SDS management oddities

[sidemarkers]

I've had my SDS engine management since 2003 with great results. Last weekend I returned to my car in a parking lot after running errands. Started it up and noticed my tps value had changed and the car was running erratically and was leaning out on acceleration. I adjusted the tps to where it was prior. Got home and noticed that on my gauge display with the key on (not running) the MAP value was -4.33, when it should read 0 vacuum . Replaced the MAP sensor today and swapped out the battery and still have the same problem. I hooked up a hand held vacuum gauge and compared the reading to my SDS gauge mode and the SDS is showing around 4 inches more vacuum across the rpm range...needless to say this is causing the lean condition, but what is causing the faulty MAP sensor reading? I emailed the SDS rep and he's very patient and informative through all this.

[bobdj1955]

Ground wires ???? Thinking tps issue is related.

[sidemarkers]

Checked grounds, replaced cracked spark plug wire insulator and replaced coil lead wire grommet. All better!

[sidemarkers]

Acting up again... When engine is cool it runs good. When engine is at operating temperature and under load it hesitates and backfires out the exhaust and it gets worse under boost. When it backfires the engine goes rich. Changed the plugs and reduced the gap from .027 to .024 also checked resistance on plug wires which were acceptable, but not great. Ordered a new set online, should be here next week.

When I start the car the tach twitches.

Checked fuel delivery Bosch pump is putting out 45 lbs and checked boost reference on regulator...all systems go.

Thinking it's the coil pack.

[bobdj1955]

How is your hall effect mount / gap. Is the wiring routed away from high power sources, ignition wires, alt wire, fan wires, coil wires???

[sidemarkers]

I tidied up wiring this morning. The mount is probably overkill it is so solid! The drive to Home Depot felt great today.