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Discussion Starter · #1 ·
hi everyone,well what was supposed to be a simple valve cover gasket replacment turned into a timing belt replacement also when I discovered it in bad shape .I did everything right replacing the belt,but when I tried to start it last night,i got nothing,no spark,no power loss lamp.I waited awhile to check all the wires reconnected the battery,and it finally started.It got too dark so I decided to wait until today to time it,and again,it will not start,waited a bit,turned the key,power loss light came on,heard the fuel pump energize and it almost started until the battery went dead,it was then I noticed smoke coming out of the power module,so i disconnected the battery and took it out to recharge it and went through all the wiring and found nothing out of the ordinary,no burn wires,no melted fusible links,all the wires look good,i got power going to the module,I swapped LMs,and still nada.Its my power module taking a crap?Any help would be appreciated.
I got no spark,no signal to the coil,no fuel pump,no injector pulse,no power loss lamp.:shrug:
 

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I had this happen one night after I droped the hood shut a little harder than usual - smoke started rolling out the front corner where the air intake to PM is

I opened up module to find it quite toasted inside & had to replace it
 

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Discussion Starter · #3 ·
thats what mine did,it smoked,but why would it blow after changing a timing belt?:confused:Before condeming it,I checked voltage at the LM,it was good,I checked for signal from the power module to the coil,and nothing.Like i said,when I turn the key,no sound from the fuel pump(it wont energize),no injector pulse,no spark.The fusible links are not melted.I opened the power module and found a tiny bit of the gel melted,the burn wire odor seems stronger where the relay is,isnt that the ASD relay?(the black relay that says "Bosch")And do they burn out like that?Also the Power Loss light not coming on when the key on
Anyone have a PM they want to sell?(if thats what it is)
im going to look it over some more tomorrow weather permitting,I really want to make sure again there is nothing else wrong with the wires so I dont fry another PM.
 

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To test your ASD, turn the key on, and ground the black/yellow wire coming off of the diagnostic connector by the vac solenoids, on the pass fenderwell. If the pump kicks on, then the ASD relay is working as it should.
 

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Discussion Starter · #5 ·
To test your ASD, turn the key on, and ground the black/yellow wire coming off of the diagnostic connector by the vac solenoids, on the pass fenderwell. If the pump kicks on, then the ASD relay is working as it should.
ok,thinks,ill try that.And if it doesnt,its fried then,right?Im going to go try it right now
 

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Sounds as if you have a power feed shorted to ground or you lost a ground and the power feeds found an alternate path back to ground which would explain why no fuseable links have burnt.
Chances are since you removed the valve cover it is going to be on or near the injector harness or wires over by the timing belt.
Check all of the power feeds into and out of the PM.
Most of them are constant battery power.
The LM is supplied power from the PM.
Check all of the PM/LM ground wires for continuity to ground and be sure all of your engine grounds are connected/secure.







 

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Discussion Starter · #7 ·
well,i grounded it with the key on and sure enough the pump kicked on :confused:So does this mean its not the power module?But if the relay didnt fry,what did?
 

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When you ground the DB/YL wire in the diagnostic connector with the key on/engine off you are bypassing the LM which controls the ground side of the ASD relay, it only verifies that the ASD circuit is operational.
To see if the ASD is actually being actuated by the controller check for power at the + coil while cranking the engine without the diag connector being grounded.
 

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Discussion Starter · #9 ·
Thanks NAJ,ill check tomorrow.Check grounds with my multimeter?Probe a ground on pm/lm with one lead and the other test lead to another ground,right?Or to the battery ground?And which power feeds should i check?
 

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Discussion Starter · #10 ·
When you ground the DB/YL wire in the diagnostic connector with the key on/engine off you are bypassing the LM which controls the ground side of the ASD relay, it only verifies that the ASD circuit is operational.
To see if the ASD is actually being actuated by the controller check for power at the + coil while cranking the engine without the diag connector being grounded.
ok,ill go do that right now.:thumb:
 

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Discussion Starter · #11 ·
ok,tried it with a test light while cranking the engine,and got nothing,tried with my multimeter read nothing,no power at all =\
 

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That means the controller is not seeing a crank signal from the HEP.
The ASD is actuated for 1 second with initial key on to pressurize the fuel rail and the controller will not actuate it again until it see's a crank signal from the HEP.
With the key on see if you have 8 volts present at the OR wires at the HEP connectors.
 

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Discussion Starter · #13 ·
Well,I checked the HEP OR wires and nope,no voltage at all.I also made another discovery.The connector at the end of the HEP itself was barely hanging by one wire(the black connector)
 

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Start by checking all of the power inputs to the PM, power outputs at the PM, inputs to the LM and outputs at the LM and grounds at the LM/PM.
Since this all started after the valve cover/timing belt were removed/replaced and the CEL/power loss lamp are inop I would double check the harness in those areas to be sure you did not pinch a wire under the valve cover or damage/disconnect a wire in those areas.
To check the grounds use your ohmmeter connected to - battery or a body ground and probe the ground wire, you should have continuity.
Power feeds into PM.
10 Pin connector cavities 2,3,4
Power outputs from PM.
12 Pin connector cavities 6,12(8 volt output)
Power feeds into LM
Red connector cavities 7,8,23(8 volt input)
Blue connector cavities 2
Power outputs from LM
Red connector cavities 1(5 volts)
Blue connector cavities 1(5 volts)

Grounds
PM 10 Pin connector cavities 9,10
LM Red connector cavities 24,25
 

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Discussion Starter · #15 ·
ok,did some checking,heres my results

all grounds checked out good(continuity)

LM

Blue Connector
cavity 2 -12V
Red Connector
cavities
7:12volts
23:1Volt(?)
8:(not used)
Power Module
10 pin

cavities
2-12V
3-0v(?)
4-12V

12 pin

6-12V
12-0v(?)

Didnt check the LM outputs,will do that in a bit,just taking a break.Wondering why I have 1.3 v on 12pin cavity 12,0volts on 10pin cavity 3
 

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From what I am seeing you lost your "Fused J2 Power" Input to the PM at the 10 Pin Connector Cavitiy #3.
You also lost your 8 Volt Output from the PM 12 Pin Cavity #12 to LM Red Connector Cavity #23.
That is why you do not have 8 volts present at the OR Hep wires.

Start by finding out why you lost the fused power input to the PM.
It comes from the battery thru a fusable link and you will find that the fuseable link is melted.

Sending you a PM.
 

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Discussion Starter · #17 ·
From what I am seeing you lost your "Fused J2 Power" Input to the PM at the 10 Pin Connector Cavitiy #3.
You also lost your 8 Volt Output from the PM 12 Pin Cavity #12 to LM Red Connector Cavity #23.
That is why you do not have 8 volts present at the OR Hep wires.

Start by finding out why you lost the fused power input to the PM.
It comes from the battery thru a fusable link and you will find that the fuseable link is melted.

Sending you a PM.
yeah,looks that way,I got your diagrams,looks like ill be tearing into some wires thanks!:thumb:
I was able to solder the HEP wires back together this morning.Where exactly is the location of these 2 fusible links?
 

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Not sure on the older cars but on my car they are all together in a bunch near the battery.
If you noticed in the diagram the fusable link you are looking for is down the harness.

It starts at the + battery BK wire, changes to RD, then comes to a large splice where all of the fusable links are tied in.
Then the OR fusable link to another splice with a RD and PK fusable link.
It is that PK fusable link you are looking for.

Remember that the fusable link burnt because of excess amperage flow which brings you back to your original issue, a wire shorted to ground.
 

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Discussion Starter · #19 ·
Well,i tore into the wiring,and none of the fusible links look melted,i didnt get a chance to tear into the wiring on the passenger side .tomorrow im going to check the wires under the dash ,behind the glove box(the harness to the LM) and the harness goes below the PS pump,im going to check it all.
 

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You probably will not see the burnt link, you have to feel it.
They are designed to melt internally without damaging the insulation.
The link will not be solid, it will feel rubbery if it is burnt.
Use your test lamp and test for power on both sides.
 
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