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Old 02-25-2014, 01:02 AM   #261
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Watching anxiously for this thing to run. Sux man. Good luck.
Oh trust me, I am too!!!
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Old 02-25-2014, 01:49 AM   #262
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Lets think of it this way: I thought I read earlier someone posted that 50%DC on the VVT chingaderas was 0° or "neutral" in terms of advance/retard. As I was trying to get to in my earlier post, does more oil pressure cause it to advance or retard? I know we can't measure the pressure directly, but we can infer its getting too much or not enough from what we are seeing? I'm just trying to figure out if there is a way to determine a blockage or surplus in flow.

Maybe I'm way off base Don't drink and think kids
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Old 02-25-2014, 08:27 AM   #263
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Vlad needs to do a datalog with the crank and can patterns I bet everything is still skew wiff still in spite of the can change.

The lack of starting is due to this. No sync, no start. What's causing it is the question
Its nothing to do with injectors, or vac ports.
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Old 02-25-2014, 09:54 AM   #264
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Lets think of it this way: I thought I read earlier someone posted that 50%DC on the VVT chingaderas was 0° or "neutral" in terms of advance/retard. As I was trying to get to in my earlier post, does more oil pressure cause it to advance or retard? I know we can't measure the pressure directly, but we can infer its getting too much or not enough from what we are seeing? I'm just trying to figure out if there is a way to determine a blockage or surplus in flow.

Maybe I'm way off base Don't drink and think kids
I think 50% DC is "hold position". Because oil is always flowing through the actuator, it is always trying to change position. The way to get it to hold a position that is not fully advanced or retarded is to with 50% PWM. Since the mechanical portion of the VVT cannot move as fast as the solenoid, it ends up not moving at all.

I am having a hard time thinking of where an oil blockage could be that would only cause the cam to advance. much of the oil control system flows in both directions, which would imply the blockage is acting as a check valve. this my be due to my poor understanding of the oil control in the system. I will try to take a closer look at my car when I get a chance and see if I can find something.
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Old 02-25-2014, 10:21 AM   #265
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Can you command 0% and 100% duty on the VVT while cranking? It would be interesting to see what the resulting cam angles would be in those completely opposite situations. In other words, if there is enough oil pressure at cranking speed to fully retard/advance the cam, does the cam in fact respond to changes in VVT duty?
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Old 02-25-2014, 12:12 PM   #266
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Can you command 0% and 100% duty on the VVT while cranking? It would be interesting to see what the resulting cam angles would be in those completely opposite situations. In other words, if there is enough oil pressure at cranking speed to fully retard/advance the cam, does the cam in fact respond to changes in VVT duty?
Mmh not sure if there is enough oil pressure for the VVT to work correctly at cranking.
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Old 02-25-2014, 12:14 PM   #267
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Welp, I just multi-quoted every single post and typed up a 2 page response, when the stupid site decides to log me out.

How appropriate for the current thread theme of: FAIL

I'll re-type a response later today.
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Old 02-25-2014, 01:16 PM   #268
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Originally Posted by Davezorz View Post
I think 50% DC is "hold position". Because oil is always flowing through the actuator, it is always trying to change position. The way to get it to hold a position that is not fully advanced or retarded is to with 50% PWM.
No, it varies with pressure and viscosity of the oil (what oil and it's temp). There is a reason it's set up closed loop.
I have seen 15 to 55% DC for stationary cam values, but my cam is a bit harder to turn.
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Old 02-25-2014, 01:20 PM   #269
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Welp, I just multi-quoted every single post and typed up a 2 page response, when the stupid site decides to log me out.

How appropriate for the current thread theme of: FAIL

I'll re-type a response later today.
Just one question need answering, does it run?

If not, composite log, cams identical, ...?
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Old 02-25-2014, 01:27 PM   #270
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I can only imagine how enormously frustrating this has to be.
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Old 02-25-2014, 02:27 PM   #271
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You said it has fuel, right? Have you yanked the fuel hose off the rail to make sure it's actually coming out when you crank it over?

*I unknowingly removed the fuel pump fuse during one of my BMW swaps. I spent 3 days double-checking wiring, swapping out known good fuel pumps, etc. Put the fuse back in (once I discovered it) and it started right up and ran.
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Old 02-25-2014, 02:29 PM   #272
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For the love of god.

A datalog. PLEASE.
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Old 02-25-2014, 03:32 PM   #273
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Originally Posted by NiklasFalk View Post
No, it varies with pressure and viscosity of the oil (what oil and it's temp). There is a reason it's set up closed loop.
I have seen 15 to 55% DC for stationary cam values, but my cam is a bit harder to turn.
can you explain why that is the case? Unless my understanding of the system is flawed, viscosity and pressure make no difference, because with a 50% pwm, you are dividing the pressure equally between the advance and retard chambers of the VVT gear.

I do not deny that the cam angle may drift and need constant corrections. The values you posted would seem to imply that the cam would tend to advance on its own.

Last edited by Davezorz; 02-25-2014 at 03:46 PM.
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Old 02-25-2014, 04:32 PM   #274
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50% PWM DC doesn't mean that the valve is in the middle position. Try it with a valve on the bench and you'll see. With a 50% DC, it will eventually open up fully.
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Old 02-25-2014, 04:40 PM   #275
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Originally Posted by Reverant View Post
50% PWM DC doesn't mean that the valve is in the middle position. Try it with a valve on the bench and you'll see. With a 50% DC, it will eventually open up fully.
I am half tempted to force my VVT to 100% and attempt to start my car just to see if it will start. I am just wondering how far out of alignment the cam has to be before it won't start.

(for SCIENCE!)
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Old 02-25-2014, 04:52 PM   #276
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For science, it will always start but it won't idle, it will just die violently a few seconds later if you don't give it some throttle.
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Old 02-25-2014, 06:05 PM   #277
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Originally Posted by Chiburbian View Post
I am half tempted to force my VVT to 100% and attempt to start my car just to see if it will start. I am just wondering how far out of alignment the cam has to be before it won't start.

(for SCIENCE!)
I doubt you can do that due to lack of oil pressure, as it's the pressure that works against the spool valve to advance the cam.

Lack of oil pressure will not prevent a motor from starting.
Lack of oil pressure will damage bearings.

At full advance (like stated by Reverant), it will be reluctant to idle.
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Old 02-25-2014, 06:40 PM   #278
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Brings up a good point though, is this thing making oil pressure?
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Old 02-25-2014, 09:27 PM   #279
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Brings up a good point though, is this thing making oil pressure?
It's not going to make oil pressure until it starts. The engine has to spin the oil pump fast enough to make pressure.
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Old 02-25-2014, 09:43 PM   #280
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I believe he said it ran for some very short duration of time after the lash was set, then it died never to restart again. I'm wondering if it came up to pressure in the short period of time.
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