Wingnut, first off, great post! I had a few questions for you.
1. If you turn on the ignition, the gp indicator lamp comes on, and goes out when the gp's are supposedly ready. If you leave the ignition in the "on" position for say 10 seconds after the indicator lamp turns off, do they gps remain active? Do they remain active but go into the "pre-glow" period?
The reason I ask is that I have hard starting at temps between 20-40F, by performing this technique, sometimes the car will start w/less than 1second of cranking, other times it will start with 4-6 seconds of cranking (assuming same temperature both times).
I have been battling hard starting for over a year now. November 2003 my MIL came on twice in 2 weeks, first time for gp relay, 2nd for gp harness, both were fixed by the dealer. Hard starting occurred before and after this double whammy, with no difference in starting prior or after.
I have followed through this post: When I checked the resistance on gps(setting m.m. to 200ohm), I used the same ground point as in your picture. I rigorously wiped down all gp and ground surfaces with a rag to remove surface grime. Then when I measured each one, it was hard to get a stable reading. I kept my hand stable, but resistance would jump all over the place in the double digits and then settle between .7-1.1 very briefly, and then hit single digits, double digits, or read even nothing. It only read .7-1.1 for a very short period. The same thing occurred on all four plugs, which when they were within .5-1.5 ohms, all measured about .8.
I checked the harness by unplugging the coolant temp sensor, and received ~12V for all 4 plugs. I checked the voltages in the fuse box on top of the battery and all the wires measured 12V (same process as shown in your pictures).
Lastly, this is the last thing I noticed. It was ~30F this morning. The car had been sitting all night long and the first thing I tried was unplugging the coolant temp sensor. I turned on the ignition, and the gp indicator was on for roughly 20 seconds. As soon as the gp indicator went out I turned the car over and it started within 1 second.
I let it idle for about 1 min and then turned it off. About 30 mins later I went outside, stil same ambient temp, got in the car, turned on the ignition (coolant sensor is plugged back in now), gp indicator was on for less than 1 second, turned the car over once it went out, and it took about 4 seconds of cranking time!
The last thing I can think of is the coolant temp sensor is faulty. The weekend over thanksgiving I noticed on 2 consecutive days while driving, the engine started warming up to op temp, and then the needle went back down to zero, and then finally warmed up. This is the only time this has happened, has happened since.
This is long, but does anyone have any ideas?