I recently bought another ram, previous owner had stated to me the truck typically will start when gas pedal is being pumped, and told me he believes it’s a pcm issue due to several years ago it had happened and he took it into the dealership and they installed and programmed a new pcm and from what I can tell he seems to be telling the truth due to the pcm looking newer with a sticker on it stating part number and what not. Anyways I’ve done some research and have worked on the truck a little myself, and from what I gather it does seem to be the pcm. When I go to turn the key and put it in the on position I hear a lot of chattering in the engine bay and it’s the ASD relay and the Fuel relay, so then naturally I go and check the fuel pump and listen if it whines when you put the key in the on position and it does so I don’t believe it’s the fuel pump. So then I go to autozone and pick up a new fuel pump relay and install it and there’s no difference in trying to start the truck, it cranks but no start. Also he just recently installed a new fuel pump last month in the truck so I really don’t believe it could be that. Aswell if you pump the gas pretty fast and hard and turn the key it acts like it wants to start and occasionally will. So I’m not sure where to go from here and what to do, if anyone has any pointers that would be great!
EDIT: I should also add, once you get the truck started and it’s running it runs great, nothing off with the motor idles how it should runs and shifts through gears fine, no check engine light either.

 

Test the battery.... Specifically, a load test. Weak battery will cause those symptoms.

 

Aye aye don't condemn the PCM based on this. You need to look at some live data. I'd like to know if the TPS is working as it should given that fiddling with the accelerator seems to affect it. Also an ECT sensor might cause this. Could also be cam sensor and the skinny pedal is a red herring

In the future just jump relays, don't blindly throw new parts at them. And if you suspect a fuel issue test fuel pressure.

But truly, there's a 1% chance it's your PCM

If you have a local shop known for good diagnostic abilities, that might be your best bet. At the very least watch vids and read on how to diagnose and invest in those tools rather than parts you can't prove are faulty.

 

I load tested the battery didn’t go under 10.56v while cranking so it doesn’t seem to be that. Any other pointers to check out while I’m under the hood? Also thank you for the help thus far!

 

what would be the best way about testing the tps and ect, given its hard to get the truck going to read codes what would be an alternative? Also thank you for the help thus far!

 

Need a scanner that can read live data.......

 

Agree with Keith_L, it's very unlikely the PCM is bad (again). Also it sounds the truck is running fine once started. Relays chattering makes me think it's a power/ground issue. I would start by measuring voltage to battery negative (not random grounds) on both sides of the relay coil.

 

I have one tomorrow I will be doing that and give an update on situation, anything in particular to look out for I’ve never read live data before so new to that aspect of things. As well as ill be having to replace the tps with a new one since today I went to unclip it from the harness and the tps came apart lol, I didn’t even use really any force just wiggled it lightly to get the harness disconnected.

 

I’m very new to doing any wiring testing or anything any good tips it would definitely be greatly appreciated! Also thank you for the help thus far!