Chrysler Repair: ABOUT 1994 Chrysler LHS 3.5 no spark, no fuel pump, 1994 chrysler lhs, chrysler lhs

Question
 
     Chrysler Repair > 1994 Chrysler LHS 3.5 no spark, no fuel pump


Topic: Chrysler Repair

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Question
Hello,
I have a 1994 Chrysler LHS I am working on (3.5 Engine). I was working on the heating system and

had most of the dash out. After fixing the heating problem and re-installing most of the dash, I

started the engine and it ran fine. I only ran it for about 5-minutes. I turned the engine off

and when I went back to re-start it, the battery was too weak to start the engine (lights were

on). I connected a battery charger and tried to start it and now it will not start. There is no

spark, and the fuel pump does not run. There is also no voltage on the green/orange wire on the

coil harness plug. I cannot find any fuses blown and of the 3 fusable links I found (2 at the

battery cable and one behind the washer bottle that goes to the Alt. output) none of which were

blown. I have changed the PCM, BCM and coil pack with still no luck. I cannot get the check

engine to give me a code by using the "on/off/on/off/on method. When I try this, the check

engine light goes off and stays off. I also connected a snap-on scan tool to the blue connector

under the dash and it says it cannot communicate. There is one 12v + wire in this connector that

is working. Any advice will be greatly appreciated. I keep thinking there is a fuse/fusable link

or main wire somewhere that is bad?  
Mr. morgan suggested a bad connection under the dash, but it has since been taken all back apart with no luck. The weird thing is that it started 2 or 3 times before the battery was too weak to start. If it had been a communication problem with the BUS, Would not it have not started the first time? Thanks!  

Answer
Hi Eric,
Before going into details, I wonder if the battery is either too discharged or not putting out sufficient voltage to run the system. So do look into that possibility. If the battery is near the end of its warranty life I would recommend replacing it. Also check the battery - post clamp wires to be sure that you have good ground connections on that cable (left frame rail and left front of engine).  I would also suggest that you check each of the fuses to be sure that they actually conduct because they can look good but have a subtle crack that opens as soon as current starts flowing thru the fuse. Make sure that you have voltage coming from fuse B in the power distribution center (20 amp) because that is the one that is needed to power the pump and the coil if the ASD relay will close at the command of the PCM. You could jump across the ASD relay (front pin to back pin), if indeed you have 12V on the front pin of the socket and that should get you a fuel pump, spark coil voltage, and generator field coil supply voltage. See if it starts then.
If we take the Snap-on at its word (cannot communicate) then that could be equivalent to a message on the Chrysler DRB II "not receiving bus messages correctly". If so, My '94 CCD bus manual says that for that message what you do is to turn the ignition 'on' and then remove, one at a time, each of the modules that are in the network and watch for the message to go away. When it goes away, that most recently removed module is the one that is killing the network. Start with the TCM and then go:PCM,Anti-lock brake controller (if equipped,ie), traveller (ie), mechanical instrument cluster, vehicle theft security module (ie), compass/mini-trip module (ie).
Then if that doesn't reveal anything, turn off the ignition switch and wait for 2 minutes. Then disconnect the air bag module and again turn 'on' the ignition switch. If still no change in the message, then disconnect the Auto temp control head (ie), overhead travel info center (ie), body control module, and if that doesn't clear the not receiving message then there is something wrong with the DRB cable, cartridge, or wire connections to the data link plug.
That is the best I can see to try, given what you tell me.
I would be very interested to learn what happens. I say your question to Wil and was hoping you would solve it before you asked me! I happen to have the '94 LHS shop manual so we should have a good shot at figuring this out.
Roland