Fuel pressure issue - 95 Astro - please help (2024 Update)

There is a "sock" type filter for the big chunks at the fuel pickup in the tank. If these plug / clog or collapse they can cause similar problems.

Good luck, Don

You need to determine if this thing is going too rich or too lean when it acts up. Ideally, a test drive with a scan tool installed so you can view O2 sensor volts and the fuel trim numbers. Plug color and watching the O2 sensor on a DVOM is a do-able method if you don't have a scan tool.

The fuel pressure shouldn't drop off as it does, weak pumps and/or a failed pulsator usually manifest themselves as hard starting after an overnight set. Entirely possible that it's the CPI and regulator (again), who did you get those components from?

Did you re-use the old pulsator when you changed out the pump? Pulsator = the oval shaped piece that connects the fuel pump outlet to the sending unit , black plastic with a stamped tin cover.

Thanks for the suggestion. That sounds like it is very likely what is wrong.

I did have a leaky fuel injector that I just replaced. I will get the converter check/changed saturday if necessary.

Thanks

KENG wrote:

(worst)

driving.

I do not think I replaced the pulsator, unless it came with my autozone pump. The CPI and nut kit where ACDelco parts.

I kind of think it might be the catlytic converter now. That is what a couple people have told me and it seems like these symptoms could be caused by a clogged converter. I will test it first since it is a bit easier. Then I guess I will either do the test drive you suggested and change the pulsator.

Thanks for the suggestions,

Dave

If you would get a data logger, do they have them for a 1995 car/van ? ///////////////////////////////////////////////////////////////////////////////////////////////////////////

My fuel pressure is _supposed to be between 35 and 45 psi according to the book, but I see on SOME occasions it goes outside those bounds, especially while idling. In fact, it seems only while idling. So I don't know what that is all about. NO DTC CODES either thrown or pending, according to my OBDII scanner. But my data logger picked this up. Notice what happens at the 13 minute point when I was idling the car while eating lunch one day....

Fuel pressure doesn't come back to normal until minute 25, when I accelerate and travel off again.

For 11 minutes my system was over pressurized, but no MIL or DTC codes. And out of 115 trips on this particular log, it only happened this _once_.

Anyhow, if you can fit a data logger on a 95 Astrovan ( haven't a clue if you have an OBDII port ) you can use a data logging chip to watch your fuel system while you drive around.

//////////////////////////////////////////////////////////////////////////////////////////////////////////// CAUTION: BANDWIDTH BUSTER AHEAD: ////////////////////////////////////////////////////////////////////////////////////////////////////////////

NOTE: the three digits on the right, two to the left of the decimal point and one to the right, show fuel pressure at 5 second intervals from start of engine.

Time into trip is left of that

If you do this, you have narrowed down one possibility. And you can log fuel trims right along with that.

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Title : View / Trip Log / Trip 22 / Plot / Fuel Pressure (psi) / Start Time Rows : 1 Columns : 1 Column 01 : Start Time []

1/21/2005 1:56 PM

Title : View / Trip Log / Trip 22 / Plot / Fuel Pressure (psi) Rows : 606 Columns : 2 Column 01 : Elapsed Time [] Column 02 : Fuel Pressure (psi) [psi]

0:00:00 48.7 0:00:04 47.4 0:00:09 46.6 0:00:14 46.1 0:00:19 46.6 0:00:24 44.4 0:00:29 44.8 0:00:34 43.1 0:00:39 45.7 0:00:44 40.5 0:00:49 44.8 0:00:54 39.6 0:00:59 41.8 0:01:04 39.2 0:01:09 41.3 0:01:14 40.5 0:01:19 38.3 0:01:24 38.7 0:01:29 40.5 0:01:34 41.3 0:01:39 39.2 0:01:44 38.7 0:01:49 41.8 0:01:54 40.0 0:01:59 37.9 0:02:04 40.0 0:02:09 39.2 0:02:14 40.5 0:02:19 41.3 0:02:24 38.3 0:02:29 39.2 0:02:34 40.5 0:02:39 39.2 0:02:44 40.5 0:02:49 39.6 0:02:54 40.5 0:02:59 40.5 0:03:04 38.7 0:03:09 40.0 0:03:14 38.7 0:03:19 39.2 0:03:24 39.6 0:03:29 39.2 0:03:34 37.9 0:03:39 39.6 0:03:44 38.7 0:03:49 38.7 0:03:54 39.2 0:03:59 39.2 0:04:04 38.7 0:04:09 39.6 0:04:14 40.9 0:04:19 38.7 0:04:24 38.3 0:04:29 40.0 0:04:34 40.5 0:04:39 40.0 0:04:44 39.2 0:04:49 39.6 0:04:54 40.0 0:04:59 38.7 0:05:04 40.5 0:05:09 38.7 0:05:14 40.5 0:05:19 40.0 0:05:24 38.7 0:05:29 40.5 0:05:34 39.2 0:05:39 38.7 0:05:44 38.7 0:05:49 39.6 0:05:54 41.3 0:05:59 38.7 0:06:03 38.7 0:06:08 41.3 0:06:13 37.9 0:06:18 39.6 0:06:23 38.7 0:06:28 38.7 0:06:33 38.7 0:06:38 40.0 0:06:43 39.6 0:06:48 38.3 0:06:53 40.5 0:06:58 40.5 0:07:03 39.6 0:07:08 39.6 0:07:13 40.9 0:07:18 38.7 0:07:23 38.7 0:07:28 39.2 0:07:33 39.6 0:07:38 39.6 0:07:43 37.9 0:07:48 41.3 0:07:53 41.3 0:07:58 40.0 0:08:03 41.8 0:08:08 40.9 0:08:13 38.3 0:08:18 40.5 0:08:23 38.7 0:08:28 39.6 0:08:33 38.7 0:08:38 40.5 0:08:43 40.0 0:08:48 39.2 0:08:53 39.6 0:08:58 40.9 0:09:03 39.6 0:09:08 39.6 0:09:13 40.0 0:09:18 39.6 0:09:23 41.8 0:09:28 41.3 0:09:33 41.3 0:09:38 40.5 0:09:43 42.2 0:09:48 41.3 0:09:53 42.6 0:09:58 42.6 0:10:03 44.4 0:10:08 41.3 0:10:13 42.6 0:10:18 40.9 0:10:23 44.4 0:10:28 41.3 0:10:33 43.9 0:10:38 43.1 0:10:43 44.8 0:10:48 43.9 0:10:53 44.4 0:10:58 42.2 0:11:03 41.8 0:11:08 44.8 0:11:13 44.4 0:11:18 44.8 0:11:23 46.1 0:11:28 45.3 0:11:33 43.9 0:11:38 46.1 0:11:43 42.2 0:11:48 43.1 0:11:53 46.1 0:11:58 43.9 0:12:03 45.3 0:12:07 47.0 0:12:12 44.8 0:12:17 47.9 0:12:22 45.3 0:12:27 45.7 0:12:32 46.6 0:12:37 45.3 0:12:42 45.7 0:12:47 46.6 0:12:52 46.1 0:12:57 45.3 0:13:02 46.6 0:13:07 46.1 0:13:12 46.6 0:13:17 48.3 0:13:22 47.4 0:13:27 49.2 0:13:32 46.6 0:13:37 45.3 0:13:42 48.7 0:13:47 47.9 0:13:52 48.3 0:13:57 49.6 0:14:02 49.2 0:14:07 46.6 0:14:12 47.4 0:14:17 48.3 0:14:22 47.4 0:14:27 47.4 0:14:32 49.2 0:14:37 50.5 0:14:42 49.6 0:14:47 49.2 0:14:52 48.7 0:14:57 48.7 0:15:02 50.9 0:15:07 48.3 0:15:12 51.3 0:15:17 49.6 0:15:22 48.3 0:15:27 49.2 0:15:32 53.5 0:15:37 50.5 0:15:42 51.3 0:15:47 50.0 0:15:52 50.9 0:15:57 50.9 0:16:02 50.0 0:16:07 50.5 0:16:12 53.1 0:16:17 52.6 0:16:22 49.2 0:16:27 49.6 0:16:32 51.3 0:16:37 51.3 0:16:42 51.8 0:16:47 50.5 0:16:52 51.8 0:16:57 53.1 0:17:02 52.6 0:17:07 51.8 0:17:12 52.2 0:17:17 53.1 0:17:22 51.3 0:17:27 50.9 0:17:32 51.8 0:17:37 51.8 0:17:42 52.2 0:17:47 51.3 0:17:52 53.5 0:17:57 52.6 0:18:02 52.2 0:18:06 51.3 0:18:11 50.9 0:18:16 50.0 0:18:21 51.8 0:18:26 51.8 0:18:31 53.1 0:18:36 52.2 0:18:41 52.6 0:18:46 54.0 0:18:51 53.5 0:18:56 54.0 0:19:01 51.3 0:19:06 52.6 0:19:11 52.6 0:19:16 54.8 0:19:21 51.8 0:19:26 55.3 0:19:31 53.1 0:19:36 53.5 0:19:41 52.2 0:19:46 52.6 0:19:51 53.5 0:19:56 53.1 0:20:01 55.3 0:20:06 51.3 0:20:11 55.3 0:20:16 52.6 0:20:21 54.0 0:20:26 54.4 0:20:31 58.3 0:20:36 55.3 0:20:41 54.0 0:20:46 53.5 0:20:51 54.8 0:20:56 53.5 0:21:01 55.3 0:21:06 54.0 0:21:11 54.0 0:21:16 53.1 0:21:21 54.0 0:21:26 54.4 0:21:31 53.5 0:21:36 52.2 0:21:41 54.4 0:21:46 54.4 0:21:51 54.4 0:21:56 54.4 0:22:01 55.3 0:22:06 53.1 0:22:11 54.8 0:22:16 55.7 0:22:21 54.8 0:22:26 50.9 0:22:31 54.4 0:22:36 54.0 0:22:41 54.0 0:22:46 52.2 0:22:51 54.8 0:22:56 54.8 0:23:01 54.4 0:23:06 56.1 0:23:11 56.1 0:23:16 52.6 0:23:21 55.7 0:23:26 53.1 0:23:31 54.4 0:23:36 55.7 0:23:41 55.7 0:23:46 56.1 0:23:51 54.0 0:23:56 54.4 0:24:01 54.0 0:24:06 53.5 0:24:10 53.5 0:24:15 50.9 0:24:20 51.8 0:24:25 51.8 0:24:30 55.7 0:24:35 50.5 0:24:40 51.3 0:24:45 51.8 0:24:50 50.9 0:24:55 47.0 0:25:00 46.6 0:25:05 44.8 0:25:10 50.5 0:25:15 46.1 0:25:20 46.6 0:25:25 45.3 0:25:30 42.6 0:25:35 44.8 0:25:40 45.7 0:25:45 47.0 0:25:50 46.6 0:25:55 45.7 0:26:00 44.4 0:26:05 44.4 0:26:10 47.9 0:26:15 44.4 0:26:20 47.0 0:26:25 43.9 0:26:30 43.1 0:26:35 41.8 0:26:40 44.4 0:26:45 42.2 0:26:50 45.3 0:26:55 41.3 0:27:00 43.5 0:27:05 37.0 0:27:10 43.1 0:27:15 39.2 0:27:20 38.3 0:27:25 39.6 0:27:30 40.0 0:27:35 38.3 0:27:40 40.9 0:27:45 40.5 0:27:50 38.7 0:27:55 40.0 0:28:00 40.9 0:28:05 41.3 0:28:10 39.2 0:28:15 40.9 0:28:20 38.3 0:28:25 40.0 0:28:30 40.0 0:28:35 40.5 0:28:40 39.6 0:28:45 40.0 0:28:50 40.9 0:28:55 37.9 0:29:00 38.7 0:29:05 40.0 0:29:10 39.6 0:29:15 40.0 0:29:20 39.6 0:29:25 40.0 0:29:30 40.0 0:29:35 40.5 0:29:40 40.0 0:29:45 39.2 0:29:50 42.2 0:29:55 39.6 0:30:00 38.3 0:30:05 39.2 0:30:09 40.5 0:30:14 38.3 0:30:19 40.5 0:30:24 39.2 0:30:29 40.0 0:30:34 40.5 0:30:39 42.2 0:30:44 40.5 0:30:49 40.0 0:30:54 40.5 0:30:59 39.6 0:31:04 39.2 0:31:09 42.2 0:31:14 40.5 0:31:19 40.5 0:31:24 38.7 0:31:29 40.0 0:31:34 38.7 0:31:39 40.0 0:31:44 38.7 0:31:49 37.9 0:31:54 40.0 0:31:59 40.5 0:32:04 38.7 0:32:09 40.9 0:32:14 39.2 0:32:19 39.6 0:32:24 38.7 0:32:29 41.3 0:32:34 39.6 0:32:39 40.0 0:32:44 39.2 0:32:49 38.3 0:32:54 37.9 0:32:59 40.9 0:33:04 39.6 0:33:09 38.7 0:33:14 41.3 0:33:19 40.5 0:33:24 39.6 0:33:29 38.3 0:33:34 40.0 0:33:39 37.9 0:33:44 41.8 0:33:49 38.7 0:33:54 39.2 0:33:59 40.0 0:34:04 39.6 0:34:09 38.3 0:34:14 41.3 0:34:19 39.2 0:34:24 39.2 0:34:29 41.3 0:34:34 38.3 0:34:39 39.6 0:34:44 39.6 0:34:49 40.5 0:34:54 40.0 0:34:59 40.9 0:35:04 40.0 0:35:09 40.9 0:35:14 40.9 0:35:19 39.6 0:35:24 39.2 0:35:29 38.3 0:35:34 38.7 0:35:39 40.0 0:35:44 38.3 0:35:49 38.7 0:35:54 38.7 0:35:59 40.5 0:36:04 40.5 0:36:09 41.3 0:36:13 40.9 0:36:18 38.7 0:36:23 40.5 0:36:28 39.6 0:36:33 40.5 0:36:38 41.3 0:36:43 39.6 0:36:48 39.6 0:36:53 38.7 0:36:58 39.6 0:37:03 38.3 0:37:08 39.6 0:37:13 37.9 0:37:18 39.6 0:37:23 39.6 0:37:28 40.0 0:37:33 39.2 0:37:38 40.9 0:37:43 38.7 0:37:48 38.7 0:37:53 39.6 0:37:58 40.5 0:38:03 40.5 0:38:08 38.3 0:38:13 40.0 0:38:18 38.3 0:38:23 39.2 0:38:28 40.9 0:38:33 39.2 0:38:38 41.3 0:38:43 40.0 0:38:48 39.6 0:38:53 39.2 0:38:58 37.9 0:39:03 39.2 0:39:08 40.9 0:39:13 38.7 0:39:18 40.9 0:39:23 39.2 0:39:28 40.5 0:39:33 38.3 0:39:38 39.6 0:39:43 40.5 0:39:48 40.9 0:39:53 40.0 0:39:58 38.3 0:40:03 37.4 0:40:08 40.0 0:40:13 40.5 0:40:18 40.0 0:40:23 39.6 0:40:28 43.5 0:40:33 40.9 0:40:38 40.9 0:40:43 40.9 0:40:48 39.6 0:40:53 39.2 0:40:58 39.2 0:41:03 39.6 0:41:08 38.3 0:41:13 40.0 0:41:18 38.7 0:41:23 39.6 0:41:28 38.7 0:41:33 40.5 0:41:38 39.6 0:41:43 40.0 0:41:48 40.5 0:41:53 39.6 0:41:58 39.2 0:42:03 40.0 0:42:08 41.3 0:42:12 41.3 0:42:17 38.7 0:42:22 39.6 0:42:27 39.6 0:42:32 41.3 0:42:37 38.3 0:42:42 38.7 0:42:47 40.0 0:42:52 39.6 0:42:57 40.9 0:43:02 39.2 0:43:07 38.7 0:43:12 39.2 0:43:17 38.7 0:43:22 38.7 0:43:27 40.9 0:43:32 40.0 0:43:37 35.7 0:43:42 40.5 0:43:47 38.3 0:43:52 40.0 0:43:57 40.9 0:44:02 39.2 0:44:07 39.2 0:44:12 39.2 0:44:17 40.9 0:44:22 39.6 0:44:27 40.5 0:44:32 39.2 0:44:37 40.9 0:44:42 40.5 0:44:47 38.7 0:44:52 38.7 0:44:57 38.7 0:45:02 39.2 0:45:07 40.0 0:45:12 41.3 0:45:17 40.5 0:45:22 39.2 0:45:27 40.0 0:45:32 38.7 0:45:37 41.3 0:45:42 39.2 0:45:47 40.5 0:45:52 40.0 0:45:57 41.3 0:46:02 40.9 0:46:07 41.3 0:46:12 38.7 0:46:17 40.0 0:46:22 41.3 0:46:27 39.6 0:46:32 39.6 0:46:37 37.9 0:46:42 40.0 0:46:47 40.0 0:46:52 39.2 0:46:57 39.2 0:47:02 39.6 0:47:07 38.7 0:47:12 40.0 0:47:17 39.2 0:47:22 39.2 0:47:27 40.0 0:47:32 40.0 0:47:37 40.9 0:47:42 38.3 0:47:47 41.3 0:47:52 37.9 0:47:57 38.7 0:48:02 41.8 0:48:07 38.7 0:48:12 39.2 0:48:16 41.3 0:48:21 38.7 0:48:26 39.6 0:48:31 40.5 0:48:36 40.5 0:48:41 39.2 0:48:46 38.7 0:48:51 39.6 0:48:56 40.5 0:49:01 39.2 0:49:06 39.2 0:49:11 39.6 0:49:16 40.9 0:49:21 41.8 0:49:26 40.5 0:49:31 41.3 0:49:36 41.8 0:49:41 39.6 0:49:46 38.7 0:49:51 37.9 0:49:56 39.2 0:50:01 40.9 0:50:06 38.7 0:50:11 41.3 0:50:16 38.7

Title : View / Trip Log / Trip 22 / Plot / Fuel Pressure (psi) / End Time Rows : 1 Columns : 1 Column 01 : End Time []

1/21/2005 2:20 PM

Bad tank of gas with lot's of water/crud. It keeps plugging things up.

Notice how it started right after you filled up? Pump out the tank. Fill with known good fuel. Replace the fuel filter again. Brt the problem goes away.

I think that is what I will try now. I just replaced my exaust/convert from the O2 sensor back and it did not help.

This is getting expensive :(

I think that is what I will try now. I just replaced my exaust/convert from the O2 sensor back and it did not help.

This is getting expensive :(

The only way I know of monitoring your fuel pressure "while you are driving around" is to have somebody plugged into your OBDII connector with a real-time scanner, OR, use a data logger ( e.g. Davis DriveRight CarChip, or record on a portable PC with a program like AutoTap ).

I find that static one-shot readings don't really tell the whole story of what is going on, that is why I keep a data logger plugged into the OBDII port all the time. At 5 second test sweeps, it monitors up to

25 continuous hours of running time. At 60 second intervals, 300 continuous hours of running time. I keep it at the 5 seconds sampling frequency and can watch what is really going on during all kinds of driving conditions.

I might pull it out ever 2 or 3 weeks and look at the graphs. If everything looks OK, I clear the chip memory and plug it back in. Even once a month would be OK, as I've never used more than 22% of the memory although I take a _lot_ of short trips.

You can then discard the data, or save it to a file for future reference. I call it my "flight recorder."

Lg

Why would you do this? Did you confirm that the cat was blocked up, or are you just throwing parts at it?

Have you replaced the external fuel filter? First thing to replace and the cheapest.

If not that I will suspect the filter or pump in the tank. A lot of labor there emptying the tank.

No labor emptying tank. Use a siphon hose, and then to get the last bits, run the engine until it stalls from no fuel. Depending on how much fuel is in the tank now, just put it into a couple of large-sized gasoline cans.

Lg

Labor if you have it filled (27 Gallons)

Nice guess Larry but since his PCM has absolutely no clue what the fuel pressure is, your data logger won't work. It may be able to moniter several things but fuel pressure isn't among them. Bob

Another nice try Larry, stick a siphon hose in your Taurus and let us know how much luck you have siphoning the fuel out of it. Bob