Hi Wrenchtech. Excuse me for popping in again. You're right about the injector pulse but these cars also have a related issue with the anti-theft system. We ran into this problem twice at the dealership and once with a '95 Intrepid that was donated to our school by Chrysler. This only pertains to cars that do NOT have the factory anti-theft system installed.
The first thing is to listen for the hum of the fuel pump for one second when the ignition switch is turned on. If that is not heard, there's a wiring problem to the pump. That one second each time you cycle the switch to "run" is plenty to develop fuel pressure at the test port, so if there is still no pressure, suspect the fuel pump relay, the wire to the pump, or the connector is not making good contact. Don't overlook the ground wire.
Forget the pressure regulator. Problems with those are almost unheard of on Chrysler products. Since the engine runs on starter fluid, you know it has spark. Most of the sensor failures that cause the fuel pump to not continue running during cranking will also cause no spark, so we can rule out sensors. The problem that has been known to develop is the Engine Computer and the Body Computer accidentally self-program themselves to have the anti-theft system and they will stay in theft mode until they get a disarm signal, (which is never coming). To prevent retyping this novel over and over, I have a copy / paste version of my previous reply. Disregard what doesn't apply to your situation but look at the swapping computers information:
Ok, first of all, roll the driver's window down, hop out of the car, use the power lock button on the door to lock the doors, close the door, then wait for at least a minute. The anti-theft system will arm if you have it. Now reach inside and open the door with the inside handle. If the horn starts blowing and some lights start flashing, you have the anti-theft system. This is real important to know when it comes to replacing the Body Computer or the Engine Computer. If you have the anti-theft system, you can use any computer from the salvage yard, but from then on, that computer will only work on another car that also has the anti-theft system. DO NOT borrow a friend's computer if his car doesn't have the anti-theft system.
Both computers have anti-theft programming that can not be undone. If your car does not have the anti-theft system, you must find a used computer from a donor car that also did not have anti-theft, and that can be impossible to find out from the salvage yard since there's no easy way to tell unless the car was running when it was brought in. Even then, they might not have bothered to find out.
When you install either the Body Computer or the Engine Computer with anti-theft programming into your car without anti-theft, the new computer will teach it to the other one. A Body Computer will teach it to the Engine Computer or a replacement Engine Computer will teach it to the Body Computer. At that point the car will not start because both computers are waiting for the disarm signal that's never coming. Both computers will have to be replaced at the same time. If you just replace one of them, it will immediately learn the anti-theft programming from the other one as soon as the ignition switch is turned on.
If you buy a remanufactured Body Computer from the dealer, it will come without the anti-theft programming. It will work in any car as soon as it is installed and will self-program itself for anti-theft only if the system is on the car, when it learns it from the Engine Computer.
I just wanted to get all of that out of the way in case you do need to replace the Body Computer, (Body Control Module) ( BCM).
Okay, back to the live version of me. Use that information only if it comes to replacing a computer. If your car is equipped with the factory anti-theft system, computers aren't the issue as they will exit theft mode when you unlock the doors. If you're using a key to unlock the doors vs. A remote key fob, there could be broken wires between the driver's door hinges. The system will also disarm by unlocking the passenger door.
When armed, you will still have spark but not injector pulses. I never checked whether the fuel pump was running for that first one second or during cranking when it's in theft mode.
Also check for diagnostic fault codes. On the older cars signals were needed from both the camshaft position sensor and crankshaft position sensor for the Engine Computer to turn on the automatic shutdown (ASD) relay which sent current to the ignition coil(s), injectors, and fuel pump or pump relay. On newer cars my understanding is the engine will still run if one of those sensors fails but injector firing times are mixed up. I am 99 percent sure you still need both signals on a '95 model for the plugs to fire, but it's still a good idea to check for fault codes.
Remember, all of this story means nothing if you aren't hearing the pump run for one second. If that is the case, troubleshoot that circuit.
Saturday, June 11th, 2011 AT 8:40 PM