. If your VW has A/C you will need to bump up the idle to compensate for the lack of a load dependent idle stabilizer (DIS). The second method may not be smog legal but most smog places don't have a clue about the DIS. Another possible cause is the hall sending unit wires. The early pre-83 models had short wires in the distributor hall unit that like to break. With the cap and rotor off look at the wires going from the plug in the side to the hall unit. You will see the insulation broken off and the bare wire. On the replacement hall repair kit the new unit comes with a plastic cover with long wires-this cured the problem. @@ TT @@ X-NEWS: dev7d.mdcbbs.com rec.autos.vw: 2053 Relay-Version: M&E Bulletin Board System - V6.0 13/10/90 VAX/VMS; site mdcbbs.com Path: dev7d.mdcbbs.com!jan Newsgroups: rec.autos.vw Subject: Re: idle stabilizers Message-ID: <1991Oct4.134002.1@dev7d.mdcbbs.com> From: jan@dev7d.mdcbbs.com Date: 4 Oct 91 13:40:02 GMT References: <99oL0124eaLf00@amdahl.uts.amdahl.com> <2660@airs.com> <2OCT199110592715@venus.lerc.nasa.gov> <3266@gold.gvg.tek.com> Distribution: na Organization: McDonnell Douglas M&E, Cypress CA Nntp-Posting-Host: vxd1 Nntp-Posting-User: hartnett Lines: 45 In article <3266@gold.gvg.tek.com>, jimd@gold.gvg.tek.com (Jim Delwiche) writes: > In article <2OCT199110592715@venus.lerc.nasa.gov> aeporro@venus.lerc.nasa.gov (Bob Porro) writes: >> > > I think there are two kinds of idle stabilizers. The older (at least > CA spec) cars have the DIS as you mentioned, which is a little box > which fits inline on the low voltage side of the ignition. It's > located on the driver's side, near the hood hinge. It has to be > bypassed when setting the timing and idle speed, since it plays with > ignition timing to keep the idle at ~800rpm. > > On the newer cars, the idle stabilizer is some kind of doohickey > (that's a technical term) on the fuel injection system. I don't know > anything about what it is or how it works. The above statements are correct! Earlier VWs (carburated as well as FI) had the DIS which would stabilize engine idle speed by either advancing or retarding the ignition. Using a strobe with the DIS in place would result in your timing mark to jump all over the place. Not all VWs had the DIS, and so far I haven't really figured out why. Probably has something to do with polution control. The newer VWs have an idle stabilizer VALVE. This valve bypasses the throttle body (the thing your accelerator cable is attached to (*) ) and therefore regulates the amount of "idle" air. It's like having your own little mechanic continually adjusting your "idle speed" screw. This valve sometimes fails due to a number of problems (some will say fails *often*). One of the more common problems is that it gets contaminated with soot & oil, preventing the valve from moving smoothly. VW&P recommends cleaning the inside of the valve with Brake Clean (I use carb cleaner) if rough idle/stalling occurs as a first attempt. The valve is expensive to replace. In this regard, you may also want to clean the sensor plate and the little screen on top of it (K & KE FI cars) as that get gunked up as well, resulting in unstable idle. Jan (*) Ironically, your *gas* pedal/cable controls air flow (vacuum), not the amount of gas (directly). Only diesels really have a "gas" pedal. X-NEWS: dev7d.mdcbbs.com rec.autos.vw: 2168 Relay-Version: M&E Bulletin Board System 10/13/90 VAX/VMS V5.3; site mdcbbs.com Path: mdcbbs.com!uunet!uunet!cs.utexas.edu!uwm.edu!news.bbn.com!bbn.com!jhamill Newsgroups: rec.autos.vw Subject: Fuel injector seals/importance of Message-ID: <66891@bbn.BBN.COM> From: jhamill@bbn.com (John Hamill) Date: 15 Oct 91 21:31:36 GMT Reply-To: jhamill@spcink.bbn.com (John Hamill) Sender: news@bbn.com Distribution: usa Organization: Bolt Beranek and Newman Inc., Cambridge MA Lines: 33 Here's a story on fuel injection troubleshooting I thought I would post. I was working on a friends 84 GTI last week. Seems as though he thought his lambda sensor was bad because the garage he went to disconnected it because the car wouldn't idle right. When the sensor was connected, the idle starting acting really erratic, going up and down as much as 300-400 rpm. The garage disconnected the lambda sensor and told him the control unit was bad and would cost mucho money to replace. My friend, thinking the lambda sensor was bad, bought a new one, hooked it up, and the idle promptly went bad again. He then went to a junkyard and bought a used control unit, installed it, and hooked up the lambda sensor again. Idle went bad again. He had now spent $64 on a new lambda sensor, and $100 for a used control unit. Then he called me and asked if I would look at it. I checked everything, and the idle would be *perfect* without the sensor hooked up, and crappy with it. I figured the new control unit was bad too, but having two in a row with the same problem didn't add up. I pulled the injectors and they sprayed fine. I replaced the injector seals and voila! the problem was fixed. Just goes to show, fix the *simple* stuff first, then move on to the more complex. What was happening was that too much air was leaking past the seals, causing the lambda sensor to tell the control unit that the fuel mixture was incorrect. The control unit, in turn, altered the fuel mixture based on the information it was getting from the lambda sensor (which was incorrect). This in turn caused the idle to go haywire. The fix, 4 new injector seals, cost $1.50. Funny thing was, the car idled fine without the lambda sensor hooked up at all. jh I don't believe Anita Hill for a moment!