Thread for Actuaries to Diagnose Auto issues

I’ll find my recent post with the issue.
Short story: Car was not starting. It was cranking (so, not the battery) and I could crank it for a good 5 minutes (thanks Diehard! yippee ky-yay!) before it eventually would start.

Went to repairman, he replaced an ignition coil (now all four have been replaced).

And, only a couple of days later, it was/is doing the same thing, so ignition coil was not the cause (but probably needed replacing anyway due to codes)
It only does this when the engine is cold. It’ll eventually start, and I can drive around, stop, do whatever I do, get back in and voila! it starts just fine when the engine is warm. Not only that, but the “check engine” light isn’t even illuminated. (It was before, prompting the ignition coil replacement.)
So, I’m wondering what else it could be. Tried checking online. What appeared to be a GPT chat bot tried to get me to talk to someone, so I shut them down. Not falling for that trick.

Again, same as last “old-timey doctor with only a stethoscope” (my) diagnosis is that the new-timey computer is not enriching the fuel enough when the engine is cold, and that only after cranking for five minutes does the engine warm up enough to accept the proper combination of air/fuel/spark. So computer replacement (“what are you doing, Dave?”) seems a reasonable solution. Not even that expensive.

Any gearheads here have any other ideas? No, the $30K-$80K solution (“Just get a new car, one without an engine!”) is not on the table yet.

Maybe you can use some of the suggested areas in this article:

https://axleaddict.com/auto-repair/My-Car-Struggles-to-Start-When-the-Engine-is-Cold

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Not a gearhead but…it’s possibly a sensor malfunction. Solution, they start replacing sensors til they find the busted one.

The stupid sensors break more than other things and often don’t throw a code that’s good enough to diagnose.

If u really want to diy the diagnosis, buy.or rent a scanner.

I got a cheap one on Amazon, like $30 or $40. Good for knowing exactly what codes are being thrown, at least gives you something to google.

And at least on my car, it will display the intake air temp. It’s possible that sensor is faulty and DTNF could maybe confirm that it’s working correctly. If it doesn’t know it’s cold then you have a problem.

Otherwise Arthur’s link looks pretty good in terms of things to check.

I like this site! Thank you.

But, I still wonder because after it starts, it runs perfectly fine. Seems to me a lot of the issues noted would keep messing things up even when warm. Like a dirty air filter or worn plug wires.

Watching a video and I’ll try his diagnosis step of, “Turn the key to the on position, wait ten seconds, turn it back to lock, repeat a couple times.” Seems more like a fuel pump or fuel filter issue. Could be the air sensor as well.

Imma just go with this. When it’s not obvious, it’s always a sensor.

That is some major old-timey-doctor diagnosis!! And probably true.

Well you used to go through spark, fuel, air, one of those three to start figuring stuff out. But with EFI, well, you’ve already replaced pretty much all of that already. So the result is, figure out which group of sensors is impacting the car, then start replacing cheapest to most expensive, or, most common one to break down.
My mechanic has gone on a rant about sensors before because it really seems to be just start replacing them til it works again.

I would definitely pull out the air filter and see what it looks like. Should be easy to do and easy to tell if it’s a problem.

Myself I always take it to a shop but it’s helpful to know what you’re in for. With this vague diagnosis you could easily spend a lot of money to find the answer.

It is there now.
Tried that trick above and no problem starting, but not perfect, to get it to the shop.
Doctor took out his MRI/X-ray machine (equivalent), took out the air sensor near the filter.
And, overnight stay to see if the patient coughs when it’s cold.

OK, car is back, I have not started it today, but it was fine last night starting cold.
So, let’s see about today.
Doctor found nothing wrong with the car yesterday morning, started without a problem. Replaced some old fluids with new fluids as scheduled.

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Bump, because it happened again.
Last drove it on Sunday (no issue), and last night I tried starting it and it took over 10 minutes to start. Engine is turning, but either there is no gas or there is no spark possibly no compression.
When it finally started, it was as if nothing had happened. Well, except the check engine light is on now. Sounds the same as it always had. That tells me that eventually the gas arrived or the spark finally occurred or compression occurred. I stopped the car, had a dinner, and it started up fine after that. Started it this morning, no issue.
So, I’m going to park it on the street, slightly downhill-facing, to see if the fuel pump is not pumping fuel and maybe gravity is required, forever. It is normally parked in my driveway, slightly uphill-facing. Maybe that’s it.
Or, time to hit the local Toyota dealer. Or several.

Be careful, this could be a deep and painful rabbit hole… and good luck.

Yeah my truck is making a ticking sound from the engine. Which means one of two things. Either the exhaust manifold needs some new bolts, which is cheap…or cam/lifter problems which is possibly a new engine.

My mechanic said if it was internal parts I’d probably already be broken down, since I’ve driven probably 1k miles since it started. I guess we will know more on Wednesday. Or on Sunday when I drive for a few hours to go ice fishing.

First, after parking it on the street, slight downhill, for a week, I’ve had no starting issues.

I saw an article about bad gas from Costco (GA, not CA), and now I’m wondering about it, as I usually get my gas at a suspiciously low-cost station in my town (closer than Costco and about the same price, and right down the street from a B-R). And I use Premium (Dude!), as the compression ration of the engine is quite high.

So, how do I check my gas tank for water or otherwise shitty gas?

I get #1, #4, and #5 on this list. Runs smoothly after eventually starting (five minutes of cranking). Check Engine light comes on after these lengthy cranking sessions, but has not been on since the last issue. I am getting a few MPG lower for the past couple of tank loads, including the current one (estimated). Could be caused by the amount of fuel burned during the cranking.

I’ll see if someone can check the gas, Not sure my usual guy can.