2.5 Lost ALL Power On Acceleration

[tajvelocity]

1999 Mazda B2500, ~145,000 miles.

Here's what happened:

I accelerated up an on ramp and when I shifted from third to fourth, not much happened and I started to slow down, like I would give it all the gas and the engine did not respond. I don't have a tach, but I think the revs were falling. I pumped the gas furiously and was able to kind of sputter off the exit to the side of the road and then into a parking lot. It was making some knocking sounds and nothing would happen when I hit the gas unless I floored it, then the back tires would chirp and lunge and it would move a little. It was idling terribly (and smelled pretty bad too, no smoke or anything like that though) when I parked and then it died. I poked around and jiggled some wires and hoses for about ten minutes. I looked under to see if anything was leaking and didn't see anything. I started it back up and it seemed to be running...fine? I made it through the city without incident, but when I decelerated and put it into second to turn into my street, it started happening again. I made it to a parking spot and there it sits. I started it last night and it idled fine but I haven't driven it yet.

I thought maybe my clutch was finally going, but that wouldn't explain why it ran so poorly. Would one loose plug wire cause such an issue? That's all I can think of as to why it started back up and ran more or less fine. I checked the IAC last night (it's only a couple years old) to see if it was dirty and it looks ok. When I unplug it when the truck is running, it dies immediately indicating that it's working I guess.

Any ideas? I'm lucky that I can cycle/walk to work, but I need to figure this out before the weather turns...

Thanks.

 

[RonD]

When was fuel filter last changed?
Every 5 years or so is a good time

If filter is clogging up you will notice it first in high fuel demand situations
After sitting long enough fuel is pushed thru clogged filter by fuel pressure to get engine running again.

Knocking could be Lean condition as fuel mix dried up


And could also be fuel pump itself, in tank "sock/filter" or pump itself is starting to go



2.5l also uses a timing belt, which can slip a tooth causing low compression, so lack of power, belt should be changed every 100k miles

 

[tajvelocity]

When was fuel filter last changed?
Every 5 years or so is a good time

If filter is clogging up you will notice it first in high fuel demand situations
After sitting long enough fuel is pushed thru clogged filter by fuel pressure to get engine running again.

Knocking could be Lean condition as fuel mix dried up


And could also be fuel pump itself, in tank "sock/filter" or pump itself is starting to go



2.5l also uses a timing belt, which can slip a tooth causing low compression, so lack of power, belt should be changed every 100k miles

You know, it's definitely been more than 5 years since I changed the fuel filter, and I've never changed the fuel pump. This was certainly a high fuel demand situation. I did the timing belt and related stuff 3-4 years ago. Maybe I'll try putting in a new fuel filter this weekend.

 

[RonD]

There is a Schrader valve on the fuel injector Rail on the engine
Looks like a tires air valve, because thats a schrader valve as well

May even still have the cap screwed on to it

1998 and up Rangers used Returnless fuel system running 60psi pressure
1997 and earlier used 35psi

60 psi is alot of pressure, you know what 30psi is like if you ever let air out of a vehicle tire, so 60 is double that

You can test the pressure with a gauge.

Fuel injected engines maintain minimum 50% running pressure when key is off, and that's for months.
So after your truck sits for 6 months it should still show at least 30psi, more likely would be 50psi.

Running pressure would be 55-65psi

 

[tajvelocity]

There is a Schrader valve on the fuel injector Rail on the engine
Looks like a tires air valve, because thats a schrader valve as well

May even still have the cap screwed on to it

1998 and up Rangers used Returnless fuel system running 60psi pressure
1997 and earlier used 35psi

60 psi is alot of pressure, you know what 30psi is like if you ever let air out of a vehicle tire, so 60 is double that

You can test the pressure with a gauge.

Fuel injected engines maintain minimum 50% running pressure when key is off, and that's for months.
So after your truck sits for 6 months it should still show at least 30psi, more likely would be 50psi.

Running pressure would be 55-65psi

About that...I was having an intermittent starting issue last winter and rented a fuel testing kit from Autozone because I suspected the fuel pump. I could not for the life of me get ANY reading from the fuel line. I screwed it on and it didn't show any pressure, even when running! I could depress the valve needle with a screwdriver and I expected to be showered in fuel because I knew it was something like 30-60 psi, (I can get a very audible burst of air on my mountain bike valve which only runs around 15 psi) but only got the tiniest bit of air and fuel. At that point I just said F it, it was starting and running at that point (and has been all summer) so I just figured maybe the schrader valve was clogged or maybe I was using the tool incorrectly, although I don't know how that's possible as it's pretty self explanatory.

I should probably try a different pressure tester soon to get to the bottom of that so I don't get stranded this winter. Meanwhile I'm trying to track down a fuel filter today. All this when I was planning to be doing the inner and outer tie rods before winter! Old(er) trucks, AMIRITE?!

Stay tuned...

 

[tajvelocity]

UPDATE:

Yeah so after getting the wrong part once (THANKS KOI), I got a new fuel filter on a month or so ago and so far so good!