[Taco-Giz]

Hello everyone,

I’ve had an issue lately where, when I first start my car in the morning, it spits and sputters for about 3-4 seconds, like something is holding it back, and then it starts. After it’s been running for a few seconds, it restarts just fine, or if I use it multiple times during the day, it fires right up.

However, each morning after sitting overnight, I get that slight not sure I wanna start on the initial startup (battery is brand new a day or 2 old). What do you think could be the reason for this or is there a way to tune it out..?

This issue is recent, and I’ve been running E85 for the past 10,000+ miles without any issues, aside from long starts for the oil pressure to build up.

It only started happening a week or so ago (kinda same time or a bit after I did my oil change actually.. Not sure if it's related??); it almost feels like those old V8s that had a hard time starting.

Thanks again for your time!


Video: https://www.youtube.com/shorts/8JALtwRRaUM

[ctrlz]

Possibly a leaky injector.

[Taco-Giz]

Originally Posted by ctrlz

Possibly a leaky injector.

Thanks for your answer, How can I tell which one it is..? It's odd tho cause I could let the car off for like 5hours straight and it will fire right up. it's really overnight or I guess for more than 5hrs lol

Could it be my spark plugs.? I have roughly 58K miles on it and I never changed them. I also drive it a bit hard from time to time..

[bishopts]

I would try spark plugs first. Leaking injector is a good guess too. While doing plugs try and keep them in order. Notice if one of them is a little more black than the others. Also look at long term fuel trim. If one bank is more negative then that's the side that's got a problem.

[Taco-Giz]

Originally Posted by bishopts

I would try spark plugs first. Leaking injector is a good guess too. While doing plugs try and keep them in order. Notice if one of them is a little more black than the others. Also look at long term fuel trim. If one bank is more negative then that's the side that's got a problem.

Thanks for your reply!

Here's what I got (screenshots attached as well):

At idle:
Bank 1: -22.7 %
Bank 2: -20.3 %

Slight tap on the gas:
Bank 1: -18.0 %
Bank 2: -16.4 %

Slight accel:
Bank 1: -17.2 %
Bank 2: -16.4 %

Thanks!

[bishopts]

Its pretty rich. I would do plugs and retest.
Once you've done plugs clear the freeze frame data and fuel trim. At idle is the only one you want to look at on this one because of the consistency.
On your retest look at fuel trim from cold, 3 mins after startup, and at operating temp.
Cold, you're still going to be negative because of cold start fueling, 3 mins its not going to be much better but it should be moving toward 0, at operating temp it should be between -5 and +5 on both long and short term.

[Taco-Giz]

Originally Posted by bishopts

Its pretty rich. I would do plugs and retest.
Once you've done plugs clear the freeze frame data and fuel trim. At idle is the only one you want to look at on this one because of the consistency.
On your retest look at fuel trim from cold, 3 mins after startup, and at operating temp.
Cold, you're still going to be negative because of cold start fueling, 3 mins its not going to be much better but it should be moving toward 0, at operating temp it should be between -5 and +5 on both long and short term.

Thank you for the advice!

FYI: It was just a minute after a cold start. I just waited for the catalytic converters to complete their aggressive warm-up and for the RPMs to drop. That might explain why it was slightly high. I'll run some tests tomorrow after the engine has warmed up and record a short video to show the cold start.

I'm currently trying to find the spark plugs for this car locally; otherwise, I'll have to import them along with the appropriate socket.

It's a PITA to find parts and tools here lol.


Update: I ended up buying/importing BOSCH 96307 spark plugs, pre-gapped at 0.035".

The Owner manual specifies that the spark plug gap should be between 0.035" and 0.043", and I noticed that most LT1 owners set their gap at 0.040".

I could only find NGK 4344 Iridium IX or NGK 91418 Laser Iridium spark plugs, but they come pre-gapped at 0.044", which is outside the recommended range.

Also, since I'm running E85, it seems that others running on E85 also go with a smaller gap (0.035"–0.038").

Thus, I chose to go with the BOSCH 96307, pre-gapped at 0.035" because I didn't feel comfortable re-gapping them myself and I had to import them because a single Bosch plug costs 147 bucks on Amazon here...

[bishopts]

Don't run bosch plugs. At all. They will cause problems

[bishopts]

Ungapped junkyard plugs from a completely different engine will be better than bosch

[Taco-Giz]

I feel the love, haha! Bad experience with Bosch?

To be honest, I've had plenty of bad experiences with NGK in the past, but I wanted to give them another chance. Too bad they weren't 0.040" otherwise, I would have.

BTW, after a long drive today, my values are still more or less the same (I think it's normal tho since I got E85 tune on it and that E85 requieres more fuel delivery):

I'm between these values:
Bank 1: -18.0%
Bank 2: -16.4%

And these:
Bank 1: -17.2%
Bank 2: -16.4%

Here's a video of the cold start this morning:

https://www.youtube.com/shorts/8JALtwRRaUM

[bishopts]

Fuel trim is fuel correction. So if you're having to take away 18 percent of your current value then you have 18 percent too much fuel. If you're tuned for it then you would have 18 percent less from the base setting in the tune and your correction would be 0.

[bishopts]

The video does show a very wierd startup. It almost seems like timing

[Taco-Giz]

Originally Posted by bishopts

The video does show a very wierd startup. It almost seems like timing

It happened out of nowhere. I haven't done anything to my car except that I replaced the brake booster and master cylinder a few weeks ago and my oil change.. Which I went from 5w30 to 0w40 then back to 5w30.. Then a week or so later, this happened..

[bishopts]

Maybe fuel? Like a bad batch of fuel.