1286 trouble code

[SkidMark]

Hi guys
I am having problems with my e36 m42 engine in my 1979 320i. It is throwing a 1286 (knock control test pulse) code. I have tried everything I can think of to remedy the problem, I traced the wires from the knock sensors to the dme and did a continuity test with a multimeter, everything ok. I purchased a new rebuilt ProgRama dme, still 1286 code. I figured if I had a bad knock sensor it would throw a 1225 code, so I tried swapping the #1 and #2 knock sensors but still no change... I am also getting a 1222 (02 sensor lean/rich) code. I am wondering if these codes could be related? I have also replaced the 02 sensor, to no avail... Any ideas would really help, Thanks m42 club!!!!!

[Tgoode318]

1222 is one of the codes from hell. First thing since you have replaced the o2 already is to take some throttle body cleaner or brake cleaner etc and spray around all the hoses and intake boot, Listen for An increase in Engine Rpms.  If you hear the engine rev up then you have an air leak from one of the hoses or intake boot. Next, does your car stall/idle badly if you let off the gas at idle? If so your Icv Could be bad. If this is the case you can Buy a new one or do like i did and clean yours with carb cleaner and toothbrush. The next thing to check out after that is your PCV Valve, when mine went bad you could hear a loud wishing noise coming from it. If The pcv is bad it could Throw the 1222 as well. There are a few more things that could cause the 1222 but the ones i listed are the most likely culprits. Try these fist and let us know if you still have the problem! Good luck

[Tgoode318]

Hey skidMark Did you ever get your 1286 Code fixed? If you fixed your knock sensors it sounds like you might need to check connections.
It Sounds like were in the exact same boat I had the 1222 and 1224 about a month ago fixed them But last night just randomly did a stomp test (for peace of mind ) even though i have had no cel light and what do you know 1286!! From what i know about the knock pulse test the engine performs a random check of the knock system and if the knock sensors are bad or loose it will throw this code also it could be crudded up electrical connection like the b+ jumping terminal in the hood, And last but not least it could be a fault on the dme and the only way to correct is to replace the dme or solder the bad connections. Let me know if you fixed it and what you did. if any one else has suggetions or 2c please help! When i get home from work today i will have more time to check out whats going on!

[SkidMark]

I think I have the 1286 code fixed. But, I really haven't given it a good testing. I have tried EVERYTHING you can imagine to remedy the code, BRAND NEW dme, traced and tested the wires from dme to knock sensors, cleaned and tested the connections at dme, and finally new knock sensors. I don't really know which thing I did cured the code as I did them pretty much all at the same time. I have driven the car around a few times since and the code has not returned, yet.... I don't want to curse myself..  I built a set of coil-overs for the car so its been on jack stands for a week, but, I got her all buttoned up this last weekend so I should be able to tell you more this week after I go beat it up for a bit. I didn't have the $$$ to buy NEW knock sensors and the only ones I could find at the local pic n pull  were from a 96 e36 m44 engine. They had a different plug so I soldered and heat shrink tubing the plugs from my old sensors onto the m44 sensors. Seems to work fine, but I will probably go ahead and order the right ones, or not if they keep functioning.. They were free, you have to love pic n take, took me like 3 hours to get them out intact but it is what it is... Keep in touch brother and good luck!!!!!! Skid

[Tgoode318]

Update on Cel Code 1286=finally Solved! The first thing i did was replace the ground strap located right by the dme compartment.  Next i Took the dme apart and gave a good cleaning with compressed air/ electrical cleaner. Then i used the compressed air in the dme compartment to make sure it was clean and dry/dust free inside. After that I made sure the Dme hooked up exactly right and sat properly in its compartment as i remembered a Desktop computer i once built where i forgot to put the washers on the case/motherboard improperly grounding it resulting in the computer failing to run. Perhaps that was the case here as the dme was some what loose and out of position upon initial inspection. After putting every thing back i then checked the knock sensors to make sure they were nice and snug which they were. Started Up the car Stomp tested her and 1444!! NO CODES : )))

[SkidMark]

Well that is good to hear!! My car is still throwing the 1286 code. My dme is not even mounted or grounded, that may be the cause?? I have it in a tupperware box that is water tite, ad the box is mounted to a peice of plywood..  The dme is a brand new programa unit so im sure its clean and has good solder joints and connections. I will place a groundstrap to the dme itself and then to ground and see if it makes any difference. Worth a shot!!! Thanks for sharing your findings!!! Always appreciated!!!   Skid

[Tgoode318]

Skid its worth taking a look at, i think that could be it. In this diagram (6) http://www.realoem.com/bmw/showparts.do?model=BK53&mospid=47472&btnr=12_0496&hg=12&fg=10
you can see the metal shelf that the dme must properly rest on to (im guesing) Properly ground it. Also i was Missing part  05   Fillister head self-tapping screw to properly secure it in the metal shelf.

[SkidMark]

Goin out to the shop to run a ground to dme. Keep you fingers crossed for me!!! Skid

[Tgoode318]

Fingers Crossed!

This is the ground i replaced.