Let’s get to the bottom of these No Starts

[JarheadJohn]

Here is the BIG question for everybody.......got your thinking caps on ????, what tells the injectors to work?????. We know he has air, fuel to the injectors, it will run on starting fluid so we know he has spark. Maybe ECM has crapped the bed, or just out of pure happenstance a bad wire from crank or cam sensor.

Well, both of those sensors were replace, and I didn’t notice an issue with the plug in connectors, but I will look closer. Especially the cam sensor since that’s the one controlling the injectors.

 

[JarheadJohn]

Finally got some more cash, and am awaiting the arrival of a quality OBD2 scanner. Hopefully we can get to the bottom of this.

 

[Thewetdream]

Just for the fact he has pressure at the fuel rails and it will try to run with starting fluid shot at the intake……. I’m thinking a ecm because it tells when those injectors to open in sequence and if they aren’t getting the slight voltage from the ecm to open to allow fuel into that cylinder it’s not going to fire……. Just my .02 I could also be 100% wrong

 

[Thewetdream]

9v battery hooked up to a injector just to hear if it clicks open but again that might be useless to do

 

[Phirebeard]

If you can find a friend with a real scan tool (like a $5000 Snap-on one), they should be able to check the injector pulses and even send a pulse command to see if they're working. Though if the 9V battery trick works, that's definitely easier lol

 

[Ribtipram]

Im going with bad crank sensor. I believe it also controls injector pulse

 

[Ribtipram]

But i do think that should throw a code

 

[Burla]

The 2011 Ram 1500s do not have a fuel pressure sensor. Nor do they have a fuel rail pressure sensor.

what is this?

 

[Ribtipram]

My bad i missed he changed the cps.

 

[Canadian-Hemi]

Finally got some more cash, and am awaiting the arrival of a quality OBD2 scanner. Hopefully we can get to the bottom of this.

What scanner did you purchase, I'm in the market to replace my ELM327. Mine seems a m/s slow with any real time readings.

 

[lust_won]

I had a problem with my truck not starting and it was the PCM board. It was cracked. It controlled almost everything. It would crank and not turn over. worth looking into.

 

[StuartinBakerLake]

Gentlemen, Let me shed some light on this situation.
An engine needs three things to run. Fuel, air and spark.
Starting fluid makes it run for a brief period time, and there is fuel at the fuel rail, so we can deduce that there is a working pump and that the coils appear to be firing.
If the injectors are not opening, you won't get fuel into the engine. Crank it for a few seconds then pull a plug and see if they are wet. If yes, Injectors are good. If not, then I'd start by looking at what controls the injectors. They are essentially 12V solenoids that open and close based on commands from the PCM. The coils are operated the same way.
This truck, like many MOPARs, has an ASD (Auto Shut Down relay) that supplies power to the PCM, injectors and coils.
If there is no fuel AND no spark, the ASD relay, or the power supply to the ASD relay may be at fault.
I'd do a Google search for the appropriate Engine Controls wiring diagram based on year and engine. Look at the diagram and start by looking at where your power comes from.
If you cannot find the diagram, I can email it to you.
(source, I am an Automotive Technician with over 30 years in the trade)

 

[Sherman Bird]

Finally got some more cash, and am awaiting the arrival of a quality OBD2 scanner. Hopefully we can get to the bottom of this.

When you get your new scanner, go to the engine computer live data settings and crank the engine while observing the RPM PID. It should register about 200-ish RPM while cranking, the Crank sensor and wiring are good. I recently had a 2004 Ford Ranger towed from another shop to mine after that shop decorated the underhood with shiny new parts such as you describe. Frustrated, the Ranger's owner's Dad (the dad is my customer for years) referred the young man to me. I started from scratch, and the RPM registered 1900 RPM on my scanner. Yes, this brand new aftermarket crankshaft sensor was bad. I installed a genuine Motorcraft part on it and got a more normal 180 RPM. Although that didn't fix IT'S crank, no start problem, the problem had to be eliminated. I was able to diagnose a bad Computer due to no toggle of the coil pack and replaced said computer. Post repair diligence showed high KV demand due to some prior knucklehead putting too hot heat range spark plugs in the engine.

I would check for toggle at an injector if I were you. Noid lights can be had pretty cheap at your parts house.

 

[Daniel47]

I had a similar problem on an old F150. (RAM owner now). The ECM (computer module)
has circuits in it that generate each cylinders spark at the correct time by switching the coil packs
on and off. If you do not have a spark in one or more cylinders, it is possible that your ECM is bad.
I think that the fuel pump relay is also controlled by the ECM. My F150 had 2 dead cylinders.
I removed the ECM (easy-on firewall usually) and sent it to a diagnostic service that I found on EBAY.
They will test the module and repair it, if possible, for about $90. Mine wasn't fixable and had to replace
it for $350 (refurb). Truck was fixed. Good luck.

 

[JarheadJohn]

Just for the fact he has pressure at the fuel rails and it will try to run with starting fluid shot at the intake……. I’m thinking a ecm because it tells when those injectors to open in sequence and if they aren’t getting the slight voltage from the ecm to open to allow fuel into that cylinder it’s not going to fire……. Just my .02 I could also be 100% wrong

Is there anything that goes THROUGH the TIPM before the ECM? It would not seem so.

 

[JarheadJohn]

what is this?

Someone recommended a fuel pressure sensor. The 2011 doesn’t have one.

 

[JarheadJohn]

Gentlemen, Let me shed some light on this situation.
An engine needs three things to run. Fuel, air and spark.
Starting fluid makes it run for a brief period time, and there is fuel at the fuel rail, so we can deduce that there is a working pump and that the coils appear to be firing.
If the injectors are not opening, you won't get fuel into the engine. Crank it for a few seconds then pull a plug and see if they are wet. If yes, Injectors are good. If not, then I'd start by looking at what controls the injectors. They are essentially 12V solenoids that open and close based on commands from the PCM. The coils are operated the same way.
This truck, like many MOPARs, has an ASD (Auto Shut Down relay) that supplies power to the PCM, injectors and coils.
If there is no fuel AND no spark, the ASD relay, or the power supply to the ASD relay may be at fault.
I'd do a Google search for the appropriate Engine Controls wiring diagram based on year and engine. Look at the diagram and start by looking at where your power comes from.
If you cannot find the diagram, I can email it to you.
(source, I am an Automotive Technician with over 30 years in the trade)

This is where I’m at….fuel at the rail, and dry plugs after cranking.

 

[Sherman Bird]

I had a similar problem on an old F150. (RAM owner now). The ECM (computer module)
has circuits in it that generate each cylinders spark at the correct time by switching the coil packs
on and off. If you do not have a spark in one or more cylinders, it is possible that your ECM is bad.
I think that the fuel pump relay is also controlled by the ECM. My F150 had 2 dead cylinders.
I removed the ECM (easy-on firewall usually) and sent it to a diagnostic service that I found on EBAY.
They will test the module and repair it, if possible, for about $90. Mine wasn't fixable and had to replace
it for $350 (refurb). Truck was fixed. Good luck.

Ford used multi-strike coils for many years..... i.e. they fired 3 times when they were commanded to fire at RPM's under 1500. At higher RPM's, they went to single event firing. The ECP/PCM/ Computer employed mosfet transisitors to handle such a high demand load on the circuit. but they failed more often than what I saw on other brands of vehicles. I do not know FCA's particular strategy on the twin plug coils on the Hemis. I'd think they are fired simultaneously.

Either way, the diagnosis of whether or not the engine fuel injectors are being commanded to cycle on and off during cranking event can easily be determined with an inexpensive noid light for that purpose. Noid lights are cheap and they plug into the connector of the injector. I use a PICO oscilloscope to quickly and accurately diagnose these type of problems, but I am a professional with the training and experience to use such advanced and expensive equipment. For the DIY'er, a noid light works wonders!

 

[StuartinBakerLake]

Here are the wiring diagrams for the fuel system and the ignition system

 

[SYKRAMMAN]

These electrical gremlins are my nemesis, I'm dealing with an evap code atm and it's driving me nuts.