For the 2nd time in a month, my car dumped me again. This time I was prepared a little better and took more note of what was happening, plus I had installed a manual fuel pressure gauge on the rail.
Conditions: Both times have been after extended driving (an hours time). Weather has been mild, temps in the 70's. No WOT, just general cruising around.
Symptoms: Car stumbles and then dies. Turns over but doesn't fire. Let sit for a couple of minutes, cranks up and runs fine for a couple of miles, then repeats. After a few times, it will seem to recover and run fine, long enough for me to get it home. Next day, runs fine and strong.
Observations: This time I watched the SM O2s and CCs each time. On startup and takeoff, O2's oscillate as normal (50 to 750). When the car starts to stumble, the O2's begin to drop until they reach around 50. At this point, feathering the accelerator will keep it going for 10 to 20 seconds but then it dies again. Switching to Crosscounts, the crosscounts stop moving also when it is stumbling. While waiting to restart, key to on, fuel pump comes on as expected and fuel gauge indicates around 38psi. Then psi begins to drop until cranked.
It would seem because of the O2's reading 50 or less and the CCs stopping that the O2 sensor is going bad? Do these usually act up as a result of extended periods of heat? Because, it seems weird that letting it sit for a minute or two allows it to restart, but then after another minute or so, stumbles again. Can the O2 sensor also allow the car NOT to start immediately and require sitting like it does? That seems to point more towards fuel, but I dunno.
I also have a Walbro of the recall vintage so I'm always a bit wary of a failing pump. But it seems to prime fine and when not running for extended periods of time is strong on WOT and I get no KR. I also have kept the tank full (less an hour of driving) because I had heard that the pump can fail when not submerged and it heats up.
I'm appealing to the experts to help out here and explain what is going on and what I should look to fix.
Conditions: Both times have been after extended driving (an hours time). Weather has been mild, temps in the 70's. No WOT, just general cruising around.
Symptoms: Car stumbles and then dies. Turns over but doesn't fire. Let sit for a couple of minutes, cranks up and runs fine for a couple of miles, then repeats. After a few times, it will seem to recover and run fine, long enough for me to get it home. Next day, runs fine and strong.
Observations: This time I watched the SM O2s and CCs each time. On startup and takeoff, O2's oscillate as normal (50 to 750). When the car starts to stumble, the O2's begin to drop until they reach around 50. At this point, feathering the accelerator will keep it going for 10 to 20 seconds but then it dies again. Switching to Crosscounts, the crosscounts stop moving also when it is stumbling. While waiting to restart, key to on, fuel pump comes on as expected and fuel gauge indicates around 38psi. Then psi begins to drop until cranked.
It would seem because of the O2's reading 50 or less and the CCs stopping that the O2 sensor is going bad? Do these usually act up as a result of extended periods of heat? Because, it seems weird that letting it sit for a minute or two allows it to restart, but then after another minute or so, stumbles again. Can the O2 sensor also allow the car NOT to start immediately and require sitting like it does? That seems to point more towards fuel, but I dunno.
I also have a Walbro of the recall vintage so I'm always a bit wary of a failing pump. But it seems to prime fine and when not running for extended periods of time is strong on WOT and I get no KR. I also have kept the tank full (less an hour of driving) because I had heard that the pump can fail when not submerged and it heats up.
I'm appealing to the experts to help out here and explain what is going on and what I should look to fix.