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Posted (edited)

 I need some advice on what further tests to do before I start disassembling the camshaft.

The code is "1341 = Camshaft adjustment Bank 1 below limit value."  But I think this is misleading. Normally , this would be just a failed Solenoid or Variocam actuator. Btw ,these comments apply equally to a Bank 2 fault.

But if you look at the Durametric data below ,there is a hint of a cheaper but much more stupid error.

I recently rebuilt the engine. It runs beautifully. But has only run a few hours because I can't get rid of the 11341 fault code to get a Smog Test.

The Actual Values alone are clear but not when you look at the Deviation, not so much. All values are with a warmed up engine(fans kicked in several times)

1,  Actual angle at idle rpm, Bank 1, 0.3 to 0.8 deg. At 3000 rpm  only 2 degrees ! Bank 1 solenoid measures 13 ohms(perfect) but will not activate with Durametric , nor with the Ahsai 12v battery test.

2.  Actual angle at idle rpm, Bank 2, 0.02- 0.2 deg . At 3000 rpm 20 degrees - perfect. Bank 2 solenoid can be activated by Durametric or by the external 12v source.

 

3, Deviation Position 1 at idle is 14.9 deg and stable  - it should be +/- 6 deg !

4. Deviation Position 2 at idle is zero  and stable- 0.00 ,nada .

Please check my logic/knowledge here because I need help.

My theory is that I must have failed to time Bank 1 correctly. It is so far out that the Camshaft Advance will not activate ?

The stable deviation is because of new chains,IMSB , chain rail pads and tensioners.

So I need to re-time Bank 1. If it seems to be perfectly timed - look for a Camshaft Position Sensor problem ?

I'll bench test Bank 1 Actuator to see if it has a firm 1/16" 'jump' .If it is doubtful I'll replace it because of the time involved.

Fortunately I have the cam tools and Insite's helpful classic post on timing the M96.

Before I start dismantling , what else to test?

Maybe connect between the Bank 2 harness and Bank 1 to try to activate the camshaft advance (Jake Raby suggested this in a related Thread)

I get no reading on the Multimeter when I connect to the Bank 1 harness but do get the correct voltage (10V) on Bank 2 . No, I did not connect to chassis ground(thanks Ahsai!)

This is an interesting example of needing to use 2 different(but related) readings from Durametric to make an accurate(??) diagnosis. If I had just fitted a new Actuator +solenoid($1000 ! ) ,the basic fault may still be present.And I would have to repeat all that dismantling again !

So thanks for any suggestions of more diagnostic tests.

 

 

Edited by Schnell Gelb
  • Moderators
Posted

Let's start with the basics, cam deviation values on these engine's are +/- 6 degrees, so obviously you have a problem.  Before disassembling anything, I would hand rotate the engine to TDC and pin the crank pulley, and then pull the cam plugs on bank 1 and check the cam slot position(s)  (you did not include the year of the engine, so I don't know if it is a 3 or 5 chain engine, so I don't know if you have one or two slots).  At this point, you have basically put the engine in the starting position for an IMS swap, so the IMS cam locking tool should slip right in; if the cam slots are not in the correct position to accomplish this, the cam is out of time and needs to be reset.

 

Good luck.

Posted (edited)

Thanks JFP That is a great start.

Btw it s a 2001 S - so a 5 chain. So I need to look for 1 slot or 2 ,please?

I fixed the +/- 6 deg mistake in my Post.Thanks.

Edited by Schnell Gelb
Posted (edited)

Agree with John. Based on 2, it sounds like your solenoid/actuator is not working. Just to double confirm it's not the transistor inside the DME nor the harness, you can unplug the bank 1 solenoid and connect a small 12v 3w bulb to the harness connector. You can use the bulb from your frunk or engine lid. Now just fire up the engine and rev it to 3k. The bulb should light up. If so, the only explanation is a bad solenoid/actuator.

Edited by Ahsai
Posted (edited)

Duncan, Thank you for your suggestion. I remember your epic thread with Imo in Canada and the burnt transistor in the DME.  He even located and fitted a replacement transistor iirc. Incase anyone following needs the "IMO" transistor for the DME, it is very difficult to find as a spare part. Here is a link for it - a BIP373 Coil driver:

https://www.diyautotune.com/product/replacement-bip373-coil-driver-q16/

I have not completed the exact test you propose, so thank you for the suggestion.

I did make a special harness with a modified EV1 connector . It fits on the connector for the solenoid . This is hardwired to a dedicated pair of leads to a cheap MultiMeter. With the MM set at 20vdc ,Bank 1  never shows any voltage on the MM, regardless of engine speed or coolant temperature.The same test on Bank 2 shows  10v when the camshaft timing advance kicks in. The custom harness is long enough to reach into the cab so it is easy to read and idiot-proof. But I'll certainly try your test with the 3W bulb to simulate a resistance.

In previous Threads you explained an external 12v supply test.This makes the Bank 2 solenoid click. Bank 1(with the suspect timing 15 deg off) is silent. I made a dedicated harness for that test also.

I made a 3rd test  harness to go from the solenoid connector on one Bank ,across the engine directly to the solenoid on the other Bank. I try that also.

As you suggest , I am trying to eliminate DME and wiring problems by substitutions.

JFP's test suggestion will be embarrassing if it confirms I got the timing perfect on one Bank and failed on the other. Regardless, I'll confess so others can learn from this.

Thank you both for your helpful suggestions.

Edited by Schnell Gelb
Posted

You're welcome! Yeah, Imo was able to fix his problem by replacing the transistor inside the DME. Based on the 0v DMM reading, that sounds like a DME/harness problem. Um, that's strange...unless you truly have two problems. With key ON engine OFF, do you get 12v on pin 1 of the bank 1 solenoid? The DME grounds pin 2 to activate the solenoid.

  • Moderators
Posted
7 hours ago, Schnell Gelb said:

Thanks JFP That is a great start.

Btw it s a 2001 S - so a 5 chain. So I need to look for 1 slot or 2 ,please?

I fixed the +/- 6 deg mistake in my Post.Thanks.

 

A five chain will have one slot on the exhaust side cam.

Posted (edited)

Thanks JFP. Here is a link to help others see what we are referring to on a 5 chain M96.It is a Thread started by Insite on camshaft allocation with excellent photos and descriptions:

http://986forum.com/forums/performance-technical-chat/26418-diy-setting-cam-timing-m96.html

This is one of several YouTube videos showing the work & tools that may be required:

https://www.youtube.com/watch?v=nE_X27JSTyE

 

Edited by Schnell Gelb
Posted
10 hours ago, Ahsai said:

You're welcome! Yeah, Imo was able to fix his problem by replacing the transistor inside the DME. Based on the 0v DMM reading, that sounds like a DME/harness problem. Um, that's strange...unless you truly have two problems. With key ON engine OFF, do you get 12v on pin 1 of the bank 1 solenoid? The DME grounds pin 2 to activate the solenoid.

Thanks Ahsai. I'll do the test work this afternoon .So many details of life seem to interfere with Porsche repair time :-).

Posted (edited)

I did the test that JFP suggested above and Bank 1 looks perfect.So why is there a cam deviation at idle of 14.9 degrees at Position 1? Surely that would be visible?

Fortunately I kept lots of notes and diagrams from when I rebuilt the engine so I was able to compare the orientation and position of the 1/2 moon and notch now to my previous records. I tested the positions of the Exhaust cam  notches and the Inlet notch over 4 successive rotations to make sure.

For anyone trying this with the engine in the car - you need a rack and very good inspection lights.It is very obstructed unless you take off other parts(exhaust for example).

Tomorrow I'll fit new green plugs and do the electrical tests that Ahsai suggested. Then we'll have some useful data to work on.

The suspects are :

1. Variocam actuator +/- solenoid - very expensive and requires major ,awkward dismantling. - but at least it can be done without removing the engine :-).

2. Wiring harness to Bank 1 ( I did some clumsy electrical work on the SAI harness and perhaps I damaged nearby wiring).

3. Camshaft position sensor, Bank 1. I have not read that these fail  so this seems unlikely'.Is it possible to make a mistake assembling the cam position sensor ?

The combination of Code 1341, no cam advance but a huge cam deviation (14.9 degrees)at Position 1 is a weird combo of symptoms.Bank 2/Position 2 is perfect per Durametric.

Thanks for any suggestions as always.

 

Edited by Schnell Gelb
  • Moderators
Posted

With the cams mechanically where they are supposed to be, the problem has to lie with the system that reads the position or interprets the deviation values: Cam position sensor, crank position sensor (used as a reference in the process), wiring, or the DME.

Posted

"3. Camshaft position sensor, Bank 1. I have not read that these fail  so this seems unlikely'.Is it possible to make a mistake assembling the cam position sensor ?" <- That is not possible as the sensor goes in only one way.

 

Your case is indeed very strange. Sounds like multiple failures. Look forward to see what you find electrically.

Posted

Thank you both. I'll get to work this evening with more tests and report back.

If the fault was the Crankshaft Position Sensor, that would produce  problem on both Banks not just Bank 1 ? Unless it was a wiring problem.

The DME theory - that 'should'? also cause the same problem on both Banks? Unless it was a wiring problem.

An interesting  test -  I have a 12v source to connect direct to Bank 1 solenoid.It has a MOM switch & fuse on the test harness that I can operate and watch the Durametric trace. That may indicate I have a lazy/sticky actuator? The Bank 1 solenoid reads 13 ohms but produces no "click" from an external 12v source like Bank 2.

I am trying to be thorough and systematic with the tests because once I start dismantling things - it is too late for some of these tests.

This time I'll let the engine warm up at idle ,no revving to 3000 rpm to activate the cam advance. That should give a better observation of the peculiar camshaft deviation readings on Bank 1. Then I'll stop the engine and connect up the MOM switch harness and observe the trace for Bank 1 Actual Angle. I speculate it will be a small saw tooth profile as the solenoid struggles to move a sticky/plugged/leaking Variocam actuator. All idle speculation without more diagnostics.More later today I hope.

Posted (edited)

The test with the MOM switch+external 12v power source direct to the solenoid was a failure. Repeated pulsing of the MOM switch produced no response on the trace from Durametric  Actual Values. I am reluctant to operate the MOM switch for more than a few seconds in case the 12v overheats the solenoid. It is intended to operate at 10.5v (iirc a post by Ahsai), not 13v from a motorcycle battery.

The only new data point is that immediately after one restart in the MOM-switch tests , The Deviation on Position 1 was much reduced - just  9 degrees instead of the 'usual' 14.9 degrees. When I operated the MOM switch , Deviation jumped back to 14.9 deg. & remained(as usual) rock steady.

It seems unavoidable to remove the camshaft cover for Bank 1 and inspect. That is a very tedious task that  I can enjoy over the weekend and report back.

I try to predict the surprise that will be revealed in such cases because it is a good (or humbling) test of your understanding of an issue. I cheated by researching many other posts on the "1341" but none had a hint of what this specific issue is. The root cause is probably  engine assembly error !

To recap , there are 2  related issues on Bank 1 only - Bank 2 is perfect on this just rebuilt engine:

1. Deviation of 14.9 degrees at idle at Position 1

2. No change in Actual Values of Camshaft advance with increasing r.p.m. or Activations/prompts from Durametric or an external power source.

For those following this in future, this is the stage to order the oddball left hand threaded studs and nuts to compress the Actuator for my 2001 S. Older cars had right hand thread. Also prepare your 'while you are in there' list - spark plug tubes,oil pump seal,coils(?) ,plugs. And if you are working on Bank 1 - the AOS and it's corrugated tube. Mine are all new.

Edited by Schnell Gelb
Posted

BTW, i agree it sounds like your solenoid/actuator is not working but I was wondering if there are other faults on the harness/DME side since you said you got 0v from the harness.

Posted
3 minutes ago, Ahsai said:

Any chance to try the 2 tests I suggested above (12v test on pin 1 and light bulb test)?

Yes.Thank you for the gentle reminder to be systematic.

I'll postpone the dreaded dismantling and do that .Logically your hint makes great sense. I have a Noid light that will fit into one of the many test harnesses I made because the Noid has EV1 type pins.

Posted

All those test harnesses came in useful.

1. connect a multimeter to one Bank wiring harness at the solenoid connector(NOT to Solenoid side of wiring) set to 20vdc scale

2. connect a Noid light with another test harness to the other Bank.

Connect Durametric ,key on engine off. Activate Bank 1 & /or 2. Nothing. Ugh !

Start engine -nothing.

Run engine for a few minutes.Accidentally leave Durametric Activating Bank 1 & 2 camshaft advance. Blip throttle to 3000 rpm. The Noid lights up (4 ohms btw) and the Bank 1 voltage spikes to 13+v.

So we have no DME problem and no wiring harness problem. We(I) did have a misunderstanding about the ability of Durametric to operate the Camshaft advance key on Engine Off.Others who follow this please note that you have to run the (my?) engine for a few minutes before the Camshaft advance circuit ' wakes up'.

Still no click when I use an external 12v source to activate Bank 1 Actuator.Solenoid on Bank 1 still reads 13 ohms.

So one problem is the actuator .When I remove the Camshaft cover perhaps others will be revealed.

Since the Solenoids are more likely to fail (except for me!) than the Actuator, I'll buy a new Actuator+solenoid and keep the old(good) solenoid as a spare. But only after I bench test the old Actuator.

Thanks for hanging with me on this guys.

 

 

Posted

Good news about the dme and harness. So the problem is confined to the solenoid/actuator. Are you dropping the engine? Might be a lot easier.

Posted (edited)

I shall try to remove the camshaft cover with the engine in situ. I am currently trying to research the subject . For others following this Thread, if you have a 'while you are in there' list of engine&trans-out jobs, it is an easy decision - take it out. But I have just had it all out and did everything .Or so I thought.

My hack idea is to remove the front engine mount, both transmission mounts and both headers while the engine is supported from above and below.I shall then try to push the engine over to create the space to remove the camshaft cover. The car is up on a Mohawk 2 post lift and I'll use an old Wudel transmission jack and the HF engine support bar.

I have never read of anyone doing this. There  may be a very obvious reason for that. Hopefully JFP will give a quick verdict on the proposal.Others have mentioned just lowering the engine a little by removing the front engine mount and rear wheel.

Grateful for any shared experiences for this procedure.

This link I just found suggests less fuss required than I had indicated above:

 

Edited by Schnell Gelb
  • Moderators
Posted

If it were in my shop, I'd drop the engine.  It becomes overly complicated to try and do this in the car, and you can do a quicker and cleaner job out of the car on a stand.

Posted (edited)

" If it were in my shop, I'd drop the engine " oh, if only it was there :-) !

Before dismantling I decided to make one last Durametric test. Now is throws an 0301 Misfire code. Despite all new coils,plugs and spark plug tubes. Decide it must be because of the peculiar Position 1 deviation and the apparent Variocam malfunction. Yes, I realize that logic is feeble. But after rebuilding this engine over years and thousands of $, the alternative is to abandon the car. During the last test the fairly new AOS failed !

I found a thread with the 1341 code that was repaired by Jake Raby some time ago. The cause was a tiny amount of debris plugging the actuator. That is quite possible in my case also. An optimistic explanation for this case also. Or more time and money down the drain ! Time will tell.

One point of confusion I have about Terminology with Durametric - Deviation is measured at Position 1 and Position 2. Actual Values Angles are Bank 1 & 2. What exactly is the difference between the Positions ,where are these Positions- is it just another term for "Bank" ?

Edited by Schnell Gelb
Posted (edited)

I re-chcecked the Timing for Bank 1 - perfect.

Removed the scavenge pump for Bank 1 to do a visual & physical check. The 4 x M6 bolts are tight on the exhaust sprocket.They are in the middle of the slots.The chain seems tight when pushed with a screwdriver (engine is still in the car-so far!).

The CAMshaft Position Sensor is connected and secure. A loose CAMshaft Position Sensor could cause aberrant readings perhaps? I do not have the  code for a failing CAMshaft Position Sensor- which are 1397, 0341 & others

 

I am still puzzled about the connection (if any) between the lack of response from Bank 1 Variocam Actuator to a prompt from Durametric to advance  and the alarmingly high Position 1 Deviation of 14.9 degrees shown on Durametric at idle.

Position 2 is perfect.Bank 2 Actual Values are also perfect. Bank 1 is the only problem.

I have read many similar Posts multiple times and 14.9 degrees  is a record extreme reading. We usually find  Deviation discussed with IMSB failure. This is a newly rebuilt engine with a new IMSB.

So presumably there is a discrepancy (noted by the DME) between what the CRANKshaft Position Sensor reads and what the CAMshaft Position Sensor should read ? So it sets Code 1341. Since the problem only affects Bank 1 , I presume that the Crankshaft sensor is O.K. but the Bank 1 Camshaft sensor maybe in pre-code-setting failure.Yes, a bit of a stretch. Replace the Cam sensor anyway ? I have to replace the AOS and that has to be removed to access Bank 1 Cam sensor so, 'while I am in there'....I'll replace it. HINT - if you remove the AOS to replace the CAMsensor on Bank 1 -please plug the big hole left by removing the AOS from the crankcase half. The 5mm Allen screw that holds the Cam Sensor may fall in there .Can you imagine.......?

The only other WAG is the Timing Chain Tensioner for Bank 1. For my 2001 S there was a minor (?) upgrade to the Tensioner, There was a more significant upgrade to the IMS-to-Crankshaft Tensioner. I am skeptical that the Bank 1 Chain Tensioer is defective because with the engine off for several days it seems to be keeping the Bank 1 chain tight. Nevertheless  I removed it to inspect.It was pumped up and the spring was very strong .The part number for the latest  Bank 1 Tensioner is 996-105-186-02 .The superseded part ended -01.Here is a RennTech link that discusses the issue. It may fix a rattle at start up but no other substantial differences?

I hope all these links are helping others who follow this path

See Post 14 here for Part numbers and Part drawings:

http://rennlist.com/forums/996-forum/554040-chain-tensioner-or-chain-adjuster.html

 

Edited by Schnell Gelb
Posted

Not to hijack this thread, but my problem is clearly related, so I hope this is acceptable. I also posted this over on Rennlist... See below

 

"So, I posted a few weeks back that I had gotten a CEL after I had done some work to my cooling system (fixed a leaking hose above the oil pump housing). After refilling with coolant and driving 50 miles or so, the light went away initially, but has come back now after 300 miles or so. I read the stored code with a generic reader and got a 1341. After checking around a bit I decided to break down and get a Durametric. I got to hook it up after work today and this is what I got.

80-img_1509_1__25e5c0c206267ce60c79f0454

80-img_1510_1__aa68d0f722a7d66be23c0c94c

80-img_1512_1__13ef9422e63b3473cae47f31e

Per the fault code "camshaft adjustment bank 1 below limit value" - What exactly is the meaning of this? Worn chain pads? Bad adjuster? Both? Any ideas (preferably educated wink.gif ) would be appreciated burnout.gif "

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