Starter sticks and horrible MPG

[Doug118]

The truck turns over but doesn't want to start. The starter eventually times out and when I turn the key to start again, it starts like nothing is wrong. If I turn the key back after timed-out, the truck does the same no-start symptom. Also now when I'm driving, I'm getting roughly 3-4mpg. Once in a while I will get a code for Lean bank 1 and lean bank 2. While trying to start, it smells like the truck is just dumping fuel out of the exhaust. I've changed all EVAP stuff, purge valve, and MAF.

Anyone run into a similar problem? Or have any other ideas as to what it could be?

 

[BG1988]

what about the map sensor? and what are the codes?

CHECK the vacuum hoses are well you have a leak letting in unmetered air or the map sensor is dead

STOP driving it immediately.. you will burn up the catalytic converter costing you even more money.. about another $900


the starter is a separate issue and treated as such (I had a faulty map sensor cause random issues though like cause rough shifting, ultra high revving of the engine (typical start up is about 1200 rpm it was starting up at 2,000 rpm) engine runaways (that happen twice) and random other issues like loss of power steering , loss of braking system, loss of power etc....that happen once)

P0171/P0172 causes

engine speed
BARO
coolant Temp
MAP
Inlet Air Temp
MAF
VSS
Fuel level
long fuel trim data


P0174
lean bank 2


engine speed
BARO
coolant Temp
MAP
Inlet Air Temp
MAF
VSS
Fuel level
long fuel trim data

 

[wjburken]

The issue with starting is very similar to what I had going on with my ‘07 XL. You turn the key to start and it times out then you hit again right away and it fired right off. Turned out my fuel pump was not holding pressure. The first turn of the key built up the pressure in the line and then the second turn you were up and running. That all went away when I swapped the fuel pump. At first it seemed like it was worse on hotter days but soon it was all the time.

I would get a fuel pressure gage and see what kind of pressure you are seeing on your fuel rail.

 

[BG1988]

The issue with starting is very similar to what I had going on with my ‘07 XL. You turn the key to start and it times out then you hit again right away and it fired right off. Turned out my fuel pump was not holding pressure. The first turn of the key built up the pressure in the line and then the second turn you were up and running. That all went away when I swapped the fuel pump. At first it seemed like it was worse on hotter days but soon it was all the time.

I would get a fuel pressure gage and see what kind of pressure you are seeing on your fuel rail.

he says he smells unburnt fuel and getting 3-4mpg it means it using about 400-450% more fuel then normal..
normal being 14MPG and is getting 4mpg


so it's injecting 4x the normal amount of fuel per cycle


that is why vacuum leaks might be the issue map sensor or one of the others

 

[HiHoeSilver]

he says he smells unburnt fuel and getting 3-4mpg it means it using about 400-450% more fuel then normal..
normal being 14MPG and is getting 4mpg


so it's injecting 4x the normal amount of fuel per cycle


that is why vacuum leaks might be the issue map sensor or one of the others

Or it's shooting fuel out a rusted line, hence the smell from the "exhaust". That's what mine was doing.

I concur with @wjburken. Check the pressure at the rail.

 

[wjburken]

he says he smells unburnt fuel and getting 3-4mpg it means it using about 400-450% more fuel then normal..
normal being 14MPG and is getting 4mpg


so it's injecting 4x the normal amount of fuel per cycle


that is why vacuum leaks might be the issue map sensor or one of the others

I was commenting on the failure to start on first key turn. His description matched my experience to a tee.

I do not believe a bad fuel pump would cause the poor mileage. In addition to the MAP or vacuum leaks, I would not rule out an O2 sensor going rouge either.

 

[swathdiver]

The truck turns over but doesn't want to start. The starter eventually times out and when I turn the key to start again, it starts like nothing is wrong. If I turn the key back after timed-out, the truck does the same no-start symptom. Also now when I'm driving, I'm getting roughly 3-4mpg. Once in a while I will get a code for Lean bank 1 and lean bank 2. While trying to start, it smells like the truck is just dumping fuel out of the exhaust. I've changed all EVAP stuff, purge valve, and MAF.

Anyone run into a similar problem? Or have any other ideas as to what it could be?

Seems like a fuel delivery problem to me at first thought. Do you have access to a bi-directional scan tool like the Tech-2? You can see what the pressure is when the key is turned on, whether it is holding or not and if it meets the commanded pressure once started and a whole lot more.

 

[BG1988]

I was commenting on the failure to start on first key turn. His description matched my experience to a tee.

I do not believe a bad fuel pump would cause the poor mileage. In addition to the MAP or vacuum leaks, I would not rule out an O2 sensor going rouge either.

a bad fuel pump would improve the MPG

 

[HiHoeSilver]

a bad fuel pump would improve the MPG

Not if it's spraying fuel all over under the truck like mine did.

 

[Doug118]

The pump is going bad, resulting in very low fuel pressure. Starter needs to see 60psi in order to start, which it is having a problem doing. Once started, the computer sees low fuel pressure, which makes it think the truck is running lean, so it just pours fuel into the cylinders to compensate, resulting in horrible fuel comsumption

Got the new ACDelco pump on order. Can't wait to tackle this job