2000 Dodge Ram 1500 5.9L

Engine runs good when running but when the ambient temp gets hot (90+), the engine will shut down much like when the key is turned off. The engine will restart after sitting a few minutes since replacing the fuel pump – prior to replacing the fuel pump, the engine would have to cool down much longer.

Recently replaced the ignition coil, plugs and plug wires, crank position sensor, fuel system relay and the complete fuel pump assembly.

At a loss – before putting a match to it, I would appreciate any thoughts and/or recommendations.

Thank you

ADDED 26 August - Battery issues to day - Autozone test indicates battery was shorting out - chnged batteries but have not driven enough to know for sure if the basic problm is fixed..

Question - could the battery shorting out result in the engine shuttin down???

Thanks

 

Possibly cam sensor, or PCM failure. Wouldn't be the first time for either. Have some way to chat with the PCM?

 

Thank you for the quick response.

I have no way to test the PCM........ is there a process to check the PCM?

What about the Mass Air Sensor!

A check at the local Autozone indicated all sensors are ok.........but, if one is breaking down when hot, it wouldn't show when the engine is operating normally..........???

Thanks again for your help

 

No mass air flow sensor. System using a MAP sensor. (manifold absolute pressure) If it failed, it would still run, just badly. (and set a code too.)

Something is getting hot, and failing. Cam sensor is cheap.... (relatively speaking....) Need to see if the PCM will communicate when you have the no-start condition. Do you get a "No Bus" error on the odometer when it won't start?

 

No error codes when engine shuts down....... when engine shuts down, no spark to the plugs prior to change of fuel pump. Have not been able to check for spark since changing the fuel pump.

 

Replaced fuel system relay.......wonder if the ignition relays might be breaking down when hot?

 

Bad ground? Had a 78 Mustang that did something similar to this. Found a broken ground strap that caused it.

 

Entirely possible. Also, check the ASD relay, that's the one that supplies power to the injectors, and coil. Just swap it with the horn relay. Should be the same.

 

Yeah, relays can fail, especially ones that are on constantly when engine is running. I've even had a worklight relay that turned itself on in the middle of a night

I had a Jeep XJ 4.0 with Renix fuel system, and one summer it developed a problem; started to run on 5 cylinders after getting hot enough. Weird thing was that in the morning it would run perfectly, but after being in a direct sunlight for a day, it didn't took long drive to loose the one cylinder (#5 to be precise). Tried to find problem for days, until it got so bad that all I needed to do is to rev the engine and it lost #5. Then I started to think... ambient temp hot and we have a problem (on a cloudy day it worked much better, had some issues but still)... black Jeep... wait, where's the PCM? Right next to go pedal. Took the PCM off from it's bracket, and when the #5 was lost I placed the PCM to a plastic bucket which had ice bags in it, waited for a while and boom!! Started to run smoothly! Took the PCM out from the bucket, after a while no #5, back to bucket and we got #5 back! So when the INSIDE of the Jeep got hot enough, PCM failed.

So long story short, if the relay don't fix the problem, try to cool the PCM to see if there's the problem.

 

appreciate it........will pursue! The PCM is in the engine compartment on the pax side firewall but you never can tell......

Thanks