ignition coils ok?

No misfire or obvious issue, but I'd like to make sure things are optimal. It takes 5-6 cranks to cold start at ~60F.

Jan 2021 the mechanic replaced spark plugs and 1 coil that was causing a misfire, which I believe happened after I washed the engine bay and maybe got a little water in one.
Jan 2022 I put in new OEM spark plugs + wires.

I'm testing the coils resistance as per the FSM image below. Primary resistance is zero on all. Secondary resistance on all is not reading! I have a new OEM coil and its secondary resistance tests perfect, around 12 kiloohms I think. See one of my pics below showing the terminal in question on a new vs used coil. All 3 used coils look that way. The used coils consist of 2 Toyota and 1 Denso, so I suspect the mechanic put in the Denso in 2021, the label on which looks arguably (?) newer than the Toyotas. To reiterate, I changed the spark plug wires this year, so if those were causing the corrosion on the terminals then they no longer are, or perhaps I caused it by maybe getting water in there with one of my engine bay washes. I cleaned the terminals with electrical cleaner and a Q tip, no help.

Obviously they're working with the truck starting up ok, but what's up with the secondary resistance? On the new coil I get a reading easily.

I'll buy a couple new coils if you think replacing all 3 might have an effect or at least make sense for preventive maintenance considering the look of that corrosion.

 

My 2003 base takes 5 cranks sometimes because my battery is often times down to about 50% capacity now having run it down to needing a jump so much (charging phone, food warmer)

 

Good to know. I don't think I've ever done that since getting this battery. It's 3 years old. I have it scheduled to replace next year.

 

Replace all three for peace of mind and keep one of the old ones as a spare in the back of the truck.

As far as how many cranks it takes to get going, the 5-6 seems pretty average. Could replace the starter if you wanted to yell at the placement of it on the engine/engine bay too.

 

It's an Ultima starter from OReilly, installed 12 years ago. The receipt says limited lifetime warranty. A friend I hired to replace it was exclaiming at how hard it was to get to once he got in there and had to remove various things to do it.

 

Yes, that’s my sarcastic reply for replacing the starter because it’s a pain in the ass lol.

I have found a shortcut to make it easy to replace the starter though. Depending on your skill set and how nimble your hands are, you can separate the starter from the solenoid with two long bolts that combine the part and the electrical cable. This way you can fit them through more narrow areas by separating them. You just have to make sure you can put it back together correctly with the notch on the starter as well as tightening the bolts up.

It is a tight fit but I was able to fit an automatic/cold weather starter on my manual transmission.

That being said, I would be looking at your battery, alternator or the fuel delivery system for the multiple clicks it takes to start up. Potentially battery is getting old, or the alternator is not charging at the correct volts. Try hooking your battery up to a charger not a trickle charge for 24 hours and see if that decreases the number of cranks to start.

I am not a professional though, my neighbor who’s a mechanic just laughs when he sees me working on my truck in the front yard.

 

That’s why I chose a rebuilt Densa starter OEM. Slightly more compact design, no trouble installing.

 

What do you mean by 5-6 cranks? 6 key cycles or 6 crankshaft rotations? Mine takes about 2 seconds to fire, sounds like about 1.5 crank rotations.
I don't think it would hurt to change out those corroded coils but if they're running fine once started, w/ no noticeable misfires, I'd probably be looking more at fuel pressure. Especially pressure bleed off at engine off.

 

I guess I mean 6 crankshaft rotations. I feel like up until recently it used to be about 4 for years. Seems to be 6 each time cold now.

It accelerates fine uphill. Fuel filter is clean. Would monitoring the fuel trim % under certain conditions reveal anything here, or is it best to check fuel pressure with a gauge? I'll look into that. I was going to do that a while back, but something about it intimidated or confused me. I can't remember what.

 

For sure monitoring fuel trims under load would be beneficial but you mentioned the hard cranking on cold start which would make me want to hook a fuel pressure gauge up and check to see if the pressure is slowly bleeding off over time after the motor is shutoff which would indicate a bad check valve in the pump.

 

I think you're onto something, backflowing through the fuel pump check valve. It was sitting for a few hours, and I started at 6 cranks, shut it off right away, and then restarted at 3 cranks.

I'm guessing it wouldn't be leaking on the fuel injector end, because I don't have the symptoms of leaky fuel injectors from a few sites I looked at. And there's no fuel dripping to my floor from a leak in between.

Anyway a few extra cranks seems like a fairly low-consequence thing in this situation? It seems like it must be backflowing only a certain amount, not completely emptying the line.

 

Assuming that's what it is you could live with it for a while at the risk of additional wear on your starter. Personally I like to get to the bottom of things and don't want further headaches down the road. It would give you an opportunity to buy some new tools (fuel pressure test kit) if you don't already have one LOL