Mopar friends, I need your assistance.

'68cuda416

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Today has been a **** day.

This automotive problem has been ongoing, so I am going to use it to distract from my other issues of the day.

The vehicle: 1994 ram 3.9 v6, 5 speed. A billion miles. Bone stock except for a gutted cat.

This truck runs GREAT until it gets thoroughly warm. Then when you shut it off and go to restart, it's flooded. When driving it doesn't really act up that I've noticed, but park it and let it heat soak, and it's flooded. You have to hold the throttle WOT, and then it'll clear out but if you don't get moving...... glug glug

All 6 plugs come out BLACK and it'll stink my whole yard with fuel vapor. Doesn't smoke until it floods, and then it smoked black. Idle is great until it's Noah Time.

New plugs didn't fix it, cap and rotor are new, tried another coil, the previous owner replaced all manner of sensor with factory ones. He even replaced fuel pump (I got 40 psi when it's flooded, didn't try when it would run).

I can't even figure out any codes. No CEL.

The clean idle and lack of smoke tell me that the plenum gasket is probably ok. There's no downstream o2, since it's obd1.

Any advice on a magnum efi that floods when hot?
Been a long time since I had to work on vehicles of this vintage but it appears and you could verify that the fuel pressure regulator is attached to the rear of the throttle body? If so disconnect the vacuum hose from it and smell inside it for gas or easier yet if gas comes out then it obviously needs replaced.....when it starts to act up really bad you again should pull the hose off and look for signs of gas.....someone else made that recommendation and it is very valid and also very easy to check if bad.
 

6pak

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I put a 195 in the 02 Ram 5.9 I had.. Napa Perscribed. Went back to a 180. Just to hot for mid south Fla. Didn't notice any adverse affects, just the temp a Lil lower!
OP stated OBD I. I’m sure these behave differently.

But - to figure this out , You would have to monitor real time w a scan tool. - Something will be out of whack. If not, something the old OBD I doesn’t monitor.
 

jos51700

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So I did the key flip for the codes, and zero codes present. Fuel pressure is 40 psi at cranking. Where the hell do I get a scan tool for this thing? I don't see an OBD connector anywhere?
 

TT5.9mag

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What does the fuel pressure do after you stop cranking? Does it drop rapidly or hold for a bit?
 

jos51700

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An update:
Re tested fuel pressure, 45 psi and held it for twenty minutes after shut off.
Borrowed a scanner from a friend and everything was norma... Hey why's that coolant temp sensor reading -4 degC when it's 85 degF out? I already had the sensor think that might be the issue so I replaced it and........ Sold the truck.
But! That seems to have resolved it, and I kinda didn't want to sell it after driving it and not having problems!

If you have an efi Ram that floods, the coolant temp sensor is a cheap easy place to start. Install takes less than five minutes if you have a 1/2" deep well socket
 

408 swinger

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I had to go back and read what I struck out on! Lol. Just tryna help. Glad ya got it.
 
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