gasandgears

Hello all,

Hoping you guys can help with this because I'm at a loss.
Here are the details.
A couple of weeks ago I started off working on replacing the chain tensioner / brake pads on my 2000 996 /911 - 5 Chain engine.
1. Engine stayed in the car (what a mission on Bank 2 (4-6)!
2. Took apart valve covers and followed instruction as per Bentley manual and 101 Projects. Used the camshaft holding tool.
3. Removed camshafts and tensioner / actuator and then readjusted the chain to correspond with the divots on the exhaust and intake camshaft. The reason is that when I removed them they were out of place. They landed below and above the intake camshaft sproket so I reset per manual.
4. I reconnected the battery and waited about one hour (fyi - forgot to leave ignition on / car off for the minute to reset everything. It was around 30 sec.
5. At first car did not start. I repeated the steps 2 ties and then it finally started slowly. (Hooked up Duarmetric)
6. The car started up but very rough almost to the point it was going to stall out. Then it acted like it was in limp mode. No power at the accelerator. After about a min of running it went into closed loop mode and then still ran rough but started backfiring.
7. I turned off and on 2 more time with same symptoms. It starts very rough and then eventually starts to back fire. This also came with the smell of rotten eggs from the exhaust and then when I went to feel the exhaust, CAT Converter Bank 1 was burning hot so I disconnected the power to see if there might be a short.
8. Considering this sounds like a classic issue of timing, I removed the caps and went to TDC for Cyl 1 (see photos for exhaust and intake position) and all looks correct.
8. I turned over the engine 360 deg and removed the caps and went to TDC for Cyl 4 (see photos for exhaust and intake position) and all looks correct.
9. The only Fault code the Duarmetric gave me was Code 1571 / Porsche code 39 ( I assume that was because I didn't do a reset after connecting the battery.

So all the settings seems correct for timing seem correct (see photos). What am I missing?

Thanks in advance

Bank 1 - Exhaust and Intake


Bank 1 - Cylinders 1-3 / Front of Engine




Bank 1 - Cylinders 1-3 / rear of Engine


Bank 2 - Cylinders 4-6 - Exhaust and Intake


Bank 2 - Cylinders 4-6 / Front of Engine




Bank 2 - Cylinders 4-6 / Rear of Engine

Ahsai

Is the intake leak free and what are the cam deviation readings fron durametric now?

In your second photo, there looks like a horizontal hairline crack on the head? I hope that's just dirt.

Macster

Can't say for sure the timing's off but from my experience with engines if this is suspected one must do what it takes to ensure the timing is correct. There is no room for error.

The converter gets plenty hot under normal conditions. Its normal operating temperature is near 1000F. The DME purposely feeds too much fuel to the engine so there is unburned fuel in the exhaust and this is combined with air from the secondary air injection system to burn this in the converters to heat them faster so they can begin efficiently processing exhaust gases sooner. The converters heat up pretty quickly. By my observation by the time the secondary air injection pump shuts off the converters are hot enough the engine controller can go closed loop. Thus the converters even with a healthy engine get to approx. 1000F in sometimes under a minute.

But backfiring is a sign the engine is running overly rich, way rich. My Boxster never backfires from a cold start even though it is running rich. The Turbo manages to produce some faint backfires from a cold start but nothing beyond that.

Just so it is clear if the engine is spitting back through the intake -- which is not a backfire -- this is a sign the engine is running too lean.

The smell can be normal. A converter can get off on the wrong foot chemically speaking and produce that rotten egg smell, hydrogen sulfide I think. It is from the sulphur in the gasoline. After a bit though the converter should get on the right foot chemically speaking.

But the smell can be from an overheated converter, too.

Find and fix the reason for the engine not running right and the converter should smell better.

kmagnuss

I remember Jake saying something about setting the timing wasn't like it said in the book... it was some weird two step process and it was pretty much impossible to know how to do it unless you've done it before (oxymoron of sorts).

gasandgears

Just dirt. Scared me for a second. Couldn't get readings form the Durametric because it started to backfire so much I shut the car off before causing any damage.

gasandgears

K. Any link to that? Txs.

Ahsai

Those values are stored in the DME so you can still read them even when the engine is off. Might give us some clues.

gasandgears

Let me try to get those readings and shot them back.
Going to "reset" the ECm with the batery disconnect and then follow "relearning" to see what happens.

trendy996

Sounds like a bad adjuster. I can't remember the proper word for it right now but, it's the solenoid between the camshafts/chain. If that goes bad it will cause the engine to backfire/miss

Schnell Gelb

OP - you are setting the timing from some document/manual(?), yet there is still a timing problem. Suggest you find an alternative source document to use to re-do the timing. Just in case you had misunderstood some ambiguous part of the Instructions ?
Reset the timing ,put [I]both[I] cam holders in position .remove tensioners and check them ?Refit and hook up Durametric ,clear all and restart.Read Durametric?

gasandgears

I used the Bentley manual as well as 101 and they both have the similar instructions except for the 101 which basically says to put the camshafts back in when done also, Wayne uses the camshaft timing tool to hold the cams in place. The bentley manual says to use the Porsche camshaft support tool (which I used from the EWK kit) and then to "fine adjust camshafts" with the actual timing tool (which I did not as all seem to line up correctly and don't have clearance on bank 4-6 to attach it) and rock the **** with camshaft sprocket loose and then tighten down.
So I visually aligned the chain and cams as per manual and all looks correct.
I may have to tear it back down but want to avoid if possible.

gasandgears

Forgot to add one change.
I installed new Bosch 7403 spark plugs all around and kept coil packs as they looked good.

gasandgears

After writing that last note, I think my prayers may have been answered. Counter guy gave me Bosch 7403 spark plugs but it seems he should've given me Bosch 7413. Hopefully I installed the wrong plugs.
standby...

gasandgears

Update:
Switched out and installed the correct spark plugs and no more misfires / backfires.
Did the initial reset (wait 1 min with ignition on / turn ignition off / wait 10 sec)
On first start up misfired / back fired once but I assume that was left over fuel.
Car now runs but very rough and threw 2 codes:
- P0300 : Porsche Fault code 62 - Misfire damaging cat. converter
- P0301 : Porsche fault code Cylinder 1 misfire damaging to cat. converter
Also, took these readings:
Actual angle for camshaft bank 1: -12.53
Actual angle for camshaft bank 2: 3.05

On positive note the main reason for doing all this work was the original problem / issue of tensioner / brake pad wear which was giving me a -10 / -2.92 reading is now:
Camshaft position 1 deviation: 0.00
Camshaft position 2 deviation: 0.00

So the question is now are the Actual angle for camshaft readings within specs?

Will be starting new thread on this. Txs all.

Noz1974

Ok that's good!! I would re check the timing, lock it at TDC and check each bank in turn, make sure the single notch on the other end of the cam is facing the right way when you check that particular bank, I think it faces away from the engine on bank one and towards on bank two, I've got a copy of the porsche technicians guide I can check but am not home till next week.
When you put the timing tool on the slotted part which will move in and out should do so easily without any resistance even a degree or two will make it hard to push in, I think this is where your problem lies, if your car ran well before ,it is the only thing that has changed, maybe just check the crank and cam sensors are still plugged up ok too and look ok
Hope you get it sorted, I think if you re check at least you know for sure its not that if it doesn't fix it !