Ranger fails to restart after hard braking

[brages]

Vehicle: 1997 Ford Ranger, 2.3L "Lima", manual transmission. 265k miles, no CEL, runs fine.

My son has had two incidents driving this truck. Both times, he stopped suddenly when a light turned yellow in order not to run the red. The engine died (my guess is that it died because he was braking hard and left it in gear, but I do not know). The truck then failed to restart. It will crank and crank but not show signs of beginning to start.

The first time this happened, I tried a bunch of stuff and after I switched the fuses between the headlights and the fuel pump, it started running and ran fine. The fuse wasn't blown, though, so I think it was just random that it started working.

The second time this happened, I tried fiddling with the fuses, fuel pump relay, and inertia switch. I jumpered the inertia switch connector to bypass it. Still no start. So I would rule out fuses, relays, and the inertia switch.

I pressed on the schrader valve to check fuel pressure. Fuel pressure was low. Then I had my son turn the key on. A little more fuel dribbled out for a couple of seconds then stopped. Off then on, a little more. Tried it again, a geyser of fuel shot out. Then, after that, the truck ran fine again.


A clue: this truck has quirk where if has been sitting for a few minutes or more, when you try to start it, it revs up for a couple seconds, then dies. On your second try, it will start normally. Or if you turn the key on for a couple of seconds before starting, it will start just fine. So there is *something* suspect in the fuel delivery.

I have replaced the fuel pump, fuel filter, and and fuel injectors in this truck. None of these had an effect on the starts-then-dies problem (I was hoping they would).

The second time this happened, the tank was about 1/4 full. I don't remember how full it was when this happened the first time. Both incidents happened in the same area, maybe 3-4 miles away from our house, after leaving our house. So the truck was mostly warmed up, but hadn't been driven long when it happened.

I'm telling him just to go through on the yellow, but I'd like to get this fixed, lol.

 

[brages]

After this happened the first time, I figured it was just something flaky with the inertia switch. But the second time, I ruled out the inertia switch.

My new theory is that the hard braking with 1/4 tank caused the pump to suck air briefly, and for some reason (a leak somewhere?) it had a very hard time re-priming itself afterwards.

Also I am thinking about replacing the fuel regulator because i suppose it could be the reason the fuel pressure apparently drops when the truck is turned off.

 

[ragtoplvr]

Your fuel pump is failing. Under hard break with tank near empty it get s uncovered and sucks air. then when you restart it is bound up and will not start.


Test, see if this happens with a full tank. Lots of bad things happen when you drive on the last 1/4 tank.

Rod

 

[Kira]

I do not know your engine/vehicle one bit.
Is it the case that your FPR has a vacuum line on it?
If so pull it off and if there's fuel in the vacuum line the FPR is bad.
I've read that on boards.

edit: A list of bad things which can happen due to driving at or below 1/4 tank would be a smart thing to make.

All I've heard of is that there may be less fuel to cool the pump.
With today's ethanoled gas there's no collection of crud at the bottom of the tank (I have heard).
What else can be bad?
A big slosh of gas can break a cheap baffle free?

 

[brages]

No fuel in the vacuum line for FPR and it seems to work correctly with a fuel pressure gauge attached.

 

[Dave9]

^ Meh, every single tank of gas, I drive below 1/4 tank, including on a '98 Explorer which probably has the exact same factory pump, but not necessarily the same tank.

I am going to assume your son is not an idiot (

) and took it out of gear to try to start it. Pressing on the fuel rail valve is only the start, more definitive would be to check the pressure. If I remember that era correctly, it probably uses a return (to tank) fuel system with a lower pressure than modern vehicles, around 35PSI.

The question is whether the replacement pump is working properly. If so, still check fuel pressure at the rail, it could be the pressure regulator. If (as above) I recall this generation correctly, the regulator is on the fuel rail at the return line portion, not built into the sending unit in the tank. I could be wrong.

 

[brages]

Originally Posted by ragtoplvr
Your fuel pump is failing. Under hard break with tank near empty it get s uncovered and sucks air. then when you restart it is bound up and will not start.


Test, see if this happens with a full tank. Lots of bad things happen when you drive on the last 1/4 tank.

Rod


That is an interesting idea. You think that when it sucks air, it immediately overheats and seizes, then after it cools off a bit, it starts running OK?

I'm planning on pulling the bed off for some frame rust work (sigh), so that might be a good time to experiment with making the fuel pump run dry.

 

[brages]

Originally Posted by Dave9
^ Meh, every single tank of gas, I drive below 1/4 tank, including on a '98 Explorer which probably has the exact same factory pump, but not necessarily the same tank.

I am going to assume your son is not an idiot (

) and took it out of gear to try to start it. Pressing on the fuel rail valve is only the start, more definitive would be to check the pressure. If I remember that era correctly, it probably uses and return fuel system with a lower pressure than modern vehicles, around 35PSI.

The question is whether the replacement pump is working properly. If so, still check fuel pressure at the rail, it could be the pressure regulator. If (as above) I recall this generation correctly, the regulator is on the fuel rail at the return line portion, not built into the sending unit in the tank.



Your memory is mostly correct. I think the pressure is closer to 40.

Both times when this happened, my son called me and I got it started after messing around with different stuff for 15-30 minutes or so.

 

[Dave9]

A new pump especially, should not have any problem from a brief moment of sucking air, and at 1/4 tank, it isn't all that likely that merely coming to a stop would cause air instead of fuel. Steep slope stop maybe, but not on fairly flat ground.

 

[brages]

One problem I have is that I have not duplicated this issue. I don't really want to get stuck away from home in a dead truck and I don't want to be slamming on my brakes in the neighborhood. But I suppose if I can figure out how to reproduce the problem, it will help figure it out.

 

[ragtoplvr]

Too bad Click and Clack no longer perform. RIP Tom. This would make a fun "stump the chump".

Rod

 

[irad]

I think it is a fuel cutoff momentum switch. Something similar happened to my mother's Grand Marquis. I drove thirty miles to her disabled car, reached in the trunk, reset the red switch and told her to drive to her house.

 

[thastinger]

Think your fuel pump "impact" reset switch is under the carpet on the passenger side, up high on the firewall, this would be my main suspect.

 

[brages]

Originally Posted by ragtoplvr
Too bad Click and Clack no longer perform. RIP Tom. This would make a fun "stump the chump".

Rod


Yeah, I loved that show and grew up listening to it as a kid. As I learned more about cars, I started disagreeing with their diagnoses more frequently, LOL

 

[brages]

Originally Posted by thastinger
Think your fuel pump "impact" reset switch is under the carpet on the passenger side, up high on the firewall, this would be my main suspect.


That is what I was thinking after the first time, but there are several reasons I think it is not the inertia switch:

1. The first time it happened, the truck began running again without the inertia switch being reset.

2. The second time it happened, I tried to reset the inertia switch and it wasn't tripped.

3. The second time it happened, I manually tripped then reset the inertia switch and it didn't fix it.

4. The second time it happened I bypassed the inertia switch with a jumper wire and it didn't fix it.

 

[andyd]

It is the fuel pump / pickup/sender unit. It is essentially the same one used in a lotta cars. I got a Chinese clone of the OEM part for 40$ from E Bay. I burned the original out running it on fumes since I took the Rat off the road. If you want to test it by running it dry , you as well have a new pump on hand. Go for a seller who has the pump in the states, cheapest parts ship directly from China, takes longer. Pump works great,

 

[brages]

I replaced the fuel pump a few months ago. I was trying to fix the starting issue, but it didn't change it.

Maybe the new pump is failing already, but I dunno.

 

[brages]

It's actually more like 3/8 of a tank, not 1/4.

 

[eljefino]

How much oil does it burn?

I had a 2002 corolla 1.8 that burned a quart every 400 miles. If I shut it off to buy gas, it would restart then stall. It would then restart and run fine. I theorize the valve seals were worthless and it dripped down, fouling plugs.

There could be something with oil sloshing around and going somewhere it shouldn't, wreaking havoc.

Maybe try parking it facing down as much as possible then coming back the next morning to see if anything weird happens.

 

[Lubener]

Originally Posted by brages
No fuel in the vacuum line for FPR and it seems to work correctly with a fuel pressure gauge attached.

Did you have 30-45 psi of fuel pressure?? Pressure should go up when you disconnect the vacuum from the FPR.