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Another Rn + 20G, My 'build' Thread


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Yeah! It's still knocking. Although this time it's barely audible; you have to strain to hear it with your ear basically on the block. I figure I'll sand it again when I change the break in oil.

In other news I blew an intercooler hose about a mile from my house and now the car won't start. I love my car so much!

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So I ran an XRAM dump and found the following two error codes:

O: xerflg6.1 error continuous positive

O: xerflg6.3 error reference mark sensor

The only problem is I don't know what a reference mark sensor is. I checked resistance between #A6 and #A20 (crank sensor) and found 330ohms, which is correct. So I'm guessing it's my cam sensor.

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Damn!

I've always looked at the cam sensor as nothing more than a reference for the ECU for cam phase. That's my assumption for its function, anyways.... So in my mind it is the most likely candidate for that error ... But it's coincidental failure is certainly suspect

Good luck

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It was the cam sensor. I had 4 extras, 3 of which were bad (why did I even keep them? :arob: )

Took it out for another test drive, popped a different intercooler hose and now no spark again. I didn't have my computer with me so I couldn't run diagnostics, but I'm going to guess it is another cam sensor. WTF?

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I still do not understand how these cam sensors fail on these cars. Around here, it jut seems to be accepted as a fact of life. That's not good enough for me.

I have had similar sensors fail due to prolonged oil contamination and eventual collapse of the supporting plastic for the permanent magnet... That I get. But to have 3 out of 4 "bad" sensors laying around sounds really suspect to me.

Were they all used sensors? High mileage?

What is the failure mode and WHY?


I still can't make sense of how the cam sensors themselves seem to just fail on m4.x


What were the conditions when the car failed?

Edited by mattwebb502
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The hoses popped because of boost, the first one was at 10psi and the second was at 16psi. I think it's just coincidence that the cam sensor failed when the hose popped. I've been through probably 8 sensors on this car.

They have all been used except for one which I returned shortly afterwards purchasing because it was $120. I think they're robust, until removed from the car. I once got one from an 850 with 180,000 miles, only to fail after 3 start attempts.

It is only a 3 wire hall sensor, so it shouldn't be that susceptible to failure, but I've never looked into fixing one since I can get them for $3 at the junkyard.

The newer style, all metal housing sensor is much more robust, at least in my experience.

I plan on grabbing a handful tomorrow.

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I still do not understand how these cam sensors fail on these cars. Around here, it jut seems to be accepted as a fact of life. That's not good enough for me.

Most of the time when you read about a sensor failing, its due to it being on a higher mileage vehicle, or from being knocked around, or getting moisture/oil in it when taking it off to work on something. These cars are almost 20yo and a majority of them that have these sensors fail are probably the originals. Old parts with 150k+ miles wear out and break. It is kinda accepted as a fact of life, around here. And that logic is good enough for me. It seems to me a lot of stuff around here is not good enough in your opinion...

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It seems to me a lot of stuff around here is not good enough in your opinion...

Sorry I meant no offense. I have become addicted to these forums and value them for the resource that they are.

What I was getting at was that it might be good to take a more critical look sometimes than it is to just operate on the conventional wisdom. I get that the sensors fail at high mileage (for some reason), and I was unaware that all of these failures he has had were from high mileage junkyard units. This latest round of coincidence is pretty suspect in my eyes, that's all.

What I mean when I say that the conventional wisdom is "not good enough for me" is that I like to find the root cause with my own eyes -- and especially after so many failed sensors.

If/when I have a failed sensor on either of my cars you can bet that I'll do a meticulous tear down and inspection on the bench. But that's just me -- I get some enjoyment in the challenge of a diagnosis and the hunt for a culprit.

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When shopping your local JY for used cam sensors always look for the newer style sensors which are less prone to fail....

Old style....

New style....

The newer style, all metal housing sensor is much more robust, at least in my experience.

Not to mention, the old ones are a PITA to remove. They're almost a press fit.

I picked up 2 of the new style ones today, and what do you know? It was a bad cam sensor. For now I'm gonna say its a crazy coincidence between popping an intercooler hose and destroying a cam sensor. But if it happens again, time to start investigating.

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The%20purps.jpg

Hit 50 miles today and changed out the break in oil. Oil was very clean, no ferrous material. The only bummer about Royal Purple is how dark it is...

I chose the HPS since it is API-SN (E85 compatible) and has over 1200ppm of zinc.

Comparison.jpg

Pretty drastic difference between the wheels. The new wheel has a taller exducer which acts as slight increase in exducer diameter. If you look at the bottom of both wheels you can see the inducer tips are extended on the new wheel. Also, the hub bore is smaller.

Suffice to say, the new turbo is great! I have a conservative starting tune at 20psi now and have not encountered any surge. Seat of the pants feel tells me its as fast as it ever was before, although running 6 psi less pressure.

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