Chrysler Repair: 97 LH: no fuel pressure, spark coils, hesitation problem

Question
QUESTION: Hi , I have a 97 Intrepid 3.3L that was given to my nephew- It was running , but had a hesitation problem. And was also hard to start (long crank time). It had only 15psi fuel pressure but was running (didnt think it could) and the needle was shaky- I replaced filter and got it to run once , but not since. It now has zero psi. I replaced the pump twice- borrowed the 2nd one to try. Still nothing. I removed the line from the filter's outlet and no fuel there.I can hear the pump run for a second when the key is on , it does this twice turning the key on quickly and not on the third try. It also has codes 12 & 42. I don't have much Chrysler exp , and I don't understand the ASD relay theory much. ANy help is very much appreciated , Thanks   Chris

ANSWER: Hi Chris,
The autoshutdown relay is a safety device that kills the power to the fuel pump and spark coils and oxy sensors if the engine stops turning. The 42 code says there is a problem with that ASD  control circuit.
The actuator coil of the relay depends upon fuse 18 in the fuse block behind the dash (remove left end cap for access) and that gets its power from the ignition switch which gets its power from fuse A in the power box in the fuse compartment. The coil will activate on signal from the pcm when it is satisfied with the output from the engine rotation sensors. That signal (grounding the other end of the coil) comes from pin 51 of the pcm. The ASD does close (pcm grounds other end of it) when you turn the key to 'run' but clicks off after a second again (safey shut down action), until you start cranking the engine on 'start', but you may not hear it because of the noise from the starter. The exact same actuation circuit goes to the fuel pump relay, so they should be acting in tandem. One or the other relay might be bad, so try subing relays around in the box (say trying the fan relays if they are the same part no.) to see if that gets things going and of course check the you have 12v from fuse 18 on the driver-side pin of the ASD and fuel pump relay sockets when the ignition is in run AND when cranking (pull the relays to measure), and then check that the passenger-side pins grounds out when you are cranking.
12 code merely means the battery has been disconnected sometime in the past 50-100 key cycles.
I hope this gets you going, snd let me know if something interesting comes up by asking a follow-up question.
Roland
PS: Because you don't have a sensor code (11 or 54) that makes me wonder if the ignition sxitch might be bad in the Start position (check of voltage at the coil pin of the relay) or the fuse 18 or A is flaky intermittent.

---------- FOLLOW-UP ----------

QUESTION: Hi Roland, This is what I've found. Fuse 18 is good with 12v on both sides.I swapped the relays around , but still no success. It is about 10 degress here now , but there is 12 v on the LH terms of the sockets in run , but drop to +/- 9V. not sure if the air temp is affecting this. The grounds are at 12V showing a neg on a DVOM. I did use a test light first for the grounds and it did not light up- not sure if this indicates anything.   Thanks Roland , Chris

Answer
Hi Chris,
I am not to clear about the pins and the measurements, that is why I used passenger side and driver side to describe the pins. And of course which points the DVOM leads are attached to will affect what you get. The bottom line is, is the ASD relay closed or not, and similarly is the fuel pump relay closed or not when you are cranking over the starter motor. If you don't get 12V on the rear pin of those relays when you are cranking then it won't start. So leave the relays in the sockets, but attach a short wire to each of the rear pins of those relays (or somehow get a probe on the pin (or the dark green/orange, dark green/black wires, respectively that are attached to the rear pins) before you stick it in the slot so that you can measure for 12v compared to chassis ground on those pins when you are cranking it over. Is it there or not?
If not, and you have 12V on the driver-side pin of the sockets when cranking, then the pcm is not grounding the other end of the coils on the opposite side to close the relays. Other than an open wire to pin 51 or a missing sensor signal (which should cause a 11 or 54 code), the only other explanation is a fault pcm. The fact that you do get the one second 'on' phenomenon makes be believe the pcm is working and the wiring is good. Which leaves the issure being a weak sensor signal which is not so bad as to fault code.
You can check the sensors by measuring their signals between the black/light blue wire of the sensors (signal ground) and the light blue/dark blue (crank) or the tan/yellow (cam) sensor while you turn the engine over by hand using a socket on the crank pulley bolt, and of course the ignition in the run position. You should see pulsing as you turn the engine, between 0.3 and 5v, several times per revolution. If you see that, then those signals should be causing the pcm to energize the ASD and fuel pump relays when you are cranking with the starter motor. You can probe through the sensor wires using a straight pin to make connections.
Roland