Hey Gents & Gals,

So I'm going to type this thread up along with showcasing what modifications I have done to my build - as I'm curious to troubleshoot what exactly is going on with my idling.

Engine Modifications:
- Shiftech Custom Upper Intake Manifold
- Motordyne ISO Thermal Plenum Gasket
- Motordyne MREV 2 Lower Plenum
- Mishimoto Performance Radiator
- Mishimoto Baffled Catch Can
- Ported Lower Intake Manifold
- Custom Stage 1 Long Block
- Moly Coated Race Bearings
- NGK 1 Step Colder Iridiums
- 111 Compression Ratio
- Wiseco Pistons .20 Over
- AFE Takeda Stage 2 CAI
- 75MM Throttle Body Kit
- Eagle H Beam Rods
- Tomei 256 Procams
- L19B Head Studs
- ARP Rod Bolts

Fuel & Exhaust Modifications:
- DW 1,000cc VQ Drop-In Injectors
- DW 340 In-Tank Fuel Pump Kit
- Invidia Gemini Exhaust
- Berk HFCs

Transmission Modifications:
- Bulletproof LVL10 Torque Converter
- Bulletproof LVL 10 Valvebody Upgrade

That being said, now that you know the performance modifications to my build - minus the suspension modifications - here is what I am dealing with; as I can't pin-point what exactly is the issue despite being tuned. First and foremost, there is nothing wrong with the tune (UpRev) that I got from R/T as they did a great job during my dyno session. 💯💯 In fact, none of the issues that I am about to describe took place after my dyno or even months later. However, this past winter here in the DMV (i.e., DC, Maryland, and Virginia) something happened as I don't know what. 🙄🙄For example, I was running E85 during the winter because it didn't get super cold this past winter. And when I say running E85? I meant simply going out to get groceries a block away. Nothing more, nothing less, no full sends, no dicking around, and no car meets - as the G stayed garaged 98% of the time. Once the snow cleared off the roads? I switched back to my 93 octane map; as this is where things started getting interesting.

The moment I switched maps? Things were fine up until a few days later the car sat for several days. After several days? I tried starting the car and noticed a few things: The fuel pump would prime, the injectors would spark, and the engine would prime - but wouldn't turn over. I checked the battery? No issues. I checked the alternator? No issues. I checked the starter? No issues. I checked the fuel system? No issues. For whatever reason? The car wouldn't immediately start, and if it did? The idles would bounce - as a few of my muscle friends pointed it could be the injector size are too big for an NA setup (i.e., temporarily that is). However, DW said 1,000cc's shouldn't be an issue if the tuner knows what they are doing to get the correct AFR. Well, we achieved that. Except, something happened this past Winter; after switching to my 93 octane map, in order for things to cause sporadic idling issues. 🤔🤔

 

Main Scenario: I start the car, the car idles fine, the engine warms up, I drive the car out of my garage, I approach a red light, and the idle goes up and down - if not resulting in the car stalling. As a result, I attempt to start the car up again, the car starts up with some hesitancy, and so I proceed to apply the gas slowly (i.e., to get the RPMS up) so I can drive it home. Why? Because the car looks too damn good to be stuck on the side of the road. 😁😁 Mind you! Is how this doesn't happen "all the time." If anything, it's totally random; as if the G is possessed by Annabelle the doll. 😂😂 Seriously, it's almost as if she has a mind of it's own. 😈😈 When she runs? She pulls, she gapes, and she's fun. 🤗🤗 When she has issues? She has issues that are unexplainable.🥴🥴 As a result, I investigate.

Other Concern: Whenever I start her up, the serpentine belt area squeals. What used to last for 25-32 seconds is now 10 seconds before it goes quiet. When it was 25-32 seconds, my tech and I thought it was the idler pulley. Thus, we deleted it with the kit from Z1. After we installed the kit and re-balanced the belts? The squeal went away. Thus, we think the problem was solved. Well, turns out there was some play in the Power Steering Pump as we ordered a brand new one. We installed that, the squeal went away. Fast forward few weeks later the bottom idler pulley torqued off - during a highway pull - causing me to lose the bolts and washers. As a result, I replaced them, re-balanced the belts, and the squeal went away; that is, until days later it came back. Now, I doubt the belts come loose over time and need re-tightening, and I doubt a belt would contribute to idling issues (i.e., as mentioned above in my 1st paragraph), but any help and/or insight is welcome at this point.

P.S. My coworker (i.e., an old head) believes the idling issue is tied to my stock return-less system vs. running a full return. If this is the case, can someone explain why in layman terms? Both DW and R/T suggested running a return would be better over a return-less; especially because it would help with proper fuel delivery, fuel pressure, and such. Because right now? My fuel pressure is reading at 80PSI whenever the engine is churned over. At prime (i.e., key in ignition)? It reads 40psi. And no, I am NOT boosted yet. 🙃🙃 Attached are some pics and vids that makes me think I'm running rich...considering the black soot from my exhaust tips.

 

I'd bet money it's the injectors, they're almost 300% the size you need. The issue is they never achieve a high enough duty cycle to actually stay clean. E is tough on the fuel system ESPECIALLY if it sits for any length of time. Usually you can get out and stomp it and the high duty cycle will get enough flow to clean off the varnish. But you have 1000s on a setup that only needs like 350s so your duty cycle is probably barely getting out of the teen percentage while WOT.

Remove and flow test the injectors. Also verify fuel pressure, E is hard on pumps too. Normally you never leave E in the fuel system.

Check the filter/strainer baggy on the pump, might be all crapped out as well.

 

I mean if the injectors were too big that's one thing. But plenty of people run that size on N/A builds or temporary N/A builds before boosting. DW exclusively said they shouldn't be an issue unless you're going 1,500cc and up as historically not all injectors were fabricated the same. These days in modern times 1,000cc shouldn't be an issue. You mentioned WOT. Here is the thing, after a few highway pulls on WOT? The idling issues tend to go away. My guess probably because of the duty cycle you mentioned and/or the injectors self-filtered to say the least. Running sea-foam before switching my map to E85 helped, however, after flashing tonight to my E85 map the car had idle issues. So right now I have the hood up so the fuel can evaporate - in the event it's flooded with fuel. You have to remember, the block is modified along with my fuel system. Stock injectors aren't really the go to for E85. Yes, some people use the GTR injectors, but if I'm going for 700+whp in the future, the injector size matters + fuel pump or pumps. That being said, after the tune session the car ran fine. If the car sat for a period with E-85 affecting my fuel system, then I'd imagine sea foaming my tank and fuel system wouldn't help on my 93 map. However, it did.

Fuel pressure is verified with Z1s gauge. 80 psi when the engine is churned over; implying the entire system is over pressurizing. The filter/strainer baggy on the pump might be the culprit...as I read that on several threads (i.e., tuner, muscle, hot rods, etc) as one person found out that is the case. So we shall see. But I do thank you for your contributions though; as the goal is to make this fully track while I work on my Stage 1 TT 335i sedan project as my new daily/professional sleeper. 🙂🙂

 

It's not that they CAN'T tune for it, you just scale your duty cycle to whatever you need. The problem is the E85 on big injectors and honestly the timing gains for NA E85 just don't really justify it's use. I would strictly stay on premium pump gas and NOT use E in the car until later when you do go FI.

Do you happen to know what the psi on the fuel system was after it was tuned? 80psi seems REALLY high, do you know if they drilled the pump? Sounds to me like they drilled the aftermarket pump way too big, like they drilled it for the later FI install and then REALLY scaled back the injector duty cycle due to the 80psi on the returnless system???

It would help if you knew the exact injector duty cycle, if they did drill the pump for that pressure you might be down to single digit duty cycle NA, that's going to be really hard for the ECM to make fuel adjustments even in the best scenario.

Basically what starts happening is the computer can only make like 10% fuel adjustments, if duty cycle WOT is only 10% then it makes a 1% correction that's literally 10% more fuel.

When you have WOT at like 80% with correctly sized injectors then it can make 1-2% corrections, with severely oversized injectors it can't. Not saying this is what's going on but that's my assumption. What is your LTFT? Do you have TorquePro for Android or something that can watch STFT and LTFT.

I would also pull the plugs and see what exactly is going on in the combustion chamber, if you're blowing black soot out the tailpipe you probably have really fouled plugs, if so then just replace them with stock heat range plugs. If you only have one black plug and the rest are fine it's probably just a sticking injector or the other injectors are slightly plugged. When you're running single digit duty cycle all your injectors have to literally be balanced PERFECTLY because even a small variation causes a crazy amount of fuel inconsistencies across the entire bank.

The bigger issue is very sooty exhaust also tends to foul out the O2 sensors, a correctly sized set of injectors (aka stock injectors for NA) is only about $300, that's a lot cheaper than fouling out a full set of upstream and downstream O2 sensors.

Yes a return system would be better for the long run (when FI), they're not really that expensive or difficult to install but the returnless system is perfectly fine for NA or FI up to about 500whp.

Verify with the tuner that 80psi is what they were shooting for (or at least what they recorded when tuning), pull the plugs and replace if needed, check LTFT, Torque Pro can also check injector duty cycle so you know what it's doing under WOT. I would also pull all the spark plugs a day later after the car sat overnight, turn the key to on to prime the system then pull the plugs. This is an easier way to check for a wet plug, sometimes if it's just a very slight leak on an injector it evaporates quickly on a hot plug.

 

Okay, first and foremost I just have to say this and get it off my chest. You do realize my entire block is NOT stock right (i.e., an Import Parts Pro Stage 1)? My plugs? They're one-step colder plugs (i.e., PLFR6A-11) vs stock plugs (i.e., PLFR5A-11) because the engine's modified. Like please understand I'm not a youngster, a tuner who attends takeover meets, or any of that bull****. And I say this because a lot of your responses are implying the car is stock. Like if I was stock, then why would I be running an 11:1 Compression Ratio? Stock compression ratios for 1st and 2nd and 3rd gen VQs are: 10.0:1, 10.3:1, and 10.6:1. Timing? My timing has been adjusted by R/T for obvious reasons (i.e., through the use of an ARC Uprev License). That being said, let me respond to your other comments as they do play a factor.

Fuel PSI? I'm not sure what the pressure read before the tune. If it read high, then I would assume R/T would have told me and/or made adjustments as necessary as a line item on my receipt. Whereas, with the pump being drilled? I'm not sure if they did that as again, that would have been a line item on my receipt for work being performed. However, it's interesting how you mentioned about the pump being drilled. Why? Because I've read some pumps require drilling on multiple threads (i.e., MyG37, My350z, etc.). Even a tech from Z1 Motorsports mentioned something about drilling being required so proper fuel pressure could be achieved. Well, when I phoned Z1 days after, another tech mentioned how he never heard of any pumps require drilling. Fast forward a day later? I phone DW. They too said their drop-in fuel pump kits don't require drilling. Yet, a few people on threads wrote type ups stating it may be required; along with how to do it.

The plugs? I'm popping the hood today since it's raining as I have nothing better to do besides PC gaming, conducted some market trades, and assembling furniture for my place. If anything, the only plug I could possibly think might be an issue is #1 as when threading the plug in, it was a little difficult to thread in compared to the others. My solution? Ordering a whole new set of one-step colds, a spark plug re-thread cleaner kit, and maybe filing a claim with DW since the pump is still within warranty.

O2s? I'm not worried on costs as I have shop connections for most parts and/or labor should I choose NOT to do it myself.

STFT and LTFT? I will find out as I do have Torque Pro, Autotel, and the Uprev Tuning License.

Again, I don't want to give you the impression my block is stock when it's NOT. The only mod that I don't have are headers. Like I doubt R/T Tuning would "silently screw over a consumer who traveled out of state" to pay money for a dyno session. Now did we have a few post-dyno issues? Yes. Those issues being when the car was under load - with the steering wheel being fully turned to the right or left - the car would run rich; although I could be wrong as it may have ran lean. However, the tuner (i.e., Vince) resolved that followed by saying my injector size for an N/A setup was a bit too much. Like seriously, I'm not flaming R/T; nor will I allow other threaders to flame them and/or question their work. Seriously! They did a solid job with the parameters and modifications. For me? It's more like WTF happened after the winter for me to encounter these issues? It didn't happen after the tune, it didn't happen on the drive back, or weeks and months after. If a plug or plugs are fouled? Well today shall be the tell-tell sign. Ultimately, I am not looking for people "to conform to my analysis" as I'm genuinely curious on what the issues or issue could possibly be. If the injector size are too big then I'll order DW 750cc's or GTR 550cc's and have R/T re-tune. It's just when I go FI I don't want to deal with injectors again which is why I dropped 1,000cc's. 😅😅

 

Yeah I get it and I'm not trying to **** you off or create drama, or knock the guys who did you build, or insult your knowledge about cars. Written material is interpreted differently by each person who reads it. I'm legitimately trying to help you get your car running normally again but I have no clue what your experience is so I usually just default to "explain with great detail what I think the problem might be" and let the reader sort it out. I understand you're going for parts that fit into a much bigger picture in the future.

The plugs might be an issue, even with almost full bolt ons it's still perfectly fine to run stock heat range plugs, you don't actually NEED colder plugs until you're around the 325whp range which even FBO isn't going to achieve. Pull and inspect them, that's going to say a lot, if they're all evenly fouled they probably just need to be hotter to self-clean and hopefully that gets you back on the road fully functional again.

I mentioned drilling the swirl jet because that was typically done to correct the high fuel pressure issue (at idle) with aftermarket pumps, it was commonly done with the Walbro pumps which used to be the go-to pump for this platform, it CAN be tuned around the pressure though. Also it's not the pump itself that gets drilled, it's the orifice and swirl jet in the regulator/housing that is drilled.

They might have just decided not to do it because the car was coming back in for the rest of the build shortly anyways and maybe there was talk about going fuel return so no point in extra labor hours for something that was getting deleted soon anyways???

Hope this helps.

 

The swirl jet? I just read about that as I didn't do it. The block was already built from Import Parts Pro whereas the bolt-ons I did myself.

https://conceptzperformance.com/ipp-...-s1_p_5150.php

That said, the injectors and plugs will arrive next week. For the swirl jet? I'm avoiding and just going to source-piece fabricate my own return because nobody really knows the diameter size to get the proper fuel pressure. Not worth the risk to drill.

 

Ok I looked a couple months ago for another user and sure enough someone did a pretty decent write-up on the drilling complete with pictures, this will give you an idea what the process typically entails. The drill bit size though can vary based on the total LPH rating of the pump as well as actual psi on the car. When I drilled mine I'm almost certain I used the same sizes this guy has listed on his page, it was at night on the side of the road with a bunch of other guys and someone just happened to have a Walbro sitting in their trunk AND the drill bits from another project so I just bought it all off him and put it in my car. I'm NA, pressure holds at a steady 53psi.

Here's that thread.

http://www.christurnbull.com/project...-g35-fx35-etc/

I STRONGLY recommend using a hand drill bit holder, I didn't have one at the time so I just had a pair of vice grip pliers grabbing the drill bit, it sucked but it got me back on the road, use an actual drill bit holder though. You definitely don't want to use a power drill because you'll punch through the other side of the swirl jet in a heartbeat, or the burr on the metal edge of the regulator will pull the bit down into the rest of it.

It is a trial/error system to get that hole perfectly sized, the 0.070 swirl and 7/64 regulator worked for me (I think, I don't have those bits anymore and don't feel like tearing my pump out to measure) but it's going to vary depending on the pump. I gut feeling is if you went with the sizes he listed you'll be CLOSER to target pressure but still probably closer to 60psi.

However if you do make any changes it's going to affect the volume of fuel the injectors are delivering which will require a retune since they almost definitely DID tune around the higher pressure.

Since it worked last season with that pressure I would keep hunting/troubleshooting the system to find out what changed between then and now.

 

Saw your DM response as indeed I am aware how to remove the gas out of our tanks - just like as you and others described, however, I was wondering if there was a more "modern way" to get it done haha.

Regarding the tuning around the higher pressure? If that's the case, then that's a problem as only time will tell when R/T responds to validate if they did or not vs. assuming on threads. I mean you could be right, however, I'm more of a concrete type of guy.