Dodge Repair/ECT Sensor Inaccurate? (Part 2)
QUESTION: Mr. Finston,
I wasn't able to continue on the original thread. This is on the 2004 RAM 1500 with the "warm" shutdown issue.
I want to take a moment to bring you up to date on where we stand. Houston, we've got a problem .... When in the no-start situation, I do have spark (jumping 0.40 gap) and I have verified that the fuel pump is operational for about one second when first energized, as you describe. Additionally, fault code readout is available through the odometer window. There are no codes.
ANSWER: Hi John,
It would be good to verify with a helper whether the fuel pump is running when you are cranking over the engine in the 'no start' condition. He will have to listen carefully to hear it over the sound of the starter motor cranking. If that is running then we have an issue of no start with no codes. Usually about the only thing left is the egr valve being ajar,but that wasn't needed in the '04 Ram as I read the manual. Take a look at the under hood sticker to verify that nonetheless. You could also listen for the clicking of the injectors if that is loud enough over the cranking sounds.
It would have to be a fuel supply or mixture issue if you have spark. Let me know if any of these bear fruit.
Thanks for the ratings/nominations.
---------- FOLLOW-UP ----------
QUESTION: Mr. Finston,
Quick update: have verified the fuel pump is running when cranking over the engine in the "no-start" condition. I can feel the vibration through the tank wall, as well as, hear the pump running with my ear against the tank cavity where the pump rests against the tank floor. Additionally, you are correct with regard to no EGR valve utilized on this application. Also, I do not hear the injectors pulsing when in the "no-start" condition (large screwdriver against my ear).
Here's one more iron in the fire ... this truck was driven for quite some time with what the PCM described as a large leak in the evaporative system (one of the nipples on the fuel tank rollover valving was broken off the valve assembly. The PCM set the above-referenced code for this issue, which was corrected by replacing the fuel tank. The PCM no longer indicates any issues with the evaporative system. The truck was stalling, erratic idle, and all the rest while the evaporative system was malfunctioning. Question: could the truck being driven for quite some time with the faulty evaporatve system have hurt some other component of the vehicle, in your opinion?
As to the past history with the evap system, I don't believe that has any residual effect on the present problem.
Because you are not getting injector action my suggestion would be to measure the output signal pulsations from the camshaft position sensor when that is the situation (hot, no start). Those signal pulsations are whet tells the pcm which injector to fire. The signal wire is tan/yellow on pin 34 of the #2 pcm plug (which is next to the inboard-most plug) while the ground is black/light blue on pin 27 of the same plug (or at pins 2 and 3 respectively of the sensor plug itself). Pin 1 is a 5v supply wire from pin 29 of the pcm plug (violet/white wire). You could preposition pins through the insulation of those wires so as to be quick to check the no start pulsations.
With the ignition switch in the run position, rotate the engine by hand via a socket and breaker bar on the crank pulley bolt, while observing the voltage to see whether is oscillates frequently between 5 and 0.3V. If that pulsation were not present in the hot no start situation then that would explain why no pulsing of the fuel injectors.
I hope that will explain the problem's cause.
You have been so kind to give me 3 nominations this month, which means you can do it twice more if you believe I warrant that.