Well, here's what my FSM says about unstable idle for a GA:
1 Check EGR valve for sticking.
2 Perform Power Balance Test; Wtih engine running, disconnect one injector at a time, replacing each one before you pull another one off. Notice if there is any one cylinder that doesn't produce a momentary engine speed drop. If one does then you could have a bad injector or bad wiring for that injector.
3 Check injectors by using a screwdriver to listen for a ticking sound. (This seems pointless since you'd have figured out if an injector was not working while doing step #2)
4 Check ignition spark by pulling one plug wire off at a time, connect a known good plug and ground against something and crank the motor to check for spark.
5 Check plugs by removing them and check for fouling, etc.
6 Check fuel pressure; release fuel pressure by pulling the fuel pump fuse and start car. Once car dies, crank engine a couple times and put fuse back in. Install a fuel pressure gauge just after the fuel filter. At idle it should be 36 psi.
7 Check O2 sensors. This will be different since you have OBDII.
8 Check for intake air leak by pinching the blow-by hose and see if engine speed rises. If so you have a leak.
9 Check Idle Adjustment Screw for clogging; Pull tps off and start car, and see if you can adjust the idle to 600 rpm +/- 50 rpm for manual, 725rpm +/- 50 for auto. If not then your TB or that screw could be clogged.
10 Check compression; 192 psi is standard 164 psi is the minimum. no more than 14 psi variance between cylinders.
11 Check ECU harness connector
12 Try a known good ECU
Rob '93 SE-R
PM or e-mail me for Progress swaybars $190 shipped, B13 Progress coilovers $1300 shipped and B13 Progress LCA brace $160 shipped.
Last edited by toolapcfan; Sep 20th, 2003 at 09:33 AM.