bad gas mileage.

[broncobuckinaround]

trying to figure it out.

rebuilt 6000+ miles ago. new fuel pumps and filter. no codes that i know of.

i believe the fuel pressure reg has been replaced. its the shinniest part on it. plus no fuel smell or strong taste.

i dont believe the injectors are sticking

o2 sensor has been replaced with a denso direct fit.

mufflers are new.

no fuel leaks, also fixed gas tank vent. it was clogged with crystalized gas and dirt. this is wear it started. evap is hooked up properly. but i have no idea if the o2 is picking up on the rich mixture and leaning it out. plus im having an issue where ill drive for a bit start it and it will die but restarts with no issue. only when i shut it off and start.

 

[ford4thot]

No codes "that you know of"??? Get codes read

 

[broncobuckinaround]

i cant find a place here in town that has a scanner that can read them.

 

[wildbill23c]

What are you considering bad gas mileage? Maybe your catalytic converter is plugged.

 

[broncobuckinaround]

200 miles per tank. as opposed to 350 is what i was getting before i cleaned the tank vent. anyways the cat is new.

 

[wildbill23c]

Hmm, maybe cleaning isn't such a good idea LOL. Possibly fuel theft? Something else may be a fuel leak somewhere you haven't found. My 84 Ford Ranger started having issues when I would fill up the fuel tanks on it, the nozzle would shut off making you think the tank was full, then a few days later you are wondering why you are down a quarter of a tank or so. Both my fuel tanks started doing that before I got rid of it. My bronco 2 fuel gauge isn't exactly accurate but I get around 300 miles to a tank around town.

200 miles to a tank, there's gotta be a serious fuel leak somewhere or someone is stealing gas from you.

 

[broncobuckinaround]

people know better than to mess with my stuff around here. lol plenty of altercations have happened. lol.

anyways. i checked really carefully for leaks and theres no smells or wet spots or dry stops where gas could have been leaking.

can you thing of a sensor that would make the system run rich or lean.

my 88 b2 was getting 425 ish miles to a tank of gas.

 

[wildbill23c]

I'm sorry I'm not that smart when it comes to this stuff, maybe an EGR valve, fuel regulator, something of that nature. If you can't find fuel leaks I'm like you must be some sort of sensor somewhere, but I'm not exactly the greatest person to ask when it comes to fuel injection LOL.

Someone on here has gotta know an answer, as I'm sure you aren't the only one with this problem.

I know the ethanol fuel evaporates really fast, but I don't think it would evaporate out of the tank that fast, so there's something that's not right somewhere.

 

[broncobuckinaround]

i agree bill. there's has to be someone on here that know something. lol. ill check the FPR again. idk maybe when i fixed the o2 connector it got water in the buttconnectors. ill lookem over again.

 

[Gilbee01]

You said that part of the lines had crystals in it ? I think it might be you injectors and also how long was the vehicle parked for?


-gil-

 

[wildbill23c]

Hmm, crystals in the fuel vent line, causing plugged fuel injectors, is this what you are getting at Gilbee01?

 

[RonD]

Fuel injected engines have a "choke" but it is a little different in that it is computer settings not a plate you can see.

Fuel injected engines have an ECT(engine coolant temp) sensor, this is a two wire sensor, not to be confused with the one wire sender used by the dash board temp gauge.

The ECT sensor is only used by the computer, if this sensor shows that the engine/coolant is cold then the computer runs in open loop, this means it uses preset fuel/air mixes that are rich and it also advances the timing.
So pretty much what a choke plate did on a carb.

As engine warms up, per ECT sensor data, the computer starts to run leaner mixes and will eventually go to closed loop where the O2 sensors are used to set fuel/air mix.

A failed ECT sensor or computer reading of ECT data could cause a "run rich always" issue.
This would set an OBD code since computer has a cold start timer, if engine isn't warming up, per ECT sensor data, with in 5 minutes the code is set.

ECT sensors can be tested with OHM or Volt meter, computer sends 5volts to ECT sensor and gets a lower return voltage, the lower the return voltage the warmer the engine, so return might have 2.5v cold and below 1v warmed up.
-50degF would give 4.5v, lol, 3v is about 70degF outside temp.

ECT sensors rarely fail, symptoms are:
1. good cold start and running, harder warm start and poor mpg
or
2. poor cold start and poor running, good warm start and running, mpg doesn't change

1 or 2 but not both

 

[Hahnsb2]

Figure out the MPG, miles per tank is a rather useless figure.

 

[Gilbee01]

My suggestion is that if you said that it was rebuilt a while ago how long did it sit before or during the rebuild? Also you said that you found crystals and dirt in the tank vent and was wondering if that could have been pushed threw the system and effecting the injectors or something else with the fuel Distribution. There are alot of things that could be the problem. I was just asking the first thing to come to mind.. Also are these the original injectors or did you replace them during rebuild??


-gil-

 

[broncobuckinaround]

i did not replace the injectors but performed a bench test on each one. all of them were performing perfectly. i also cleaned the tank at the same time they were out. and also flushed the lines.

it does have an issue with long crank time and then a strong smell of fuel after it starts. but it happens cold and hot.

ill do a bench test on the ects

the car set for two years, it was driving right after the rebuild and everything was cleaned out. its always had the long crank time.

i would like to install the 19lbs injectors from summit. but should i upgrade my ignition. lol but after my mileage issue is solved.

its got a new distributor, cap, rotor, wires and plugs. coil was cleaned and tested. timing was done at ford. they said i was doing good just by doing it by feel and sound. i was only off by a few degrees.