99 Pete 379 HELP PLEASE

Best Practices for 99 Pete 379 HELP PLEASE

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ECM connections would be my first guess, given that these have been apart recently.

You say oil pressure is acting up, does the check engine light or gauge drop when jakes are on? If so it probably has an issue with missing oil galley block off plugs in one or both jake heads. Did they test the solenoids on the jake and or re-oring them before putting them back on? And the wire connections to the jakes need to be checked, plus the terminals are tight to the wires. It's easy to over look the galley plugs, Normally you find them stuck to the magnet on the oil drain plug. One other thing the switch's in the dash have those been checked? Truck Shop

Truck Shop said: You say oil pressure is acting up, does the check engine light or gauge drop when jakes are on? If so it probably has an issue with missing oil galley block off plugs in one or both jake heads. Did they test the solenoids on the jake and or re-oring them before putting them back on? And the wire connections to the jakes need to be checked, plus the terminals are tight to the wires. It's easy to over look the galley plugs, Normally you find them stuck to the magnet on the oil drain plug. One other thing the switch's in the dash have those been checked? Truck Shop Click to expand... The oil pressure doesn't drop, nor does the engine light come on. We will test the switches in the dash, he said he check everything and couldn't find anything. He seems to know his stuff pretty well and we have never questioned anything but this. I appreciate your feedback and will bring these things up to him so we are reassured everything is perfect! If not time for a second opinion I assume.

Does this happen with cruise on or off or both? Truck Shop

The cruise doesn't work, the box is messed up.

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Has anyone checked for codes? The cruise and jakes are tied into the ecm. If you had bad connections at ecm- open cuircuts, it should be showing something. The jake wiring under the valve cover are built into the injector wiring harness. The only other switch I can think of is the clutch switch. Truck Shop

Great, thank you! We are going to be going through everything on Friday and will keep yall updated! Hopefully we can figure it out!

60 series Detroits are very common for under valve cover wiring harness failures. What happens ins engine oil gets between the copper and the insulation of the wires, which then wicks all the way down the harness into the ECM, causing an internal ECM issue. I would disconnect the Jakes wires from the injector harness, and test for current output to see if it is a ECM or wiring issue.

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