Swapped Jeep 4.0 with crate motor. Will crank, wont start.

Asked by Jan 17, 2015 at 04:27 PM about the 2004 Jeep Grand Cherokee Laredo

Question type: Maintenance & Repair

I made sure the cam position sensor was aligned to #1 at top dead center.  The fuel
pump isn't getting power, I checked with a meter.  It turns on with a jumper in the relay
socket.  It will not start with the jumper in place.  Which also means no spark.  Why am I
not getting either?

2 Answers


it sounds like you might have either damaged the crank sensor or you don't have the cam sensor in right ...the spark and fuel is determined by the crank sensor the cam sensor is just there to ensure it is going to the right place ...the engine will run with the cam sensor disconnected it will just use a default setting for fuel strategy....do you have a scan tool to see if the crank signal is present ??

1 of 1 people found this helpful.
Best Answer Mark helpful

Finally had time to troubleshoot the crank signal. I don't have a scan tool, so I used a meter to see what I could find. I found a very important ground I missed connecting to the engine block. Crate motor runs great!

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