After 6 months of intermitent stalls and hicuups and replacing MAF, Maf connector, FPCU, ECU in multiple combos, I finally replaced CAS with brand new unit..................problem has gone away so far 5 days of perfection.
Upon destructive disassembly the problem was found to be oil leaking into unit..............where tiny drops of oil were confusing the 360 - 1 degree optical wheel. The 90 degree Hall effect wheel had a fine rust film which came off with brake cleaner [not a problem]
oil would leak in and migrate from the center shaft on startup and slowly out to the edge and then fling itself off until the next time a few drops at a time.
The CAs is spinning at cam speed 325 idle and 3500 redline.............at high rpm the leaking oil flew off so fast it didn't have time to confuse ecu.
1980 Hz at idle [ 325 rpm/60 x 360 slots]........>>>>>> 20,700 Hz at redline
The clearances were greater cold so the the problem always occured early in the warm up process and went away mostly after 10-14 minutes.......always worse on cold days than warm days.
Something similar occurs on J30 [fairly common on high mileage] but the design is a little different.Never threw a code.
As a side effect the first crank fast idle and warm up idle improved in stability and engine smoothness. What I thought was a bad motor mount was the unstable warm up idle.
The Consult shows a much narrower range of idle rpm scatter also acceleration is faster [tighter rpm/ignition control].
The system actually has 3 independent circuits the Hall magnetic 8 pulse and the optical 1 degree [360 pulse] plus optical 90 degree [4 pulse].
A USED CAS could have the same leakage problem so always monitor the pulse train with an oscilloscope.................you cannot dissassemble the optical section without damage and cannot put it back together again.
90-93 Q and 04-96 are different and I have never disassembeled a 94 yet!
I'm going to make an adapter cable that will make it easy to connect to the CAS and monitor the pulse train.
CAS oil leak on Q at 312,000 miles
Re: CAS oil leak on Q at 312,000 miles (Q45tech)
this looks like the same problem with my Q .and when i removed the cas it had oil in the hole where it was in stalled 92 q45 116,000 miles
also got a new cas and replaced it but did not fix the problem so my question is.......... the hole that the CAS is installed into should not have oil in it at all ? next question............ before you fix this problem when driving your Q did it have no acceleration and have trouble getting over 1,500- 2,000rpm or is this a safe mode setting retarding my engine ?
how did you fix the leak
also got a new cas and replaced it but did not fix the problem so my question is.......... the hole that the CAS is installed into should not have oil in it at all ? next question............ before you fix this problem when driving your Q did it have no acceleration and have trouble getting over 1,500- 2,000rpm or is this a safe mode setting retarding my engine ?
how did you fix the leak
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: CAS oil leak on Q at 312,000 miles (ejXa q45)
Unfortunately half a dozen things can cause the exact same driving symptoms and the problem never showed a code on Consult or any identifiable out of range signal.
Sometimes you can have 2 or more problems interracting with each other.
Unfortunately you cannot tell from the outside whether the oil is getting inside so substitution is the only method if the problem is intermitent.........unless you drive around with a digital oscilloscope looking at the pulse waveform. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-----^^^^^^^^^^^^____^^^^^^
Sometimes you can have 2 or more problems interracting with each other.
Unfortunately you cannot tell from the outside whether the oil is getting inside so substitution is the only method if the problem is intermitent.........unless you drive around with a digital oscilloscope looking at the pulse waveform. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-----^^^^^^^^^^^^____^^^^^^
Re: CAS oil leak on Q at 312,000 miles (Q45tech)
312k... F'n AWESOME 206k seems like cheating death...