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Excessive Cranking Fuel Pressure / Difficult Starting Hot

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Mopar1973Man

By Mopar1973Man

Excessive Cranking Fuel Pressure / Difficult Starting Hot

The hard starting problem is caused by a Bosch VP44 injection pump with a damaged diaphragm internally. A torn diaphragm is typically caused from a Bosch VP44 injection pump that was operated at below 10 PSI for an extended period of time. So technically you should replace the Bosch VP44 injection pump to repair the damaged diaphragm but most rig up an oil pressure switch or a starter delay relay.

Since Revision 027 the Bosch VP44 Injection pump has not had a rubber diaphragm. So the other reason that woul cause hard starting is excessing cranking fuel pressure. So this little mod will turn of the lift pump dring cranking to ease starting the engine.

Here is my idea...

lift-pump-delay.jpg.a13188c3f9e7bbc301c0

This will cause the lift pump to remain off during the period of timing the starter is operating as soon as the key is released the lift pump will function normally and remain controlled by the ECM.

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