Date: Mon, 03 Mar 2003 19:56:52 GMT From: "Mark Plumlee" <turbospgnospamsouth.net> Subject: Re: '91 Saab 900 2.1 non-turbo w/poor performance on acceleration
timing way off? like 180* "Lance Morgan" <alancemornospamo.com> wrote in message news:2a52f3e9.0302220739.70c192b5nospaming.google.com... > "Brian Dean" <BJDinNCnospamsouth.net> wrote in message news:<wii5a.5391$Ye6.2696nospam.atl2.webusenet.com>... > > I have a 1991 Saab 900, 2.1 non-turbo with 140,000 miles in good repair. > > > > Beginning several weeks ago, it began to lurch when accelerating under load. > > This lurching feels like momentary complete power cut-out by the engine ... > > sudden in nature with immediate resolution... i.e., it seems to studder > > rapidly while accelerating under load. If the clutch is pressed in it will > > clear and rev freely. > > > > This occurs at start-up and continues, regardless of operating temperature. > > > > There are NO problem codes set by the on-board diagnostics. > > > > The vehicle has a new dist rotor, dist cap, and spark plugs. All are > > correct factory specified components. > > > > The head gasket was replaced about 10,000 miles ago without incident and the > > car ran faultlessly until just several weeks ago (probably less than 500 > > miles with this problem). > > > > Any ideas would be appreciated... > > Brian > > This type of problem can be difficult to diagnose, due to the number > of possible causes, and the interaction between the (LH 2.4.2) fuel > system and (EZK) ignition system. > > For DIY, you'll need to sequential trouble-shoot the two systems, > using either a Bentley or Haynes service manual, on-line resources, a > fuel-pressure gauge, a digital test meter, basic tools, and patience. > > I, too, would lean towards a fuel system problem, while not ruling out > an ignition sys problem. A partial list of things to check: > > - fuel pump output > - fuel pressure, including quick return of pressure after pinching > line > - air mass meter (AMM) > - LH system and fuel pump relays (right-hand side kick area) > - O2 sensor > > - vacuum leaks > - ground points > - general/physical wiring inspection & continuity and/or voltage drop > testing > > - wiring and physical tightness of crank sensor behind crank pulley > - ignition amplifier (sometimes called ignition module) > - ignition coil > - worn distributor > > Sometimes it's ultimately less costly and frustrating, and more > expedient to take these type probs to a good saab mech - not only due > to seasoned experience, but also being able to plug diagnostic > equipment into the LH and/or EZK test harnesses [can help to pinpoint > "ECU" (LH fuel control unit, right-hand side kick area) and/or EZK > control unit (left front wheel area) failures, as well as other > components], and other advanced tools like oscilloscopes, etc > > Lance > 91 900S
