Coil pack question

Hey ya'all. Been a while. Scavenged through the articles and found some good stuff on compression check and leak down.
First off , i have a 303 code, happened a few weeks ago, fiddled with the packs, checked the plugs and all seemed good, made sure there was good wire conections then cleared the code. Ran just fine. Fast forward 3 weeks and the code came back accompanied by a rough running truck... did the same checks and didnt work this time.
Question, if it was the coil pack fault, which i dont believ it is(yes ive swapped them) would it misfire on 2 cylinders? I unplugged it and it just ran for 2 seconds and died.
Starting to tinker now. Thanks for the help and the tacoworld in general

 

Oh yeah.. im hoping for injecor issue at the worst. Is there a way to confirm or rule that out?

 

And i can pretty much rule out tge plug wire, because the coil pack go directly the the cylinder with the code , 303. And the wire goes to 6
Make sence, or am i aver simplifying it?

 

You're thinking correctly. Did you swap #3 plug with either #1 or #5? Since it is a waste spark system you don't really need to worry about switching to #6 but #2 or #4 would be fine if they are easier to get at.

Does the coil tube have any cracking or dried out rubber?

 

Sooo sandman. It is wasted spark then? Both 3 and 6 will get spark each time the coil fires, only 1 cyl is on comp and 1 is on exhaust?
Anyways , all the rubber and conections seem good
One thing i noticed, taking the spark plugs out and noticed fuel smell. So i started smelljng the plugs, 3 of 4 that i removed so far smelled of fuel. The odd one is the suspect cylinder. So i can kean twords an injector issue, yes?

 

Yes it's waste spark as you describe. I wouldn't use fuel smell as an indicator without knowing which cylinder was on an intake/compression stroke as it was shut off, those cylinders would be "wet" while ones on combustion/exhaust would be "dry" and might not smell of fuel.

 

Gotcha.. i just cleared the code and switched the plugs around, assuming it will pull the same cyl 3 code. See if it will throw a code just idleig.
Is there some way to check the injector in place?

 

Look up injector leak down test, plenty of youtube vids on it that can explain it better than I can. Timmy the Toolman is excellent, a lot of 3rd gen 4runnner content which is closely/directly applicable to 1st gen Tacomas.

https://www.tacomaworld.com/threads/testing-injectors-for-leaks.615297/

https://www.youtube.com/watch?v=MNmt4UVQzDk

 

Did the compression check.
Cyl 1 -180 & 175
Cyl 2 - 170 &170
Cyl 3 - 165 & 170 $ 180
Cyl 4 - 170 & 180
Cyl 5 - 160 & 175
Cyl 6 - 170 - 160 -165 - 180
This is telling me i should do leak down, since these 2 are connected in numbers and coil?

 

Itvwas running idle for like 20 mins looking for a code. Thatvwould be considered "running temp"?

 

Those compression numbers look fine to me, anything within about 10% is said to be good.

Coolant temp is what will tell you if you are at "running temp". Most of the country is particularly cold right now so it may take longer. May have to do a drive cylce as well.

 

There's a test you can do w/ an Ohm Meter on the coils to see if they are in spec. I THINK I put up a post about it several years ago... let me see if I can dig it up. But that's how I located my bad coil. I think I had one go bad a few years after this post and found it that way... I was thinking it was a wire or plug and was wrong.

I don't know how my injectors have lasted almost 300k. I've been waiting for them to die for about 6 years now.


EDIT: Found it. Post 5

https://www.tacomaworld.com/threads/p0304-arghh.591089/#post-19763926

"I'm guessing you have a 3.4? I just resolved my P0303 with new plugs. I had one that was shot. Follow the FSM for testing coils and wires. The wires for example need a resistance no more than 25 K ohms. Theres a procedure to check coils below. (The high tension terminals are the contacts that touch the spark plugs and where the plug wire plugs into the coil.)

(c) Inspect the primary coil resistance.

Using an ohmmeter, measure the resistance between the

positive (+) and negative (–) terminals.

Primary coil resistance:

Cold 0.67 – 1.05 Ohms

Hot 0.85 – 1.23 Ohms

If the resistance is not as specified, replace the ignition coil.


Inspect the secondary coil resistance.

Using an ohmmeter, measure the resistance between the

positive (+) and high–tension terminals.

Secondary coil resistance:

Cold 9.3 – 16.0 Ohms

Hot 11.7 – 18.8 Ohms

If the resistance is not as specified, replace the ignition coil.


As for the injectors, I'd replace them all at the same time to be sure that they all flow the same rate of fuel. Heres a link to a company that remanufactures OEM injectors. Theres a core charge and they only accept OEM in return. https://motorwestperformance.com"