Hi guys.

 

Been getting a bit of det under high load at low revs (higher gears), I know I'm running lean but just thought I'd double check the timing as well. Base timing was at 20 deg so I reset to 15 deg. By trial and error I've found that I can tighten the top and bottom bolts of the CAS without affecting the timing but tightening the middle bolt causes timing to advance by 5 deg. The CAS doesn't move at all when tightening the bolts. Not sure why this is?! Perhaps it's not on straight?? Not sure how this would be possible though considering it sits on a gear and inside the cylinder head housing. It looks straight enough. Time for a new unit??

 

BTW, just fitted dual LC-1 widebands and gauges (hence I know it's running lean ;)). A real PITA overall but worth the pain I think...

 

Cheers

 

RobH

Edited October 7, 201213 yr by RobH

what afr u running on load and normal coasting ?

Hi guys.

 

Been getting a bit of det under high load at low revs (higher gears), I know I'm running lean but just thought I'd double check the timing as well. Base timing was at 20 deg so I reset to 15 deg. By trial and error I've found that I can tighten the top and bottom bolts of the CAS without affecting the timing but tightening the middle bolt cause timing to advance by 5 deg. The CAS doesn't move at allo when tightening the bolts. Not sure why this is?! Perhaps it's not on straight?? Not sure how this would be possible though considering it sits on a gear and inside the cylinder head housing. It looks straight enough. Time for a new unit??

 

BTW, just fitted dual LC-1 widebands and gauges (hence I know it's running lean ;)). A real PITA overall but worth the pain I think...

 

Cheers

 

RobH

 

Check this out from Jeff Rob....he goes on to say if the rear bearings knacked it can effect signal drifting,as your pinching down the middle bolt it might be lifting the bearing in its housing .

http://www.300zx.co.uk/forums/showthread.php?126423-Inside-Out-quot-CAS-UNIT-quot

Hmm..interesting, thanks. I guess the acid test is to replace with a known good one (as usual).

 

Mark, under low load 'cruising' AFR is around 14.5:1, I'm reasonably happy with that. Under high load at low revs (i.e. foot down hard at 3K in 4th or 5th gear) it's staying around 13.5-14:1, I'm not happy with that at all. I'm part way through building a custom map, just trying to ensure everything else is working right before meddling with the fuel map any further.

 

Cheers

H

yeah that is on the Lean side on load ... should be 12>11.5:1 really

Hmm..interesting, thanks. I guess the acid test is to replace with a known good one (as usual).

 

Mark, under low load 'cruising' AFR is around 14.5:1, I'm reasonably happy with that. Under high load at low revs (i.e. foot down hard at 3K in 4th or 5th gear) it's staying around 13.5-14:1, I'm not happy with that at all. I'm part way through building a custom map, just trying to ensure everything else is working right before meddling with the fuel map any further.

 

Cheers

H

 

your welcome to try mine as i have my motor in bits...ime only CH63

Znut, apologies for the late reply, been a bit tied up with other vehicles :-\ . Thanks for the offer, I may well take you up on that, out of interest my bird is from Spital (also CH63).

 

Had the injectors cleaned and tested by injectortune, seems to be a good service if their before and after test data sheet is to be believed. All injectors were flowing under 550cc by varying degrees and now all are exactly 550cc (hmm...). Oddly it's now running leaner. I suspected an intake leak, having had upper plenum and a multitude of hoses off, but testing it shows it's pretty well air tight...back to programming the ECU via the laptop I guess, if I ever get chance :(

 

Cheers

H

Edited November 5, 201213 yr by RobH
typo

Out of interest, I've tried another CAS with the same result, set the timing accurately and by the time the bolts are tightened it's out by 2 or more degrees again. I've adjusted so that by the time the bolts are tight it will be 15 degree precisely but can't help feeling this shouldn't be necessary. Perhaps there's a slight problem somewhere behind the CAS. It does show how important it is to confirm 15 degrees after tightening everything up.

 

H

Out of interest, I've tried another CAS with the same result, set the timing accurately and by the time the bolts are tightened it's out by 2 or more degrees again. I've adjusted so that by the time the bolts are tight it will be 15 degree precisely but can't help feeling this shouldn't be necessary. Perhaps there's a slight problem somewhere behind the CAS. It does show how important it is to confirm 15 degrees after tightening everything up.

 

H

 

Is the CAS housing flat on the block where it bolts up...the outside face should be a true 90 degrees to the end of cam for it to sit right when held down by the 3 outer bolts

Yes, as far as I can tell it's straight. I suppose as long as the base timing is correct it's not too big an issue, it is bugging me a bit though :-\ . It's also adjusted close to the limit in a clockwise direction, as I understand it it should be more or less central to the range of adjustment. The cams are non standard so I'm wondering if that may be something to do with it...

 

Cheers

H