Misfire, Shuddering/shaking, lopey idle... (1 Viewer)

[fuzzywuzzy]

Couple questions - I'm having a long of the same issues and just starting my diagnosis. Also started after a fill-up after sitting with low fuel for a few weeks. Yesterday with the engine running the wires were pulled from cylinders 1 and then 2, seems like I'm getting good spark but there was no change in idle when pulling the #2 wire so that cylinder is suspect. Plugs have less than 500 miles on them, wires, cap, and rotor have less that about 1000 on them. Inside of distrib cap looks fine, no spidering, etc. Haven't checking EGR, charcoal filter, or TPS.

Planning on doing a compression check this afternoon just to rule out HG. I have a 91 3FE - If I decide to purchase a replacement ECU is there a range that I can plug in to mine like 91/92 or just 91 or.....?

 

[BILT4ME]

Couple questions - I'm having a long of the same issues and just starting my diagnosis. Also started after a fill-up after sitting with low fuel for a few weeks. Yesterday with the engine running the wires were pulled from cylinders 1 and then 2, seems like I'm getting good spark but there was no change in idle when pulling the #2 wire so that cylinder is suspect. Plugs have less than 500 miles on them, wires, cap, and rotor have less that about 1000 on them. Inside of distrib cap looks fine, no spidering, etc. Haven't checking EGR, charcoal filter, or TPS.

Planning on doing a compression check this afternoon just to rule out HG. I have a 91 3FE - If I decide to purchase a replacement ECU is there a range that I can plug in to mine like 91/92 or just 91 or.....?

91-92 will be the years of compatibility for you.

You have the 3FE, so the occurrence of failed HG is minimal. That's typical of the 1FZ-FE (93-97)

Do a search for anything written by @jonheld He is the "guru" on the 3FE and can walk anyone through it.

He has a troubleshooting checklist on here somewhere that NEEDS to be followed step by step.

If he does chime in here, you must listen and do what he says. Seriously.

 

[fuzzywuzzy]

Is this the one you're referring to? If so it doesn't make any reference to the plugs, wires, ecu, injectors, etc. Just want to make sure I'm heading down the right path, seems like a jump to the EFI considering his document mentions No Start and mine's running, albeit rough.

http://www.sdsysdesign.com/tlc/images/Strife/3FE EFI Diag.pdf

 

[BILT4ME]

Is this the one you're referring to? If so it doesn't make any reference to the plugs, wires, ecu, injectors, etc. Just want to make sure I'm heading down the right path, seems like a jump to the EFI considering his document mentions No Start and mine's running, albeit rough.

http://www.sdsysdesign.com/tlc/images/Strife/3FE EFI Diag.pdf

That would appear to be the one, however, I do not have nor have needed it for a 3FE because I don't own one.

I will let him chime in here.

I would follow it as far as I could. If I do/don't have a CEL. In your case it IS running. Go to the next step.

It DOES state that the ignitor can be intermittent... maybe that's what's happening here?

I'm grasping at straws for you.

I'm hoping he will chime in soon. He is typically very responsive.

 

[fuzzywuzzy]

I appreciate it, maybe if I look in my wiggly driver's window and say @jonheld three times he'll appear? I'm going to check my compression to rule out any HG issues and check vacuum hoses when I get home. Also, going to check ECU to make sure nothing looks funky in there like OP was experiencing.

 

[jonheld]

Couple questions - I'm having a long of the same issues and just starting my diagnosis. Also started after a fill-up after sitting with low fuel for a few weeks. Yesterday with the engine running the wires were pulled from cylinders 1 and then 2, seems like I'm getting good spark but there was no change in idle when pulling the #2 wire so that cylinder is suspect. Plugs have less than 500 miles on them, wires, cap, and rotor have less that about 1000 on them. Inside of distrib cap looks fine, no spidering, etc. Haven't checking EGR, charcoal filter, or TPS.

Planning on doing a compression check this afternoon just to rule out HG. I have a 91 3FE - If I decide to purchase a replacement ECU is there a range that I can plug in to mine like 91/92 or just 91 or.....?

Head gasket and ECU issues are very rare on a 3FE. I would be looking elsewhere.
Since this issue started after sitting for a few weeks, perhaps you have a stuck valve. When was the last time you did a valve adjustment? The FSM wants one every 15K miles.

I strongly suggest using all OEM ignition parts. They are all still available and a higher quality than aftermarket.

The ECU pulses 2 banks of 3 injectors, not each injector individually. So unless you're having an issue with 3 cylinders, I wouldn't be looking at the ECU.
Igniter failure is a common issue, but it would kill spark to the coil. Again, not just 1 plug.
Pull the plugs and check for a cracked insulator.

Keep in mind that the 3FE is a tractor motor with 1986 EFI "technology". Always check the easy things first.

 

[fuzzywuzzy]

I have to work on my Tacoma tonight so hopefully will look into Cruiser Friday or Saturday. Don't want to say too much but ran great on way home from work yesterday and then back to work this morning. (fingers crossed)