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3rd Gen Plebeian
1997 Plymouth Grand Voyager Rallye
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Post #3 on this page-

ENGINE START-UP MODE

This is an OPEN LOOP mode. The following
actions occur when the starter motor is engaged.
If the PCM receives the camshaft position sensor
and crankshaft position sensor signals, it energizes
the ASD relay and fuel pump relay. These relays supply battery voltage to the fuel pump, fuel injectors,
ignition coil, and oxygen sensor heating element. If
the PCM does not receive the camshaft position sensor and crankshaft position sensor signals within
approximately one second, it de-energizes the ASD
relay and fuel pump relay.
The PCM energizes all injectors until it determines
crankshaft position from the camshaft position sensor and crankshaft position sensor signals. The PCM
determines crankshaft position within 1 engine revolution.
After determining crankshaft position, the PCM
begins energizing the injectors in sequence. The PCM
adjusts injector pulse width and controls injector synchronization by turning the individual ground paths
to the injectors On and Off.

You are either not getting a valid crankshaft position sensor signal, or camshaft position sensor signal, and the PCM is de-energizing the ASD relay.
 
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Discussion Starter · #22 ·
Post #3 on this page-




You are either not getting a valid crankshaft position sensor signal or camshaft position sensor signal, and the PCM is de-energizing the ASD relay.
Nothing in the area of the crankshaft sensor or the camshaft sensors have been removed or damaged. The motor ran fine until I started removing under dash wiring. The firewall and the abs have been removed. The ASD is turning off before cranking. I did have the issue you are covering when replacing the engine around 10 years ago.
 

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3rd Gen Plebeian
1997 Plymouth Grand Voyager Rallye
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Nothing in the area of the crankshaft sensor or the camshaft sensors have been removed or damaged. The motor ran fine until I started removing under dash wiring. The firewall and the abs have been removed. The ASD is turning off before cranking. I did have the issue you are covering when replacing the engine around 10 years ago.
It exactly fits a crankshaft position sensor or camshaft position sensor fault though.
ASD energizes, cranks, ASD and fuel pump shut off 1 second later.
Maybe a ground path fault. The crankshaft/camshaft sensors are two of those things that are extremely picky about ground path, if they are grounded through the same path as the starter there will be an obscene amount of electrical noise on their signal lines. The PCM probably has a dedicated ground straight to the engine just for sensors
 

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Discussion Starter · #24 ·
Exactly my thoughts on a ground path. I have been chasing and marking wires for weeks. It all worked until I cut the firewall out. I had the rear ground splices bolted to the airbag module bolts on the floor. I am really wondering if the airbag module is sending a bad signal to the pcm. If my thoughts are correct the airbag pic bus is one of the main items that cause the asd to trigger. Btw during today's tests I still have no action on the dash lights or gauges. I am almost ready to harvest a new/used interior wire harness. Or rebuild the cut one. I don't think the missing seatbelt lines would cause this.
 

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Why not completely remove the airbag controller? You're not using it. Only thing it will do is throw a light that you can leave unplugged. Never seen an airbag signal kill the engine right after a start. It's only meant to do it right after a crash.
 

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Discussion Starter · #26 ·
When I removed the airbag module the first time I had the crank but no start issue. Re-mounting the module had the motor running again. With this happening I assumed it had to be there for normal operation. I hope you can confirm this part is not needed.
 

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Powertrain should function without other systems attached. Don't have a van of that generation at the shop to test it on, but I've dealt with wrecked cars that needed lights off to be able to pass a rebuild inspection. Never seen an airbag keep any from cranking. Are you certain it was the airbag module you disconnected?
 

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3rd Gen Plebeian
1997 Plymouth Grand Voyager Rallye
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I would suspect that the engine would automatically shut down in an accident, this is a simple and common safety feature, and this would be communicated by the airbag system.

But, the vehicle should immediately be able to restart for safety reasons. Not being able to start a vehicle and "drive" it immediately after a serious accident could be life threatening. Somebody could be pinned, the accident could be in a busy and dangerous area like the bottom of an icy hill...

I see this in industrial equipment. We put impact sensors that automatically lock out equipment. But anyone, even unauthorized users, are able to restart the equipment and drive it with limited function in emergency mode afterwards, even though they'd need RFID badge or password access to start it under normal situations.
 

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Discussion Starter · #29 ·
Powertrain should function without other systems attached. Don't have a van of that generation at the shop to test it on, but I've dealt with wrecked cars that needed lights off to be able to pass a rebuild inspection. Never seen an airbag keep any from cranking. Are you certain it was the airbag module you disconnected?
It cranks with no problems. It does not start. Further testing and voltage checks today. Didn't have much time to spend. I have 12 volts to the coil and injectors while cranking. Nothing to the hot wires with the key just on. I do have an injector pulse while cranking. I do not have ignition pulse while cranking. Also, chasing issues with the instrument panel and dash lights. I have power to the gauges but no lights or movement of the needles. I am attempting to add details as I go. Headlamps work turn signals do not. On a side note, I did have all the wires to the steering column off and the column removed for a while. I don't know if this could have caused any issues with the security key or not. Excuse me for being a bit flighty with my thoughts I am still having some after-effects from having the damn virus and being down for a few weeks. I am copying this reply to add it to the discussion with edy.
 

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Discussion Starter · #30 ·
I would suspect that the engine would automatically shut down in an accident, this is a simple and common safety feature, and this would be communicated by the airbag system.

But, the vehicle should immediately be able to restart for safety reasons. Not being able to start a vehicle and "drive" it immediately after a serious accident could be life threatening. Somebody could be pinned, the accident could be in a busy and dangerous area like the bottom of an icy hill...

I see this in industrial equipment. We put impact sensors that automatically lock out equipment. But anyone, even unauthorized users, are able to restart the equipment and drive it with limited function in emergency mode afterwards, even though they'd need RFID badge or password access to start it under normal situations.
It cranks with no problems. It does not start. Further testing and voltage checks today. Didn't have much time to spend. I have 12 volts to the coil and injectors while cranking. Nothing to the hot wires with the key just on. I do have an injector pulse while cranking. I do not have ignition pulse while cranking. Also, chasing issues with the instrument panel and dash lights. I have power to the gauges but no lights or movement of the needles. I am attempting to add details as I go. Headlamps work turn signals do not. On a side note, I did have all the wires to the steering column off and the column removed for a while. I don't know if this could have caused any issues with the security key or not. Excuse me for being a bit flighty with my thoughts I am still having some after-effects from having the damn virus and being down for a few weeks. I am copying this reply to add it to the discussion with edy.
 

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No need to double post. Pretty sure we both read all replies when we check. ;)

Security shouldn't be an issue. Security cuts fuel, not spark. I think it should just play dead, but that's how it is done.

So there's no voltage to coils or injectors with the key in Run? And your turn signals don't work... Did you turn the key to Run before trying them? If not, do it. If you did, or try and they still don't work, then you have an issue with the ignition switch not activating the Run circuit. Of course this assumes that the turn signal circuit is still functioning properly.

I'll see if I can get the power distribution diagrams.
 

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From the manual:
The ignition coil assembly consists of 2 or 3 independent coils molded together. The coil assembly for the 3.3/3.8L is mounted on the intake manifold. The coil assembly for the 2.4L is mounted on the cylinder head cover. Spark plug cables route to each cylinder from the coil.

The coil fires two spark plugs every power stroke. One plug is the cylinder under compression, the other cylinder fires on the exhaust stroke. The Powertrain Control Module (PCM) determines which of the coils to charge and fire at the correct time.


The Auto Shutdown (ASD) relay provides battery voltage to the ignition coil. The PCM provides a ground contact (circuit) for energizing the coil. When the PCM breaks the contact, the magnetic energy in the coil transfers to the secondary causing the spark. The PCM will de-energize the ASD relay if it does not receive the crankshaft position sensor and camshaft position sensor inputs. Refer to Auto Shutdown (ASD) Relay-PCM Output, in this section for relay operation.
And power and ground distribution attached.
 

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Discussion Starter · #33 ·
From the manual:
And power and ground distribution attached.
Thank you for the information. I haven't dug into manuals like this since the 70s while in the Army. On the turn signals, instrument cluster, and other items The key was in the run position. I do have power going thru the switch to the start and run lines. I do have a question about a term I haven't come to grips with yet. Wires that are labeled sense and return. Example "Ignition Switch Sense" "Ignition Switch Sense Return" I will be putting the files you sent to me asap.
BTW I love your tag line. If and when I get DT running I will have to work on a good tag line. DT being Dodge Trike ;)
 

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The attached diagram should answer that question better than I can. :p
BTW I love your tag line. If and when I get DT running I will have to work on a good tag line. DT being Dodge Trike ;)
"Big Kid, Big Toy" ;)
 

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3rd Gen Plebeian
1997 Plymouth Grand Voyager Rallye
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I was reading the manual for Megasquirt ECUs, might be needing one for the 4.0L swap I'm doing, and came across this information, what I was getting at with ground, but stated better.

61085



61086



61087
 

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Discussion Starter · #36 ·
I was reading the manual for Megasquirt ECUs, might be needing one for the 4.0L swap I'm doing, and came across this information, what I was getting at with ground, but stated better.

View attachment 61085


View attachment 61086


View attachment 61087
Makes sense to me. When computers are involved the signal and the data being carried are much more than just connect/disconnect. I have started tracing reconnecting ground wires today. I have thought for a while now I have some ground issues. I pulled some of the grounding splices from the saved parts today. The connections show to be grounded but might not be activating the pcm correctly.
 

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Discussion Starter · #37 ·
Well guys I am still lost on this ignition pulse problem. Spent a good part of the day tracking down body wires that were removed. Checking voltages checking connections that kind of stuff. Tested the camshaft and crankshaft sensors 8 volt and 5 volts on both tests ok in the run position. Cranking the signal lines are active. Tested ignition coil and the resistance on primary and secondary are good. Measured resistance between grounds nothing more than 1 ohm. Measured voltages on the different B+. Nothing more than 0.1 volts. ASD relay. works as it should power the injector b+ fuel pump and ignition coil b+ for a second or so then shuts off. Turning the switch to start enables ASD relay sending b+ to all 3 again. Took both positive and negative battery terminals apart to clean the extra connectors to be sure of good b+ and grounds. My next step will be checking the ignition, b+, and ground lead's to the PCM. Also still no activity to the gauges dash lights or the turn signals. Posable I could have crossed something and cooked part of the PCM.
 

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3rd Gen Plebeian
1997 Plymouth Grand Voyager Rallye
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Well guys I am still lost on this ignition pulse problem. Spent a good part of the day tracking down body wires that were removed. Checking voltages checking connections that kind of stuff. Tested the camshaft and crankshaft sensors 8 volt and 5 volts on both tests ok in the run position. Cranking the signal lines are active. Tested ignition coil and the resistance on primary and secondary are good. Measured resistance between grounds nothing more than 1 ohm. Measured voltages on the different B+. Nothing more than 0.1 volts. ASD relay. works as it should power the injector b+ fuel pump and ignition coil b+ for a second or so then shuts off. Turning the switch to start enables ASD relay sending b+ to all 3 again. Took both positive and negative battery terminals apart to clean the extra connectors to be sure of good b+ and grounds. My next step will be checking the ignition, b+, and ground lead's to the PCM. Also still no activity to the gauges dash lights or the turn signals. Posable I could have crossed something and cooked part of the PCM.
Do you have a second battery to crank with? One battery wired to engine ground and starter B+, the other battery wired to the normal positive and negative battery cables. Leave the normal B+ cable from the harness disconnected from the starter.

This would power the van EFI system from one battery, and the starter independently on the second battery. It would eliminate any major noise issue from the starter.

Wondering if the instrument cluster has to be talking on the communication BUS for the 4th gen to run?
 

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Discussion Starter · #39 ·
Do you have a second battery to crank with? One battery wired to engine ground and starter B+, the other battery wired to the normal positive and negative battery cables. Leave the normal B+ cable from the harness disconnected from the starter.

This would power the van EFI system from one battery, and the starter independently on the second battery. It would eliminate any major noise issue from the starter.

Wondering if the instrument cluster has to be talking on the communication BUS for the 4th gen to run?
The instrument cluster does have a bus line going to it if that was what you were asking.
On the starter, I believe you are thinking about running the cranking from 1 battery and the electronics from the other battery. I am not sure where you are going with this suggestion.
 

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If I read correctly, after a few seconds, the ASD relay cuts power. Sounds like something I have read the SKIM security system does if it doesn't recognize the key. We have SKIM on our 2002 T&C. People say if the SKIM fails, best bet is to get a non-SKIM PCM from the junkyard. There is a red Security lamp in the upper dash display. Do you know if the donor had SKIM?
 
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