Rich Hard Start - The Ongoing Struggle

2013 3UR-FBE 178k miles

For the past year I've been dealing with hard start issues, everything from a little rough idle, to misfires and bangs, to simply not starting at all.
At the beginning of the road I attributed it to FFV, so I replaced the fuel pump and filter and restored acceptable fuel trims. No luck there so I moved on from FFV at fault.
Had some errors that led to replacing the bank 1 O2 sensors. Also replaced the coolant temp sensor on the off chance that was it.
I've done regular maintenance (plugs, pcv, filters, etc) cleaned MAF, cleaned TB, cleaned intake manifold, but all to no avail.
Gas mileage is in normal range between 14.5-15 usually. Once it's on the road it runs fine.

But I'm getting close to the end of my rope and I'm getting ready to pull the valve covers to try and find out what the heck is going on. Before I do that I wanted to post a video of a hard start I recently did and see if anyone had any other ideas. All I can tell you at this point is that I have no codes right now (other than ones you'd expect from a hard start) and that once it does start the fuel stench from the exhaust is unreal for the first minute.
Thanks for any ideas you can throw my way!

https://youtube.com/shorts/M3GK5o49WRg?feature=share

 

Leaking fuel injector or bad fuel pressure regulator?

what to the long/short term fuel trims look like per bank?

 

Haven't looked at the shorts in a minute, but the long was -1.562 bank 1, -3.254 bank 2

I haven't suspected anything from the fuel system like the injectors or fpr as I don't have any other symptoms that would point to them like declining mpg, poor detonation. There's no issue after just a few minutes of idling, not even really warm. I feel like a problem with one of those 2 things would persist or worsen after warm-up.

 

Weird injector was my first thought too. With the supercharger guys injector issues often cause starting issues exactly like you're talking about, though the specific issue hasn't really been tracked down besides that some aftermarket injectors seem more prone to it. But same symptoms.

My other question is what exactly are the codes it's throwing at startup? Also do you know what the truck thinks the ethanol content is? Is it at 0% or is it higher?

 

Only codes I see are P0300, 303 and 305. Currently the alc% is reading 0, it's been about 60ish days since I last reset

My suspicions have been narrowed down to fpr, injector, coil, or I dropped a valve follower/rocker thingy or bad spring maybe

Oh and oil smelled strongly of fuel today, but to be expected I suppose.
I only get this on cold starts though, runs perfect on the road, and starts warm or hot just fine. Even warm weather makes it more amicable.

 

Ordered a set of remanufactured injectors, fingers crossed they're not shite

 

@snivilous
Replaced all the injectors, it's been about 5 days now. It hasn't cured rich exhaust problem though lessened it, and the hard start issue persists. Back to the drawing board.

 

Which coil packs and plugs are in it?

 

Plugs are DENSO 3421, did those shortly after I got.
Coils on 1 and 3 are Delphi, the rest are all Toyota/Denso OE.

 

Describe the hard start. Is it just cranking? Trying to catch at all? Catches then kind of chokes and barely running?

 

Most troublesome when it's cold, 50 or lower, this morning it was 39. First two tries nothing tried to catch. Next two it half heartedly tried to catch. Next one I got a good catch, followed by another try it kind of chokes/barely running for a few seconds then dies. Final try got it started, sluggish/low rpm for about 3-4seconds-ish then rpm rose and it was fine. During these the system sometimes tries to start for the full 10 seconds or sometimes decides to stop trying after only 4 or 5, not sure why.
One thing to note though is that the misfires on hard start have ceased and the the ecm has cleared the previous permanent codes for misfire.

 

I would test fuel pressure if you can next time. It sounds to me like it's not getting fuel and only after trying for awhile it finally builds up enough pressure. Maybe shit in the tank, pump going out, FPR clogged, wiring issue, etc. but if you can see the fuel pressure next time it hard starts, like crank it once and if it doesn't start look at the fuel pressure gauge and see what it says that will at least narrow down if it's fueling or at least what half of the fuel system.

 

I'll give it a shot, is there a spot I can install a gauge or do I have to just jack in with hoses?
Fuel pump is a DW300c less than 5k miles on it, tank was cleaned out and main line purged when I put that in, so hopefully neither of those.

 

Hopefully someone else can advise where to hook a gauge in, I've never plugged one into my truck. With how cheap gauges are I would probably just buy one to permanently install off of the fuel rail somewhere, though I think you can rent a fuel pressure testing kit from autoparts stores too.

 

Ok, that's what I'm hoping is that I can just install one permanently, I'll see what I can find out here

 

On the one hand I would be surprised if it's the pump, flip side is there might be an installation issue. I've seen it plenty of times (even fucked it up myself) putting in a pump and either forgetting to swap the little plastic spacer or the wiring isn't well seated or a hose isn't clamped or connected well enough and the truck runs but has pressure issues. I bet the pump is fine, but based on the fact it was swapped not too long ago actually makes me lean more towards something related to the pump being an issue. Hopefully not, but seeing the pressure during cranking should quickly tell us if there's a downstream fuel pressure issue.

 

Well in that case my hope is that it's not cause I did the whole pump and filter swap when I first started chasing this problem last year

 

Problem -> Replace pump -> But injectors bad -> Mess up pump -> fix injectors -> now pump is bad but original issue is fixed At least if that is the issue you're near the finish line of solving everything!

 

Would this do? https://www.tundras.com/threads/general-supercharger-thread.85513/page-423#post-3436747
I'm trying to find it on the mentioned site, but not having much luck

 

Yea that'd be fine. I know there's barbs you can get that hook into the stock fuel pressure lines (like that post shows). I bet there's a barb with a 1/8" NPT that you can plug the gauge into and mimic that. That may be what @VWTim did, or maybe he has a part number for that setup.

 

I think he got this - https://www.racetronix.biz/p/adapter-qdf-5-16qdm-5-16-1-8-port/qda-56f56mp

 

That will work.

 

That looks exactly what I had in mind!

 

I threw that link on the supercharger thread first post, that's good to know!

 

The ambient temp thing still bothers me though. Is it simply because on colder mornings it wants to mix more fuel than on a warm afternoon? Doesn't make sense to me, I feel like I would have troubles elsewhere other than just start, like WOT.

 

Have you cleaned the MAF? All connections good? IAT's are read from it and could possibly throw it off.
Also since deleting some of the FFV system...do you have it in high psi mode?

 

Yep, cleaned it real good last year. No evidence of any wiring or connection issues or anything that points to them

 

And it's only in low psi mode?

 

Yes, only on startup

 

@snivilous
Ok, got those parts today - it leaks. The machining and quality are nice, I just think this is hit or miss on stock parts that aren't as well machined, tolerances are too broad.
But I was able to get a reading on the gauge even though it drops fairly quick and in the second or two it takes to move back around to the gauge I found it at 39lbs. So if that seems to be fine what is the next test?