Cam timing

[Stl-986]

Took my 2000 to the dealer today. 3 hours of diag later they are stumped...but want to do further diag to figure out my misfire codes on bank 1 & P0341. Lead tech thinks that the intake cam wheel (his words) has slipped and rotated. They checked timing and it's spot on for exhaust & cam visually, everything lines up. Apparently the end of the cam is pressed on and they have seen these slip & rotate and the only way to tell is to get the cover off and visually inspect. Of course the only way they do it is to drop the engine. They also tested wiring to the cam sensor and it tested good & within spec.

Anyone ever hear of this happening?

The only other issue is of course the DME. I have another DME but of course it isn't matched with the immobilizer that is installed.

This is what he says can slip & rotate. Haven't heard of seen this happen before so I'm stumped.


Just for reference codes are P0300, P0301, P0302, P0303 & P0341.
New AOS
new bosch cam sensors (both banks)
vacuum lines replaced
new vacuum canister
new check valve
coil packs swaped to bank 2, codes dont follow
new bosch plugs
new spark plug tubes 7 orings

The crux of all of this is that using Durametric I can't activate either cam solenoid, software just locks up. It locks up also when I try to activate anything when the car is running such as SAI, engine fan, fan stage 2, etc. I can activate things when the engine isn't running though. I can manually activate it by giving it 12v and idle changes when I do. Almost bought another car just so I can have something to swap dme/imob/key with to rule out the dme.

[Homeoboxter]

Hmm.. Sounds pretty crazy. Are you referring to the sprocket or to the plate that provides the signal for the camshaft position sensor? As far as I remember the sprocket is manufactured together with the camshaft as one piece, so it`s hard to believe it can spin on the shaft. The plate looks like being pressed on, but that just spins freely in front of the sensor and I don`t see what could force it to slip on the shaft. It`s also hard to believe that they can`t check that without pulling the engine. If you remove the green plug, the sensor and the scavanging oil pump you should be able to see pretty well if anything has slipped, especially with a borescope. They could also pull the spark plug and with a borescope check when the valves start opening and refer that to the crankshaft position to get an idea if anything is misaligned. I have heard of the IMS sprocket to spin on the IMS but then nothing would line up at TDC...

[Stl-986]

Yea I agree.

I'm not overly happy with the St. Louis dealer. Have had some issues in the past with a couple other cars that they messed up programming on (deleted a working key when adding a new one for example). Of course they did the exact same troubleshooting I did which the FSM points to the DME but they didn't want to point to that being the issue.

While it does make sense what that said and their recommended next steps it just doesn't sound like something that could happen without other things going bad or showing other signs of issues. He did state he was hesitant to suggest DME due to the cost to replace and actually said they send them to ECU Doctors in FL for repair (happen to actually be going down to Miami next week so they are going to look it while I am down there).

Still also think I have a vacuum leak cause I only have 9-10in of vacuum but 1 smoke test said there are no leaks and dealer didn't do one today but if there is a leak I sure can't find it.

[Stl-986]

Oh and he was saying just the end piece is pressed on and could have "spun"


Agree, there has to be a way to check this without removing the engine. Sure it makes it easier but they wanted $3200 to drop the engine & continue to diagnose it...and that's before any parts that may be needed.

[blue62]

you need to find a shop that has an oscilloscope and a tech that is good at reading waveform.
An Oscilloscope will give you the info you need.
like cam position in relation to crank position at time of cam sensor signal.
I would think that would tell you if something is out of wack with the cam assembly.

[Stl-986]

Agree as well....which guess what? FSM says that is what to do for P0341. lol

[blue62]

The shop telling you that the only way to check the issue is visually well they are full of s**T. they are just trying to fleece you.
Like I stated an oscilloscope is what you need. More importantly is a tech. who is very good at reading wave forms and is honest.

[Stl-986]

100% agreement. The down side...it was the St. Louis Porsche Dealer not an indy. Just another reason to add to the list of things I dont like about the local dealer.

I had debated the past couple of weeks of just getting a scope I thought that putting that little amount to just having the dealer look at it. Should have gone with my gut.

At this point I am still thinking the issue is: vacuum or DME. Went ahead and sent the DME off to ECU Dr, I"ll pick it up next week when I am in Miami. Worse case it isn't the DME and it only cost me the test fee. Backup to that is I am going to drive it out to KC when I get back and have KC Rennsport look at it.

[blue62]

Thought I would add that if your only pulling 9-10 inches of vacuum that is very low.
Your looking for 18-20 at sea level steady needle. look for around 1inch less for every thousand feet in elevation. So if you are in say Denver (a mile high). 13 inches would be like 18 at sea level.

So low vacuum like you have is a good size vacuum leak or late valve timing.
What is the action of the needle at idle? Steady? or????

A smoke test is a good way to find a vacuum leak but they are not absolute.
If you have a Vacuum leak it could be in a system like the EVAP system. One way valves in that system can prevent finding leaks with a smoke test.

No Oscilloscope at the dealership? Wow whats the world coming too????