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YOUR RESEARCHDual Camshaft Position Sensor Errors Need Help!
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Put the old pumps back in properly and the problem was gone.
Leading evidence: 'gone' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'gone' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check cel codes and i get the following' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
When I first started it I checked the oil pressure and coolant.
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Performed · outcome unconfirmed · Original poster
When I put it together I double checked the timing according to the service manual.
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Performed · outcome unconfirmed
By the way I now have over 10,000 miles on my engine since I repaired my intermix/cracked head and it is still running strong.
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28 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Outcome without a verified action link
Put the old pumps back in properly and the problem was gone.
I have just completed a rebuild of my 1999 996 3.4L. On first startup it ran a little rough as the ECM relearned the engine. I had a few starts and stops as I refilled and burped the coolant and the engine began to run better. After a few minutes of run, I shut it down to check all the other fluid levels. Now, it will not start. I checked the CEL codes and I get the following:
P0341 Camshaft Position Sensor 1 - Signal Implausable, Short to Ground, Short to B+
P1397 Camshaft Position Sensor 2 - Signal Implausable, Short to Ground, Short to B+
I have no other codes. What are the chances of a dual sensor failure? Has anyone had this problem? Could It be something other than a sensor failure?
I cleared the codes and tried again, same story.
Any help is greatly appreciated...
Haven't had the problem but can offer a suggestion or two .First I would bet it's a timing or cam advance issue .If you have a Durametric easy test for Bank 1 .Test for actual value cam deviation -if it's plus or minus 6 degrees it's good .Second step try drive link bank 1 camshaft if idle changes that's working .Unfortunately on a 1999 the DME reports nothing on Bank 2 ecept error codes .
When I was reassembing my camshafts it was a bit tricky on the piston in the actuator -think it had to be in a vertcal position .Shop manual has a caution on this .
No Durametric here, just Innova CEL code reader
When I removed the cams and Vario actuator I kept all that as a unit. The chains, cams, and varios were never apart. I also verified the timing between the IN and EX cams with the timing dots before they went back in. For the IMS to cam chains, I followed the Porsch tech manual to set it and verified it twice. What gets me is that it ran ok for the first few times. I also popped off the oil pump units off the head to make sure the timing had not slipped on the adjustable sprokets. I am thinking this is an electrical issue. I see that the Position sensors have a B+, Signal and Ground connection. They share a common signal return line back to the ECU. when I get home tonight I an going to check the voltage on that signal line to see if it is +5 or grounded. Either one appears to be a possibility in the CEL code. These hall effect sensors are unlikely to fail and 2 at the same time is very remote. The bad part is that you cannot get to any of this stuff unless you drop the engine to get some working room.
Given that the engine ran at first I doubt the problem is all in the timing. And a short to ground error is not a timing error. Check the wires and sensors. A Durametric might help but the cam shaft deviation and drive links require that the car be running. Is yours a 5.xx DME or a 7.7 DME?
Definately a timing issue .Could be electrical or mechanical .I believe codes P0341 and P1397 trip because the dme can't establish that #1 (or4) cylinder is where is supposed to be in relationship to the crankshaft .The short to ground and short to b+ are two conditions that generally cause this .That assumes everything else is right .
What I don't know is why it ran and then quit .Might be worth a shot to reseat the engine harness plugs .
Dave
Thanks for all the insight. I will be working on it over the weekend and hopefully determine the source of the problem. BTW, this is my youngest sons first car. We just picked up the seats from the shop and they look amazing. We had the bottom and back center replaced with Arms Red leatther and left the rest of the leather Space Gray. I will post pics later.
Lucky, Yes. My first car was an Opel out of a junk yard. Sorry I did not doc the rebuild. I took plenty of pics of the engine coming apart but none going together.
Mystery solved....And a new one started..
I spent today looking and finally dropped the engine. What I found is really strange. Both cam banks were off by about 15 degrees. When I put it together I double checked the timing according to the service manual. It ran so it had to be correct then. When I first started it I checked the oil pressure and coolant. Coolant was low so I went through a few stop start cycles and burping. Got that filled and shutdown to check all fluids. The oil barely touched the dipstick and my son asked if "10" was OK for the Oil pressure. After a minute or two of sheer panic, we added oil and called it a night. That was the last time it ran. Here are my thoughts.... For both cam banks to be off the same amount it had to be a slip of the crank to IMS chain. The only way that I can see that happening is if the oil pressure was not enough to keep the tensioner pumped up or the tensioner is bad. If it were, I think that I would have heard the noise. No tension in the chain and the slack goes to the bottom. Skip a tooth or two and bam
I am lucky that there was no valve contact. If you have any thoughts on this I would like to hear them.
Did you prime the oil pump? Also, you should have enough Bearing grease on the journals to protect the motor from metal on metal contact... Except piston and valve contact of course..
Yes, I pre-lubed all bearing surfaces as well as rolled over the engine with the starter prior to cranking the engine to get the oil circulating. Having to add a little over quart after running the engine bothers me
My WAG is you made a mistake in setting the timing or a chain slipped. I've dealt with SOHC engines with just one chain and even one chain is tricky. The job take 3 hands and 2 sets of eyes. God only knows what the Porsche engine with the chain drive from the crank to the IMS and then two separate chain drives one each from the IMS to each exhaust cam and each exhaust cam in turn has a chain drive to its intake cam.
Oh my head...
Sincerely,
Macster.
It is not necessary to remove the engine to reset the cam timing. I have a method for doing this on both the 3.4 and 3.6 engines even without the Porsche tool. PM me with your email address and I will send you the info.
I will be happy to share it with anyone by email. I will also try to put the instructions into a format to post here. My challenge is I am caught up in a problem with upgrading my computer from Windows Vista to Win 7 and so I can't start Work right now and the files are in Doc. format. I can send them as an attachment to an email but can't edit them right now.
Dharn55: I read your method and that is what I used to do it the first time and again today. I think that I understand more about what happened now that my last post. When I timed the cams the sprockets were bolted down with the bolts about mid way in the elongated slots. When I started retiming today both the 1-3 and 4-6 sprockets were rotated to the end of the slots. I searched the posts and find only a few mentions of the sprockets slipping. Coming from a V8 background, I am not used to seeing slots in gears or sprockets. The 4 small 6MM bolts and very light torque just looks like an invitation for this to happen.
There is something else going on here .There are 250,000 cars runing without cam timing slipping .The sprocket on the end of the ehaust cam drives the cams and the return oil pump .I am betting the pump is the culprit for two reasons -could act as a hydraulic brake and there seems to be a quart of oil missing .I'll bet the oil is in the cam cover .What I don't know is if the return oil pump is simply reversed if that is the cause .
Dave
What torque did you use on the bolts on the sprocket? The spec is 10.5 lbs. With all 4 bolts at 10.5 lbs the sprockets should not slip. As a precaution when setting the timing and torquing the bolts I tighten two down. Then put loctite on the other two and torque them. Then take the first two back out and loctire and torque them.
With regard to reversing the scavenger pumps, I made this mistake during one of the several times I worked on my cams due to blowing out the expansion plugs. A careless error, but not that hard to do. It had no effect on the cam timing, just caused erratic oil pressure readings as the pumps were pumping oil out of the sump into the heads rather than from the heads to the sump. This in turn would cause some "starvation." Actually took me a couple of months of trying to identify the problem. Replaced the primary oil pump, swirl pots and other components. Nothing seemed to help. Then bought a set of new scavenger pumps thinking they might be bad. When I went to install them found the old pumps reversed. Put the old pumps back in properly and the problem was gone. A really dumb mistake, but Oh Well
I don't think this would cause the bolts/sprocket to slip.
By the way I now have over 10,000 miles on my engine since I repaired my intermix/cracked head and it is still running strong.
Dharn, do you think you could send me those instructions as well?
I'm getting a P0343 error and wondering if it has anything to do with timing or if the sensor itself is just messed up. Any idea if it's possible to replace the sensor without pulling the engine (3.4L 2000 996)
halcyon_m
PM me your email address and I will get something off to you. And yes you can replace a cam position sensor with the engine n the car by the one on the drivers side is a real PITA to get at.
Sorry to revive a relatively old thread, but I have to ask, rkellison, did you ever figure out the problem? How coincidental is this... just last week we put my father's 996 motor back in after having the IMS upgraded, clutch replaced, AOS replaced, etc. (preventative maintenance) and the car is having very similiar symptoms -- while driving it will cut out. Attached are the DME codes. His too is a 1999 3.4L. We primed the oil pressure before starting the car. Anybody else have suggestions?
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