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Malibu fuel pump stays on


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Hi new to the forum and to the Malibu club. Here’s some issues I’m having I bought an 04 Malibu sunsetter with the hammerhead 380 and it had a small bilge pump fire and now I’m trying to get it back to running and the issue I’m having is the fuel pump kicks on and stays on, and the next issue is I replaced the crankshaft position sensor and can’t find any pigtails to plug it in. Everything else is working good all electronics are fine. 

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Posted (edited)

welcome to the crew.

this wiring diagram may help.

those relays are under an 8" x10"(ish) protective shield above the transmission.

all relays are alike (fuel pump, ign, starter).

for future issues note that the 3 fuses are located under that cover, also.  they are in a very automotive connector looking unit.

if you swap them (relays) around and your problem moves to another area then that is likely your issue.

Edited by tvano
esl
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I assume you have already gone through all the wiring that was anywhere near the fire to make sure that the insulation didn't melt and you have 2 wires contacting each other in a bundle?

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Thanks for the help guys, yes I did go through all the wires, the fire was contained to only the rear so the engine is all perfect and the front where the ecm and relays are is good too, I checked all the relays they seem to be working clicking like they should I swapped them around too and no issues, I’m gonna recheck the whole harness for any wire chafing if that could’ve possibly happened, I had all the injectors tested and cleaned so they’re all working properly 

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4 hours ago, tvano said:

welcome to the crew.

this wiring diagram may help.

those relays are under an 8" x10"(ish) protective shield above the transmission.

all relays are alike (fuel pump, ign, starter).

for future issues note that the 3 fuses are located under that cover, also.  they are in a very automotive connector looking unit.

if you swap them around and your problem moves to another area then that is likely your issue.

Thanks a lot for this!! I think it’ll help a lot I’m gonna go in and start messing around some more, anyone have a picture of where the crankshaft position sensor wire goes? Mine got melted and i dont know if there was even a plug in there

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The fuel pump may stay on if the ECM thinks that the oil pressure is high enough.  Check to see if the oil pressure sensor is working correctly.  Note that you have two sensors; one for the ECM and one for the dash.

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So I went through all the wires all intact, I’m thinking the ecm might just be bad, how can I test the oil pressure sensors? And does anyone know if the hammerhead 380 had a crank position sensor? Mine was burned but looked like no plug was in it

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1 hour ago, Dan04 said:

So I went through all the wires all intact, I’m thinking the ecm might just be bad, how can I test the oil pressure sensors? And does anyone know if the hammerhead 380 had a crank position sensor? Mine was burned but looked like no plug was in it

If the ECM didn't get cooked, it is probably good.  A bad connection somewhere makes much more sense.  The ECM pressure sensor is just a switch as I recall, so you should be able to put a meter on it.

I'm not familiar with that engine, so I can't answer about the crank sensor.  @COOP or @csleaver might decide to chime in here for you.

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If any of you are in the western mass Area I’d love for someone to come help I’ll pay whatever just want to get it running good, I’d rather do that than keep throwing new parts at it with no result 

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I also have a 99 mastercraft that needs a new engine due to improper winterization willing to get rid of not free but a good deal if anyone’s interested 

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I came to the conclusion for the crank sensor that it’s there just for the oil not to leak out. There’s no wires for it in the plugs for the ecm

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electricjohn

My '04 Monsoon does not use a crankshaft position sensor.  AFAIK, the devices that enable the fuel pump after key-up is a crank signal on ECM terminal J1-15, or a distributor reference signal on terminals J2-15, 31, & 32. Oil pressure switch only sounds alarm (and may enable limp mode).

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15 minutes ago, electricjohn said:

My '04 Monsoon does not use a crankshaft position sensor.  AFAIK, the devices that enable the fuel pump after key-up is a crank signal on ECM terminal J1-15, or a distributor reference signal on terminals J2-15, 31, & 32. Oil pressure switch only sounds alarm (and may enable limp mode).

So that leads me to the ignition module, I took it off yesterday and checked it, will test it today, I got another one I’ll try out see if that changes anything 

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Another thing I was wondering can the fuel pump be stuck open?

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43 minutes ago, Dan04 said:

Another thing I was wondering can the fuel pump be stuck open?

I just assumed that it runs the whole time. If the fuel rails have sufficient pressure it should work. You can verify fuel pressure by having a local auto parts place lend you a gauge set. They want a deposit, but refund that when you return the unit.

Is the engine cranking but not starting?

Steve B.

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I have a fuel pressure tester, the fuel pump just keeps dumping fuel with key in second position when it should shut off after a few seconds mine doesn’t, it locks the motor up with fuel

13 minutes ago, Steve B. said:

I just assumed that it runs the whole time. If the fuel rails have sufficient pressure it should work. You can verify fuel pressure by having a local auto parts place lend you a gauge set. They want a deposit, but refund that when you return the unit.

Is the engine cranking but not starting?

Steve B.

 

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15 minutes ago, Steve B. said:

I just assumed that it runs the whole time. If the fuel rails have sufficient pressure it should work. You can verify fuel pressure by having a local auto parts place lend you a gauge set. They want a deposit, but refund that when you return the unit.

Is the engine cranking but not starting?

Steve B.

Also I pulled all the spark plugs out because there’s so much fuel everywhere I don’t want it sparking. The engine cranks without hesitation

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I never got it running yet due to the fuel filling the entire engine and cylinders til it dumps out the throttle body

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imho if you are filling the chambers and running fuel out of the throttle body you have one or more stuck (open) injectors.

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