My 1222 Code

[jlevie]

I just match the ID and cross section from an o-ring kit. It is metric so the match will come there.

[jeffnhiscars]

Would you have a spec or source for replacement dipstick o-rings ?

[jlevie]

The complete list
of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hoses, valve, and expansion tank
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

While leaks in some of those can be found by inspection or by spraying carb
cleaner on suspect areas, not finding leaks that way doesn't eliminate the
possibility. Only a smoke test will really work. And since carb cleaner, or similar, only works on a pretty large leak, you really should have a smoke test run.

There are only two long term fixes for leaks at the throttle body elbows. A new throttle body or JBweld. Silicone, Permatex, etc., starts leaking again in a while. Just be sure to clean the bore and nipple with acetone or lacquer thinner first and let the car sit for 24 hours in 60F or above without stating the engine so that the JBweld can cure.

[jeffnhiscars]

I took some TB Cleaner to the intake side and got some increased revs at the breather hose elbow to TB connection...no big surprise there. I pasted some Ptex#2 around the joint and ran a zip tie around the TB to hold it for now.

We'll see

[jeffnhiscars]

Understand that a 1222 code is a Lambda (mixture too lean or too rich) fault, while it could be caused by a problem with the O2 sensor, that usually sets a 1221 code. In this case, with a new O2 sensor, the likely cause will be intake leaks. Especially since the CEL appears at idle and goes away with an increase in throttle. There are other possibilities, but start with a smoke test of the intake and repairs as indicated.

I wont say an intake leak is impossible, but its all just been put back together and rather thoroughly checked.

I'll re-check for leaks especially at vacuum hoses I reused but may also put the old sensor back to see if the problem goes away before I start looking for a smoke machine..since the drop in mileage coincided with the new O2 install

[jlevie]

Understand that a 1222 code is a Lambda (mixture too lean or too rich) fault, while it could be caused by a problem with the O2 sensor, that usually sets a 1221 code. In this case, with a new O2 sensor, the likely cause will be intake leaks. Especially since the CEL appears at idle and goes away with an increase in throttle. There are other possibilities, but start with a smoke test of the intake and repairs as indicated.

[jeffnhiscars]

If you've read the build thread you know the Zinno Cabrio is doing great. If you haven't read it dont read this :p

I've put about 3k on the car since getting it back on the road and that includes 2 trips to Florida of about 1200mi @ so its mostly highway miles. I recently started getting a CEL only at idle and after the car had been out for a good run. It starts, runs, idles and drives perfectly so I figured it was probably a sticky oil pressure warning switch since its due for a change and the light always goes off the instant I hit the gas.

Since the car just turned 100k I figured I'd throw in an O2 sensor just because. I reset the DME with a battery disconnect and took off for Florida. Everything was great except my highway mileage (calculated AND per the OBC) had dropped from 25 to about 22 and it has stayed there. Keep in mind Im comparing 2 trips on the same route within month with no other changes.

Today I pulled the codes..which I didnt think I could do on a 7\87 build..and I got a 1222 (Lambda Control). This does not indicate an O2 fault but rather an O2 input issue. In going through the list (you have to read the build thread to know how long that list is), the only thing that I have not recently removed, replaced or adjusted was the CTS so I ordered a Bosch today from Amazon Prime for $14.

I also took a VOM to the O2 sensor and did not get voltage at the harness side of the heater wires which I should, and the O2 Heater Relay seems to be ok which suggests a break in that wire which could be fooling the O2 sensor in to running rich, especially if the CTS is off. I havent checked the diagrams to see if the heater should be kicking in at cold start and in running it for a few minutes I got resistance readings at the O2 sensor in the .25 range with no change with revs or the oil cap removed.

Other than retesting the O2 sensor after a good run am I missing anything..or should I try putting the old sensor back ?