1990 22r problems

It wont pass emissions, we've narrowed it down to a few things... the HC is high... what would cause that? Clogged cat?

Also, is there an o2 sensor/emissions computer in the 90' 22r's? (or is there supposed to be?)

My Calif. 84 22r had a computer & an O2 sensor, so I'd expect a 90 to have them too.

Yes it is in the PS kick panel, will not run without it. <img src="/forums/images/graemlins/smile.gif" alt="" />

Greg, to clarify, is that thing carbed or EFI? Last carb in the US was '87. (term 22R v. 22RE)

You can run the VIN thru carfax and see what they have in the database for it originally, if it's in there.

High HC for carb typically is the AAP or the cat. If your dipstick smells like fuel, make sure you change your oil and filter before going back in once you fix things.

Carbies were available until 1991 in the non sr5 2wd trucks.

High HC's is caused by an incomplete fuel burn or from running rich. What are the numbers? A new cat can knock the HC's down abut 100 or so and would be the cheapest place to start when you start replacing items. A failing/lazy O2 sensor will also cause it to run rich. You should also pull and check the EGR valve and PCV valves either if those get clogged it can also cause rich conditions. If you do have a 22re and not 22r an air leak in the intake after the AFM will also cause it to run rich.

It's a 22r.... carbie, we bumped the timing up a bit and the truck ran alot better. havent done the e-test since doing that. Can timing effect HC?
Also, there is no o2 sensor, there is a pipe welded in place of where the o2 sensor is in a normal truck, still havent found the wiring for it.....
oh also a full tuneup was just done on the truck...
I will get some more info later in the day, it's a friends truck...

Is it a factory weld over the O2 bung, or is it a private job. If factory does Canada emissions require an O2 on your carb'd '90?

Since it is carb'd, there is an air injection valve(at least on the older ones), that adds air to the exhaust gasses to help burn the unburnt fuel. If this is bad you will also get higher HC's than normal, which a new cat will not fix.

Timing can effect fuel burn and cause higher HC's, though I am not sure how much.

Did it fail at both idle and 2500 or dyno tests?

Just for reference, I have an "84 4Runner with a booger weld over the O2 sensor mount, but I found the single wire wrapped up on the driver's side inner fender near the coil. Wasn't easy to find among the thousands of crappy innovations the previous owner did.

Mine failed on high HC on idle last year. Dealer told me I needed a new cat but a set of plugs and wires and some ethanol-blend gas did the trick. If you can't get the gas, dump a bunch of gas-line anti-freeze in.

Okay - hey guys - this is for my girlfriends truck.

I have done:
-plugs
-wires
-rotor
-cap
-coil

Fuel pump works - all vacuum lines work.
Replaced catalytic convertor from a 2000 tacoma last night.
Truck runs well, but ***** gas mileage. Also, it does cold start now, but requires alot of patience.

The truck does have an emissions computer - but nowhere in the haynes manual can I find the diagram or any indication that it has an o2 sensor - only for EFI and up.

Also - the truck is getting 250 km's to 40 litres of gas, that is 14mpg. I bought my girlfriend this truck for GOOD gas mileage - shouldnt it get at least over 20mpg?! What gives?

Thank you for your help.

Dave

What year truck and engine?

The O2 sensor will be somewhere on the exhaust, from the manifold to the Cat. 3rd gen('89-95)CA smog equipped 22re's will have two, one on the exhaust manifold and one after the Cat. Lazy O2 sensors will cause a loss in mpg, but wont be the cause of the hard to start issue.

The timing could be off a little bit which could effect the cold start, also the cold start injector could also be going bad. The timing being a little off could also effect the mpg's, but not drop it to 14.

What tranny does it have? Auto's do get significantly worse mileage than their 5-spd counterparts.

What it is the size of tires on the truck? Stock tires are 28's, 31's which are a common replacement are about 11% bigger, which equals a 11% loss in kilos on the odometer.

Have you done a compression check? Stuck/not completely closing valves will cause a loss in power which=loss in mpg. Any white smoke on start-up? A bad/failing head gasket will also cause a loss in power and effect the mpg's

You could have a few little things going on that are adding up to a lot of mpg loss.

The truck he is talking about is the one in question.
1990 22r 2wd 5spd

its a 1990 22r 2wd truck. its on 17 inch rims with 45 series tires - same as stock height (195/70/14?) no white smoke, everyhting runs right. Why am i only getting 14mpg?!

If it has to have an O2 and doesn't the ecu could be in a full throttle or constant warm up mode, and causing it to run rich at idle.

The loss in fuel economy is something else though. I think the carb must just be dumping fuel into the engine to only be getting 14mpg.

The thing i'm confused about, is why does a carb have an ECU and how does it work? Is it for timing/electric choke?

Running rich? AAP on Carb known to go out and dump excess fuel always. Plug the hose temporarily to diagnose.

I only have the FSM for 84, so some things will have changed by 90.
In 84 Calif models, the computer primarily controlled the air injection system via the O2 sensor (Called Air Injection with feedback), sending air into either the exhaust stream or back to the air cleaner to keep the O2 levels optimum for the 3-way cat. The O2 sensor was in front of the cat (manifold, I think), & there was a *temperature probe* IN the cat. So the O2 sensor had no effect on the mixture *into* the engine, only on the amount of O2 fed to the TWC.

84 Federal & Canadian models used an "Air Suction system" without a smog pump or computer control. They also used a standard cat.

Both models appear to have some computer controls on a couple of other emission systems, like the Fuel deceleration cut solenoid,Cold Mixture heater, & evaporative emission control.

It's highly likely that by 90, many of the 84 Calif emission systems were in use in Canada & federal models, perhaps even a few other systems as well(Like timing,elect choke, EGR). Only the FSM for your model year will have all the correct details.

Dave