Bad ECM/PCM?

[MrMerica]

So I left my truck sitting for about a week while I was on vacation. I try to start it up for the first time and it'll crank all day but won't fire. My gauges aren't working, my odo is flashing my mileage, and my lift pump isn't getting any power. What do I need to look into besides checking all the grounds and fuses? Does this sound like a bad ECM/PCM? Thanks for any help.

 

The truck is a 1998.5 

[Bullet]

Sounds like a bad ground issue to me.  Are you getting a normally operating wait to start light? 

[dripley]

See if you pull any trouble codes. Does your WTS light come on at key on?

[MrMerica]

I’ve never actually seen the WTS light with this truck even when it ran. Tried hooking up the OBD reeder to it and it won’t connect. What grounds should I be looking for?

[Mopar1973Man]

Remember the PCM is the master computer to start the network, then the ECM is second in line to fire up.

[MrMerica]

Found a blown fuse so that fixed the gauge problems. Truck still won’t start, I have power to both the VP and lift pump. Fuel is getting through the lines but no fire. Dash also has a check engine light now.

[dripley]

Check it for dtc's. What year is your truck?

 

Have checked for fuel at the head? Loosen 2 or 3 injector lines and you should see a pretty good flow. 

[MrMerica]

It’s a 1998.5

 

Ive check every injector line and I’m getting fuel. OBD won’t connect so I can’t get any codes. I have a wts light briefly then a check engine light. Will crank all day but won’t fire.

[dripley]

Come to think my cel stays on with the key on until the engine stsrts. I don't know how different yours is from mine though.

[MrMerica]

Still can’t get the truck running. I have the WTS now so I don’t think it’s an ECM. Included a video of the fuel I’m getting through the lines, is it normal?

[Bullet]

Yep that looks normal to me.  Your check engine light should come on for 3 to 8 seconds (depending on how cold ambient temp is) when you turn the key forward then go out.  If your CEL is not doing exactly that then something is not right with pcm/ecm.

 

The fact that you can't connect to read codes strongly suggests pcm/ecm problems. 

[IBMobile]

Rule out a bad VP44 by doing a "hot wire" test.

Do this https://www.bluechipdiesel.com/runningtests  or the test below.

 

 

Edited January 6, 2020 by IBMobile

[dripley]

4 hours ago, Bullet said:

Yep that looks normal to me.  Your check engine light should come on for 3 to 8 seconds (depending on how cold ambient temp is) when you turn the key forward then go out.  If your CEL is not doing exactly that then something is not right with pcm/ecm.

 

The fact that you can't connect to read codes strongly suggests pcm/ecm problems.

You do mean the WTS light dont you?

 

 

[Bullet]

1 hour ago, dripley said:

You do mean the WTS light dont you?

 

 

Oops....  Yes I meant WTS...not CEL.  Thank you @dripley

[MrMerica]

I have power to the VP/Lift pump and a WTS so that leads me to believe it's not the ECM. All grounds have been checked/replaced. Are there any suggestions on sensors I maybe be missing that can cause this? I'm replacing the crankshaft position sensor today.

[dripley]

You might try checking for codes again since your normal functions seem to have returned. 

[MrMerica]

Still nothing. I will admit its never have an OBD reader connected before and the connection seems a bit sketchy (Power comes on and off if I move the OBD port too much) so unsure if it was even working prior to my current problems.

[dripley]

Those ports are a bit flimsy. Figured it was worth a shot instead of just spending money sensors that might be fine.

[MrMerica]

How much pressure should I be seeing out of my injector lines? As you can see in video there’s isn’t much pressure. Not really the crazy “spraying” everyone says to expect.

[dripley]

23 minutes ago, MrMerica said:

How much pressure should I be seeing out of my injector lines? As you can see in video there’s isn’t much pressure. Not really the crazy “spraying” everyone says to expect.

They spray when you just loosen them a half of a turn or so. You have good flow, the injection event does not need a ton a fuel. The injection event is around 4000 to 4500 psi.

Also the fuel you are seeing there gets pushed thru 7 tiny holes in a split second per event.

 

I had an injector line snap off at the head a couple years back. I ended up clamping some fuel hose on it and ran it to a 5 gallon fuel can in the bed. In the 15 miles back to the job I had near filled that can up with no more flow that you are seeing.

Edited January 7, 2020 by dripley