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deMort
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Joined: 21 Mar 2015
Posts: 6632
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PostPosted: Tue Jan 08, 2019 8:20 pm    Post subject: Reply with quote

I expect it will be fine and at the end of the day its there to check the cat , it has no bearing on the performance of the car.

Its kinda strange that an eml is triggerd far more by save the planet stuff than it is for actuall engine running faults !

I scoped a brand new cat with new sensors today .. it hardly moves from Lambda .. 0.5 v ..

Basically stamp on the throttle to the floor and back up ( engine running ! ).. there will be some switching to rich (higher voltage ) then lean ( lower voltage ) and that proves its working fine .

Front sensors .. so pre cat .. graph both and your looking for a constant rich / lean switch ( 0.2 - 0.8 v ).. they should almost mirror each other .. if one is lagging behind then your getting into ageing faults .. this is where one lambda sensor switches slower than the other and so generates a fault code .

You dont actually have any codes so nothing is out of specs .. but its always interesting to have a look and get your head around these things .. hence i waffle on about it Very Happy

Fyi .. 997 has different sensors so the above is not true ... these are called wide band sensors .
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Ghianightmare
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PostPosted: Tue Jan 08, 2019 11:30 pm    Post subject: Reply with quote

deMort wrote:


I scoped a brand new cat with new sensors today .. it hardly moves from Lambda .. 0.5 ..


...dirty... Hand you’ll have the RSPCA on your back now Very Happy

But nice to see the scope got some use in this thread Thumb
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wasz
Sepang


Joined: 28 Dec 2012
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1999 Porsche 996 Carrera 2

PostPosted: Wed Jan 09, 2019 5:44 pm    Post subject: Reply with quote

deMort wrote:
Its kinda strange that an eml is triggerd far more by save the planet stuff than it is for actuall engine running faults !


I heard the origins of these lights is in emissions regulation. In the states it was a legal requirement that a light alerted you to emissions fault, and the car would not pass inspection The regulators didn't care about engine faults... and mfrs didn't want to concern drivers with minor faults that could be picked up at service.
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deMort
Long Beach


Joined: 21 Mar 2015
Posts: 6632
Location: Brighton


PostPosted: Wed Jan 09, 2019 8:29 pm    Post subject: Reply with quote

Ghianightmare wrote:
deMort wrote:


I scoped a brand new cat with new sensors today .. it hardly moves from Lambda .. 0.5 ..


...dirty... Hand you’ll have the RSPCA on your back now Very Happy

But nice to see the scope got some use in this thread Thumb



Floor .. ill try to leave the cats alone in future Very Happy

Wasz .. you are correct .. CARB was one of the first emmissions based regulations in the world .. it pre dates OBD .. a police officer could pull your car over .. plug in a tool and check the emissions .. if it failed then it was a tow truck .

Strange that USA has now moved away from the kyoto agreement but hey hoe ... thats politics .

To have a warning system thats based more on the save the planet stuff rather than enigne faults is strange , i dont understand it but thats how it is .

CARB = California Air Regulations Board .
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infrasilver
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Joined: 04 Oct 2010
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Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Wed Jan 09, 2019 10:20 pm    Post subject: Reply with quote

I decided to clean my throttle body while I am still waiting for other parts but it was as clean as a whistle.



Took it out for a 25 miles drive today and it still seems fine even driving straight from cold. I'll try to get some readings tomorrow and post up what it is actually doing.
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infrasilver
Fast & Furious
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2001 Porsche 996 Targa

PostPosted: Thu Jan 10, 2019 10:36 pm    Post subject: Reply with quote

deMort wrote:
Fuel adaption figures if you can get them please .. Rkat , frau , frao .. or tra / stft depending on the tester .


Got some readings today as you requested. The RKAT ones don't seem to be uniform in comparison?



I also had a fault code pop up, P0420 code 40, Cat Conv efficiency bank 1
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deMort
Long Beach


Joined: 21 Mar 2015
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Location: Brighton


PostPosted: Fri Jan 11, 2019 8:31 pm    Post subject: Reply with quote

Ok .. interesting ..

First off .. have you fixed the carbon canister fault ? this will effect the readings .

Second you need to induce a fault .. say unplugging the maf sensor to generate a fault code.

When you clear a dme fault code it will reset the adaptions .. after this you do a r/t of approx 20 miles to get the true reading of what the engine is doing .

RKAT is mixture adaption at idle .. basically the injector duration is increased or decreased depending on what the lambda sensors see .. so a rich mixture and the injector for that cyl will open for a shorter period .. lean and the oposite ... the car will always try to maintain Lambda for each cyl .

Lambda = the correct fuel / air ratio for optimum performance + save the planet ... also called the stoichiometric ratio .

You may well know this stuff already but not everyone does Very Happy

Your current figures ..

6.9 % is the max limit the car can adapt to , your figures are inside of that limit so the car is compensateing .

This is also only on idle .. the car is running fine when above idle .

B1 is a slightly rich mixture .. its acceptable imho .

B2 has a air leak , its minor but its still an air leak .. the car can easily compensate for this so no real action is needed but if you wanted to then you would smoke test the inlet mainifold .. or at least i would .

There is nothing listed that would indicate a hesitation .. soo ..

The next step would to be to look at misfires .. you may need to drive the car and log these .. i think the durametric can do this .

I would also want to graph the pre cat sensors both sides and graph them on a run .. again im pretty sure the durametric can do this .

This would be the next step and posting the pictures will help .. remote diagnosis isnt easy Smile

I will say .. if this is new kit to you then have a play .. look at what you can then ask questions .

Fault code off hand indicates an old tired cat .. it wont effect performance .. unless its damaged but its save the planet stuff ..

Its always worth bearing in mind though .. a partially blocked cat will have an impact on peformance .
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infrasilver
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Joined: 04 Oct 2010
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PostPosted: Sat Jan 12, 2019 3:05 am    Post subject: Reply with quote

I collect the vent pipe from OPC today so will update the tank thread once fitted. I have also rigged up the vac/pressure gauge to the fuel filler cap, again this will be on the other thread.

I did clear the Cat bank 1 code but i have yet to drive the car again, will take it for another spin this weekend once the vent pipe is fitted and I can check the vac gauge at the same time.

My bank 1 Cat may have collapsed internally, I had an aged Cat fault about a year ago and fitted new lambdas, I could hear particles in the Cat when I refitted it but nothing too bad, I checked it again Friday and it sounds worse than it did so I think I will need to source a good used one. I also need to fit a new N/S silencer at some point so a complete exhaust refresh may be coming soon.

I had previously checked for misfires when I was chasing the coil pack fault and there were none showing. All the new coil packs are now fitted as of Friday, I checked the new ones against the ones I removed, all the new ones measured 1.0 ohms and the old ones measured either 0.7 or 0.8 all at room temperature.
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infrasilver
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Joined: 04 Oct 2010
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Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 7:15 pm    Post subject: Reply with quote

I fitted the vent pipe that I collected from OPC today and I found that even with a new valve you can blow through both ways and if you suck in the direction that the tank would require to counteract the vacuum in the tank that is more restricted through the two small diaphragms. An old vent pipe I had lying around is exactly the same as the new one but its good to find out how it should work.

I have pulled the car out of the garage to put some miles on it on Sunday and it drove fine up until I stopped at the shop to pick up supplies. I started the car again and I noticed the A/C display flashing and the voltage gauge surging up to over 15v, the engine was also dropping revs in time with the other things happening.
I pulled away from the shop and the car felt sluggish again, could the alternator regulator be actually causing the hesitation?

See my other thread http://911uk.com/viewtopic.php?t=131774

I've added a video in that thread to show what is happening to the display.

I also noticed when I was running the car in the garage yesterday that when the engine lid fan kicked in the same thing happened, the engine revs drop and stuttered. Battery is only a few months old so I don't think that could be it?

Could this issue actually be my hesitation issue Question
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deMort
Long Beach


Joined: 21 Mar 2015
Posts: 6632
Location: Brighton


PostPosted: Sat Jan 12, 2019 8:37 pm    Post subject: Reply with quote

Ok .. we have a few seperate posts atm so keeping each one to itself is easier .. you have 3 faults atm as far as i see .

Tank vent .. you have fitted the new pipe .. you now need to do a few miles and watch the vacum gauge .. you will soon see if you still have a problem there i think but as it seemed to take a long trip last time i would ask that you keep the gauge on for a while ..

My concern is a seperate venting issue either with the carbon canister vent pipe or the actuation of the purge valve .. never seen either but im erring on the side of caution here .

Once this is fixed we can move onto the hesitiation fault .. which seems like a fuel pump to be honest .
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infrasilver
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Joined: 04 Oct 2010
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2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 8:54 pm    Post subject: Reply with quote

deMort wrote:
Ok .. we have a few seperate posts atm so keeping each one to itself is easier .. you have 3 faults atm as far as i see .

Tank vent .. you have fitted the new pipe .. you now need to do a few miles and watch the vacum gauge .. you will soon see if you still have a problem there i think but as it seemed to take a long trip last time i would ask that you keep the gauge on for a while ..

My concern is a seperate venting issue either with the carbon canister vent pipe or the actuation of the purge valve .. never seen either but im erring on the side of caution here .

Once this is fixed we can move onto the hesitiation fault .. which seems like a fuel pump to be honest .


Unfortunately 3 threads with different issues but they sort of interlink, unfortunately the voltage regulator has taken priority as I don't want to damage anything by keep running it.

Could the pump be affected by the power spikes? The car ran fine tonight until the A/C unit started flashing, the engine stutters and the fans (interior and engine cooling bay) also fluctuate all in turn?
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deMort
Long Beach


Joined: 21 Mar 2015
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PostPosted: Sat Jan 12, 2019 9:00 pm    Post subject: Reply with quote

ill answer here but it should be in the seperate thread for people in the future who search for faults ..

You have an electrical surgeing fault so it seems .. very strange but easy to prove .. remove the wiring from the alternator .. tape the hell out of the main power lead as you are in a world of pain if that shorts out .

Then run the car .. it wil be on the battery only .. if the fault persists then its not the alternator .
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infrasilver
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PostPosted: Tue Jan 15, 2019 10:38 pm    Post subject: Reply with quote

I think the hesitancy issue has cleared after fitting a new voltage regulator to the alternator, I'm unsure how or why this has cleared it and I am still apprehensive that it may not be fixed but I have taken it for a 40 mile trip and the issue didn't return at all. I have linked the thread below, it's the same as the link I posted above but with an update and hopefully the answer to the fault Dont know

http://www.911uk.com/viewtopic.php?t=131774
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deMort
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PostPosted: Fri Jan 18, 2019 10:42 pm    Post subject: Reply with quote

Can i just say .. lets see how it goes .

Im not convinced but it seems to have cured the fault .. im struggleing to see how but to be fair i learn all the time and if this is a fix then its something i have learned and so in atticipation .. thank you .
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Alex
Le Mans
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Joined: 06 Mar 2014
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2000 Porsche 996 Carrera 4

PostPosted: Fri Jan 18, 2019 10:56 pm    Post subject: Reply with quote

+1 on that.........although my sparky mate has told me tales of cars having lumpy tickover, poor acceleration, etc. due to poor battery life and bad earth straps (plus other electrical gizmos). Dont know
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infrasilver
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PostPosted: Wed Apr 03, 2019 3:53 pm    Post subject: Reply with quote

I have been driving the 996 a little more and I still don't think this is 100% cured as I still have a little bit of hesitation but not as before, I currently can feel the pull of the car is very strong (as it should be) up until around 5500 revs and then it takes its time getting around to the rev limit where before it would just get there fairly sharpish. I'd not previously had the chance to get it right around the rev counter.

I have felt this for a little while now and it may have been there when I had the hesitation at lower revs but it was maybe masked because I wasn't really getting up in those rev ranges but compared to the original hesitation it's like night and day once I had fitted the alternator regulator.

I hadn't updated because I knew something wasn't right so I wanted to change the rattling bank 1 Cat and fit new Lamba's to bank 2, bank 1 already being done last year, just in case some of this was causing the problem.
I changed the Cat and lambda's at the weekend and have taken it for a spirited 350 mile drive and it is definitely struggling right up the top end still. I also got an engine management light pop up but then it cleared itself from the dash.

My previous reading from the Cats



What I am seeing today, engine wasn't fully warm though.



Fault codes stored from Monday's EML which had now cleared itself apart from in history.



I also in addition to everything else I have changed recently = MAF sensor, plugs, coil packs, lamda's, bank 1 Cat, alternator regulator I also swapped my original fuel pressure regulator back just to eliminate that too.

What the next logical step, air leak or something else I can change?

EDIT to say I found these possible causes on another thread, I think deMort had already mentioned air leak further back in the thread?

Quote:
Potential causes:
– Incorrect signal from MAF sensor
– Intake air system leaking
– Fuel pressure too low
– Volume supply of fuel pump too low
– Fuel injectors fouled

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deMort
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PostPosted: Wed Apr 03, 2019 6:59 pm    Post subject: Reply with quote

Air leaks tend to cause problems at idle .. so Rkat .. when we talk about flat out .. throttle to the floor then its going to be negligible ..

For flat out performance we need fuel and lots of it .. lambda goes out of the window at this point , the car will ignore the lambda sensors and just dump fuel ..

That's a crude analogy anyways .

Sooo .. we need high fuel pressure and an exhaust that can dump the gasses.

Have you ever changed the fuel pump ? lack of power at full throttle and that's the first thing i would be looking at followed by any problems with the cat .

fault codes all relate to mixture adaption but that will be when it looks at them which is not on full throttle .

I could go with .. is the throttle actually opening far enough .. so remote its untrue but again .. nothing is ruled out till its ruled out .

Knock sensor .. again i cant see it .

Wrong plugs ..

Poor injectors ..

Start with the fuel pump and go from there .. there is i think .. a mesh filter on the base of it .. no debris in the tank that can block it ?

My thoughts anyways .
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infrasilver
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PostPosted: Wed Apr 03, 2019 9:15 pm    Post subject: Reply with quote

deMort wrote:
For flat out performance we need fuel and lots of it .. lambda goes out of the window at this point , the car will ignore the lambda sensors and just dump fuel ..

Have you ever changed the fuel pump ? lack of power at full throttle and that's the first thing i would be looking at followed by any problems with the cat .


This was in the back of my mind, I replaced the pump with a used one, when the tank collapsed because it also lifted the pump up, I changed it as a matter of course rather than it being faulty, I still have my original one to try. Cats both seem to be fine now.

deMort wrote:
I could go with .. is the throttle actually opening far enough .. so remote its untrue but again .. nothing is ruled out till its ruled out .


I'll run it to make sure the butterfly is fully opening at full throttle.

deMort wrote:
Knock sensor .. again i cant see it .

Wrong plugs ..

Poor injectors ..


Knock sensors are as old as the car, I would assume this would flag a fault code but maybe not. I have also wondered about the plugs, they are new but due to them being 4 electrode type I wasn't able to check the gaps, I just ordered for my car but the amount of things I have recently that are wrong is untrue. Again the injectors are old and may need a refurb?

deMort wrote:
Start with the fuel pump and go from there .. there is i think .. a mesh filter on the base of it .. no debris in the tank that can block it ?


I will swap the pump over in the next few days, yes mesh screen on the base of the pump I also have some news that I have found a fuel filter for the 3.6 cars, it can be changed but unsure if the filter is available separately? I will update my collapsed tank thread on this because I also had fuel gauge issues when I filled up last week that I think has now been cured and I was going to post the results there.
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deMort
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Joined: 21 Mar 2015
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PostPosted: Thu Apr 04, 2019 7:23 pm    Post subject: Reply with quote

Fuel pump .. please swop it and see .

knock sensors and i meant they might be seeing a knock .. it will retard the ignition . we are into pretty unlikely here but it can be seen on a tester depending on what one you have .

throttle is again the outside choice but i have seen x1 996 have a defective throttle .. it had worn basically but different symptoms .. i'm going with whatever i can think of here Smile

Plugs are pretty much pre set these days .. if they are listed for your car then the gap will be correct .

A clean of injectors is always a good idea . if only to rule out problems .. a single injector with a poor spray pattern would be similar to a misfire at low rpm .. at high rpm then a lack of power i feel .

Be careful if you get a company to test them .. its often a case of .. you need new injectors .. ask to see the test if so .. you are looking for a cone pattern at 40 psi .. jet or dribble = no good .

I'm not with this atm though .. fuel pump / pressure first .. if you have a filter / i think this model does then change that first .. then test .. then pump .. then we go from there Smile
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infrasilver
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PostPosted: Thu Apr 04, 2019 8:59 pm    Post subject: Reply with quote

I will change the pump back to my old one as I think I have been having problems since changing it and I'll also clean the injectors and fit new seals, I have my own process of doing this with a jig, carb cleaner and a 9v battery. Thumb
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