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I have a 01 Dodge Ram 318. My wife is the only one that this has happened to.I finally got the truck to not start for me. Drove up to the store, after getting home, I turned the truck off and tried to start it. It would start, but after I took my foot off of the gas it would shut off. After 4 or 5 times it finally stayed running. I can hear the fuel pump running the whole time, I dont have a pressure guage, but I pressed the shrader valve and got plenty. Dont know if this is a fuel problem or something else. Any advise would be appreciated.  

lets start with the simple and cheep stuff...

do you have a digital volt meter... if you don't.. they can be had for 7 bucks to 25 bucks..

a lot of parts stores have these from innova for about 16 bucks..



harbor freight stores have these for about 20 bucks



either will last you for decades..


next.... i would take a digital volt meter...

set it to 20 volts DC scale...

start the engine and turn on the headlights..

1. test between the positive and the negative battery posts.  14.1 to 14.8 volts is expected.

2. test between the negative battery post and the engine block. 0.04 volts is expected..

3. test between the negative battery post and the body... 0.02 volts is expected..

4. test between the Engine block and the body..  0.02 volts is expected.

if you get 0.00 on the last 3 tests.. change the meter setting to 2 volts DC scale.. and retest.. the last 3...

this test takes about 2 minutes...

post your results by test number..

if you get more than the 0.04 or 0.02 volts on the display...

you have a bad ground between those parts..



why do this test....   bad grounds will stop any new car in its tracks...

why... electrons flow from Negative to positive...  if you loose a ground.. or it becomes intermittent..  you won't have any power for that circuit...  just like a table light when the plug falls part way out of the wall...  the light will go out..

also i have fixed a LOT of cars lately with that  2 minute test... some hot water and a stainless steel wire toothbrush ...

finding the ground connections.. removing them from where they are bolted down after counting how many wires are on each one..   wire brushing both sides of the ring terminals...   wire brushing the back side of the nut.. wire brushing the mounting pad...  washing with HOT water..  

putting them back on.. and counting to verify the number of wires is the same...

the verifying with the same test again...  

I know the battery is probably getting old. Here are the results.
Test 1- 13.60
Test 2- 0.02
Test 3- 0.01
Test 4- 0.03  

the charging voltage is a little LOW...  i would expect it to be up in the 14.1 to 14.6 volts range...

you might want to take a look how the fan belt is tightened..

you can also do a alternator output terminal to the positive battery post voltage drop test..

...........

do you have a timing light so you could tape the trigger into the ON position..  hook it over a coil wire with the timing light under a wiper blade to allow you to monitor the ignition system...

see if it stops sparking before the engine comes to a complete stop... or does it continue sparking slower and slower until the engine comes to a stop...

if the light stops flashing instantly and then the engine spins to a stop..  you have an ignition failure or power failure

if the light continues till the engine stops.. then you are looking at a fuel injector side problem..



did you get any codes??  you should be able to turn the key from the off position 3 times in 10 seconds with the final position being on.. and codes will be displayed via the odometer display..  P0XXX

let me take a look at the other parts that engine uses....

i am taking that you have a Ram 1500 318 2 wheel drive pickup....  

more stuff to examine and test...

signs of high voltage leakage from the coil windings to the inside opening of the coil laminations..   look for dust circles.. white discolored areas where continued sparking is happening..

spark output from the ignition coil...  you need to get over 1/2 inch of bright blue spark... closer to 3/4 inch is better.. without that much spark output.. it just won't be enough to light the spark plugs under the compression..

i have had these fail.... on jeep models that use a similar design.





there is also the crankshaft position sensor...

they can also go intermittent...



diagnosing one of these is more of a challenge..


just curious...

did you test on the voltage drop test.. to the battery posts.. not just the terminal...



you can monitor the crank sensor signal with some scan tools...

the sensor in the distributer is the more than likely the cam position sensor..   it tells the computer when to trigger the fuel injectors and also were the cam is...   they go bad also...  

testing the crank position sensor..

http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f802e2bb3



http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f802e2b96

its hard to tell what is failing without a scan tool...  or without knowing if its the ignition system or NOT thats quitting..  

Ok The timing light stops exacatly when the key is turned off. The ODBII meter shows no codes. when I started the truck, the rpm's dropped low as if to almost shut off, but went back to normal. Could this problem be with the controls on the throttle body or fuel problem?  

intermittent fault tests.

http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f802e2c04

the ignition switch

http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f802e2cde


i cannot seem to find any wiring diagrams.... for the engine system...  

this is what the fuel pump relay looks like.. there are probably several of these...




if your owners manual describes their function.. and location...

you might want to either swap some around...  keeping track of each ones original location..

as these can go bad... and the sockets they plug into can loose grip on the relay terminals...    a sharp probe can help by looking carefully and the female connector and figuring where to probe to tighten the grip ...  

When I rev the motor up and let off the gas it shuts off. If I ease off the gas slowly it will stay running. The engine doesn't miss or skip and I have no check engine light. Had a friend hook a scan tool to the truck and didn't find much of a problem. I tested the fuel pressure and got 47psi. Could it be a weak battery, dist. cap, rotor or coil or maybe a fuel problem.The scan tool did pick up a restriction at the filter. But I might as well change the pump. Just trying not to spend any unneccesary money.  

at this point i would go in a different direction...

toward the throttle body and what ever idle control valve they use..

i am going off to do some research... i will post more info later tonight...


this is the idle air control motor ..



if you look at the live data.. you might be able to see the IAC..   some scan tools can control it in OEM mode...

when the throttle is opened as you accelerate.. the computer moves the idle air control valve closed until it stops.. then backs it out to about 120 counts or so.. as you let the throttle off..   the throttle blade closes.. then the computer closes the idle air control valve step by step.. bringing the engine speed back to idle..

when there is carbon build up around the throttle blades...  there will be less "known to the computer" air leakage around the blade.. so the idle air control motor needs to be stepped back farther.. or the engine will die when you take your foot rapidly off the throttle..   excessively high intake manifold vacuum readings will cause the computer to turn off the fuel injectors or narrow their pulse width till there is just not enough fuel to keep the engine running..

look at the IAC counts.. if your scan tool displays it..   on GM cars.. which use the same style of idle air controller...
i like to see 80 to  100 IAC at cold start up...   20 to 50 at idle with the engine warmed up to operating temps...

post the results..

for the IAC counts..
for the TPS
for the ECT
for idle RPMs.


(idle air counts,    throttle position sensor voltage,  Engine coolant temp sensor voltage,  rpms at idle.  these are SCAN tool display only.. not from the dash board...  i need to know what the computer is seeing...

back to the research..  

Thanks for the help. Turened out to be the IAC.