Hello guys

I own 08 X GSR. After I bought the car a year and a half ago the car always felt sluggish. Car came with a bolt ons. I did not check if the fuel pump is OEM. I don't push the car but it was time to get it tuned. Or. Check on the tune. It looks like previous owner had Cobb installed as he never unmarried the Cobb before pulling it out. We can re tune the the car by slapping new cobb on and go from there. No check engine lights no boost cut. Local shop hooked up the wide band and went for a spin came back and said that I should not push on the car before we check on it. Runs lean. Explains. So ecu is probably fighting and throwing the car into limp mode or pulling timing . But it could be Mechanical problem. Like fuel pump. We also popped the fuse box cover and we see this czit. Some red wires. I see that it's missing fog light relay ? My fog lights are always on when I start the car. Which explains. Also got me thinking why someone hooked up to the fuel pump relay. Red wire. I see relay was replaced with the new one ? Anyone can tell me what's going on here. Car came with aftermarket remote start and custom hids lights . Im thinking the problem is with fuel. I replaced the plugs not long ago. I should check compression as well. Thanks.

 

What are your afrs.
Does car still have a catalytic converter?

 

No cat. 14-15. At wot

 

The car would be choking over itself if it was really 15 AFR at WOT. You would have also chucked a rod by now.

 

That's what got me thinking. I don't know where to start trouble shooting. Maybe it's just a tune. Maybe replace fuel pump. Which wideband would you guys recommend AEM ? So I get some readings again. I also found huge vacuum leak by bov which was fixed.

 

14.5 at wot is very dangerous. Probably a fuel pump issue. Didnt these evo x have bad fuel relays?

 

Yes they did. That's why I wanted to replace it. But it looks like someone allready did. But that red wire from fuel pump to fog light really bugs me. Mayne it's drawing some voltage. I will order probably new fuel pump relay. Wideband. And check it again and than If it's same I get new fuel pump.

 

New relay.
Check FPR vac hose on manifold and FPR
Check in-tank fuel pump. If not OEM, could have gone bad
Check the tune, the fact you have no idea what kind of tune is on it is :-/
Might as well slap a factory ROM on there for now, depending on your modifications

 

Stay out of boost
Get a hold of a good tuner in area
Diagnose car, have fuel relays handy and just go ahead and swap them out
Assess
Tune
Enjoy

 

Yep. I ordered the relay and a wideband and check on the fuel pump, if that won't help the car is going back to the shop for more testing. First would be compression test.

 

Compression should probably last on your checklist for a lean concern. Since the car idles fine you likely have good fuel pressure but may be losing fuel pressure uptop. Or the pump may not even be switching to high voltage under boost. Did you check fpr vaccum hose that its connected and doesnt have a tear or rat damage?

 

I would put a known good tune on the car way before I would do a compression test.

Go through my list above.

 

Did you check the vacuum line to the FPR?

 

update:
installed Aem uego wideband, replaced the fuel pump relay, a Better one part # 8627A0490- the car feels and runs! better! no more sluggish at wot! at idle afr is at 14.7-14.9 - at wot 11.5/7- So i guess it was the relay!! - my next step is to check on the fuel pump/filter and replace the fuel pump anyways!

The vacuum line to the FPR is fine, but very lose, I did zip tie it, but i'm going to replace that v hose anyways

thanks guys!