dtfastbear

I originally posted this in the General section, but realized that was for "non-technical" issues.

I've just installed a new crate LS1 from Crate Engine Depot into my LS1 miata conversion to replace an engine in which I spun a bearing 2 weeks ago. It's the 99-00 vintage. Everything was running fine (well, except the bearing!) on the old engine when I removed it.

The engine cranks but doesn't seem to want to start at all. We pulled a plug and confirmed we're getting no spark. We have plenty of fuel pressure at the rail, but the plugs are completely dry, so it seems the injectors aren't firing.

We're getting a couple strange behaviors:

1) The tach is jumping all over the place when we're cranking the engine, and then ends up sitting at some random RPM after we stop cranking, then it usually drops back to zero.

2) The check engine light is staying on all the time, but SOMETIMES after cranking, we're getting no DTC codes at all.

3) We're occasionally getting a P0335 - Crank Angle sensor. We've tried two different sensors (the known good one off the old motor and the new one that came with the crate motor).

I've confirmed that the reluctor wheel is, indeed, still the 24 tooth wheel. I've inspected the crank sensor connector and wires between the sensor and PCM for damage. Nothing visually stood out, but we haven't checked for connectivity between the sensor plug tips and the connector at the PCM. We did disassemble the sensor connector and verified that connection is good.

I've searched 20 other "cranks but won't start" threads and none have lead to a solution.

Any suggestions?

Cheers,

Dean

NHRA4MULA

iTrader: (29)

you checked the relay in fuse box under the hood right marked ING .. I know it sounds stupid but I have seen the same no spark type condition I believe if the tachs moving its reading cam and crank ....hope this helps

5.3LJimmy

iTrader: (10)

The way you describe the tach jumping leads me to believe the crank sensor signal is screwy. It sounds as though you have covered all the bases except checking continuity back to the PCM. I believe that the injectors will fire without the crank signal as long as they are getting a signal from the cam sensor. This makes me think you may have a combined issue, which is likely a ground connection shared by the injectors and crank sensor.

dtfastbear

Thanks, guys. On the list for tonite are definitely:

- recheck all fuses and relays
- continuity and resistance from Crank sensor to PCM
- recheck all grounds
- check power to injectors and coils

I think you're right - it's going to be #2 or #3 above.

I'll definitely post back here as we eliminate issues and finally SOLVE it!

Cheers,

Dean

O2Form

The rain in spain falls mainly pn the plains.

5.3LJimmy

iTrader: (10)

The OP stated they confirmed it has "no spark".

dtfastbear

We have a winner!! As we were tracing the wires back from the crank sensor to the pcm in order to check continuity, we discovered a wire that had been stretched and cut, I imagine when we pulled the old motor. We repaired that wire and it fired instantly!

Thanks guys. Proves once again that logic eventually prevales.

Cheers,

Dean

5.3LJimmy

iTrader: (10)

Awesome! I'm glad you got it figured out.

O2Form

FANTASTIC!!!! I love happy endings.