1G car sputters, hitting fuel cut, backfires when sputtering.

[xander123]

I just got my car running again, old spark plug wires were 8mm but they were worn so I replaced them with a spare set. Before this the car ran as normal, but the new set is only 7mm, and those and spark plugs are the only things I've changed.

Yesterday at WOT, car hit a super aggressive fuel cut in first gear, so I pulled over to make sure all sensors and everything were connected. I tried again to see if I was overboosting but I was only hitting about 10psi, when normally I’m at about 12.5. The car also sputtered, seemed like it was struggling to burn the fuel maybe? When it stopped sputtering it backfired about 4 times.

So I’m thinking maybe my spark plugs or the wires are causing something? My exhaust is also leaky so I was wondering if my o2 sensor would be reading wrong and then causing the ECU to do something?

1990 tsi
gm maf
550 injectors
small 16g

 

[NOSLO2PT0]

Why do people think still Fuel cut has anything to do with fuel? The electrical in his fuel system could be built for 1000hp and in 100% working order, and the car would still hit fuel cut if the right conditions were met.

 

[We're on Boost]

Why do people think still Fuel cut has anything to do with fuel? The electrical in his fuel system could be built for 1000hp and in 100% working order, and the car would still hit fuel cut if the right conditions were met.

So when you read post #25, read "lack of fuel" instead of "fuel cut". Since there is a difference.

 

[NOSLO2PT0]

So when you read post #25, read "lack of fuel" instead of "fuel cut". Since there is a difference.

Then post “lack of fuel “ issue instead of “fuel cut” issue, since they are completely different.

 

[Murdertalon]

I have a proper fuel delivery setup, rewire I did myself, fuel injectors freshly rebuilt and new fuel filter.

I haven't checked fuel pressure, my fuel pressure regulator could be the auto one or just bad this idea is because weird parts were on my 1g that didn't belong. Like a turbo from a retarded auto.

 

[waltah]

I may try to gap them smaller I don't remember what my current gap is but it's super large on the iridium plugs.

I'd recommend staying with the recommended plug gaps. The reason is the peak voltage on all the HV parts goes up in proportion to the plug gap: Double the gap, double the voltage. Big gaps = you will have more coil/wire/transistor failures.

It is true that you may get better ignition under light load with a wider gap. But under full boost it's a lot harder to get that spark across the gap and at that point you're testing all the HV parts. Trust the factory to know what they're supposed to be able to deal with.

There is a reason the plug gap recommendations for turbo engines are so much smaller than those for the n/a ones. The slightly reduced light load performance is part of the price of having what amounts to a 4 liter engine in a 2 liter block -- that is, a 2.0L engine with 15 psi of boost = double the fuel/air mixture.

Iridium plugs are fine: The super tough metal of the center electrode makes it possible to use a very sharp point (which would burn away in no time if copper, etc.) and a sharp point lowers the voltage needed for a spark. So maybe run the maximum recommended gap rather than the minimum. But you'll save trouble -- and all these failures are mostly 'hot day after a hard run' failures! -- by staying within the recommendations.

 

[1990TSIAWDTALON]

I didn't know you could gap iridium plugs. Those that I put in my 5.3L V-8 were non-gap (leave them alone) plugs, and with that very tiny electrode, I can see why.

 

[We're on Boost]

I didn't know you could gap iridium plugs. Those that I put in my 5.3L V-8 were non-gap (leave them alone) plugs, and with that very tiny electrode, I can see why.

Yeah, there's a lot of confusion about it in user forums. But for NGK Iridium IX plugs in particular, it's like I wrote in post #9. Tracking down that kind of info from NGK, I come up with these pages posted by NGK of Australia.

On the Iridium IX Details page, note that the side electrode is "Nickel". In other words, pretty conventional. And it doesn't have any added little pad of some exotic stuff at the tip like the "Laser Platinum" and "Laser Iridium" do. It's only the center electrode that is exotic.

On the gap adjust page be sure to read the last paragraph!

https://www.ngk.com.au/products/spark-plugs/

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