Vmac iii engine brake.

[mackrmodel686st]

Im sure this topic has been brought up before, but doing a search doesn't bring anything up. So here goes. 2001 vmac iii 427. Engine brake only works on the first stage. Had the second stage working for a day, then cut out again. Does anyone know which head the second stage is on? I'm thinking the problem is in the wiring to the valve cover spacer. Thanks. 

[Adkat]

You can test it with the engine running, put a + jump wire to the pin at the cover spacer and see what each head is doing. 

If they both work, your issue is in the loom or switch. If one doesn't fire you'll have to open up the valve covers and dig a little deeper. Could be solenoid or broken wire.

[Joey Mack]

Rear head.  AdKat is right 

[mackrmodel686st]

AdKat, that is the plan. I just didn't know which head was which. I know both solenoids were good 6 months ago when we had the heads off the truck as I checked them myself with a power probe. Had one of the shop guys help me look at it yesterday and it started working when he messed with the wires going to the spacers. Makes me think it's the connector at the spacer on the outside. The plan is to steal a connector from a parts truck and try it again, just didn't know which head the second stage is on. Thanks. 

[Joey Mack]

You could just unplug the wires from the spacer, hook a test light to the wire, get the engine temp above 150, and then use the engine brake while sitting in the shop. Test each plug on low and high setting..  easy breezy

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