[E92_James]

Anyone else have this problem? I have Index 12s, brand new sparks and coils, yet something strange happens on every cold start now.. and it doesn't happen on warm starts

Basically the car sounds like it's about to stall and has trouble idling for the first 5-10 seconds of starting, then it idles normally.. however the gasoline smell is more than usual (don't care because I'm catless but it concerns me because I spun a bearing on my old motor due to index 9's killing it)

Is it possible that my Index 12s are going bad? When I replaced my motor with a lower mileage one (60K miles on the new one) it came with all index 12s so I thought I was finally over the injector problems considering I lost an engine from the injectors I get so worried about them now..

No issues on pulls or anything like that, and no long cranks like the old motor. Also forgot to mention new HPFP installed 4000 miles ago

Side note, I do have an exhaust leak from the connections at the downpipes to turbos where the v-band clamp sits and it's making my AFRs all funky, sometimes the service engine light comes on and when I scan it it says bank 1 and bank 2 AFR but I've been living with that for half a year, when I smoke tested the car I saw smoke from the connection at where the V-Band sits at the turbo and downpipe, and lovely cramped xDrive it's going to be a pain to re-adjust those downpipes that and I bought new v-band clamps for that too.. my wastegates sound so disgusting with that leak, they rattle so much on idle now, can't wait to fling a single turbo in this car and call it a day.

Tomorrow morning I'm going to take out the spark plugs and see if they're wet, I'm hoping they're not because injectors are very pricey.

[Steve Sas]

I'm no expert on direct injection but the main high pressure fuel rail should hold pressure overnight when the car is off. Not sure to what extent.

Is not possible to check high side fuel pressure before car is cold started?

But removing spark plugs in the morning is a good start.

[mweisdorfer]

Originally Posted by E92_James

Anyone else have this problem? I have Index 12s, brand new sparks and coils, yet something strange happens on every cold start now.. and it doesn't happen on warm starts

Basically the car sounds like it's about to stall and has trouble idling for the first 5-10 seconds of starting, then it idles normally.. however the gasoline smell is more than usual (don't care because I'm catless but it concerns me because I spun a bearing on my old motor due to index 9's killing it)

Is it possible that my Index 12s are going bad? When I replaced my motor with a lower mileage one (60K miles on the new one) it came with all index 12s so I thought I was finally over the injector problems considering I lost an engine from the injectors I get so worried about them now..

No issues on pulls or anything like that, and no long cranks like the old motor. Also forgot to mention new HPFP installed 4000 miles ago

Side note, I do have an exhaust leak from the connections at the downpipes to turbos where the v-band clamp sits and it's making my AFRs all funky, sometimes the service engine light comes on and when I scan it it says bank 1 and bank 2 AFR but I've been living with that for half a year, when I smoke tested the car I saw smoke from the connection at where the V-Band sits at the turbo and downpipe, and lovely cramped xDrive it's going to be a pain to re-adjust those downpipes that and I bought new v-band clamps for that too.. my wastegates sound so disgusting with that leak, they rattle so much on idle now, can't wait to fling a single turbo in this car and call it a day.

Tomorrow morning I'm going to take out the spark plugs and see if they're wet, I'm hoping they're not because injectors are very pricey.

Codes???

1) Check LPFP pressure - should idol at 72-3 or even 82ish

2) Pre-cat o2 sensors

[E92_James]

Originally Posted by mweisdorfer

Codes???

1) Check LPFP pressure - should idol at 72-3 or even 82ish

2) Pre-cat o2 sensors

I checked all spark plugs this morning all were dry and the car started a little better today it idled rough for half a second and ran fine ... also forgot to mention I have brand new O2 sensors both banks since October

I figured because its Index 12 it should be fine, maybe an issue with my map? MHD 2+ 93 V9, or the exhaust leak coming from the connections at the downpipes to turbos (vband clamp)

I'll be doing some more investigating when I'm free today and see what could be going on.. I have new OEM V-band clamps sitting in my garage that i've been meaning to replace

[Brandoch]

Carbon build up?

[BSM n54iS]

I just read the first sentence and thought HPFP immediately

Get codes, but I had the exact same problem along with so many others for some reason last year. I made a thread about it

[E92_James]

Originally Posted by BdSM n54iS

I just read the first sentence and thought HPFP immediately

Get codes, but I had the exact same problem along with so many others for some reason last year. I made a thread about it

Brand new HPFP, so far no codes oddly enough except for a inactive code "fuel pump plausibility" and 1 active code "accelerator pedal and brake pedal plausibility" but nothing out of the ordinary, that 2AAF shadow code has been there even with my old motor in the car, isn't that code relating to low pressure fuel pump anyway?

[Saif2018]

Originally Posted by E92_James

Brand new HPFP, so far no codes oddly enough except for a inactive code "fuel pump plausibility" and 1 active code "accelerator pedal and brake pedal plausibility" but nothing out of the ordinary, that 2AAF shadow code has been there even with my old motor in the car, isn't that code relating to low pressure fuel pump anyway?

Check your idle fuel pressures as recommended should be around 72psi for LPFP and around 700psi for HPFP

Also clear those codes and recheck.

You'll need to sort out that downpipe leak though,

If it stumbles only in idle then it could be carbon build up, might need a walnut blast.

[whyzee125]

I wonder if the exhaust leak is making it go super rich and causing the stumble/fuel smell?

I'd fix that and see where that gets you. Index 12's obviously can fail, like any injector, but it's really rare from what I've heard.

Good luck!

[iqraceworks]

Have you checked to make sure that they are all in fact index 12's? Also....have you checked to make sure they are all coded right?

Google "how to check for leaking fuel injectors on N54". I would start there.

[E92_James]

Originally Posted by iqraceworks

Have you checked to make sure that they are all in fact index 12's? Also....have you checked to make sure they are all coded right?

Google "how to check for leaking fuel injectors on N54". I would start there.

Yes indeed every single one are index 12s and I coded them when I swapped the engine back in august

i'm going to be fixing the turbo to downpipe leak this week hopefully that helps

[mxchris727]

My vote is the HPFP, even though it's newish. I would swap with a known working used one to see if that's the cause.

[autoart]

Double-check for a fuel leak. How are your Vanos solenoids?

[stewbets]

Originally Posted by E92_James

Yes indeed every single one are index 12s and I coded them when I swapped the engine back in august

i'm going to be fixing the turbo to downpipe leak this week hopefully that helps

I like two of the theories being presented here. It definitely makes sense that the exhaust leak could be causing your engine to run really rich. It's good that you're going to resolve that now. It also could be your HPFP.

I think it would be wise to grab a log of the cold startup process. Start the log a couple seconds before cranking the engine and take about 30 seconds worth of data. I know your HPFP is new, but that doesn't guarantee anything. I've seen this kind of log reveal a sluggish HPFP before.