truck dies after heavy acceleration

[swynx]

There's a road that goes to my house. Straight stretch. I can easily hit the top of 4th on it. This is the road this always happens on. Long stretch of road at full throttle. After you slow down the truck will die. Almost immidiatly. Some times you can press the gas repeatedly and it won't die but its just easier to let it die cuz it always starts right back up.

Just replaced the maf iac and Tps plus a new fuel pump. Had a tune up less than 1k ago cleaned most of the gunk out of the throttlebody. Each and every one of these things has given me noticeable improvements of get up and go compared to when I first got the truck.

I've been able to duplicate this in a mud hole while stuck. But ill tell you its irritating starting a truck 20 times when trying to rock out of a hole.

Pretty sure its fuel related. I would like to say there's an odd smell right after it happens but I'm unsure on what it is. Tps? Was going to take a look at it but can't find my Haynes manual

 

[swynx]

Also not sure if its related but I seem to be getting super bad mileage. My work is literally 5 mins frommy house up hill one way down hill the other way. There and back i can use an 1/8 of a tank.

 

[tmcalavy]

With fuel consumption like that you definitely have a fuel problem. Does it smell like gas when it's running? Is the tailpipe black? If not, and if it runs good the rest of the time, you may be losing fuel between the tank and the engine.

 

[country0001]

Fuel filter, could be a clogged cat. Bad O2 sensor

 

[RonD]

My bet would be the Fuel Pressure Regulator(FPR), this is operated by a vacuum line to intake.
A small leak in the FPR diaphragm would cause some fuel to be sucked into the intake via the vacuum line, causing a drop in MPG.
But what fits better is the dieing engine after high RPMs.
When you are at 2,500RPM and then close the throttle plate what happens?
Vacuum jumps way up, if there was a leak in the FPR diaphragm then alot of fuel would be sucked in, flooding the engine and causing a stall.
Feathering the throttle plate reduces the vacuum so less flooding.
Remove this vacuum line and check it for gas smell.

A stuck open injector would fit this as well, but FPR is just more likely.
You can use a vacuum hose as a stethoscope, with engine at idle put the end of small hose near each injector and listen for the steady "tick, tick, tick" of it opening and closing, no "tick" means stuck.


How does it run cold?
At first start up the computer is in Open Loop, meaning it isn't using O2 sensors, only MAF and TPS are used to run preset fuel mixes.
These are rich mixes and timing is advanced, Open Loop is the "choke setting" for fuel injected engines.
Can you get it to stall out while cold?

The ECT sensor tells the computer the engine temp, so sets Open Loop.
This sensor looks similar to the temp gauge sender, but the ECT sensor has 2 wires instead of 1 wire(sender).
If the ECT sensor is failing it could be telling computer engine is always cold, so engine is running with "choke" on all the time, which would lower MPG alot.
Although I don't think it would die at throttle down.
ECT sensor can be tested with an OHM meter, cold test then warm test, OHMs should change.

O2 sensors cause rich running as they get older, that's normal and expected as the oxygen detection chemical process is used up, just like spark plugs wear out.
But I don't see this causing engine to die either.


Now there is a "gas saving" method that is used on all fuel injected engines.
Say you are going 60mph at 2,500rpm and you take your foot of the gas pedal, when the computer sees TPS at 1volt(no throttle), it turns off the fuel injectors and leaves them off until CKP(crank position) sensor tells computer engine RPMs are down to 1,200RPMs, computer then starts injectors again at idle level,
If computer isn't restarting injectors then engine dies, but bad MPG wouldn't fit with this.

 

[swynx]

I know it needs new o2 sensors. Runs like a champ until the check engine light comes on. Then its no as responsive or quick. I can turn it off and back on and the check engine light will go away for a short period. Previous owner had them unplugged. It was about 60 degrees last night when it died. It runs way better in the cold tho. Seems to be the hotter it gets the worse it runs.on some hot days when I drive it for long periods like when paying bills it ends up being hard to drive and having no power. Like to pass in a 35 I gotta put it in 2nd

I've thought before I could smell gas after it dies. But was unsure. I live where there are alot of smells. Also I have changed the ect sensor cuz I thought the truck was stuck in choke open. Still starts and idles at 2500 then down to 1500 and eventually to 1100 and sometimes 900. Kinda getting into the 100$ sensors so I've quit replacing them. Where abouts is the fpr located?

 

[Lil-Pony]

If you know it needs an o2 replace that first.

 

[RonD]

FPR is on the fuel rail(on top of the lower intake manifold), it will have a vacuum line connected to it, remove that line and check it for gas.

 

[swynx]

Fpr is bad.