Our driver came in today with the 2001 Windstar (234XXX miles) barely running. Give it a little throttle and it died. Restarted with a little cranking and then it ran fine for a bit. Eventually - 10-15 minutes - it would start to run rough and barely run, even dieing occasionally.
Finally, it threw a code for bank one too lean. I hooked up my snap-on scanner and watched the O2 sensors and when it was running fine, everything looked fine. The first sensors were going up and down as expected and the second sensors were OK. I just changed one second O2 sensor with a NAPA one (not my choice, the boss ordered it after I told him to spend the extra $20 for the Ford one) and that one had a much wider swing that the other second sensor.
I am concerned that could be causing troubles, but I would expect it to be a consistent problem, not one that comes and goes.
I have also replaced the intake manifold gaskets last year, but I would expect a vacuum leak to be consistent as well.
I could look at the trims, but I don't know what to expect and even though I have done lots of reading about it, I still don't understand it or know what to expect for readings.
At one time, I thought that this was vapor-locking somehow since it was rather hot today, but I don't think that is possible, is it? If I got a fuel pressure gauge, what should I expect for a reading there?
The fuel regulator should sustain that pressure. Running at a higher RPM will make it dip a little and at an idle it should be near the KOEO. If your pressure is dipping, it could be the sending unit, fuel pump, either fuel filter, or the regulator. I'd go with the filter first since they do require an occaisional replacement.
OK, so KOEO I had 22 or 28 PSI. It changed from one try to the next.
KOER, was at 30 PSI and when I snapped the throttle, it jumped about 3 PSI.
The online manual I checked showed 30-45 PSI, but it didn't say if that was running or not.
I haven't had the gauge on it and had it stumble, so I don't know what that looks like.
I looked at our 2005 Windstar and it showed 48 PSI KOEO, 59 KOER and a 3 PSI drop when snapping the throttle, but the spec I saw was 67 PSI (again, IDK if that is running or not) so I am comparing apples and oranges here so that's not going to work.
after having the driver cycle the key and me watching the gauge, sometimes the pressure would jump to about 32 PSI, then drop to Zero, sometimes it would jump up and drop to 20 PSI. This sounds like a fuel pump, don't ya think?
So far it's running great. One thing that I noticed is that there may have been a bit of water in the fuel. The gauge that I have has a clear bleed hose and I drained some into a cup and just as I was going to dump it, I noticed some dirty water in the bottom. was it from the fuel system or elsewhere? I don't know for sure.
I don't know what I'm doing (obviously). I just checked fuel pressure when fully warmed up and snapping the throttle and it jumps from about 31, up to about 39 PSI. Again, I have no idea if this is normal.
YEAY! She died on me today while the fuel pressure gauge was hooked up. As it was stumbling, I looked and the fuel pressure was at about 12 PSI. When running fine it runs a steady 30 PSI.
Now, when I flushed fuel through the bleeder into a clean cup, I ended up with one very small (Maybe .020") gnat and one bigger fly (Maybe .050"). There was also quite a bit of small sediment in the bottom, much more than I would expect from the 1/4 cup of fuel.
My plan is to drop the tank and clean it out, then decide if I need to install the pump I have on the way.
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