89 Regal 3.1 Cold Start Code 43

[striker85]

Hi,

So my 89 Regal, with 3.1, throws a code 43 like clockwork everyday at cold start. I know about the piston slap, and I've always discounted that. However, every day when I start the car (I give about 30s. to 1min. warmup) and drive off, within 3-5 minutes of driving SES light comes on and EVERY time it is code 43. When the car is hot, no code. Parked for an extended period of time, code 43 shows within 3-5mins. of driving. I have replaced (within the past year) ECM, ICM, plugs, wires, all 6 injectors, knock sensor, crank sensor, IAC, filter (all), and some others I can't recall.

Any ideas where to look for this annoying phantom code? I can never seem to find a culprit. Perhaps the sensor is just picking up the piston slap? But wouldn't that be immediate? Also, could this be related to a possible collapsing lifter? I haven't ID'd or confirmed, but just suspect a collapsing lifter as part of the cold start ticking noise.

[60dgrzbelow0]

Code 43 is a Knock Sensor Code... in this case. possibly due to either a Bad Knock Sensor Wire Connector issue...or it may be that your engine just has a Bad Knock Sensor, period. If the sensor is faulty... it is likely that if your ambient environmental temperatures are particulalrly cold... this might trigger the code fault when the motor has yet to come up to to a fully comfortable (heat expanded) operating condition that can affect how much or how little the engine parts vibrate or piston slaps are in evidence. You don't mention either your engine mileage or what your prevailing cold climate conditions are ...but those would be interesting variables to mention here in your next thread response. By the way... I would not consider "30 seconds to 1 Minute" a valid length of time for any engine in any climate to properly warm itself. Not only that... imagine the difficulty your engine oiling system faces ...what with oil as thick as paraffin down in that cold crankcase....super-viscous and very difficult to effectively and quickly pump and push its way through an ice cold engine block... at least until the cylinder heat is transferred around the engine to loosen things up. The two biggest things that are engine killers are either Low or Too Infrequent Oil Changes...and... Cold Starts that force the motor to operate sooner than it is ready to do so. Try giving that "Warm Up" just a few more minutes as an experiment .. and see if the added time makes any difference.

[striker85]

Yeah, typically I let it go longer, just recently I have had to get in and go, so to speak. However, I don't lead foot it at all. I do the regular oil changes religiously. The motor has about 57k on it. I've owned the car since it had 23k on it, and the motor was replaced at 13k by the previous owner (my grandfather, who bought it brand new in 1989) The ambient temp. does seem to play a role as this problem has been an ongoing one and in the summers past it hasn't thrown a code; only in the winter months does it usually do this. Back about a year ago when the car dies (due to a faulty injector) I went bonkers replacing everything (everything previously listed) At that time, the knock sensor was seized into the block and the plastic connector broke off flush to the motor. Lacking time and tools, I brought the car to a trusted shop and had them do the replacement. So, I don't know EXACTLY what the situation is with the new knock sensor. Regardless of warm up times, it will usually throw the code, even just idling for 5 minutes...or as soon as you put it in gear and go. Which probably points to a short, maybe?

[60dgrzbelow0]

If you can find a spot on your driveway that is nice and level, not covered with snow and ice and NOT likely to allow the car to slide off its perch on some safe and well-set vehicle ramps or supports and God Forbid, fall on you...it might be a good idea to change the oil to the lowest viscosity level recommended for your engine...and while you are down there...eyeball the hell out of the area of the Knock Sensor using a good, bright flashlight (best to lower the hood just a bit, so what you are trying to see is NOT silhouetted by bright sunshine glaring down on your POV from above you) and go over the Knock Sensor itself with a few tugs on it to see if it has come loose from a poor install...or that the wire clip harness is either loaded down with oil and goo...or that there is a break in the wire(s) and at least you will have eliminated it as the cause of the problem if you find nothing wrong. If you find something and get it fixed...please let us know in here... Many (1) Timers don't come back after they have fixed (or not) their issues leaving us all wondering, "WTF happened?" ...(or would that be (2) Timers...? LOL )

[striker85]

I am due for an oil change this weekend. I'll be sure to take a peek at it see if anything is going on. I'll make sure to report back. I've been a long time lurker on this site, just now I had to make an account to seek some guidance on this issue.

Anyway, providing everything looks kosher with the sensor and wiring, what would be the next place to check? Also, I've been using 5-30 (as recommended by the book) for as long as I've owned the car.

[striker85]

Ok, just got back from work. I had my laptop hooked up to the ALDL. The entire ride home, no knocks registered yet the SES light came on. Soooooooo. Bad sensor or wiring. Just gotta check it out this weekend.

[striker85]

I said I wouldn't let this thread die before posting the solution:

I have been exceptionally busy and have been driving the car for months like this. Finally, I found a few moments to do some more troubleshooting. With my homemade ALDL hooked up running Tunerpro on my laptop, I was able to verify knock sensor operation by banging on the engine bracket (actual test step in the FSM). This only verified my suspicions of an intermittent code caused by bad wiring/connectors. I was able to fiddle with the connector from the top of the motor (tight squeeze) and have been driving for 3 days now with no code. >< I can't believe how touchy these dumb sensors/connectors are. Just jiggling the connector got it sorted. Obviously, this connector design is sub-satisfactoy and warrants me getting back in there and doing a thorough cleaning and smathering of dielectric grease...one of these days.

All in all, for those frustrated with a knock sensor code, start simple.