Sound like a fuel pump?

Yes, cranks. Has 170k on the original pump.

Filter is under the intake. Kinda doubt it's a culprit, it was changed new within the last couple of years. I would think if it was clogged badly enough to prevent a start, it wouldn't then run fine for a couple of weeks.

Other observation, I whacked on the fuel tank a few times in various places this morning with a rubber mallet, the car started right up.

This is a good way to spend a lot of money.....guessing. You need to diagnose the real problem when it exists, and I full well realize how hard intermittents can be to find.

Put a fuel pump in it and quit wasting or time.

What I was hoping for are alternate suggestions of places to look if not the fuel pump. If I felt I had all the answers I wouldn't be on here asking. "Ask around for suggestions" has worked out pretty well over the years.

It's an all or nothing scenario that started occurring suddenly. Car either runs great or doesn't run at all. 22 year old factory pump with over 170k miles on it. Does this sound like behavior an aging pump can exhibit, suddenly gets stubborn about spinning up? What else could cause this?

Folks have suggested that you measure the fuel pressure at the rail. This will tell you most of what you want to know.

Lots of things, including some ignition failures.

--scott

What I was hoping for are alternate suggestions of places to look if not the fuel pump. If I felt I had all the answers I wouldn't be on here asking. "Ask around for suggestions" has worked out pretty well over the years.

It's an all or nothing scenario that started occurring suddenly. Car either runs great or doesn't run at all. 22 year old factory pump with over 170k miles on it. Does this sound like behavior an aging pump can exhibit, suddenly gets stubborn about spinning up? What else could cause this?

I have had intermittent ignition switches do something similar. Also, I found an intermittent CPS (crankshaft position sensor) that caused this.

Sometimes other problems in the electrics will cause intermittent start/run situations.

It would be really good to know, when this rascal fails to run, what the actual fuel pressure is.

In addition, it would be helpful to know if you are getting good hot consistent spark.

I had one problem with a powertrain control system (just call it a computer) that was intermittent. But it did not act exactly like the one you are describing.

My comment was not intended to make fun of you.. Intermittents are often very hard to find. And you can spend a ton of money guessing.

Put a fuel pump in it and quit wasting or time.

Worn brushes will do that. Maybe put a mallet with remote cord?.

Greg

FWIW, I went thru a problem with an old 1989 Chevy Corsica that was fuel related. First thing I did was to test the ignition system for spark - spark was good so I knew computer was powered and crank sensor was OK. Next I tested the fuel pressure because I suspected the original fuel pump was finally bad. To my surprise, I had good pressure. I then went to Autozone and rented/bought/whatever a fuel injector noid light set, disconnected an injector, plugged the light in, cranked the engine and found I wasn't getting any pulse signal to the injectors to fire them. I then learned that on some fuel injection systems (especially the older batch-fired versus sequential injection) that the injectors can be wired in parallel 3 on each circuit for a V-6. Over the years the injector coils short circuit and have much less than their original 12 ohms of impedance. Since 3 injectors are in parallel this results in a big increase in current flow thru the transistors in the computer and it can't always handle it. So sometimes it fires the injectors and sometimes it doesn't. I have no idea if this is your problem (on a Toyota?), but it's very easy to rent the noid light set and rule out the injectors not firing.

have you thought about dirty fuel or the filter in the tank ,at the pick up point

Geez. Whack the tank, it works. Check the electrical connections at the pump.No cost, just elbow grease.

On Jul 27, 2:42 pm, "hls" wrote: .

YES!!! That is one of the simplest diagnosis you can do, when you don't hear a fuel pump running!

Almost sounds like a loose connection to the fuel pump.. If you bang on the tank and it now starts the pump could be intermittantly working. also swap your f/p relay with another one to see if that helps.

chas

When I replaced the pump, the original factory pickup wasn't particularly dirty. There was a small amount of crud in the mesh but not bad for a 22 yo filter.

As a follow up, I replaced the pump with a unit from Autozone - yeah yeah, I know "why are you using that Autozone Airtex junk??" etc. etc. Had to have the car running, couldn't wait for NAPA or the dealer to get one delivered. Will look for a deal on a better one online.

Going on a week, running good so far. One thing I noticed is the pickup strainer on the original was this oval plastic cage with mesh, the one with the Airtex is basically a flat bag, looks like a bulky tea bag. Struck me that the design on the factory pump would seem to allow for better flow but that could be wrong.

Of note, I asked a buddy who runs a well-regarded auto shop if he had a brand he recommended, he says he uses Airtex right off the shelf from Advance Auto Parts all the time, that they don't have problems with them coming back. .shrug

I had a Ford Taurus that had an intermittent fuel pump that would randomly not turn on. This was easy to diagnose because when the key was set to run, I could not hear the pump cycle on. I isolated the problem to the relay and my short term solution was hit the relay box with a rubber mallet. This worked fine, except that I had to open the hood to hit the relay which was in a sealed unit that had most of the other high amp relays. The long term solution was to get a used replacement from eBay for under $20.

Banging on a fuel tank will not move wires/change a connection.