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Discussion Starter · #1 · (Edited)
You may want to grab a brew or beer, then read this. :)

Shell, last month (April) 2021) revised it's blend of V power with Dynaflex giving more cleaning abilities and 4% more power.

Great, that sounds good! Right? Erm, maybe, I don't have any proof yet, but bare with me.

I have a tuned S5 3.0 V6 Supercharged. It was remapped 2 years ago on Shell V power. Tuners recommend using Tesco Momentum 99 when remapping as it gives the best results on reducing timing pulls due to it being souped up with Ethanol whereas VPower was other additives to increase the octane.

I believe VPower to be slightly superior over Momentum mainly due to its cleaning etc, where as Momentum is said to get you those extra few bhps on the dyno!?

Anyway, I'm not getting into 'that' debate shell Vs Tesco. This is different, I think.

I've been filling with Vpower for the past month or so, sometimes with the odd fill of Tesco. I didn't really see a difference in performance, maybe Tesco had a 'sharper' edge to it than Vpower. I also found mpg seemed slightly lower on Tesco.

BUT!

Since last month, I have found my S5 to running sweet and seemed like it was pulling harder. Now I work from home, real everyday driving isn't comparable as driving the same route to and from work, so it may be placebo as I'm not driving as much, so just enjoying driving. But like I say it seemed to be driving very well like someone had tinkered with my ECU map.

I was having a blast when all of a sudden, the power went like it does when traction control kicks in, but I now always turn my traction control to sport (Half off) since the S5's power will spin all 4 wheels. So now when driving spiritedly, I do a quick cockpit check/change to exhaust flaps fully open, Traction to Sport, Auto start stop off, and Gearbox in sport manual. :)

Going back to the power loss. It started on the gear change into 3rd with WOT. Pressed the throttle a few times, nothing, then the power came back to normal. It did it once more on the drive and this was after driving for around an hour. No CEL lights or anything. Checking with VCDS gave P0089 Valve for fuel metering - implausible signal, P2279 Leak in air intake system - intermittent, P310B Fuel pressure outside Specification on low pressure side! Bowlocks!? I've read from the guys in the US that this is common on stage 2 and it's the tank fuel pump not keeping up with demand. Also going back to stock tune, the fuel pressure wasn't an issue as the demand is lower. But the Low pressure fuel pump should regulate at 5 bar, mine went to 7.3 bar!? so I would have thought a high pressure would be ok as it would still be supplying fuel? Anyway, according to the guys who have had this, the fuel pressure drops, then over pumps giving the 7.3 bar. The solution was to replace the tank fuel pump, but I'm not sure. My fuel system appears to be running fine and the fact the pump can do 7.3bar leads me to think it can supply enough fuel?

Still with me? In the US E85 (85% Ethanol) fuel can be used and it's equivalent octane rating is the same as race fuel, up at 105 (not sure if this is US rating). Also when running on with Ethanol the mpg goes down and a higher volume of fuel is used so the fuel pumps are working harder, hence the high pressure fuel pump upgrades like Autotech's HPFP piston upgrade.

Back to me. I went out again in the car and it pulled power again under WOT in 2nd gear. The fuel was V power and low level in the tank. It doesn't cut power every time. And no fault logs in VCDS since the first time it did this power cut.

I've been researching and pricing up the tank fuel pump as last resort to cure this problem. But last week, I refilled with Tesco and not filled with Tesco for the past 2 maybe 3 fills. Been on a decent drive, no power cuts, no fuel pressure codes in VCDS, but the power doesn't feel as sharp as the shell stuff now!?

Only time will tell and if I refill again with shell to see if the performance improves and if I get power cuts again!? I will obviously update.

But it's only with the guys in the US talking about needing to upgrade the fuel pump to flow more fuel which is what high ethanol fuels need, I looked at Shell's website and they revised their V power blend in April which is when I got this fault. The car has been as I said at stage 2 for 2 years with no problems!

Also September this year the UK government has announced ALL unleaded fuels are to contain 10% ethanol in the fuels (E10). It is E5 (5%0 at the moment. So will this aafect us with Ethanol demanding more volume? If this is true why doesn't the Tesco 99 give me fuel cuts it it's octane is upped by use of ethanol.

This is my car saga at the moment and not conclusive if it is the fuel blend or an actual issue with my car. But I do want to try Shell again as the 4% extra power, I think was there on my car!

I'm going for a little rolling road run to check my car's performance/health in a week or 2, so don't want another issue as before I had a charge cooler issue when mapping my car.

Fingers crossed it was a glitch. I'll continue with my 'testing' of Tesco Momentum and Shell.

If any of you can add to my findings or suspicions, please do let me know! :)
 
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I would agree the V-Power is certainly a better "quality" fuel than the Tesco 99. But that V-Power is about 15p more than Tesco fuel :mad:. As you mentioned the Tesco fuel lacks the cleaning agents of V-Power so every 3 months I spend £15 on a decent fuel system cleaner 😁

I think longterm if you used Tesco fuel without any cleaning agent the tip of the direct injectors may suffer.
 

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Great post Dave. I only use Vpower or Momentum, with 90% of the time being Vpower.

MRC stage 2 and I have had a loss of power when WOT a couple of times in the last year since the remap.

I can't recall the error codes now, but they indicated coil packs. I've not changed them, but will check the errors next time this happens.

Like you I don't drive it often enough to recognise the difference between the two fuels.
 

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Discussion Starter · #4 ·
That's interesting you got the power loss with WOT!? Do you turn traction off as this can feel the same when traction control kicks in and the flashing traction light is not always noticeable.

When was this? Did you mention it to Doug? Would you recall whether it was V Power or Momentum?

Strangely it did it twice after the first occurrences, when it logged the fault codes, but didn't log any codes since the first occurrence!?
 

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Traction control off (long hold on the button). First time was on the way home from Doug, and was on the M25, traction off, in sport and floored it at about 70mph...

The second time was from rolling from about 20mph, full WOT and then huge power loss. Had to stop to switch off and on to reset.

Both times there were error codes, and when I looked at them the indication was coil pack cylinder 3.

I've not mentioned it to Doug since as I've not had the issue again, but I have changed my driving style to be slightly less full on/off so not had it since. Next time I'll change the coils as this was what Doug said on the day I should do if it goes into limp mode
 

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Interesting reading. I'm only stage 1 and do the same as Mr Sayek. Use momentum most of the time and the occasional fuel cleaner.
I have used vpower recently (in fact it's in the car now) but I've had no issues. Maybe it's just not requiring as much only being stage 1? In any case as I'm in for another mapping session soon I'll probably stick to momentum to be safe.
Dave I'm sure Mike will be able to give you some answers when he does his thing and maybe even find out what's happening.
Not long now. 😁
 

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Discussion Starter · #7 ·
That's the thing, it's not like I've just had a remap, it's been fine for 2 years, so it's either something to do with the fuel or my car :)

I was going to run on Momentum only for the rolling road sesh. But the fact it felt very peppy on this new blend of V Power, it made me think, but then again if it is the new blend giving the fuel cuts, then best to stick with tried and tested Momentum!?
Yep week on Sat! :)

Out of interest Joe and Mr Sayek, what fuel cleaner do you use?
 

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On the other hand though Dave, would it be better to use the vpower and have your map tweaked to suit it? Might be worth asking Jason/Mike for their opinion as I'm sure if it's better they'll know.

Regarding fuel system cleaner I'm not too opinionated on a particular brand but I used Nitrox hot shot last time.
 

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Discussion Starter · #10 ·
On the other hand though Dave, would it be better to use the vpower and have your map tweaked to suit it? Might be worth asking Jason/Mike for their opinion as I'm sure if it's better they'll know.

Regarding fuel system cleaner I'm not too opinionated on a particular brand but I used Nitrox hot shot last time.
I'll give him a shout! and see. :)
 

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Discussion Starter · #11 ·
I read some decent reviews on this cleaner
Red Line SI-1 Fuel System Cleaner

Not sure if any point using those basic Redex cleaner you see at petrol stations :)
Quite a few on the market.
I'm old school and think of Redex as more of an old fashioned additive for old 4 star engines. :) Although they do a few varieties now.

In theory, using V Power, I shouldn't need to use cleaners! :)
 

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VERY interesting read guys!!! I tend to use standard fuel and then every month ish I add some STP or Redex or another fuel additive to keep everything clean. Over here in Italy we dont have cheap supermarket fuel so we must use the standard pumps.
 

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I’ve been using shell V-power and their standard diesel and since owning and can’t say it makes any noticeable difference. I treat the car to V-power every month and also redex aswell every three months or so!

otherwise always kept to branded fuel.

like they say, Heinz ketchup or Unbranded🤮?
I know what I’d go for!

~Alex
 

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Discussion Starter · #14 ·
My Remapper has said they have seen good results from Esso Synergy Supreme 99! :)
But the nearest one to me is about 25 miles away!

As always, think the best thing is to buy and try and see which your car likes to drink! :) But as I said, as I don't do commuting anymore, this testing takes much longer! :D

But yes, I don't do supermarket fuels, except Tesco Momentum 99. Did you see the other week, Morrisons filled their tanks with sludge! About 30 cars were stranded around the filling station. The example drawn from the tanks at the station looked like an old tin of gloss paint where after 10 years it gets that browny sludge in it. :)
 
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Blimey Dave!! Also for this reason I have established a few rules and stick to them, it has always gone ok for me:

1. ALWAYS pay for fuel with credit card so you have proof of the time, date and quantity purchased.
2. NEVER run the tank too low, I usually fill up when I get down to a third or quarter tank.
3. Generally use the same trusted fuel stations, and never purchase fuel on a motorway NOR dual carriageway (cos you cannot go back).

I also carry a 5L plastic tank of derv when I travel long distances, just in case. I also run Redex or STP through every few thousand miles. Ps I have a mate who was at the time a proud owner of an almost new BMW 320d. He drove down to the south of Italy and ran down to the fuel light, then filled up paying cash at the first place he found. He then managed to drive about 20kms till the car stopped. He was recovered to a BMW official stealer who repaired the car for some 4k euro!!!!!!!! The car was worth about 20k. Gulp.
 

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I can't help much. I once had a single incident of 23044 - Valve for Fuel Metering (N290) P0089 00 [096] - Implausible Signal in early 2019. I couldn't link it to anything and it never reoccurred. But now that I have checked the file again I see that pressure was specified as 4.998 bar and the actual was 7.370 bar.

I have used either V-Power or Momentum whichever I can get, which means that most of the time it is the Shell. I can't honestly say I have noticed any difference between them and that includes my FIS-Control MMI data, although I do not monitor advance. I regularly check misfires and I'm not getting any problems with either fuel. I also have the fuel pressures shown in a table so I'll keep an eye on them.
 

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Interesting. I had a routine Dyno done a couple of weeks ago on my stage 2 S5 Crec. It threw up a couple of P0089 codes during the runs but no loss of power. Fuel was at 7 bar. I had seen this intermittent implausible signal on the fuel metering valve once before a few months back, about an hour before I got an ECU error code that forced the car into limp mode with EPC light.

I had asked Doug at MRC about it and he said he hadn't seen the ECU error with one of his maps and it was unlikely to be the map after 2 years. He said the implausible signal was related to the solenoid actuating the flow control piston (metering valve) on the hpfp.

Anyhow, that's 3 times I've had the implausible signal now and it happens with WOT at 3kish in Dynamic/Sport mode. However, unlike the OP I've been using Momentum 99 almost exclusively during lockdown as my nearest Shell is 20 minutes away.

Sent from my IN2013 using Tapatalk
 

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Discussion Starter · #18 ·
Great stuff CREC guys! :) Good, well, not good, relieving to hear that other Stage 2 CRECs get this 'glitch'!
@Dippy - that's exactly what mine said, Actual LPFP was 7.3 and specified or default is 4.99 bar and the error log started at 1800rpm to 2800rpm, which was when I was prodding the accelerator in disbelief that my lovely S5 was having a wobble! :) AND this was 2 years and 8k miles after my remap! I periodically check with VCDS and never seen these faults before. I do get a sporadic PCV valve fault logged, but this is always at idle 700rpm and when the engine has warmed up!? I don't notice anything untoward. No CEL lights.

Not sure exactly how the 2 fuel systems work on the CREC engine, or how they switch between the 2 using the same tank fuel pump. I'm guessing the LPFP (tank pump) sends 5 bar of fuel to the HPFP, which has a line off before the HPFP piston/pump to the port injectors, then when demanded a solenoid commands the fuel from the HPFP to the direct injectors in the cylinders. Maybe at this point of switch over, is where we see this fuel pressure error? As it does seem to occur at or below 3krpm.

Dippy I've also contacted Turbo Zentrum in Trafford park for a FIS Controller! :D The more I think about it, the more I leaning towards getting one. Maybe a group buy!? If I hear noises of interest, I'll start a new thread on this. They won't be in stock until July.

So anyway, it looks like it isn't the fuel, maybe a glitch from the plethora of sensors and monitoring that modern engines have!? It could be an off batch of fuel?

@HTB - so your faults on the fuel pressure, were they just on the dyno and the 3 times fault, is this the same fault or something else to do with the ECU?

Be interesting to know if these fuel pressure logs appear on the previous gen engine as this only has the 1 fuel system, direct injection!?
 

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@Dave Kwatro I had the intermittent fuel metering valve implausible signal a total of 3 times, twice on the Dyno 2 weeks ago and once on the road a couple of months ago.

I only got the ECU fault/limp mode once about an hour after the valve error I got a couple of months ago.

Interesting that we were all seeing fuel at 7 bar.

I think the injectors on the Crec have a simultaneous LP and HP feed as part of their new design to limit intake carbon deposits.

I have an Erwin self-study guide for the Crec engine that has lots of detail.

Sent from my IN2013 using Tapatalk
 
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