Another code 42 question.

[CDeeZ]

I've been getting EST error code 42 lately, ALOT. It's getting really annoying having to pullover and unplug the ECM to clear codes and get the thing out of limp mode.

Plugs and wires are both brand new. I also replaced the knock sensor pigtail since it was looking questionable. I've noticed that when I'm unplugging the ECM to reset the codes, the case itself of the ECM is VERY VERY warm. This can't be good can it? I never noticed before how warm that thing gets so I'm not sure if that's normal. I keep the ECM in the glovebox for ease of access when swapping chips.

I've been driving around with my datalog cable plugged in constantly, whether the laptop is connected or not... Could the datalog cable be picking up some kind of interference thereby causing the problem? Surely not.

What do you guys think?

[PJG1173]

an old trick we used if we suspected a desktop computer overheating was to open the case and point a box fan at it. (this was before PC's could tell you the temp of the board and processor). if the issue went away then we knew it was a cooling problem. a conversion I'm planning right now has the ecu going in the glove box. I am also looking at installing a 60mm 12v case fan from a PC in the back of the glove box to help circulate air around the ecm.

[CDeeZ]

Whoops, I'm getting a code 43 ESC (knock sensor), rather than 42. Sorry for the mispost.

[EagleMark]

The ECM does get real hot so that is not uncommon. Not sure what leaving the cable plugged in would do? If it has A and B crossed for 10K your in ALDL mode for driving is not good...

Down load the PDF from this link to diagnose each code.

http://www.gearhead-efi.com/Fuel-Inj...-CEL-SES-Light

[CDeeZ]

I have a service manual with all that stuff in it, but it will be nice to have it in PDF form on the comp as well. Thanks!

Okay, since I'm still very much a apprentice in training with this tuning bit, maybe some of you guys more knowledgeable than I would take a look at my log... The error code 43 was set during the log... So was low battery error code but I think that's because I switched the truck off before ending the recording session of the log?

I know that I'm running very rich, as I have the stock fuel tables in this log b/c I thought maybe I goofed something up there so that's why I switched the VE tables back to bone stock for the time being.

There is an intermittent knock coming from under the hood somewhere so maybe that's why I keep getting code 43. The knock has been happening for a while and I thought nothing of it since it comes and goes and doesn't sound like a rod knocking or anything serious like that.. I have looked for anything that could be loose to cause the intermittent knocking sound but I've found nothing.... Also worth mentioning, this intermittent knock sound has happened for quite a while and NEVER gave me any codes, 43 or any others for that matter so I'm pretty confused.

I remember reading on TGO that Grumpy did something to slightly desensitize the knock sensor since he was getting some false knock (I think). I beleive that he talked about a knock sensor filter, and also threading in a pipe plug adapter type thingey to slightly space the KS away from the block.. If Grumpy did this, I am not one to question it except maybe for the singular purpose of trying to understand his genius.

[EagleMark]

I'll try and find time to look over your log later, but Code 43 does not mean knock is happening, it means the knock system received low voltage for longer then 5 seconds, which could be a simple power or fuse issue. Or it failed the ESC Knock test which happens once every start up at some high load, could be a bad knock sensor or wire down there fell off, rotted, oil soaked bad connection.

There are ways to desensitize the knock sensor when needed and you can over torque them when installing ruining them or making them over sensitive. But right now I don't think that is your issue, that would be if your getting to many false knock counts. You have a failing knock system.

[CDeeZ]

Okay I went through the diagnostic flowchart for troubleshooting code 43 ESC and I ended up going to the point where the flowchart has you "momentarily touch knock sensor harness (CKT 496) with a test light to 12V"....

MOST of the time when I was touching my test light to the knock sensor pigtail, I would generate a knock signal. I checked using both winaldl, and also tunerpro.... Now I'm wondering, since it didn't generate a knock signal EVERY SINGLE TIME I did this, which way do I proceed with the flowchart??

Would I go down the path of "YES" ---> "Faulty connection at sensor or faulty knock sensor" OR..... would I go down the path of "NO" ---> "CKT 496 open, shorted to ground, faulty connection at ESC module or faulty ESC module." ?????????

I replaced the knock sensor pigtail like I said, and I soldered the joint which is how I always try to make electrical connections.


What's next guys? Remove and test either the knock sensor, or, the ESC module, or, test BOTH???? I have inspected the wire from the knock sensor which is CKT 496, and I can't find a short, a break, or a faulty connection so that leads me to believe it has to be either the ESC module OR the knock sensor, or possibly BOTH....

I know that I've replaced the knock sensor at some point but it has probably been 5 years or so and I don't recall the brand of knock sensor I used....

AFAIK, the ESC module is original!! At what, 23 years old and enduring 23 years of heat cycles could the ESC module have crapped out????

Help me out here guys, please and thankyou.


EDIT:

I'll try and find time to look over your log later, but Code 43 does not mean knock is happening, it means the knock system received low voltage for longer then 5 seconds, which could be a simple power or fuse issue. Or it failed the ESC Knock test which happens once every start up at some high load, could be a bad knock sensor or wire down there fell off, rotted, oil soaked bad connection.

There are ways to desensitize the knock sensor when needed and you can over torque them when installing ruining them or making them over sensitive. But right now I don't think that is your issue, that would be if your getting to many false knock counts. You have a failing knock system.

Thankyou Mark, I would certainly appreciate you lending your expertise to my situation. I have RBob's forced knock patch and lean cruise patch applied.... Is there a way I could send you a copy of my bin and you could see that I actually have it applied correctly, because I really don't know how to verify that.... I remember you helping me some time back with using the difference tool to see a difference of 55 bytes but I'm not totally sure I got it done right....

[CDeeZ]

Welp it looks like a simple issue of not having the forced knock patche applied, even though I thought I had it on there....

[EagleMark]

I looked through your 2 hour log and Code 43 did not come on till endish. Also hardly a knock count, so don't think your knock is working whether you have the Done patch done or not. Have to fix why you don't have knock. ESC patch done will only prevent the test. Not fix why your knock system is not working.

[CDeeZ]

Well going through the troubleshooting flowchart for Code 43 led me to "faulty connection at sensor or faulty knock sensor". But is there a way to test the knock sensor itself to be sure before dropping 35 bucks on a knock sensor which may not even need to be replaced?

[EagleMark]

I think it's supposed to read about 3900 ohms...

[CDeeZ]

Okay I replaced the knock sensor with a new Deplhi unit, I think the reason my old sensor was picking up basically nothing is that I made a doofus mistake of wrapping the old knock sensor in teflon tape... Well no surprise that tape isn't a very good conductor, therby insulating the knock sensor from grounding out and working properly...

Mark, I have a short log with both my new O2 and KS installed. I posted it also in my O2 thread... I THINK the new KS is working, based upon this latest log, but perhaps you'd be kind enough to check it out and let me know what you see?

[EagleMark]

Knock accumulater started at 5, went to 6 then 8, so I'd say it's working, but no knock to worry about. When you see a cell or cells go up in counts fast then that's knock.

Look at your BLM history table after or while playing log, then click the buttons, even history average you are overall rich.

[CDeeZ]

Thank you for checking that out for me.

Yeah, that log was using the stock 7747 fuel tables.

I have no recollection of putting teflon tape on the KS I put in there years ago, but I'm sure of the fact that I did it