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No spark signal #2 and #3 HELP!


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Ok folks- here is a diagnostic puzzle for ya...

 

2005 EJ255. Pulled from a running LGT that had one slightly burned valve- but ran pretty well considering. Did a refresh on it with new pistons, rings, bearings, gaskets, timing, etc. I've done this a dozen times before so nothing new.

 

Put motor back in car and would not start. Found no spark signal to cylinders 2&3. Coil packs, plugs, injectors all working fine. Plenty of fuel but no spark signal. Coil packs and plugs worked fine on the other cylinder leads. Pulled cover from harness and traced wires back to main plug- all good.

 

Pulled and swapped entire intake manifold and harness from another running car. Same issue as above but later found a mouse nest in the interior of the car. Figured it was not worth the effort to replace and parted out the shell and kept motor.

 

Installed same motor in an 2005 OBXT. (BTW- the intake and harness removed initially are now on a running car so wiring was definitely not the issue...). SO, same thing AGAIN. Exactly.

 

Did the same diagnostics again but this time also did compression test. Cold, never-run-with-new-rings-engine but all cylinders within 4 PSI. No CEL codes so I pulled the connections from the crank position sensor- instant code. Same for cam position sensor passenger side (did not move on to the drivers side as I was frustrated and have big hands)

 

So this leads me to believe the lack of signal is from a sensor on the original longblock. But the question is- can a sensor be bad and not throw a code? Since a cylinder is not sparking on each side would this point to the crank sensor? Remember- this engine ran fine before the refresh.

 

I have swapped a crank sensor from a known running engine but don't have it back together yet to try it. Also, timing is dead on and crank sprocket has all the teeth.

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  • 4 months later...

Wonder why none of us was this back then.

 

Checking timing is usually what we would say.

 

Glad you got it fixed.

 

Thought I saw a picture somewhere today about a pushed in pin.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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