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pulled from a boxster with DME 7.8 . i would not expect these to be that much different.
Hey Guys
I was just wondering if any of you have any info on P1397 ( cam sensor bank 2 ) . I am trying to help a buddy T/S this code after rebuilding his 996 3.4 engine.
He hung a scope on the sensor output and we can definitely see the Hall effect sensor activating and deactivating as the cam goes through the field. But the scope is capturing an overlay of both left and right bank Sensors. ( this is how Porsche does it and sends it to the DME on one line ) We were able to find a diagram of what a boxster is supposed to look like but it is way off from our profile.
Was wondering if any of you tech guys have a picture of a profile of what the motronic (5.2.2 I believe as its a 99 3.4 ) looks like for this signal that the DME is expecting . I will also ask on the 996 forum but I know we have a few technical guys on this forum also
Thanks
Last edited by theiceman; Nov 6, 2018 at 11:16 AM.
Reason: bad info corrcected ( Thanks Todd )
the two pics we have what a boxster looks like what we have ( the hall effect profile is above the crank profile ) . As you can see it lookes like something is not right . So we were looking for if anyone has a profile of a M96 7.2 cam sensor profile we can check against
you've got a 996 3.4 engine (ie, 7.2 dme) in a later boxster with a 7.8? if so, then you will get cam issues - the variocam systems are different.
no no no , it was just the only pic we could find on line was one for a boxster with 7.8. I know there are a couple of tech guys on here so just wondered if someone local had a picture like the one I posted of the boxster so we could compare. People at large don't go to this level of troubleshooting I think , they just swap out the sensor and take it to someone if that does not fix it . I thought there may have just been one or two interested parties that wanted to discuss it .
Besides that I would expect the engines at idle to post pretty well the same , as vario cam kicks in off idle.
personally I think its an incompatible replacement or a wiring harness issue . I will move to plan B , wake up the rennlister with a black/black 99 3.4 in Burlington and get him over here for a comparison. I'll probably need to bribe him with food though.
Since my heads are still sitting on a bench, I can pull one and bring it over to see if that makes a difference. Or I can ask my buddy with a 99, to drive over and see what his sensors show on the scope.
i have wiring diagrams for most iterations of 996, so if you can get me part # for the harness being used, and year of the car it is in, i can do some looking. if it is a mismatched harness then it is probably just a matter of moving some pins in the connector.
He ordered a sensor off amazon rather than pay the Porsche tax so I am thinking they are incompatible. That's what I meant by mismatched
Imre, Ed might take you up on that, if you can pop it off let me know and ill take it over to Eds. ( Mark it though so we don't get confused. ) .. just pop it in and se if it fixes it . In our troubleshooting we have established the harness is fine . So its either the sensor of we are off slightly in the timing.
We are borrowing a Durametric on the weekend for further investigative work if we cant get to the bottom of it so yeah we might have to call in your buddy to see what good looks like . I asked Colin to and he offered to help.
He ordered a sensor off amazon rather than pay the Porsche tax so I am thinking they are incompatible. That's what I meant by mismatched
Imre, Ed might take you up on that, if you can pop it off let me know and ill take it over to Eds. ( Mark it though so we don't get confused. ) .. just pop it in and se if it fixes it . In our troubleshooting we have established the harness is fine . So its either the sensor of we are off slightly in the timing.
We are borrowing a Durametric on the weekend for further investigative work if we cant get to the bottom of it so yeah we might have to call in your buddy to see what good looks like . I asked Colin to and he offered to help.
.
Ok, I'll give it a go and see if the sensor comes out of the head.
Send me a text if you do and I'll pull the sensor and go see him as too. I'll bring my little guy, he has small hands, comes handy working on tight spaces.
'99 3.4 is a 5.2.2 DME. Only four possibilities for that error, open circuit, short to +, short to ground, or faulty sensor. Here is the oscilloscope output for the 5.2.2 DME
And here is the wiring diagram for the '99 as well
For comparison I've added the output for the 7.2 and 7.8 below
The factory diagnosis manuals are quite comprehensive and make backyard maintenance on these cars quite simple; contrary to popular opinion.
Todd that is fantastic , exactly what Ed and I have been looking for, thank you so much.
. I borrowed a Porsche durametric analysis tool from a buddy and am heading to Eds this afternoon to check it out .
here is my follow up question .
We have been scoping pin 21 which is an overlay signal of both cam sensors as your schematic indicates. But your scope picture is of pin 20 and looks more like a crank pules !!
are you sure that's the cam pulse signal you indicated in your last pic ??
Last pic is for a 7.2 DME just for comparison of all three types of signals on the 996 . If you have a '99 C2 3.4 it is a 5.2.2 DME you have a throttle cable and not egas and the DME has one large black connector. In '99 only the C4 used a 7.2 DME and had egas and there are 5 small plastic connectors to the DME. Therefore you are probing the correct signal ( pin 21) as indicated in the first picture in the first post I made if you are looking at a '99 C2.
One reason why the 7.2 and 7.8 cam sensor profiles look different than the 5.2.2 signal is that there is a separate signal for each cam sensor with the later DME versions
Crank sensor on a 5.2.2 looks like this and is pin 78
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Does anyone have info on code p1397
