ECU fault codes - 34 knock sensor

veecee · Post by **veecee** » Tue Mar 20, 2007 8:01 pm

THANKS ever so much to everybody who has replied.

thanks sokar for the tip on phinx, but i managed to convince toby to "lend" mr his CAS. i fetched it last night.

caver - the mixtures i am sure are not 100%, but i do know that i have proper fuel pressure, and that the injector solenoids are being activated.

two things i noted:

1. the timing light does not flash when the problem is there, as long as its off idle - otherwise its normal. this tells me there is a total loss of signal in the coil harness.

2. there is a strong smell of fuel when the problem is there, and there are wet spots all over the driveway at the exhaust outlet!

BUT i think we've solved it. and you would NOT believe me when you hear it!

veecee · Post by **veecee** » Tue Mar 20, 2007 9:24 pm

THE SOLUTION:

it was the cas, and perhaps the engine temp sensor too!

the reason i say perhaps the engine temp sensor, is while the engine was cold this morning i took out the temp sender unit. i then plugged the hole with something else, and used a hairdryer to heat it up very hot.

so with everything else cold, the computer thought that it was hot.

it struggled to start, and when it did, it would not rev up past 1500 just like before. when we unplugged the sender the car ran fine.so i thought that i had solved it, but i was wrong - and murphy was kicking my ass.

it was also my CAS.

i drove around to find a new temp sender, but noone had stock. and this time it took much longer for the problem to come back. but it did eventually. i then unplugged the temp sensor, but it didnt solve it.

we then got home eventually when the car had cooled a bit, and made the problem come back before we swapped CAS's. and the problem went away!!!

we drove around for hours all afternoon, and it never came back. then later this evening i decided to open up my CAS. this is where i found what i think coul've caused all these faults!

veecee · Post by **veecee** » Tue Mar 20, 2007 9:35 pm

the CAS:

the CAS has two bearings on each end of its shaft. mine felt and sounded fooked. but i had no idea how bad it was until it was open.

when i got the housings apart, i noticed a wet dark grey substance on the outside surface of the smaller bearing (NSK 6000). the same substance was on the inside of the housing that held the bearing.

conclusion? the bearing was turning inside of its own housing! not good!!!
it was the same pasty grey substance you get when sanding aluminium with 1200 grit and water!!!

once i got the rear housing open - the bearing there was totally stuffed. it wasn't broken, but didnt have any lube left, and was running freely, metal on metal!

i'm convinced that these problematic two bearings were probably the cause of eddy (???) currents generated that confused either the optical pickup, or the signal that it generates.

so if the CAS sends a strange signal to the computer, then the computer sends a strange signal to the coils - and BAM...

very erratic running of a certain CA18det.

i took lots of photos while dismantling and "mantling" the CAS, and i will post a long thread with photos in the articles section.

thanks again guys!

and huge thanks to those who donated parts for testing:

Vlade
Toby.

fank!

widowmaker · Post by **widowmaker** » Tue Mar 20, 2007 10:56 pm

knock knock

Sokar · Post by **Sokar** » Tue Mar 20, 2007 11:10 pm

Awesome man, just sorry I cant be at wesbank tomorrow to watch you strut your stuff

veecee · Post by **veecee** » Tue Mar 20, 2007 11:15 pm

Sokar wrote:Awesome man, just sorry I cant be at wesbank tomorrow to watch you strut your stuff

are you two in durbs??? or the south coast somewhere??

how's the waves??? believe it or not, i used to be a surfer!

Toby · Post by **Toby** » Wed Mar 21, 2007 11:07 am

Woohoooo... light at the end of the tunnel!! Glad to see this whole saga is coming to an end

ChemCool - his car was exhibiting similar symtoms to yours, albeit much worse, but maybe you should have your CAS and temp sensor checked out?

The Calibrator · Post by **The Calibrator** » Wed Mar 21, 2007 12:10 pm

The symptoms you described sounded like a to rich mixture which is verified by the strong fuel smell and the fuel running out of your exhaust.
If you measure the resistance on your coolant temp sensor you will probably find that its going open circuit or to a very high resistance. This will make the ecu think its like -40deg and cause the flooding you described.
As for the cas issue a scope on the ouput would have picked up the fault straight away.
Like I said om te meet is te weet.
Well done on getting to the bottom of it eventually.

veecee · Post by **veecee** » Thu Mar 22, 2007 9:02 am

The Calibrator wrote:The symptoms you described sounded like a to rich mixture which is verified by the strong fuel smell and the fuel running out of your exhaust.
If you measure the resistance on your coolant temp sensor you will probably find that its going open circuit or to a very high resistance. This will make the ecu think its like -40deg and cause the flooding you described.
As for the cas issue a scope on the ouput would have picked up the fault straight away.
Like I said om te meet is te weet.
Well done on getting to the bottom of it eventually.

LOL - there were a few wet black splatters out the exhaust, but it wasn't running out. you make it sound like a tap!!! then i would agree about the mixture being too rich. when the car was idlng, it was fine. the splatters and the smell were unburnt fuel because there was no spark!

we did measure the temp sender and although i cant remember the exact figures - it wasnt an open circuit. but it did show a big range dependent on temperature.

i first thought it was temp sender, but nissan wanted R350 exvat, and they didnt have stock - luckily. i used the car on the track yesterday without hassles - so now i dont think it was that. so i dont think i will swop that part out yet.

it was my CAS. and the symptom was what people on other forums call the ECU "limp" mode. the FSM actually describes it, and states that two conditions would cause it. faulty engine temp sensor, and a faulty AFM.

i didnt think a faulty CAS could cause it too, and my idling limit was 1500rpm, not 2000rpm like everyone thinks.

if you try to run your car with your AFM unplugged, you get the same symptoms.

The Calibrator · Post by **The Calibrator** » Thu Mar 22, 2007 9:29 pm

engine temp sensor should be around 2.5 to 3k cold and 200 or 300 ohms at operating temp.
Sure was a lot of work to find a faulty cas.

Draco · Post by **Draco** » Fri Mar 23, 2007 9:26 am

Good stuff VC....again something simple that kept us guys scratching heads.

veecee · Post by **veecee** » Fri Mar 23, 2007 10:18 am

The Calibrator wrote:engine temp sensor should be around 2.5 to 3k cold and 200 or 300 ohms at operating temp.
Sure was a lot of work to find a faulty cas.

it was a lot of work!!! and plenty of annoyance!!! and i was very close to getting rid of the engine!!!

but thats because i've learnt that there can be faults on components that do not register faults on the computer box. that is why i cam still not 100% convinced it was the CAS to start with, but as soon as i put my old one back - then it doesnt run!!! go figure!

but its all good now. thanks for the info on the engine temp sensor, i'll go "meet" it to make sure its 100%.

thanks also to draco, and the others, for keeping me going with this. all i can say is there definitely is such a thing as "limp home" mode!!!! and it sucks!

veecee · Post by **veecee** » Sat Mar 24, 2007 7:35 am

check this out.

the electronic part of my CAS is stuffed, so i could get this:

http://cgi.ebay.com/ebaymotors/ws/eBayI ... gory=33690

or for a few extra dollars, you can get a brand new one:

http://cgi.ebay.com/ebaymotors/ws/eBayI ... gory=33690

has anyone ever heard of Beck parts????

Sokar · Post by **Sokar** » Sun Mar 25, 2007 9:45 pm

veecee wrote:
Sokar wrote:Awesome man, just sorry I cant be at wesbank tomorrow to watch you strut your stuff
are you two in durbs??? or the south coast somewhere??

how's the waves??? believe it or not, i used to be a surfer!

You.... Surf..... you HAVE to send me pics of that!!!!

Yeah, got back at 17:00 today, been catching up my forum reading.

So how's your cabby? Looking for a CAS?

How "badly" is yours poked? IE what parts are usable?

veecee · Post by **veecee** » Sun Mar 25, 2007 10:20 pm

everything 'cept that electronicalistic bit on the inside!!!