Smelling rich on start, UZJ100 LX470

Joined
Jan 26, 2021
Messages
11
Location
California
Hey all

I’m trying to isolate an issue with my cruiser smelling rich on start.

Done a lot of replacements in the last 1000 miles on wearables including:
-All O2 sensors replaced post/pre-cat, OE denso
-All oils on the truck
-New Denso spark plugs & coils in all 8 banks
-New engine air filter, MAF sensor & throttle body cleaned
-New denso reman starter (so the upper intake manifold gaskets were replaced)

Did I miss something?
 

OwnerCS

GOLD Star
Joined
Feb 1, 2020
Messages
1,454
Location
USA
^^^ This.

Here's a generic thing to check that I've seen happen on engines that use vacuum-operated fuel pressure regulators.

Check the pressure regulator's vacuum line for signs of fuel leaking back through the regulator into the intake.

Conditions

1) A maintenance operation required the fuel rail to be removed to reach a part under the intake manifold.
2) When the fuel rail was removed the pressure regulator was exposed to air and the regulator's diaphragm dried out.
3) Diaphram soon failed afterward. That allowed fuel to pass from the rail into the vacuum line where it was sucked back into the intake.

Not saying this is the problem. It's an easy thing to check if you run out of ideas.
 
Joined
Nov 4, 2007
Messages
10,733
Location
Colorado
Year of your 100 series and mileage?

As stated above. If on cold start only, pre CAT warm up, it's normal. If after CATs hot, your running rich.

Start by running logs on ECT and fuel trims, while driving. I use BlueDrive w/iphone to get long term logs.

Make very sure the spark plugs and coils are real Denso.

Fuel injects:
Run 44K, Chevron Techron in gas tank, one at a time. May also want to run a can of CATaclean through. Best is sending out FI, have tested and rebuilt. But this stuff real does help clean them, very well.

You've no mention of coolant service.
I can't tell you how many 100 series I find, where coolant system improperly service. Because I've lost count. I can say 8 out of 10!
Low coolant.
Air in coolant system.
Empty reservoir.
Clogged reservoir hose.
Reservoir hose not going to bottom of reservoir, (curled up). Found anther yesterday!
Bad rad cap. Found anther yesterday!
Bad thermostat.
Thermostat installed wrong. (jiggle value not at top). Found anther yesterday!
Clean all 3 radiators fins. One of the most over looked factory recommend PMs, is washing radiator fins. Found anther yesterday in need!


Make very sure no vacuum leaks. I find so many!
I see so many PCV hose and Grommets (98-02) bad.
Check the Vane pump idle-up vacuum lines. Most bad.
Check all hose, including EVAP.
Make very sure the intake manifold installed correct (98-05), and not damaged during install (06-07) and all bolts torque.

Check air filter condition and that seal not curled during install. ( I find 5 out of 10 seals damage/curled) .
 
Joined
Jul 21, 2014
Messages
182
Location
Anchorage, Alaska
Year of your 100 series and mileage?

As stated above. If on cold start only, pre CAT warm up, it's normal. If after CATs hot, your running rich.

Start by running logs on ECT and fuel trims, while driving. I use BlueDrive w/iphone to get long term logs.

Make very sure the spark plugs and coils are real Denso.

Fuel injects:
Run 44K, Chevron Techron in gas tank, one at a time. May also want to run a can of CATaclean through. Best is sending out FI, have tested and rebuilt. But this stuff real does help clean them, very well.

You've no mention of coolant service.
I can't tell you how many 100 series I find, where coolant system improperly service. Because I've lost count. I can say 8 out of 10!
Low coolant.
Air in coolant system.
Empty reservoir.
Clogged reservoir hose.
Reservoir hose not going to bottom of reservoir, (curled up). Found anther yesterday!
Bad rad cap. Found anther yesterday!
Bad thermostat.
Thermostat installed wrong. (jiggle value not at top). Found anther yesterday!
Clean all 3 radiators fins. One of the most over looked factory recommend PMs, is washing radiator fins. Found anther yesterday in need!


Make very sure no vacuum leaks. I find so many!
I see so many PCV hose and Grommets (98-02) bad.
Check the Vane pump idle-up vacuum lines. Most bad.
Check all hose, including EVAP.
Make very sure the intake manifold installed correct (98-05), and not damaged during install (06-07) and all bolts torque.

Check air filter condition and that seal not curled during install. ( I find 5 out of 10 seals damage/curled) .
You are going to make him restore the car not diagnose it 🤣.
 
Joined
Nov 4, 2007
Messages
10,733
Location
Colorado
Perhaps. ;)

But believe me I see this stuff, day in a day out. Our engine especially coolant system are so under maintained or maintained improperly.
 
Joined
Jan 26, 2021
Messages
11
Location
California
Year of your 100 series and mileage?

As stated above. If on cold start only, pre CAT warm up, it's normal. If after CATs hot, your running rich.

Start by running logs on ECT and fuel trims, while driving. I use BlueDrive w/iphone to get long term logs.

Make very sure the spark plugs and coils are real Denso.

Fuel injects:
Run 44K, Chevron Techron in gas tank, one at a time. May also want to run a can of CATaclean through. Best is sending out FI, have tested and rebuilt. But this stuff real does help clean them, very well.

You've no mention of coolant service.
I can't tell you how many 100 series I find, where coolant system improperly service. Because I've lost count. I can say 8 out of 10!
Low coolant.
Air in coolant system.
Empty reservoir.
Clogged reservoir hose.
Reservoir hose not going to bottom of reservoir, (curled up). Found anther yesterday!
Bad rad cap. Found anther yesterday!
Bad thermostat.
Thermostat installed wrong. (jiggle value not at top). Found anther yesterday!
Clean all 3 radiators fins. One of the most over looked factory recommend PMs, is washing radiator fins. Found anther yesterday in need!


Make very sure no vacuum leaks. I find so many!
I see so many PCV hose and Grommets (98-02) bad.
Check the Vane pump idle-up vacuum lines. Most bad.
Check all hose, including EVAP.
Make very sure the intake manifold installed correct (98-05), and not damaged during install (06-07) and all bolts torque.

Check air filter condition and that seal not curled during install. ( I find 5 out of 10 seals damage/curled) .
99K LX470 2000 (1999.10 datecode), california vehicle, original owner.

I forgot to mention I’ve has a couple of vacuum hose replaced (OE) as PM.

Regarding coolant, it was replaced by my indy mechanic that did the timing belt, thermostat & water pump. Toyota red was flushed replaced with green, I didn’t ask for green… Was the workshop pushing what they had so I’d be flushing it with pink soon.
 
Joined
Jan 26, 2021
Messages
11
Location
California
Aisin kit was used.

Anyway, it smells fine on idle after a ride though (hot), just that cold start smells rich & unburnt.

70/30 City/Hwy at maybe 13.8 MPG after the O2 sensors were replaced.
 

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