2G sputtering at 5lbs...

[jbus]

Ok so i just bought this car and i am a bit lost as to why she spits and sputters at 5lbs and won't spool any higher. as far as i can tell the car is all stock and with your typical bolt on mods and nothing extravagant. She has a injen intake pipe with recirc., greddy type s BOV, 2.5 inch turbo back exhuast, FMIC, ss oil feed lines, and some type of ebay TD05 turbo bolted on that looks 16g-ish. i boost leaked tested it and and fixed a couple leaky couplers and the fuel injectors and i can get the system to hold pressure without any leaks wat so ever but no change to driving symptoms. injectors look stock, there is NO type of tuning implemented at all and the MAF checks out fine (swapped in three different ones laying around and still no dice). there is a GLOshift narrow band in the car that reads totally PIG rich all the time under WOT. so i guess my question is why am i sputtering at 5lbs with no boost leaks and a almost stock set up except for the ebay turbo, shouldnt i at least hit 12lbs before fuel cut?

 

[gst-turbo]

You need a boost controller to turn up the boost

 

[jimsgsx]

Also have you taken the intake off and checked turbo for shaft play and whatnot?

 

[inthemidst]

Maybe that bigger turbo the maf is reading 15lbs at 5 lbs also check fuel pressure and compression and mechanical timing to be safe.

 

[Anmasher]

almost stock set up except for the ebay turbo, shouldnt i at least hit 12lbs before fuel cut?

I would guess that is your problem. I have no idea how these ECUs work without a turbo (or significantly less boost than stock), but I imagine if it is getting 5 psi and expecting at least 11 then there your problem. One would think the MAF would keep the AFR close to where it should be though regardless of boost pressure. Still bet money it is the ebay turbo.

 

[The Last AWD TSI]

How old are the plugs or wires or coil packs?

 

[2gmitsueclipse]

I would:

• BLT again making sure you got all of your leaks.
• Verify mechanical timing is correct.
• Get some to tune with, or at least to log.
  
• Try another boost gauge to make certain yours is working properly.
• Check and replace your spark plugs (with proper gap) along with a check of your plug wires.

 

[ThunderChild]

i havent seen any mention of a TPS check on here.

mechanical timing check is a good check as well as plugs, like 2gmitsueclipse said.

past any of that a way to log would be wise.

 

[jbus]

Swapped the plugs and wires today and the issue seems resolved. its funny how the simplest things can rack you brain some times. ha ha thanks you guys for the help and believe you me, ECMlink is soon to follow.

 

[2gmitsueclipse]

Swapped the plugs and wires today and the issue seems resolved. its funny how the simplest things can rack you brain some times. ha ha thanks you guys for the help and believe you me, ECMlink is soon to follow.

Glad it got taken care of. Your plugs were probably fouled from running so rich. If issues continue, adjust with the gap.

 

[ZMX]

Glad it got taken care of. Your plugs were probably fouled from running so rich. If issues continue, adjust with the gap.

Agree. Richness is a challenge in itself to fire through; fouled plugs make it worse.

Plugs have a harder time firing through boost (more air + fuel), and especially through rich mixtures - which can get you "spark blowout." Smaller plug gap will allow the plug to fire in tougher times, but will reduce idle, streetability, and power at all RPM - it beats not running boost at all, though. Perhaps too eagerly, many people upgrade ignition systems to handle more boost and fuel with coil on plug systems like from Sparktech, or with modified coilpacks taken from junkyard GM vehicles, etc.

 

[curt-s]

I would guess that is your problem. I have no idea how these ECUs work without a turbo (or significantly less boost than stock), but I imagine if it is getting 5 psi and expecting at least 11 then there your problem. One would think the MAF would keep the AFR close to where it should be though regardless of boost pressure. Still bet money it is the ebay turbo.

Are you referring to a boost leak big enough to cause what would be read/estimated at 11lbs at the MAF to bleed down to 5lbs before entering the engine?
Since airflow is read at the sensor and is an absolute value of the volume of air that would enter the intake system, you could have no functioning turbo and the engine would operate fine, just completely to "the left" of the fuel and timing tables.

By the way, you would feel fuel cut.. Its quite pronounced.

 

[sbz0kgx]

I had the same problem a few days ago, in my case, it turned out to be a blown ground lead on the ecu causing issues with the MAF causing the car to run extremely rich. Its the copper lead on the bottom left in the picture. Not sure if this is your issue but sounds very similar to mine.