1993 FJ80 CA smog fail

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S

stubble88

10 Year
Joined
Nov 5, 2015
Threads
22
Messages
86
Location
Agual Dulce
replaced plugs, Denso o2 censors,
no check engine light
runs great

134k miles

passes the 25 mph
fails the idle
running rich maybe?

what else should I check before taking it in to mechanic?

thanks

smog.webp
 
I'm getting ready to smog my 97 LX450 this Monday. Here is my check list:

Clean MAF sensor.
Clean PCV.
Clean or replace air filter.
Clean the intake and throttle body with spray cleaner. Remember to spray into the metal nipple where the PCV connect to.
Change plugs.
Check all vacuum lines for leaks.
Run two 1/2 tanks with Techron fuel system cleaner then 1 tank without the Techron.
Change oil the night before.
Drive for about 30 mins to heat up the catalytic converters right before I go to the smog station.

Hope this helps.
 
Or just move to a place that does not require you to do smog test.
 
Great reply Jason. Very helpful.
 
You could try 3 gallons of E85 into a half tank, then after the test fill up with normal gas. I just did this and was way under on the hydrocarbons and nox.
 
The main issue is CO is too high at idle, but not at higher RPM. This sounds more like excess fuel than too little air because air flow is low at idle any way. I would suspect a leaky injector first, because it has longer to leak at low RPM but also check the FSM for other possibilities. It has an excellent troubleshooting guide. HC is also high at idle, but I suspect that this will go away when the CO does.
 
You can download the 1996 version. It is the same engine, so the mechanical parts are very similar, but the OBD-II codes won't apply.

Edit: I looked up rich condition (P0172) in my 1996 FSM.
The Trouble areas are:
Fuel line pressure (page EG132)
Leaky injector (EG137)
O2 sensor malfunction (EG235)
MAF (EG120)
Engine coolant temp sensor (EG225)

Again, the one that makes the most sense only at idle is the leaky injector. Try some cleaner first and maybe you will get lucky.
 
Last edited:
I don't have the MAF
o2 replaced with OEM Denso
looks like replace the injectors is a major job, am I wrong? I went ahead and ordered some remanufactured OEM injectors for $128 for all 6. Thought that was a better route then $500 new ones.
if its leaking, will cleaning them make a difference?

thanks a bunch
 
Trying some crazy expensive additive. Some BG44K
But educate me on how cleaning an injector will fix the leaking. Can they get stuck open?
 
Last edited:
Yes. To leak they don't seal or stick open. Usually because of a piece of dirt. Maybe something that can be dissolved by a detergent or additive. Maybe not.

The injectors are opened by grounding them. If the wire is shorted to ground it is always on. Check the harness at EGR tube to see if there are any exposed wires.
 
What do you mean when you say it passed the 25mph test? Did it go on a dyno? I live in the Bay Area and dont have to do that. Its an awd, no dyno required.
 
If it's running rich I want to fix it.
Sorry I meant 25rpm or 2500. Yeah it wasn't on a Dino obviously.
Thanks for all he help everyone. Much appreciated.
Time to take it in and get it diagnosed
 
stubble88 said:
replaced plugs, Denso o2 censors,
no check engine light
runs great

134k miles

passes the 25 mph
fails the idle
running rich maybe?

what else should I check before taking it in to mechanic?

thanks
Click to expand...
You didn't hear it from me, but get a P.O. Box in Mariposa County and register it there. Just a thought.
 
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