no spark or fuel unless B+ and FP are jumped

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4camSC

New Member
Messages
3
Hi ya'll,
I've got a '97 sc400 that I swapped the engine from a 94 LS400. I swapped the engine to OBDII with the sensors/wire harness/cams etc. from the newer engine. After getting it together I could not start it. Upon closer examination, I found no spark, check engine light on the on position, or fuel. I then tested my FP with 12 V and it worked fine. Before I swapped it, it ran (sort of, due to the previous owners abuse). I thought it was the ECU after checking the cam and crank sensors and the ignitor's ground. Well, after further research I put power to the B+ pin and to the FP and managed to get it to run (roughly).

Any thoughts on why the fuel pump and the ECU won't come on unless jumped?
 

gloverman

Well-Known Member
Messages
3,056
Location
Hamilton. New Zealand
Are the connectors beside the fuse box plugged in tightly? Are the connectors on to the ecu in good condition? I had one the other day where one pin on the ecu plug wasnt tight causing and issue. Fortunately a quick test found it. Do you have connection with the OBD2 port for live data?
 

4camSC

New Member
Messages
3
I have checked the connectors several times, however the wire harness is slightly cooked so that is no guarantee. I believe that the connectors to the ecu are good because I have checked them and the problem happened before I even touched the ecu. The OBDII reader says the there is no communication with the ecu, and the check engine light only comes on intermittently when I crank it with +B jumped. Could the problem be a EFI main relay? When I turn on the ignition switch, power goes to the 40A fuse in the kick panel and then I can hear the EFI relay in the under hood fuse box click, but power does not go to the ecu. Just for grins I replaced the 40A fuse because it was corroded, but nothing changed. By the way, I bought another ecu thinking it was the capacitors at fault, but it changed nothing.

Thanks for helping.
 
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