larry_c4

Hey guys, I have been recently getting codes 43 and 64, which mean knock sensor and oxygen sensor. The 43 seems to be poping up alot more recently. It seems as it comes on at completely random times, at start up, and/or 30 mins into driving. It will also stay on for about 3 minutes to 20 minutes. And of course every time the Service Engine Soon light is on, the fans kick on. I really don't see a difference the way the car drives when the light is on. So where should I start here? I'm thinking the knock sensor.

Kevova

The 43 shouldn't cause the 64. The 64 (lean right o2) could cause a 43. I would look at wiring to be sure harness isn't chaffing or on exhaust. You could reseat connectors and be sure weather seals are in place. Vacuum/exhaust leaks right side of engine. Of course ground wires are always something to check.

larry_c4

The car does have muffler eliminators, but I doubt that would cause anything. I'm thinking that the 64 (o2) is causing the the 43. I checked the wires, everything seemed ok, so I am going to change the o2 sensor.

antfarmer2

I would go with the o2 (s) they get old and slow and can set off the knocks I would change the knock to for $25 it is cheap and you can do a proper flush. alot of crap hides in there. just pinch the connector to release. proper torque is important.

Dt86

This. Also if you know someone with a scanner you can see what the O2 sensor is doing. You can also check your knock sensor by tapping on an exhaust manifold bolt near the sensor and see if the computer pulls timing. You will hear a definite change in idle if it is working correctly.

larry_c4

Well, I haven't had time to fix the vette because it been in winter storage, but over the past few days I have been driving it. I used the paper clip to pull codes via the digital dash and now got 3 codes, H42, H43, H64. I cleared them all out of the ecm via dash. I have been driving it and it seemed to be running good for the first two days. But...today the SES light came on and I immediately checked for codes. Just as I thought, a H64 (Oxygen sensor) and no other codes present. This tells me that the oxygen sensor(s) are Causing the knock sensor code (43). I think by replacing the O2 sensor, the knock codes won't re-appear. Hoping to get these done this weekend.

antfarmer2

larry_c4

I changed the O2 sensors myself and it was still doing the same thing. I then noticed at high temps, the car would run really crappy and stall out. Most times it would be hard to start after. I took it to my mechanic and he said that 3 injectors were bad, therefore causing the lean and knock.

WVZR-1

Reinforces the fact that "just because" you have an O2 & KNOCK code you don't just throw parts at the car. The parts are sometimes/frequently doing their "designed function".

Have you done the suggested bad injectors yet? Is the car "fixed"?

larry_c4

The injectors just came in today, should be installed soon. It will be interesting to see if that solves the problem.

93Rubie

Codes do not mean **** most of the time.

Working on a P0171 with my class today. That code means Bank 1 System Lean, that could be a TON of stuff. We will find out tomorrow if our suspect low fuel pressure is confirmed. So far we have done nothing but look at scan data and mostly fuel trims at various RPM's.

The OP's code 42 is nothing more than a LEAN code and has NOTHING to do with the 02 unless it is fixed lean. That would pretty easy to see with scan data.

I've actually been doing some research on 02's and I have found STRONG evidence that 02's DO NOT wear out, they become contaminated with coolant, excessive amounts of fuel (misfires, etc...), or silicone from some RTV's, etc.... IF 02's become contaminated you have other issues changing it is only a band aid at best.

I hope your technician is correct on the injectors. Multec's commonly DO short. I replaced all of mine for 2 starting to short out. Proven with scope patterns. Good luck with the fix.

antfarmer2

o2's do not wear out? You better tell all the manufacturers their maintenance schedule is wrong.

Cliff Harris

They don't "wear out", but they do get coated with soot, which causes them to not work very well.

antfarmer2

with that but not "a band aid fix" they are maintenance just like oil and air filters.

WVZR-1

Operation can be confirmed with a "quality scanning device" to remove the just replace if in doubt you mention often. They're mentioned by most manufacturers in a maintenance schedule (not because it's required) but because it might/may create better driveability conditions. Most shops won't just replace but likely "scan and advise" first, even those who have it included in maintenance recommendations.

You often mention the x4 replacement which gets out of hand $$$ quickly.

THEY ARE NOT LIKE OIL AND FILTERS - NO WAY!!!

antfarmer2

I agree to a point if everyone had a quality scanning device there would be a lot less questions on the forum. But they cost a bit more than a sensor. Some thing that get old and dirty can be cleaned some need to be replaced.

larry_c4

Well, the injectors were installed today and there is no more lean exhaust or knock. But, the mechanic told me the car still keeps stalling and is very hard to restart. Now, he said that there is a pink wire that goes from the ECM to the Opti that is loosing power. I did have Cardone rebuild the ECM about 10 months ago, the ecm has less than 500 miles on it. And I dont think its the opti becaise there are no codes present. Could this be ICM related?

Kevova

Hopefully you mechanic has a good scanner and should be able to pick the signal from the opti to ecm. The ECM sends a signal out to ICM. ICM gets signal from ECM on White wire.

This tread maybe helpful https://www.corvetteforum.com/forums...e-pattern.html

93Rubie

If your mechanic has a scope that is the MOST accurate way to tell if the Opti-Spark is operating correctly or not.

Show him/her the tread if you have to for GOOD known references.

93Rubie

I'd LOVE to see that in PRINT. Manufacture PRINT. GM specifically since this is a Corvette forum.

I've NEVER seen it in print from ANY manufacture as a maintenance item. I did a search on Mitchell ProDemand last night and found nothing.