Date: 24 Feb 2003 07:34:52 -0800 From: alancemornopsamo.com (Lance Morgan) Subject: Re: '91 Saab 900 2.1 non-turbo w/poor performance on acceleration
"Brian Dean" <BJDinNCnopsamsouth.net> wrote in message news:<mf96a.38080$HV.4841nopsam.atl2.webusenet.com>... > "Lance Morgan" <alancemornopsamo.com> wrote in message > news:2a52f3e9.0302220739.70c192b5nopsaming.google.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. > > > snip >>> Brian > > > > > > 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 > > > > Lance > ____________________________________________________ > > > > Lance, Simon, and darkpoter - > snip > > Does anyone else have any experience with this test ??? ... and is 900 mls > "marginal" performance for the pump delivery rate ... ??? Sounds okay for volume, but you also need to ck pressure, per Bentley. AFAIK, the most definitive test for a fuel pump is w/an oscilloscope Note that the Bentley (or Haynes) tests are fairly good, but sometimes not perfect: a part may "test okay" per Bentley/Haynes but may still be faulty... > Also just poking around, ... I pulled the access panel under the rear > luggage compartment to inspect the condition of all the fittings and > electrical hook-ups to the fuel pump ... they all look to be in perfect > condition ... so no easy fix to be found there ... I've never seen a spec for fuel pump current draw - perhaps it's in the more detailed and costly Bentley "Official Factory Repair Manual" vs the "Service Manual" Find the elec section on grounds in Bentley, and at least ck the key ones: G1, G7 (two by engine lifting lug), G12, etc > I plan to go ahead and replace the fuel filter just for good measure....not > knowing when this was done last and that I've put 40K miles on it without > replacement... If this is helpful: make sure to get 4 new sealing washers with the new fuel filter - 2 small & 2 large, IIRC. Depressurize the fuel system by pulling fuse #30 with the car running, until the engine dies. Clean fitting parts well (don't let crud fall in the fuel lines), and 18 ft/lbs should be good for retightening the fuel filter banjo s > > Since I don't have a good diagnosis as of yet (feul system versus ignition > system ...etc...) ... I will also replace the ignition wires... as I don't > really know how old they are either. So again, this is a reasonable thing > to spend money on even without a clear diagnoses. > The spark plug wires/HT leads can be tested for proper resistance, per Bentley, but not a bad idea to replace them. The exclt Bougicords can be found new for less than $30 US. It's usually a good idea to have all "basic tune-up" parts in known good order, before troubleshooting a problem Also, don't assume that your recent/future new parts are good - probably are but may not be (i.e., ck the color temp of your 'new' plugs - all 4 burning okay? no cracks in 'new' dist cap [view at night for arcing]? etc] A lot of c900 info is available on line, thru several forum archives and searches, helping to supplement, and sometimes even exceed the service manuals alt.autos.saab http://www.saabnet.com/forums/viewforum.php?f=2 http://www.saabnet.com/tsn/bb/900/ http://216.78.172.244/entry/tech_doc_systems.htm http://www.twinsaabs.com/ http://www.dave-new.com/procedures/index.html LM
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