Lean conditions after new injectors

JimmyFC

JimmyFC

Greenie N00B Member
Greenie Member
Car ran fine when parked, aside from misfire on second Cylinder. Upon sending injectors out to be serviced, they informed that an injector was 19% low. Replaced injectors with new clean set and now the car starts fine and the misfire is gone. Car will run good for a few second then bogs way down. After the bog, the cars' STFT will jump to 24.8 and lean the car out to around 15 afr at idle. Any help is appreciated, thanks!

Year/Make/Model: 2008 Mazdaspeed 3
Mileage: 164932
Location: FL
Concern:
DTC's: (please include descriptions) none
Modifications: Corksport 3" intake, Autotech HPFP internals
ECU/Tuning Software: Cobb accessport
Tuner: Stratified
Is the concern intermittent? No
Can you duplicate the concern? Upon startup, everytime
Recent Repairs: new Injectors and injector seals from CW Turbochargers, new Intake manifold and throttle body gaskets
 

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have you checked for leaks in your intake system ie boost leak test?
I take it you're not smelling fuel at all, if injectors are firing well and not leaking then I'd suspect an air leak
 
Planning on doing a boost leak test this weekend.

Awafrican said:
I take it you're not smelling fuel at all, if injectors are firing well and not leaking then I'd suspect an air leak
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Thats the other odd bit. When I turn the car off, it smells like its running super rich, but after inspecting the engine bay there are no leaks. My best guess so far is that maybe a faulty map sensor? Will be inspecting that as well when I have it apart this weekend.
 
JimmyFC said:
Planning on doing a boost leak test this weekend.


Thats the other odd bit. When I turn the car off, it smells like it’s running super rich, but after inspecting the engine bay there are no leaks. My best guess so far is that maybe a faulty map sensor? Will be inspecting that as well when I have it apart this weekend.
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have you found a resolution? I have an ‘09 with the same issue. I boost leak tested at 30psi & found nothing. Car is pegged at +24.8 stft and sits around 15.4 afr. Unplugging the maf just kills the engine after 3 seconds. Still on stock map sensor since I’m on basemap with Farhan from Damond. He said the stock map sensor should be alright with my setup. Have been thinking on going bosch 3.5bar since I’m on a bnrs3 & a catch can setup. My thoughts are the stock map isn’t liking the bolt ons? Thing has had me stumped since June
 
The map is not causing your problems. You have a leak somewhere. Try squeezing all the hoses you might only have a leak that opens up when the motor is moving
 
Easter Bunny said:
The map is not causing your problems. You have a leak somewhere. Try squeezing all the hoses you might only have a leak that opens up when the motor is moving
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My issue is at idle my numbers are pegged. I put a new intake & tb gasket on thinking one of those were bad originally, triple checked all my connections & clamps, & nothing. Still wants to sit at 14.99-15.4 afr & 24.8 stft. MAF is OEM & oring is also brand new. I’ve tried spraying brake cleaner at gasket points, boost leak tested at 30psi & I’m either dumb enough to find an issue or I’m going crazy lol. Idk what else to do other than have it towed to a shop & them tackle it
 
Easter Bunny said:
Is the O2 reading changing or is it bad
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o2 sensors are both working properly. I just smoke tested the car through the air intake. only leak present after 2 minutes of running the smoker was at the MAF housing, oring was chipped. So I replaced with a new one, retested & no more leaks after another 2 minutes. start up and after 7-8 seconds stft & afr go back to same readings as before. +24.8 stft & idles at 15.4 afr. Although idles smoothly. Not sure if I need to relfash tune or unplug battery to reset trims but the car has not been driven in almost 7 weeks now due to hunting this issue down. I'm at a loss of words on what to try next & may have a shop put their hands on it to hopefully figure it out. I've asked so many people & followed their advice only to not have this issue resolved.
 
You need to wait longer after starting. The car is still in closed loop for a bit after starting the trims won't start updating until the O2 sensors are hot enough
 
Easter Bunny said:
You need to wait longer after starting. The car is still in closed loop for a bit after starting the trims won't start updating until the O2 sensors are hot enough
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I gotcha. So you're saying to let the car idle for at least 15 minutes or longer? It's around 95 degrees today where I'm at so it should not take long to warm up. The longest I let it idle for after the MAF oring swap was about 6 or 7 minutes to see if trims would change but letting it idle longer may change something lol.
 
That should have done it. I don't really know how long exactly you would need to idle though
 
Easter Bunny said:
That should have done it. I don't really know how long exactly you would need to idle though
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it seems that 10 seconds or so after starting up the trims go from -0.16 & climb to +24.8 almost instantly so there is for sure another leak of some sort somewhere. oddly enough before my hpfp ground went bad the trims would be around +13.6 & lower to +8 when warmed up. I changed the eyelet & crimped fresh wiring & its 's been this way since but the 2 idle datalogs I've taken show fuel pressures are perfect numbers at idle.
 
Did you ever find out what was the issue causing the STFT to be locked at +24 having similar issues and have tried all things stated above
 
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