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flightlead404 flightlead404 is offline
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Join Date: May 2015
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Quote:
Originally Posted by Reanimotion View Post
It's unlikely the accumulator is an issue

Watch the actual Control Pressure during start-up, from the earlier logs the initial few warm cranking events showed CP pegged at round 100PSI, I still suspect there is an overpressure or inrush issue when the fuel pumps startup that is holding the injector shut.

With such a high CP there will be no fuel delivered and as it's warm the Cold Start Injector is not providing any help for the initial kick to pull the air plate against the CP resistance

for peace of mind, I'd remove a variable by reintroducing the original Bosch WUR instead of the eWUR, and look at bringing the eWUR into play later in the tuning phase if required.
Especially as you know the Bosch WUR works and our tuning target is focused on the Frequency Valve anyway
Didn't think it would be, but I thought I'd toss it out there.

Not sure what you mean by "inrush". In my car the fuel pumps run for a second or two when you go to the "run" position, to bring pressure up. In the last few starts I've gone to "run", paused for a second or two for the pumps and to make sure MS is online, then gone to crank. Where are you talking about "inrush"? When cranking starts, around 150 RPM, or when the engine fires?

I can try putting the original WUR back in place. Its not the elegant solution I was looking for, but its worth a try I suppose.

I'm unclear on your statement about "no fuel being delivered". If the eWUR injector is being held shut against 100psi (Is that really likely? I know EFI systems run at high pressure, would have thought 100psi was not that far out of that range), that would mean we'd be at high CP potentially, meaning a lean system. But "no fuel"? I find that unlikely. How is a held shut eWUR injector any different than a stock WUR that doesn't have any way to bleed pressure off at all? High system/control pressure is not going to hold the CIS injectors shut, so a rev or two during cranking and that pressure should be off the system, right? I'm not sold on that idea.

If I do put the stock WUR back in place, my WUR has an enrichment that happens based on MAP (not sure if all turbos do, but certainly mine does) I forget where exactly that occurs. It seems to me that it would be better to leave the MAP line disconnected from the WUR and control that enrichment entirely with MS/FV. The entire purpose of going this direction was to have the ability to tune for the optimum AFR across the spectum, without having the big jumps and so forth that the Leask WUR+RPM switch has, and to avoid the "pig rich in some areas to avoid being lean in others" problem.

Thoughts?

Last edited by flightlead404; 02-12-2017 at 08:30 PM..
Old 02-12-2017, 08:18 PM
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