Starting problem.

[mamabear]

i have an 04 explorer that wont start, the problem started one night by it reeving up in cruse control and then the next day it would not run without the pedal all the way to the floor. we changed the fuel filter, fuel pump, the throttle body, and the spark plugs (actually have it at a shop for the last two months and they cant figure it out). we went over today and tried somethings my cousin (who is a mechanic) suggested. The vehicle is getting gas but the spark is not consistent my cousin said to check the resistance of the crank sensor but he did not know what it should be (hes a gm guy), does anyone have any ideas as to what to try?

 

[BrooklynBay]

Welcome to this forum! I've renamed, and moved your thread to the stock 2002-2005 section. Check your IAC & MAF.

 

[mamabear]

re

what are the IAC & MAF, where are they located and how do i check them

 

[BrooklynBay]

The IAC is the idle air control. It's located on the top of the intake manifold, and it looks like a cylinder. The second thing is the MAF which is the mass air flow sensor. It's located on the intake between the air cleaner box, and the throttle body. These parts require an occasional cleaning. There are a few threads on this site about cleaning these parts.

 

[jrford]

What motor? Are there any codes? check engine lights? Why did they replace the throttle body? If its a 4.6L its fly by wire . . no iac but yes on the MAF. . also cruise would be part of it. Flybywire means there is no throttle cable, but a sensor that measure the amount of movement in the gas pedal, and based on that input the PCM controls a small motor to move the throttle plate open and closed, which it also does when in cruise.

Without knowing the codes and since you already replaced the TB my first guess would be the pedal position sensor (by your foot), then the motor on the TB if it wasn't replaced, TPS sensor reports back its position to the PCM but that should have been part of the TB.

If you have the V6 or 4.0L then i'm not sure if you have FlyByWire. . ?

 

[mamabear]

re

the computer that the shop has does not give any codes. we changed the TB because when we had someone else scan it it gave a code for the throttle actuator the shop put the new TB on but when that did not fix the problem they took it off and put the old one back on. before putting on a new TB we had replaced the TPS so that is still new. the engine is a v6 4.0 liter flex fuel. so i do not know if it has the IAC but they said that they had cleaned the MAF. we pulled a spark plug and tried to crank the vehicle to see if it was getting spark and it does but not consistently, thats why we were thinking that it might the crank sensor do you have any ideas about that

 

[jrford]

crank position sensor is in front next damper, main crank pulley. Should see a tone ring behind the damper. Looks like its on the Pass side bottom.
In my FSM, it looks like the 4.0l is fly by wire for '04. There are a few things that can go wrong with it, the pedal sensor, throttle plate motor, TPS sensor. Did the new TB have a new motor on it, those fail maybe. It sounds like its still the problem somewhere, possibly.

You might want to find a better scan tool, one that can read sensors in real time and you could 'see' if sensors are 'dropping' out, and it should show throttle positions too.

Intermittent spark and only running when floored sounds like the engine is in FMEM mode, fail safe which alternates turning off cylinders. If it is that could be scary, then that means the engine sensed a big failure somewhere which put it in this limp mode to prevent further damage . .