Code P1579 on replacement engine...

[Byron in Atlanta]

I replaced 3.2 engine in my '02 Boxster S with a used 3.2 from the same model year and just got it running and everything seemed in order during my first test runs. Initially, I was not pushing the engine to make sure everything was connected right and all seemed in order. This weekend I tried to open it up a little bit and discovered that the engine cuts out at about 4000 RPM. It starts spitting and sputtering and will not rev to 5000. The symptoms reminded me of bad MAF's I suffered in the past. I checked the codes and it showed a P1579 or Crankshaft Position Sensor. I cleared the code and so long as I keep the RPM's under 4000 it stays clear. The engine runs perfectly up to 4K, is highly responsive and smooth. I can hold the accelerator at 4K and it runs fine, push to 4200 and the spitting starts. If I push it hard trying to achieve 5000RPM, it throws the P1579 code.

I replaced the Crankshaft Position Sensor with the one from my blown engine. That engine was running perfectly until it threw a rod through the top of the case. Same result, spitting and sputtering at 4200 RPM. I then took out the MAF sensor and cleaned and reinstalled it. FYI, that MAF is less than a year old and probably has fewer than 5000 miles on it. It is the one that was in the car when the engine blew, and as I previously stated, it was running fine. I tired running the engine with the MAF disconnected. It still would not rev to 5000 with the spitting starting around the same RPM's. I checked the codes after that run and had P0102 (MAF input) and P1579.

A bit more info, I upgraded the IMS bearing to the LN Engineering, and upgraded the flywheel to the Aasco aluminum version with a new SPEC clutch disk and pressure plate. I am at a loss. HELP

[Loren]

P1579 Crankshaft Position Sensor

Possible causes:

– Loose contact

– Connector corroded

– Steel toothed ring damaged

Did you use the same flywheel? If so, look for damage to flywheel.

Did you follow the wiring back looking for damage?

P0102 Mass Air Flow Sensor – Below Limit

Possible causes:

– Open circuit

– Short circuit to ground

– Mass air flow sensor

Most common cause of this fault is that the MAF is not connected.

The car won't run right above 4000 RPM without the MAF working properly.

[JFP in PA]

As the crank position sensor reads from a shutter wheel behind the flywheel, and you have a new aftermarket flywheel, I'd start there. Perhaps you should contact the manufacturer.

Edited January 30, 2011 by JFP in PA

[Byron in Atlanta]

that is exactly what I was hoping it was not, the shutter wheel on the flywheel. Was hoping to get by without having to drop the tranny. The crankshaft does have a dowel pin that sticks out to align the flywheel so I think it is timed to the crank correctly. I am suspecting either a wrong flywheel or a bent tooth on the shutter wheel. Going to check the wiring to the CPS before I dive back in with trans removal! Also, writing to Aasco to see if there is a known issue and/or fix?

[JFP in PA]

Byron, I’d first be dead certain that the sensor and wiring harness are working correctly before yanking the gearbox back out.

[Byron in Atlanta]

Found the problem...It seems the vendor that I bought the Aasco flywheel from either sent me the wrong unit, or it was damaged in shipping. Either way, here is a pic of the damage it is doing to the Crankshaft Position Sensor. Looks like the shutter wheel teeth are making contact with the sensor. It is gouged pretty good. So out comes the tranny! YEA!

[JFP in PA]

Ouch! I’ve never cared for solid lightweight flywheels for other reasons, this just adds one more reason………..