My buddy just bought a really nice 11k mile, bone stock GN. It runs pretty good with exception of a slightly rough idle, knock at WOT, and consistently high BLM's...high 140's to 150 all the time. Basically it is lean across the board.
Obviously this is due to lack of fuel or unmetered air entering the system.
I checked all the vacuum lines and they all look great. I did not bring a vacuum / boost gauge to check it out. I'll do that next time I see him.
It still has the stock crankcase evac system and it seems to be sealing good. If I pull the oil fill tube off the drivers side valve cover it runs bad and integrator shoots up. That tells me that it should not be pulling unmetered air from that. I'm going to have him plug the turbo inlet and check int / blm to see if anything changes though.
Still need to check the MAF to turbo hose for a slight tear. That would do it.
Hoses on IC and up pipe look good.
02 sensor looks new and cross counts are fine.
If it is not too much air, then we will move onto fueling....
I'll have him replace the fuel filter and see if that helps.
It has the stock fuel pump and wiring I'm guessing. I forgot to bring my fuel pressure gauge, but the pump should have no issues supplying pressure at idle and cruise. If it was that bad, the car would probably stumble bad at cruise and it is fine.
I'm assuming the chip is stock, but I'm guessing that a different chip would cause a lean condition with a stock regulator. We will check that.
Could it be lean due to new gas being E10 instead of 100% gasoline? I'm guessing it would not be that far off.
At that point I'm going to point to the injectors...or one injector. I may let it idle for a couple minutes and see if one cylinder is a little cold by using my infrared thermometer on the top of each header pipe.
Any I missing anything? Could a possible worn #3 exhaust lobe cause something like this?
I have him talked into a few tasteful mods on this car. TT chip, 160 thermostat, adj actuator, solid MAF pipe and cold air intake, test pipe, catback, new fuel pump, and hotwire kit. That all should make it really nice.
Obviously this is due to lack of fuel or unmetered air entering the system.
I checked all the vacuum lines and they all look great. I did not bring a vacuum / boost gauge to check it out. I'll do that next time I see him.
It still has the stock crankcase evac system and it seems to be sealing good. If I pull the oil fill tube off the drivers side valve cover it runs bad and integrator shoots up. That tells me that it should not be pulling unmetered air from that. I'm going to have him plug the turbo inlet and check int / blm to see if anything changes though.
Still need to check the MAF to turbo hose for a slight tear. That would do it.
Hoses on IC and up pipe look good.
02 sensor looks new and cross counts are fine.
If it is not too much air, then we will move onto fueling....
I'll have him replace the fuel filter and see if that helps.
It has the stock fuel pump and wiring I'm guessing. I forgot to bring my fuel pressure gauge, but the pump should have no issues supplying pressure at idle and cruise. If it was that bad, the car would probably stumble bad at cruise and it is fine.
I'm assuming the chip is stock, but I'm guessing that a different chip would cause a lean condition with a stock regulator. We will check that.
Could it be lean due to new gas being E10 instead of 100% gasoline? I'm guessing it would not be that far off.
At that point I'm going to point to the injectors...or one injector. I may let it idle for a couple minutes and see if one cylinder is a little cold by using my infrared thermometer on the top of each header pipe.
Any I missing anything? Could a possible worn #3 exhaust lobe cause something like this?
I have him talked into a few tasteful mods on this car. TT chip, 160 thermostat, adj actuator, solid MAF pipe and cold air intake, test pipe, catback, new fuel pump, and hotwire kit. That all should make it really nice.
