All Things Mk5 > Mk5 General Area
Bad mapping? ED30 random misfire
Jackged30:
--- Quote from: Pudding on June 30, 2023, 10:29:33 pm ---Ah you have a decat, I missed that on the first read through.
If the remap didn't include coding out the post-cat O2 sensors, that can and usually does throw the EML against a 'catalyst efficiency' fault. The engine ECU compares the O2 sensor readings in the downpipe to the O2 sensors behind the secondary cat (which you no longer have) and if they disagree with each other, you get an instant EML, which is why they need to coded out. It's just a simple on/off setting in the base map.
Do you know who remapped it? If you do, might be worth asking if they did that. It's standard on most Stage 2 maps, but tuners like Revo leave the standard O2 maps in place on Stage 1, so if it's stage 1 and the cats are binned off, it will EML.
Excessive carbon build up will cause cold misfires, as will swirl flap deletes.....although some tuners have a specific map to correct that. Do you know if yours has had a swirl flap delete?
As for injectors, they only misfire at idle and low rpm when they start to fail, but as yours is missing at 3.5-4K, it could be fuel flow that's the problem as that is the peak boost rpm, which demands the most amount of fuel. Has your HPFP got uprated internals in it?
--- End quote ---
Not a clue who mapped it, bought it blind as a “fixer upper” seller had said it hasn’t been mapped which is a load of :booty: as it goes like stink. It’s got standard internals and a new cam follower. I think I’m going to get the injectors out and have them tested and clean the valves while mani is off, other than not sure where to go next, logging fuel pressure it actual always meets requested other than peak boost rpm, literally for a split second drops and goes back up very odd to me
pudding:
Ah OK, you 100% need HPFP internals mate if it's mapped. I recommend VIS stage 1 as it uses the standard spring. The stupid money APR and LOBA ones use a crazy spring that eats through cam followers in no time.
It's hard to tell sometimes with the actual and requested fuel rail pressure as you only need to back off the gas slightly and the requested pressure drops like a brick.
What you want to see is a hard pull in 4th from 2500 - 6000 rpm (hard to do on the road, I appreciate) and the requested and actual matching each other. A few bar difference is nothing to worry about.
You can also check the requested boost pressure to see how far it's been mapped. Stock GTI is about 1 bar. If it's like 1.3 bar or higher, definitely mapped. If you have VCDS, the boost readings will be in millibar, so standard pressure will be 2000 millibar because the MAP sensor can't read below atmospheric pressure, so you deduct 1000mbar, and that's your boost pressure. If you see 2300-2500mbar, it's running 1.3-1.5 bar boost.
I wouldn't waste your time with cleaned/checked injectors, they just wear out. Put new ones in. Refurbed ones work OK for a while, but don't last.
Jackged30:
--- Quote from: Pudding on June 30, 2023, 10:58:40 pm ---Ah OK, you 100% need HPFP internals mate if it's mapped. I recommend VIS stage 1 as it uses the standard spring. The stupid money APR and LOBA ones use a crazy spring that eats through cam followers in no time.
It's hard to tell sometimes with the actual and requested fuel rail pressure as you only need to back off the gas slightly and the requested pressure drops like a brick.
What you want to see is a hard pull in 4th from 2500 - 6000 rpm (hard to do on the road, I appreciate) and the requested and actual matching each other. A few bar difference is nothing to worry about.
You can also check the requested boost pressure to see how far it's been mapped. Stock GTI is about 1 bar. If it's like 1.3 bar or higher, definitely mapped. If you have VCDS, the boost readings will be in millibar, so standard pressure will be 2000 millibar because the MAP sensor can't read below atmospheric pressure, so you deduct 1000mbar, and that's your boost pressure. If you see 2300-2500mbar, it's running 1.3-1.5 bar boost.
I wouldn't waste your time with cleaned/checked injectors, they just wear out. Put new ones in. Refurbed ones work OK for a while, but don't last.
--- End quote ---
okay mate, I’ll get some more logging done and have a look for some hpfp internals thank you for the advice mush! :happy2:
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