No Power under any level of throttle.

Lobster

Lobster

Greenie N00B Member
I have a 06 Speed6 that I purchased in rough condition. The car is very low on power, even revving feels incredibly weak. I doubt it could go any faster than 30mph. I’ve attached logs of the car idling with a few small blips of the throttle.
AFR was surprisingly normal at 14.7, and 13.x under light load. There are no check engine lights either.
In the logs, I noticed that the mass air flow rate reading was low and replaced the MAF sensor with an oem one and it made very little difference. Fuel pressure sensor, hpfp internals, and fuel filter have also been replaced so far. Any advice is greatly appreciated, thank you!
 

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Have you checked compression / leak down? spark plugs, cleaned MAF/ map, checked air filter condition?

All places you should be starting, do you know service history? Vvt being passed due could cause timing jump
 
Wow, that was quick, thank you! I haven’t done any leak down or compression tests nor checked spark plugs. I’ll look into that as soon as I get a chance. Service history is unknown and the timing chain shows no signs of jumping.
I’ve got one question though, the mass air flow rate which is reading really low around 0.5lb/min at idle, to me implied that there’s an issue with delivery of air or fuel, would spark plugs and or compression effect either of those? I need to test them regardless but I’m not experienced with all this so I’m curious.
 
What do you mean it shows not sign of jumping timing? Have you pulled the VC and timing cover and verified timing? Or have you verified the timing chain is tight at TDC with no signs of wear on the VC?

Absolutely poor compression or leak down will mean less air sucked in or pushed out of the engine, however I also said to cleaned the MAF sensor and MAP, if those are dirty it'll read incorrectly. Heck could just have a leak somewhere are you able to see LTFT? They should be +/- 5 ideally, 7 being okay, 10 definitely a leak somewhere between maf and primary is sensor (probably intake to head), you see 15+ and there's definitely a leak. Heck I've had it on my car where the maf housing likes to eat the o-ring on the maf sensor, I've replaced it twice in 9 years stupid CS intake.
 
I should have been less vague, I haven’t removed the valve cover yet to verify anything with valve timing. The chain itself is tight, that’s all. I’ll look into that more once the valve cover comes off. MAF sensor is brand new, I’ll have to check the MAP sensor as well. LTFT never goes Beyond +/- 5. Mostly the same for STFT.
During the compression test, is it going to make a significant difference whether the engine is warm or cold?
 
Does it still have a catalytic converter? If so remove the front O2 sensor and drive it. If it accelerates better then the cat is clogged
 
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