Timing and/or Oil Pressure Problem

[Beams]

Good evening,

Working on a 1965 Dart with a 225 from 1974, has an Autolite 2100 on top, with electronic ignition conversion done by previous owner.

I’ve been dealing with some long-standing starting issues that I’ve had with my car generally being: no start and backfiring through carb, or just hard starting. Car usually runs okay once started, but will oftentimes die (seems like vapor lock).

Using a timing light, I adjusted initial timing to about 12 BTDC based on the motor’s behavior (rpms, bogging, etc.). Car is starting well at the moment, sounds pretty good. Drives much better than prior to the adjustment.

THE NEW ISSUE IS: When driving the car around the block, the oil light started flashing when shifting, or when coming off the throttle. Eventually the light came on more consistently, and would stay on, but sometimes flash with the same rhythm as the motor. No real difference in the oil light if at idle, or driving. At one point, the light came on with only the key ignition, not running.

I started by checking oil—let the car sit, oil looked okay. Looking now for my oil pressure switch, and found the switch with no wire attached. I may be young and dumb, but I imagine there’s no Bluetooth option for oil pressure sending unit. Is this correct?

Could not find another sending unit in a different location like the side of the block. Now I’m wondering if there’s a stray wire somewhere in the dash making contact. Maybe it’s hooked up somewhere that I’m not seeing—either way i can’t tell if it’s bad news or bad coincidence.

Sorry for the paragraphs—just want to get as much info out there to start.

Appreciate your time.

 

[RustyRatRod]

Your wire is there. It's grounding intermittently on something somewhere. That's why the light is coming on. Look all around that area for it. It's there somewhere.

 

[Beams]

Your wire is there. It's grounding intermittently on something somewhere. That's why the light is coming on. Look all around that area for it. It's there somewhere.

Thanks, @RustyRatRod …a lot of typing for the obvious answer, but I think that’s what I was hoping for.

 

[RustyRatRod]

Thanks, @RustyRatRod …a lot of typing for the obvious answer, but I think that’s what I was hoping for.

Once you find it and attach it, the proper operation is for the light to illuminate when the ignition is on and the engine off. Once the engine starts, the light should go out.

 

[Beams]

Once you find it and attach it, the proper operation is for the light to illuminate when the ignition is on and the engine off. Once the engine starts, the light should go out.

Something like this?? Had my daughter-helper in the car verifying the light.

 

[RustyRatRod]

Something like this?? Had my daughter-helper in the car verifying the light.

View attachment 1715777724

Maybe. Have her in the car with the key on engine off and ground that wire quickly and see if she says the oil light comes on. If so, that's it!

 

[Beams]

Maybe. Have her in the car with the key on engine off and ground that wire quickly and see if she says the oil light comes on. If so, that's it!

Yep, that’s the case. Appreciate the help!

 

[RustyRatRod]

Yep, that’s the case. Appreciate the help!

You bet. Put a female spade connector on the end if it's long enough and plug it into the sender!

 

[flingdingo]

Assuming the harness is original, it should be a gray wire.

 

[KosmicKuda]

On my 64 the sending unit is located on the passenger side of the block bear the bell housing area.

You say your engine is a 1974 and obviously the sending unit is now on the oil pump/filter housing.
Maybe the original wire is too short and needs to be extended. As RRR said, the correct connector is like a female spade connector.

 

[Beams]

On my 64 the sending unit is located on the passenger side of the block bear the bell housing area.

You say your engine is a 1974 and obviously the sending unit is now on the oil pump/filter housing.
Maybe the original wire is too short and needs to be extended. As RRR said, the correct connector is like a female spade connector.

The wire is definitely too short, and the spade connector is no longer there. The car started off with a 273, so that could be part of the problem. Shouldn’t be a big ordeal to fix it from here—glad it was an easy find.

 

[Killer6]

Bluetooth option? Lololol! Sorry, that killed Me! Make sure to give the wire a good look over back to the bulkhead connector at the firewall, don't want any more false alarms, in case there's chafing/damage/cracks.

 

[67Dart273]

So far as timing/ backfiring, I would make certain the timing is actually "where you think." I dont know if slant balancers can slip, but the can, do, and have on many other engines. Investigate using a piston stop--which you can make if you can fabricate---to check the factory marks. This is practically the only accurate way to do so. Others have advocated using a balloon to do so, I'm not convinced. Some sort of liquid filld (fill the cylinder) manometer but that would be messy

Next, check all plug wires and coil wire for resistance, and examine them for damage. Also check plugs carefully for breaks in ceramic. You might have an open in the secondary system causing crossfiring because of overly high voltage. Check plugs for gap

Check rotor and cap for damage, for debri and grease/ water/ etc, and CARBON TRACKING type damage.

Backfiring can also be due to an overly lean condition on startup, not enough choke, etc

And it can be due to a valve open. Valve adjustment, valve or valve gear damage, sticking open, burned, etc etc blowing back into manifold

 

[AJ/FormS]

that's always my first go-to with a slanty; valve lash. and in my experience, a tad loose is always better than a tad tight.