Hemi Heart Attack

Just started the Hemi for the first time since September and it fired right up. Bad news I looked and saw 0 oil pressure! I run both the factory gauge and autometer electric. I run the autometer oil and AF gauge off the acc on the fuse box. Took wire off checked inline fuse reinstalled it and good news fixed the problem. 75psi. and AF working. I run msd so starting wasn't involved with problem.

The fuse was good so do you think it was just the connection?

Or

Do you think I have an ignition switch or wiring problem? Or is this a wait and see? This is on factory wired Cuda.


Thanks, Mike

I would pull the distributor and use a drill to prelube the engine.
Without having a mechanical gauge who knows if it's actually building pressure.

Even without a mechanical gauge you can usually tell that it's building oil pressure when the drill gets a load
on it when it's pumping oil.

No load, it's not pumping oil.

Considering the investment (presumed to be significant because it's a Hemi) I would install manual oil pressure gauge and maybe even a low oil pressure light or audible alarm. Food for thought.

Put a 'T' fitting coming out of the block so that you ad a sender along with an LED flashing light somewhere in sight of the driver. I do that on all my cars. You can pick a sender that has 15lb or 20lb trigger point which is better than 4lb or 5lb. The little LED is very bright, fits about anywhere, is available everywhere, and is cheap.

The first time I primed my 340, it was already in the car. I didn't know what to expect and really wasn't paying attention. When it started to pump oil, it spun that drill around and pinched my hand against the firewall. You will absolutely know if it's pumping oil or not.

If your using a Milodon pump, that is not uncommon. Which pump you using?

Melling HV pump. It has always had instant pressure. Oil pressure wasn't the problem is was a no voltage problem. I didn't even think to notice the AF gauge didn't light up when I turned the key on. I can use it as my warning light. I'll try and remember to always look to make sure it's on before starting in the future.So far I haven't been able to produce the no voltage problem.

Check your electrical connectors for corrosion
Condensation and temperature changes caused that from the moisture condensing on the unprotected wire ends and slide in connections
Murphy loves us hot rodders

I was thinking there had to be a bad connection in the bulk head or column since the oil gauges are on separate feed wires. The 1 is on the factory dash harness & the other is on the accessory spade on fuse box. Am I right to think that the feed to the acc. spade and the switched side of the dash fuse are the same???

That would explain way neither gauge worked.

Thanks Mike

I have no idea on that fuse and those two circuits, it should be easy to figure out with a volt ohm meter
Check both first for voltage and then pull the fuse to see if it kills one or both

Follow up the fuse box feeds off 2 separate buss bar's. The 1 on left feeds the left side of box and left side of fuses and is constant 12 volts. The 1 on the right feeds the right side of box and fuses and is switched on during run or accessories. The dash feeds off instr fuse and the acc. terminal feeds off the acc fuse.

So while they were on different fuses the feed to the fuses was the same. The problem was caused by either a poor connection on bulk head or switch.

Isn't amazing what we can do when we set our minds to it