Sit rep, unplugged the MAF today, seemed to run a bit smoother so I tried a spare pattern part MAF which has only seen a few months of use, and the car did seem more lively, 20bhp more lively? Hmmm, not sure, but did seem better...don't know if I've got to the bottom of it yet, will still do some logging and explore the map.

I'd be a bit wary using a pattern maf. A few have said they can cause poor running straight out of the box. Genuine mafs are best there buddy.

I know but I have it spare so chucked it in to try it, even a pattern part one will work better than a gen one on its way out, if only for a while, seems ok so far.  When I got the car (before I was wise to gen only) I put in new coil packs and this MAF - having had a nightmare with a Seat before - as I wanted a base level to start with as it seemed they'd never been changed in the paperwork.  It ran ok with it, when I had limp mode before I got paranoid and swapped back in the gen MAF, hence why it's spare.  Turned out MAF was not the issue before, but I kept the spare just in case, and there we are.  Never know, it may keep going.

I may have made some progress. The spare maf is going ok, will probably get a new gen one with a map sensor next month. And I took off the forge 007 to revise the piston and give it a service, so put back on the oem diaphragm jobby. I was surprised how easy it was to push up the piston in the forge compared with the oem. I'm thinking that the green spring in there may need a shim, or even try the yellow spring. It may have been fluttering and leaking boost. So went for a drive yesterday, with the original one on, couldn't give it full beans as I'm waiting for decent clips for the top vacuum hose so it's only zip tied on at the moment. Now I don't know if it's because I'd been driving swmbo's Megane lately but mine definitely felt more 'urgent' and pokey than before, more like it did after the remap. Quite hard to tell as only went half throttle but I think it was a bit better. I'll do logging when I get chance and pull out some bhp and torque figures from the data. The guy who did the map and the tuner don't think it's the map, and seem reluctant to help. I still suspect the timing advance may not have been pushed on far enough, which whilst not a map issue in itself it is linked and should be looked at. If what I've done has made no difference numbers wise I'll be pushing them more.

Another reason to throw away the 'piston' dump valves, the OEM ones are far more reliable and require no servicing

Another reason to throw away the 'piston' dump valves, the OEM ones are far more reliable and require no servicing

I try telling people this but most of the time they want forge because some no nothing no it all on the internet says forge are the only way to go. The OEM DV is fine, people still use them when running stage 3 tunes on the 2.7T S4

I try telling people this but most of the time they want forge because some no nothing no it all on the internet says forge are the only way to go. The OEM DV is fine, people still use them when running stage 3 tunes on the 2.7T S4

Yeah it must be able to cope with how stiff the diaphragm is. I ended up getting a forge one as I was chasing problems round the car and could get a used one so just thought I'd try it, turned out that it wasn't the problem on that occasion, but could be on this occasion. I'll know more when I explore the data and get on the dyno again but I'm sure it felt better. Spring tuning and a service may sort out the forge one for this car but to be honest I might just sell it.

I fitted a forge one a fews years ago and my car didn't feel right with it on. I think it was only on the car a week and i ordered a new oem one. The car was instantly transformed. The genuine ones work very well even on stage 1 cars apparently. I would definately order a genuine maf too i can only see problems with the aftermarket one but they're not cheap. The last one i bought was over 100 quid iirc.

I fitted a forge one a fews years ago and my car didn't feel right with it on. I think it was only on the car a week and i ordered a new oem one. The car was instantly transformed. The genuine ones work very well even on stage 1 cars apparently. I would definately order a genuine maf too i can only see problems with the aftermarket one but they're not cheap. The last one i bought was over 100 quid iirc.

Yeah I'm going to get gen new map and maf so I know exactly where I am next month. On euro car parts at the moment can get both bosch ones for £100 with current discount level. Normally it is about 100 just for the maf indeed. I'll still do the logging as well and see what the numbers throw up, like I said I'm not sure if it's completely solved yet but it definitely felt like a step in the right direction, it was wet when I tried it and was struggling for traction just like the good old days lol. Hopefully my clips will be here tomorrow/Wednesday so I can get that hose secured properly and open the ****** up.

You should be running the yellow spring in the forge valve for anything other than standard.

You should be running the yellow spring in the forge valve for anything other than standard.

I was thinking of trying that, or shimming the green up. Not sure if I can be bothered fighting to get the top off it at the moment without a vice. May try it further down the line.

How old is the car? 10-12 years? 

I bet it`s a fuel pump 

Flat line after 5000 to a red line indicates fuel issues, clogged injectors or/and failing fuel pump.

Buy this: http://www.motorsport-tools.com/sytec-hi-in-tank-fuel-injection-pump-36mm-in-8mm-out-p30311.html 

Edited 10 March, 201511 yr by Gonzaga

How old is the car? 10-12 years? 

I bet it`s a fuel pump 

Flat line after 5000 to a red line indicates fuel issues, clogged injectors or/and failing fuel pump.

Buy this: http://www.motorsport-tools.com/sytec-hi-in-tank-fuel-injection-pump-36mm-in-8mm-out-p30311.html 

Link didn't work. Doubt it's clogged injectors I run v power and it's been Terracleaned. It's only done 74k as well. Hmmm fuel pump, possibly, what other symptoms would there be with that? I did notice that with it running better been using a bit more fuel but that's about it, that could be in my head though, trip computer reads ok.

Sytec p3031.1 fuel pump, it`s a good upgrade.

You should log block 031 and see what is going on with AFR, I bet it`s leaning out at higher rpms, also causing boost fluctuation.  

Has the fuel filter also been swapped?

No fuel filters not been done yet with me and dont think Ive seen one in the paperwork, this is worth exploring I reckon. There's no driving issues as such, no cutting out, no problems starting and doesn't feel like it's over fueling. Thanks for the info on the block, I'll take a look when I eventually get chance to log.

Its worth it for under a tenner.  Easy swap too.

Your car hasn't had a new fuel filter? That's probably the problem there? I'd get on it quick. As said above they are cheaper enough too.

I'll double check the paperwork I've not specifically looked for that. Anyway a new one won't do any harm that's for sure. I'll get one of those, check the fuel log and see where it's at. Be nice if I can find the rest of the solution there, I'll still probably get a new MAF as well though.

Just ordered fuel filter, £6.60 on skodaparts, albeit plus postage. Anyway should I need one where can I get a sensibly priced fuel pump? I just had a heart attack when I saw some prices. Euro have a Bosch reduced to 80ish?

Won't be the fuel pump, only time they may have problems if going stage 2 +, stage one is easy for them to cope with.

 

I ran a stage 1 Revo map for around 4-5 years, with a K&N fitler in the standard airbox + 3" cold feed, cat back exhaust, Forge recirculating dump valve plus a cold side relocation kit, and  she made 209bhp (cant remember the torque) with no fuel problems.

 

Prior to going Stage 2, I popped along to Forge (3 miles away) and they told me the yellow spring is for anything other than standard unless looking for stooopid hp (which you won't get out of a standard turbo).

 

After I fitted a FMIC, decent down pipe and sports cat etc etc she went to Midlands VW for a Stage 2 map (generic) and came back with 226.7bhp and 260Lbft torque, and still no fuelling issues still with the yellow spring installed.

 

Go yellow, boost problems sorted! 

Oem DV is best

As for can't be fuel pump as only stage 1!!

This is not true standard pumps start to fail and can cause issue even at standard power !!

Cheers, well I'll get the filter on and explore the block to cover that base. Pumps can fail I guess map or no map so I will look into it. Am keeping the oem dv on for now, might try a yellow spring when I've got these issues sorted, I'll know where I'm at then and have a solid base. Hope its not the pump though looking at the prices!

Wasn't learning out on the dyno if I remember right.

You say DV (spring stiffness)  is the problem, can you tell how much boost you have @3500rpm and @5500rpm?

Wouldn`t be logical to presume that DV is not the problem, if it can hold 1.2bar@3500rpm but can`t hold 0.7bar@5500rpm?

Maybe I`m wrong