100-Series Won't idle, black smoke from exhaust, no CEL

[hansey13]

Hi everyone, I have searched the forum quite a bit before posting but if someone has posted about this issue before apologies for not finding it! I have a 1998 2UZ-FE with 203,000 miles. about 2 months ago I replaced the spark plugs, 2 bad ignition coils (always replaced with genuine Denso) and a bad O2 sensor at bank 1 sensor 1. These all showed as Check Engine Lights and I replaced them accordingly. It has been driving great since then, no issues at all. I'm in Hawaii and two weeks ago we got insane rains but I didn't drive the LC much. I filled my tank (almost 6 dollars a gallon for premium which I have always ran) last week and the car ran fine for about half of that tank. Now it is not idling, I have to push the accelerator at start up to get it to start and run, I have to keep RPMs above 1k or it will die. Lots of black smoke pouring out of the exhaust, no CEL (which is really strange to me) at one point on my OBD2 scanner I got a pending P0172 (system too rich Bank 1) but it went away and never triggered the CEL. I tried cleaning the MAF and throttle body which were pretty dirty but that didn't solve it. I feel like there are a lot of things it could be, but I know someone here is smarter than me and I am hoping to get pointed in the right direction without going down too many wrong rabbit holes. My thoughts in the order I am thinking. 1: Check Timing marks to see if it skipped. (I was preparing to do the belt as its been 85k since the last change.) 2: Bad Injector(s) remove them, get them tested and cleaned. 3: Maybe ignition coils or O2 sensor? no CEL makes this one feel strange. Help me IH8MUD, you're my only hope!

 

[frawstme]

Probably not much help but that sounds like it's either getting too much fuel or it thinks that its not getting enough air. The black smoke is a big indicator of that.

Try unplugging your maf and see if the idle improves (or swap in a good one). Just because you cleaned it doesn't mean that it's functioning correctly

If nothing changes then check for a leaking injector. Pull the plugs and look for one thats either very black or just completely soaked. Might as well start at bank 1.. this is likely the issue

Another thing that probably isnt the solution but relatively easy to check just incase is to have someone check your coolant temp sensor readings. If it shows insanely low readings then the ECT might have failed which would cause the ecu to dump fuel

if its none of those things the only other thing I would know to check is the fuel pressure regulator, but that feels pretty unlikely

edit:
as a disclaimer, i work in a shop but i'm mostly a home mechanic. I had similar black smoke issues with my ford and it ended up being a leaking injector. It's very possible that there's something different on a land cruiser that could cause this that I dont know about

 

[x8o8drifter]

Thinking same.
Friends Corolla did kinda the same when his MAF was on its last legs.
And also on his Civic when one of the injectors was stuck open.

 

[hansey13]

Probably not much help but that sounds like it's either getting too much fuel or it thinks that its not getting enough air. The black smoke is a big indicator of that.

Try unplugging your maf and see if the idle improves (or swap in a good one). Just because you cleaned it doesn't mean that it's functioning correctly

If nothing changes then check for a leaking injector. Pull the plugs and look for one thats either very black or just completely soaked. Might as well start at bank 1.. this is likely the issue

Another thing that probably isnt the solution but relatively easy to check just incase is to have someone check your coolant temp sensor readings. If it shows insanely low readings then the ECT might have failed which would cause the ecu to dump fuel

if its none of those things the only other thing I would know to check is the fuel pressure regulator, but that feels pretty unlikely

edit:
as a disclaimer, i work in a shop but i'm mostly a home mechanic. I had similar black smoke issues with my ford and it ended up being a leaking injector. It's very possible that there's something different on a land cruiser that could cause this that I dont know about

unplugged the MAF and it idles! Not amazingly but no smoke and sounds mostly normal! I’m assuming like everything else best to go OEM on these?

 

[frawstme]

unplugged the MAF and it idles! Not amazingly but no smoke and sounds mostly normal! I’m assuming like everything else best to go OEM on these?

Not sure there, but typically my experience with toyotas is to almost always go OEM.

I'm glad that worked, and it's normal for it to be idling poorly with the MAF disconnected. Replace it and see how it goes. If it's still idling poorly though your next step should still be to diag the injectors.

The fact that disconnecting the maf allows it to idle eliminates ECT too, so at least you dont have to worry about that.

 

[LC Lurker]

This was peak forum discussion lol