87 toy p/u w carb runs, but failed NOX on smog test, and light doesn't come on w key-bulb good.

 

This is strange The 87 EWD only shows the CEL with the EFI system.

Both the 86 and 88 don`t show any either

Maybe the socket is on the cluster that way with EFI the CEL is there

I don`t have any vehicles that with a carb to double check

Might very well be why it does not light

Has it ever worked ??

 

Hi Wyoming9, First try at this. Yes it used to work-Ca. truck/may be different? Truck runs, and has always passed smog previously. My only real continual problem has been Aux.Accel. Pump failure every couple of years (alcohol in gas) that allows gas to enter vac. lines..

 

Strange...

I do not have my manual in front of me so I have no reference to the California models....

I have not come across one of these carbureted trucks that has a circuit for the check engine light. What I have seen is that the actual light and lens are in all of the gauge clusters and are only used for EFI models.

However I have never looked at a California model in person (or at least noticed the check engine light)

Since your truck has the California emissions package, you have a more complicated emissions computer that takes in more inputs than the federal model. Maybe the emissions computer has "check engine light capability".

Does your truck have any oxygen sensors? I know some carbureted California models used them for inputs for the emissions computer.

 

Hi Old87Yota, Let me back up to my last reply, I'm pretty sure the light worked. According to the tester, it worked on the first test, and only failed the 25 MPH NO test (the state cut the max allowed just under 50% since the last test 2 years ago). On the retest, I failed NO and the light was inop. Yes, I believe there is an O2 sensor in the exhaust manifold, just above the head pipe with a single wire going into the wire run on the L/H fender behind the coil/igniter unit. I just opened up the R/side kick panel to see a box there (P/N 89550-36330 Emission Control). I'm kind of stumbling around like Mr. Magoo-only have a Haynes manual after a neighbor borrowed my shop manual (never returned). I appreciate the responses-looks like I might need the hi$ box. If I can determine what wire, I could at least check continuity.

 

EGR not opening or bad CAT

 

Still at it. Opened Emission Cont. box Looked and smelled OK. My question, will the other test lights when you turn on the key (Oil, Seat Belt, Charge, and Brake) work independently to illuminate (even if the box is bad)?

 

^^this^^ op I had similar emissions readings on my 81, replaced the cat, drove 100 miles to let it get warm, passed with flying colors

 

Hi Drop Zone & Punchy. I might need components replaced, but until I can get the check engine test light to function, I still can't pass. The other 4 lights work when I turn on the key, but not the check engine, and I never got a malfunction light.

 

My 88 book doesn't show that lamp connected to the ecc. It says it is tccs/efi only.

 

My Haynes Manual typical late model Emission Control System wiring diagram shows an Emission Control Computer (California C&C) w 16 pins. I assume that is what I have-the box in the R/H kick panel said Emission Control. On another page for Electronic Fuel Injection systems, I see a check engine light (Comb. Meter) from "Engine" Fuse (2-2) w a violet wire into "W" on the EFI ECU. I assume I have some combination of the two.

 

I will look at my 1987 Toyota Factory Service Manual wiring diagrams tonight and see if the California model has a check engine light. That way we know for sure if there is supposed to be a check engine light or not, then we can go from there.

You will not have an Engine Control Unit or Engine Control Module, just an emissions computer.

Are you failing smog because of the NOx AND the light, or just the NOx?

 

He said it was both, light inoperable is an immediate fail regardless of emission results.

88 FSM only has a 12 or 13 pin I don't recall.

 

Hi Old87Yota, sorry just saw the last 2 posts-was busy digging up cactus roots. Yes, Co94Pu is correct. The check engine light is required to pass, and I failed NO on both smog tests.

 

Thanks Co 94 PU. I missed this post.

Okay, I looked at my Factory Service Manual. The wiring diagram does not show any check engine light circuit for the emissions computer. It only shows up in the EFI computer diagram. However, the diagrams in this manual is a general overview.

I wish I had the separate Electrical Wiring Diagram manual to see all of the pinouts for the emissions computer and where all of the signals go.

Does anybody else have a 22R California model?

Are you sure the emissions testers are not looking for an EFI system?

As you can probably tell, I hardly know anything about the testing in California.....

 

Old 87Yota, I'm sure the tester knew it has a carb. Some real wiring diagrams would be helpful. My Haynes Manual shows a Typical late model-combination meter (the combination meter is actually the cluster in front of the driver), but I don't see the check engine light. It has a red wire coming into 11/12 from "Engine" Fuse (2-2) tied to various lights including oil, fuel, and brake. The schematic for the EFI shows the same input going 11/12 check engine (Combination meter) and shows a light.

 

Okay, this post confirms that you should have a light, but none of the diagrams I have show how it is supposed to work......

https://www.yotatech.com/forums/f116...roblem-300504/

 

Hi old87yota, Not sure if you mean my post confirms the light. The Haynes manual isn't year specific-covers 1979 thru 1995. The schematics are labeled "typical". The EFI schematic illustrates a check engine light with 11/12 from "Engine" fuse (2-2), then 4/12 and a violet wire going into W on the EFI ECU. The typical combination meter shows from "Engine" Fuse (2-2) R into 11/12 that gangs the lights or meters, and a From EFI ECU (1-7) G-L into 4/12. I know this sounds confused (like I am). What I need is the Ca. wiring, and the smarts to interpret it. Thanks