TheBird

I have some questions about cam timing. Bank one reads -8.00 degress and bank 2 says +5.30 degrees. HOW? If the timing chain is off by one length how much timing does that account for?

Next up, saw oil start to leak dead centre from the bell housing and thought the worst. Turned out to be the RMS has just about fallen out. Is there some part of a Re and Re that could cause this? Is there a danger that a tiptronic can stress the seal when the engine and transmission are removed together, separated, and then reinstalled? I am baffled by both of these occurences.

Any ideas? Anyone?

I'm a noob to the 996 but not to Porsche or VAG cars.

DBJoe996

Year/model? How does the car run/sound? What type and viscosity of oil? How did you get the cam timing degrees? Durametric? Any recent internal work on the engine? The RMS should not fall out unless it was blown out by too much oil pressure. Or it was installed incorrectly to begin with. So you found out that the RMS had fallen out...that must mean that you removed the engine/transmission, separated and then reinstalled everything. Did you get everything hooked up correctly on the engine? Thinking variocam solenoids and things like that....

TheBird

Ah... of course... It's a 2001 transition year C2 Cabriolet with a tiptronic. The car was super smooth and quiet on initial start up. It started developing a lopey idle after a few drives which one knowedgeable chap said looked like a vac leak to him. The timing was read on a durametric but was confirmed to be out using the PWIS system. I put fresh fluids through the car including the DRIVEN DT40 oil that some recommend. How would I get too much oil pressure? Too much oil?

We stuffed a camera up inside the bellhousing and you can see the RMS has walked way out and is sitting on an angle. The engine was freshened up about 20k miles ago by a reputable Chicago area shop. Other than shipping here to replace my engine with a detonated IMS and changing from a manual car to a tiptronic there's no differences I can think of.

TheBird

So here are some shots from the DME readings... Looks like I need an O@ sensor as well. And why would only cylinder #5 be retarded?

DBJoe996

Spark plug and coils ever been replaced? Could be a bad plug and/or coil on #5. The DME will detect a misfire on a cylinder and retard the timing.

Chris(MA)

Good suggestions; maybe OP drove in the dry then hit some rain/wet roads? water gets in the coil cracks and causes misfires

TheBird

Apparently there was some difference between the coils from my 2001 and the 1999 that this motor came from so we swapped the coil packs over to the original ones but i still have all the 'new' low mile ones that came with the motor. might be the same for the injectors as well. I'll have to check on that. Good suggestions. Wouldn't a retarded timing be because the AF is lean? Would this point to an injector?

And what about the bank to bnk timing deviation? One minus and one positive? Seems very odd!

DBJoe996

In my opinion (take it for what it is) you need to sort out the O2 sensor problem, and perhaps the MAF sensor first, and the problem with #5. If I remember correctly the MAF should read between 14-17 kg/h but I could be mistaken on that. You also need to check for a vacuum leak somewhere. All of these will affect engine running as the DME uses all of the sensors to set air/fuel ratios and running parameters. I would also replace #5 spark plug and coil pack. There are new and upgraded coil packs that you should consider, replace them all. It is possible that the #5 fuel injector is bad as well. I don't know about the bank to bank timing deviation. That would require really digging into the engine to check the timing on both banks. Possible that one of the chain sprockets on the end of the camshafts slipped (the bolts that hold the sprocket on the camshaft). Highly unlikely the chain drives jumped a tooth. Could be a variocam solenoid issue such as one side sticking open/closed. But at this point nothing can be ruled out. I would correct as many known problems first before tearing into the engine to check timing.

From Loren so I stand corrected on the MAF readings
At idle, air mass flow should be 12 - 24 kg/h.
No load, 2500 RPM should be 40 - 70 kg/h.

TheBird

well i need to drop the engine to install a new RMS anyway... while I'm at it....

Chris(MA)

don't need to drop the engine for RMS

TheBird

It's a tiptronic, i thought that means it's just easier to drop the whole shebang.

dporto

^^There's an awful lot of information to be unpacked right there... So this is a replacement engine? Where did it come from? How many miles, history? Why was the engine "freshened up" by the previous owner, and exactly what was done? It's strange to have so much negative deviation on one bank and positive deviation on the other - have you gotten a CEL ? Were the cam chain pads done in the "freshen up"? What about the chains/tensioners? The fact that your RMS has "walked" partially off the crankshaft is fairly bizzare - either it was poorly installed (which would be the simple/best case scenario), or the crankcase is uneven/poorly machined, or your crankshaft has some crazy runout, or, or, or... Good luck with it, and keep us informed on what it turns out to be...

TheBird

According to the PO of the engine it is a 1999 that was torn down not long ago (I can't recall the exact miles so suffice to say less than 25k miles). It has new chains, tensioner pads all round (this was the reason it was stripped and 'freshened up). The bores were clean, new tensioners and maybe actuators amongst other things. Apparently there has been a rash of failing seals of brands that are similar but NOT OEM. I am hoping that is the case. The engine burns no oil and there is zero smoke at start up. When it comes out we'll install the IMS Solution (Thanks to LN and the gang! What amazing work they have done through the years to figure out all that ails these M96 motors!) The engine build used new coils and plugs but I think my mechanic used my old coil packs for some reason. I'll swap those back on and clean the MAF as discussed above. We think one of the chain tensioners might be leaking as well so we'll look at those as well. I will be sure to post a follow up when we finally have things sorted out.

How do you like those NYC Link units going in all over NYC?

DBJoe996

When you had the Durametric hooked up, did you do any activations? Such as activating the variocams for each bank? Sounds like you are pulling the engine out and working out a plan. I wonder if there is any difference in the CPS (crankshaft position sensor) for manual transmission and tiptronic. When you swapped out the manual for the tiptronic, did you swap over all of the parts? Inlcuding the DME? My thinking is that the engine management map might be different manual vs tiptronic since it has to deal with the TCU (transmission control unit) and other aspects of difference between the manual and automatic, shift points, etc.

TheBird

We swapped the entire engine harness across from the original motor to the donor 1999 3.4 and used the original DME. This was done mainly to accomodate the e-throttle as the 1999 had a cable throttle Good point that some sensors might be different or even positioned slightly differently. I'll look into that. The shop did acivate and hear the actuators function for the variocams.