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3800sc swap-strange problem by Lou6t4gto
Started on: 11-19-2018 11:32 PM
Replies: 20 (303 views)
Last post by: Lou6t4gto on 12-01-2018 08:31 PM
Lou6t4gto
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Report this Post11-19-2018 11:32 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

1999 GP 3800sc into 1986 gt. car will start and run well, BUT, I have to "crank it" about 6 times before it will fire up. > As soon as the battery is connected, the fuel pump is" running non stop" ( Key not even on). you can hear the fuel flowing through the lines . once the car starts, it runs fine. shut off the key and the fuel pump still keeps running till the battery is disconnected ! WHY ??? I have 3 -3800sc conversions, and this car is the only one with "this problem". Any ideas ?

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olejoedad
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Report this Post11-20-2018 07:19 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post

Does it use the oil pressure sender with the fuel pump relay backup circuit?

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Gall757
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Report this Post11-20-2018 10:05 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

It sounds like somebody put a jumper on the ALDL connector and left it there.

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darbysan
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Report this Post11-20-2018 10:18 AM Click Here to See the Profile for darbysanClick Here to Email darbysanSend a Private Message to darbysanEdit/Delete MessageReply w/QuoteDirect Link to This Post

I would check the Fuel Pump relay to see if the contacts are stuck in the closed position. Easy to swap in another relay. If it's not that, then most likely a miswire in the harness. As for hard start, might be the engine is getting flooded because of the fuel pump issue. If that doesn't clear it up, don't know....

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Lou6t4gto
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Report this Post11-20-2018 03:07 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

"Does it use the oil pressure sender with the fuel pump relay backup circuit?"

YES. I was wondering about the oil sender, seems like it won't start until the oil pressure comes up. then runs fine

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Lou6t4gto
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Report this Post11-20-2018 04:29 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

tried removing the relay, the pump stopped, BUT Now with the relay connected, even a new one , the pump no longer comes on At All !

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Lou6t4gto
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Report this Post11-20-2018 04:51 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

it is hot (orange black wire) at both the oil sender and relay ! which wires get jumped at the aldl ??? thanks

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Lou6t4gto
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Report this Post11-20-2018 04:54 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

Oh, there are NO blown Fuses

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Lou6t4gto
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Report this Post11-20-2018 06:36 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

well back to square 1 ! the reason it "stopped working" was the 203 PLUG was" loose".
SO..... now the pump runs WITHOUT the key on (whenever the battery is connected). The Only way to "shut off" the pump is to pull the plug on the" oil sender unit" ! BUT the pump will not come on, no way, if you turn the key on, unless the oil sender is plugged in, and then it won't shut off !

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Spoon
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Report this Post11-20-2018 10:59 PM Click Here to See the Profile for SpoonSend a Private Message to SpoonEdit/Delete MessageReply w/QuoteDirect Link to This Post

Could it be a bad oil pressure sender? Sounds like it's stuck in the energized position keeping the fuel pump running. Or it's not dissipating the oil pressure (or what it thinks is oil pressure) due to a clogged or partially clogged port in the sender.

Does your oil pressure gauge respond in-step with varying throttle positions or is it sluggish? If sluggish this could indicate a port blockage in the sender.
Stuck contacts in the sender will give same results as above. Swap out the sender from one of your other conversions and try it.

Just my 2 cents...

Spoon

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Lou6t4gto
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Report this Post11-21-2018 12:21 AM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

OK, I'll get another sender, but the gauge does work. and, Why would the pump NOT work "from the relay" even with the oil sender disconnected ???

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olejoedad
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Report this Post11-21-2018 09:06 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post

It sounds like the relay is bad (will not turn on) and that the oil pressure sending unit (oil pressure switch stuck on) is bad.

If car has A/C, swap the A/C relay with the fuel pump relay, disconnect oil pressure sender and see if the fuel pump works as it should.

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Lou6t4gto
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Report this Post11-22-2018 03:38 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

Now, I've discovered that the IAC is also "Powered" with the Key OFF ! I really hope I don't have to pull the engine to pull the harness to check every wire !
is there any way the ign switch or "something else" can cause this ?

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Spoon
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Report this Post11-28-2018 12:20 AM Click Here to See the Profile for SpoonSend a Private Message to SpoonEdit/Delete MessageReply w/QuoteDirect Link to This Post

Shouldn't have to pull engine to check harness. For starters pull connectors from ECM and IAC and use a multimeter to check continuity pin to pin. If 1 pin is not in the right hole that means there are 2 errors and so on. Have a good magnifying glass and plenty of light.

Spoon

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Dennis LaGrua
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Report this Post11-28-2018 08:51 AM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post

If there is a short or open connection somewhere here is the easiest way to find it. Disconnect positive battery terminal . Now put a test lamp between the + battery terminal and the battery cable terminal. If the light is on it indicates that a circuit is energized. Now go to your fuse box and pull out each fuse one at a time and watch the light. If the light goes out ,that circuit is energized and it then must be decided if it should be or if that is a drain from a short.
Getting back to why your fuel pump won't energize; wrong relay, broken connection or bad relay as Joe has suggested.

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Lou6t4gto
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Report this Post11-28-2018 02:15 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

at the relay, Tried 4 different relays, no difference. there are 2 wires HOT going INTO the relay. ORANGE/BLACK,, and another one. I will check with a light and the fuse box. the ONLY wire that is HOT with the Key OFF is the" oil sender", I was Mistaken about the IAC,(the key Was On). have not checked with the Light yet.

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olejoedad
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Report this Post11-28-2018 02:21 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post

Your harness has some mistakes in it.

[This message has been edited by olejoedad (edited 11-28-2018).]

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Lou6t4gto
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Report this Post11-28-2018 02:36 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

well damn, I checked it 4 times BEFORE" installing" it !

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olejoedad
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Report this Post11-28-2018 06:15 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post

Did you make the harness or buy it ready to install?

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Lou6t4gto
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Report this Post11-28-2018 10:54 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

made it, my others work fine.

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Lou6t4gto
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Report this Post12-01-2018 08:31 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

OK, Was Not my harness, was the ground wire for the relay was broken internally ! Ran a new ground, and all is now well.

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