Golf MK7 all stock, cranks but no start?

   #21  

Mark Hutchinson

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Am I seeing this correctly, the high pressure actual never gets above 5 bar?

This being a direct-injection engine, 5 bar isn't near enough to start it. How about logging those four values, plus RPM during a start attempt?

-Uwe-
Will do. Did you see the graph in one of the pics where the yellow line goes way high? That could be the high pressure?
I will do what you say and get the results. Thanks!

Mark
 
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Mark Hutchinson

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Am I seeing this correctly, the high pressure actual never gets above 5 bar?

This being a direct-injection engine, 5 bar isn't near enough to start it. How about logging those four values, plus RPM during a start attempt?

-Uwe-
Here is a link to the CSV file for all 4 fuel pressures, and RPM as requested.

Let me know what you think. Thanks!

Fuel and rpm log 2016 VW Golf R
 
   #23  

HMC

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i think you are getting confused about what you should be logically diagnosing in a systematic faction, I certainly am. As Uwe has said if you want it to start, fix the problem with the rail pressure.
Regards HMC
 
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Mark Hutchinson

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i think you are getting confused about what you should be logically diagnosing in a systematic faction, I certainly am. As Uwe has said if you want it to start, fix the problem with the rail pressure.
Regards HMC
Agreed.
 
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Uwe

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Here is a link to the CSV file for all 4 fuel pressures, and RPM as requested.

Let me know what you think. Thanks!

Fuel and rpm log 2016 VW Golf R
Yep, never more than 4.8 bar in the high pressure rail. I'm not sure what could cause that, but I'm confident that this will prevent your engine from starting.

-Uwe-
 
   #26  

Mark Hutchinson

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Yep, never more than 4.8 bar in the high pressure rail. I'm not sure what could cause that, but I'm confident that this will prevent your engine from starting.

-Uwe-
Now, mixed up in that....
A fully running car gets in a front end accident, there are fault codes etc....
I would think that would not damage the high pressure fuel pump, BUT, would more likely be from the ECU limiting the pressure like an emergency fuel shut off.

What do you think? Would this still be an emergency fuel shut off after accident caused issue rather than a mechanical one?
Just want to ensure I am not missing an immobilizer (I dont see one in the codes I dont think no..) but maybe some physical type of one?

Thoughts on what could bring that pressure down so much in a (very likely) properly working high pressure pump? Must be accident related somehow and not faulty....

Relays, fuses (I have checked all of the fuses) but maybe a fuel relay? Can think of what would happen in am impact that would get damaged and cause this......
Thanks for the help.
 
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HMC

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Hi Mark,
I am not in a position to check the data or WD for your car at the moment, but I would expect an explicit DTC about crash fuel shut off, and it would stop the LP pump. So check the pressure from the LP pump first and if you don't have pressure check power and earth at the pump and troubleshoot from there.
Regards HMC
 
   #28  

Uwe

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So check the pressure from the LP pump first and if you don't have pressure check power and earth at the pump and troubleshoot from there.
Low pressure is showing at ~11 bar, so it seems there's pressure there. But what I just noticed is that the ECU is only calling for 5 bar on the low pressure side, so it's a bit puzzling why 11 bar is present.

-Uwe-
 
   #29  

Dana

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Ahh, 11 bar is likely a spoofed value because there probably isn't a low pressure senor on this engine. (I noticed this in some 3rd Gen 1.8T engine maps in the past).

Edit, Confirmed 11 bar in Uwe's CYFB R at idle: https://forums.ross-tech.com/index.php?threads/5315/page-2#post-231015
That can be ignored. My guess is there isn't a G410 sensor at all and VW programmed it to confuse people.​

I may be all wrong here but "main airbag module rebuilt and reset". I don't like that at all and the prior suggestions in that area (Crash shut-off data, etc) may be spot on. I would unplug the Airbag module entirely at some point in time just to rule a malfunctioning module.

If the low side fuel pressure is reasonable and you have moved past the possibility that an active crash shut-down signal is to blame I would try to run the engine briefly on starting fluid. As long as it runs and sounds decent mechanically I'd move onto checking the high side fuel components.
 
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Uwe

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Ahh, 11 bar is likely a spoofed value because there probably isn't a low pressure senor on this engine.
[...]
My guess is there isn't a G410 sensor at all and VW programmed it to confuse people.
Well that's rather nasty -- if they're going to spoof an actual value, they should make it match the requested value!

-Uwe-
 
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HMC

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As Jack would have said, check mechanically, electronics can lie. So first step is a pressure guage on the low pressure side and move on from there.
HMC
 
   #32  

vwtech

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You have to know low pressure. 11 bar is to high.
I would say the 4.8 bar on high side is low side pressures actual value. A gauge on low side will tell you?
Looks like high side pump isn't working and all you got is low side pressure going thru high pressure pump and showing on the high pressure switch.
Good Luck
 
   #33  

Mark Hutchinson

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Jeesh. I reversed the fuel lines by the passenger strut tower.
corrected that and it runs amazingly!!!

I will star a new thread for my further code and fault issues if that’s ok.
Thanks all for the help!!

would never have gotten it without measuring fuel pressures with vcds.

EWE. You are a genius!!
Mark
 
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Uwe

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EWE. You are a genius!!
2KAF6PG.jpg


:D

-Uwe-
 
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DV52

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Uwe etymology: Frisian name of debated origin; possibly a short form of Germanic compound names beginning with - "industrious" or Old High German agil (“sword”) (etymologically allied with Latin "acūtus", Proto-Indo-European *h₂eḱ- (“sharp”)). The Scandinavian variant Ove may have Old Norse origin.

Seems entirely appropriate ;) !!

Don
 
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Bruce

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Does seem entirely appropriate that Uwe would be named as an "industrious sharp sword". Have you ever been on the receiving side of his cutting whit? It is sharp and applied liberally at times! :D ;)

Just having some fun at your expense boss!:p
 
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   #39  

DV52

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Have you ever been on the receiving side of his cutting whit? It is sharp and applied liberally at times! :D ;)
@Uwe: my apology for talking about you, rather than to you!

@Bruce: I suspect a rhetoric question, but if not -the answer is No. I have never met, or spoken to the man - so I rely entirely on folk like you for my belief that he actually exists!

I'm not sure if you are familiar with the term "persiflage" (if not, look it up). I call it "the flage" and it's a personal trait that I seldom see in folk - but for those that have the gift and the intellect to wield it with aplomb, it can often be charismatic!!

An even more fascinating (and very rare) experience is to witness the exchange between 2 x individuals who both possess the flage. The mano-et-mano verbal duel can be extremely entertaining.

Don
 
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Bruce

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Your guess would be accurate - he exists! I also believe Uwe and I are quite "flage-ist" people Don. Seems we practice at it regularly!

In fact, I think we hire only those who possess some flair for persiflage. You know how that goes? One often hires people with a similar self-image? Well, it does lead to lots of entertaining convos within the RT halls.

I think we are hijacking this thread and we better get back on topic... else the other "flage" will be along to kick us in the "flaggeing" arse! :D
 
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