Everyone,

Need some help. Here is my problems and symptoms.

1. After driving on the highway to work i come to a stop or have to enter a city and slow down it cuts out. (i used Lucas fuel system cleaner in both tanks so could it still not be getting gas but if that is the case it wouldnt start would it.) In the mornings when i start it i have to hold down the gas until it starts what would keep it from getting gas like that or is it the plugs and wires?

2. While driving 60 to 65 the fuel gauge doesnt seem to read correctly. Ill explain. Saturday i filled up both tanks didnt drive sunday. I left for work monday morning and used the front tank for both trips got home and said less than half a tank. So today (tuesday) i switch to the rear tank just to give the front tank a rest and it says 3/4 a tank when it was full since saturday night. I check the front tank and it also says 3/4 a tank. What causes this truck to automatically switch between the tanks like that or am i just confused.

3. If im on the interstate the heater doesnt work its just warm air off the engine i think that is just a thermostat.

4. Lunging and hesitation. when taking off from a full stop i depress the accellerator and it just sits there chugs for a second and then works through it and accelorates. I have just gotten an oil change and notice a smoother running enging. I plan on getting a tune up this weekend will that help or is it another problem?

Im not sure but my truck is EFI i think it is the 5.0L 302 With automatic transmission with Overdrive.

Really need some fixes and if they are cheap and easy i can attempt them myself over the weekends to save myself money.

 

First thing, do a complete tune up. Plugs, plug wires, cap, rotor button, fuel filter, air filter. Also thermostat.
Then check your tps(throttle position sensor) use the haynes manual to do this. #4 in your post sounds like this.

 

just my thought whats the voltage out put of your charging system doing ??
also check the battery
had a battery go bad once & caused all kinds of weird stuff
took a few weeks to finaly have the battery not start the motor
a new battery & everthing quit acting weird & it ran better

 

battery is good. doing the full tune up this saturday will post back how it acts next week. just need new battery cables right now as they are exposed and gonna clean the terminals probably replace the battery in a few weeks with next paycheck need new headlights too still have the ones from 86 need some halogens in it so i can see in the mornings when i drive to work

 

Change your fuel filters. One is after the fuel pump on the rail the other is behind it. It's in the fuel reservoir, black box with a round bottom this is where the other filter is. Hard to get off, you need a strap type oil filter wrench or one of those rubber strap tools everybody sells. The reservoir has all the fuel lines going to it, one of your return lines could be crimped or something. Also your main fuel pump has a check valve in it to stop gas from going back into it. The first thing I would check is your fuel pressure at the fuel rail and work your way back if filters don't help. Also check your tank selector switch at your dash.
griff777

 

Very carefully check all of the hoses for vacuum leaks. Most of these symptoms can be caused by a leaking vacuum hose. Check the hose going to the firewall to work the heater controls.

 

OK...one at a time here
#1 If its got a carb the gaskets gold old and cracke and allow the fuel to seep back out of the carb which could be your problem at startup and on deceleration. IOf it is EFI very well could be electrical (good luck with that...ever chase a rabbit on foot?)

#2 The fuel senders on those trucks were just garbage. My 85 will actually gain fuel after sitting for a while and the float settles down, almost certainly thats the phantom feul problem

#3 gotta either be the thermo or heater core, neither of which is all that bad

#4 I would check the obvious stuff first and eliminate all of those pesky little problems (timimng, filters, plugs and wires). If that doesnt solve, get a code reader and that should help narrow down whats ailing your truck. My best guess is either carb or injectors (whichever you have)

 

Ok thursday while driving it the truck shut off. Had juice just turned off and acted like it wasnt getting fuel. Got it back to my place. and just started checkng everything. Didnt hear the fuel pump turning on so i hardwired it directly to the battery with a toggle switch in the cab. Ran fine for a day. Stopped running so i just start getting curious and just trying anything. Found a cartridge fuel filter in the bottom of the reservoir come to find out it was the reservoir to begin with. The pump was pumping and the lines were clear. So i took out the reservoir and drained the rear tank to take it out totally. Hooked two inline filters in one for the output to the pump and one on the return line back to the tank. Some one said it was my fuel pump relay that went out for becuase the fuel pump isnt supposed to be on all the time. The system is gravity fed and that is the only pump i can find so that leads me to believe that it is supposed to be running full time. If it does have a relay where is it?I will be replacing plugs wires air filter and PVC and PVC filter this weekend. the fuel filters are new due to the work today and the distributor and rotor was done a couple of days ago as it was easy. For some reason the heat works fine inside the truck now. The hesitation is gone so i guess it all goes back to it not getting any fuel. Now another question is why does it brake so hard when it is wet outside. Those brakes grab and i feel like im getting whiplash from just barely touching the brake pedal. Also please let me know if what i did with the fuel lines is legit or just a quick fix until i can have it rewired and professionally repaired blah blah blah.


Thanks again guys.
Katnip

 

fuel pump relay is a cubed looking plastic box with a couple wires going into it. It's located on the fire wall on the driver's side close to the inner fender(behind a plastic shield) 10 bucks,if that, @the local parts store...doesn't hurt to try it. They corrode often due to water and dirt thrown up onto it from the front tire. Also, there's a smaller wire going to your battery negative post. This wire also controls your fuel pump. Make sure it's clean.

 

Havi,

Thanks that is what i thought was the problem when i unplugged it and just wired to the battery it works fine. However it isnt behind the heat sheild it is just sitting out in the open past the plastic shield. Am i right in assuming its just an elctrical connection? So i should just be able to replace that segment and it will work fine? Or have what i currently done should be ok?

Katnip

 

replace the relay and not bypass it. You may burn out your fuel pump and/or cause a flood condition in colder temp. turning the key to on but not to start and you should here your pump buzz for a couple seconds and no more.

 

Havi,

It should be ok for a day or two until i can get it replaced correct? Also is it ok that i took the fuel reservoir out and just put two inline filters there instead and just took the back tank out of the equation?

 

couple days are ok. I took my rear tank out of the equation to.; I just don't use it(leaks). Inline filters should be ok, the question is would they hold up to the higher pressure that the efi's have.

 

Ran most of the day no problems the filters are FF 571 and FF 679. The 571 i had to kind of push the collar out so it would lock into the fuel line the 679 was the same size as the lines and came with the clips so it locks in fine. I should be dropping the truck off to replace the pump relay tomorrow night to be fixed wednesday.