Hi gang.

2008 Dodge Ram SLT, V6, 120k miles.

Battery is fine.  When I crank the ignition, the starter engages and the engine begins to crank.  When I let the key go (to allow the spring loaded switch to kick the key back to the "on" position) it continues to crank (even though the key is not in the crank position) until I turn the key to the off position.  Once or twice it sounded like the engine actually started to fire, barely, and then died immediately.  

I am not a car guy, but I am wondering if it could be a fuel pump issue.  A friend of mine thinks its the ignition switch, that the contacts have simply worn, and that the switch is staying in the "crank" position even when turned back one notch, and that the engine has some sort of failsafe to keep it from starting if the key stays in the crank position.

Starter?  Fuel pump?  Ignition switch?  Computer isn't throwing any codes.

Thanks.

My first impulse is to say ignition switch, but I'm not aware of there being a safety to prevent additional cranking once the engine is started.  On my 96, you could keep cranking if you wanted to.

Chevy was using the computer to control the crank til engine start in 08" unsure if Dodge was then also but possible.

If it cranks and sounds like it will almost start and then fail to, it's likely the fuel pump. Turn key off, then turn it back to the on position but do not crank it, you should hear the fuel pump come on and run for a couple seconds, then shut back off. If you hear nothing, check the F/P relays and any fuses associated. If good, put key in off position and give the fuel tank a few whacks with a rubber mallet, turn key and try to start it. If it does, yep, time for a fuel pump assy.

You can also check pressure at the schrader valve on the fuel rail in the engine compartment if you have the proper tool, just having some pressure there doesn't mean much as there is a minimum that you need.

Thanks guys.  I'm wondering what can be causing the truck to continue to crank after the key is moved back into the "on" position.  Any ideas?

Chrysler uses a wireless control module to tell the PCM though the TIPM (big fure block under the hood) to crank the vehicle. You will need at least a Chrysler  factory scan tool to figure it out. I work on a ton of Chryslers and problem like this suck big time because they don't set codes, you just have to look through tons of date to see what is working or not.

Find a decent dealership (most Chrysler dealers suck dog balls big time) and prepare to spend some money.

Spoke to a couple of service guys and a guy down at the parts store. Fuel pump is $500-700 (!) for this engine. Was advised to continue troubleshooting to make darn sure its the fuel pump. Was suggested to check relays and fuses (are they located in the same place and are they specific to the fuel pump?), mass airflow sensor (research indicates Dodge doesn't use these?), and other things before I drop $700 on a part that might not be broken.

Is the fuel pump driven by a two-lead power wire? Can I simply remove it, hook it up to 12vdc directly, and test that it runs?

How can I begin to troubleshoot the ignition switch?

Trying desperately to avoid going to Dodge to be charged $1200 for a fuel pump and $1200 for labor....

Thanks.

Did you whack the gas tank a couple times with a mallet like suggested?

When I had my 08 3.7 I had a similar issue and the fix was replacing the cam position sensor.

I had to replace the fuel pump in my 96 Ram.  They actually raised the bed off the frame to get to it instead of dropping the tank, which really cut down on labor cost.  Still ended up being like a grand for everything.

That's $2400 quote you have, is that from the dealership?  If you have it replaced, do it somewhere else and it will be cheaper.

you really still have a crap load of other tests to run.

you still haven't checked fuel pressure at the rails.
you still have to check if the pump is running at all

there are 2 relay's under the  hood you can swap to check the pump relay as well.

and there are still a few sensors to check. continuity and ohm's at the very least if you don't have the right scan tools.

I don't think you have even checked for spark yet. which is a whole other set of tests incase that is the issue and not fuel.

I had to do the fuel pump in my Tahoe, was also getting slower and slower to start. I was able to read fuel pressure on the manifold and determine it was insufficient.

Ended up being the fuel pump.  Decided it was the pump after spraying gas directly into the intake and the truck started right up.  Dropped the tank at a friend's house with his motorcycle jack.  Fuel pump direct from Canadian mfg, $402 and one week later, two hours of work total, truck is running again.

Thanks to all.

Excellent, glad you got it running.